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1 Reducing Greenhouse Gas Emissions in Atlanta Valerie M. Thomas, 1,2 John Mlade, 3 Seth Borin 1 , Nathaniel Tindall, 4 Adaora Okwo 1 , Anika Dhamodharan 1 Schools of 1 Industrial and Systems Engineering, 2 Public Policy, and 4 Civil and Environmental Engineering, Georgia Institute of Technology, and 3 Perkins+Will February 2014
Transcript of Reducing Greenhouse Gas Emissions in Atlanta › ~vthomas › reducing_ghg... · In addition to...
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Reducing Greenhouse Gas Emissions in Atlanta
Valerie M. Thomas,1,2 John Mlade,3 Seth Borin1, Nathaniel Tindall,4 Adaora
Okwo1, Anika Dhamodharan1
Schools of 1Industrial and Systems Engineering, 2Public Policy, and 4Civil and Environmental Engineering,
Georgia Institute of Technology, and 3Perkins+Will February 2014
2 LIST OF ACRONYMS AND DEFINITIONS
Btu British thermal unit. A measure of energy. Btu’s are often used to express the total
amount of heating or cooling energy. One million Btu, written MMBtu, is equivalent to approximately 290 kWh. However, with a typical 30% efficient electricity generating system, one million Btu of heat energy from a coal or nuclear power plant creates approximately 100 kWh of electricity at the plug. Modern natural gas power plants are more efficient than nuclear or coal power plants, with roughly 60% efficiency; hydroelectric plants are very efficient, reaching 90% or more.
CO2 Carbon dioxide. CO2e Carbon dioxide equivalents. Includes carbon dioxide and other greenhouse gases,
weighted by their global warming potential compared to carbon dioxide. GWh Giga-watt-hour. A measure of electrical energy, equal to 1 billion watt-hours or 1
million kWh. kWh Kilo-watt-hour. A measure of electrical energy, equivalent to 1000 watts of power for
one hour. Often the kWh number includes just the electrical energy that the customer receives “at the plug” and does not include the total heat energy used in making the electricity, which can be about a factor of three greater.
therm A measure of natural gas energy equal to 100,000 Btu, or 29 kWh. tonne Metric ton, equal to 1000 kilograms or 1.102 imperial tons.
3 Reducing Greenhouse Gas Emissions in Atlanta
1. Executive Summary
February 26 2014
Energy production and consumption bring great benefits to Atlanta. Electricity and natural gas power our homes and offices; petroleum fuels our transportation systems. Air pollution and traffic congestion are negative effects of Atlanta’s energy usage. It is increasingly recognized that greenhouse gas emissions, from use of coal, natural gas, and petroleum, contribute to global climate change and ocean acidification, and to avoid substantial climate change, the generation of greenhouse gas emissions needs to be substantially reduced. This study evaluates current greenhouse gas emissions from Atlanta, projects what future emissions may be in to 2030 under business as usual, and evaluates measures for reducing greenhouse gas emissions. Our inventory shows that use of electricity accounts for nearly 70% of greenhouse gas emissions in Atlanta. The majority of electricity usage is in commercial buildings, substantial amounts in residential buildings, and only a small amount in industry. Whilst electricity is the primary contributor to greenhouse gas emissions, the second largest source is from petroleum based fuels used by cars and trucks driving in and through Atlanta. The third largest source is the combustion of natural gas used in buildings for space heating, water heating, and cooking. There are also relatively limited emissions from landfills and other sources. Among the most important and effective steps to reducing greenhouse gas emissions are those that relate to long-term purchases, infrastructure, and behaviors. Decisions for the construction and renovation of houses, apartments, offices, neighborhood development projects, electricity-generating power plants, purchases of air conditioners, heating systems, office equipment, lighting, and fuel usage will affect energy use and greenhouse gas emissions for years to come. Changes made to increase efficiency at the neighborhood and city scale will make long-term change in the future more feasible. There are many ways that the people of Atlanta and the city government can reduce greenhouse gas emissions. Provisional suggestions for the most effective measures for the city of Atlanta are described as follows:
• Increase the energy efficiency of existing commercial buildings, and related equipment and appliances. Atlanta’s commercial energy is usage is high in comparison to other cities with comparable climates. There are numerous opportunities to save money by reducing energy usage and many programs can be further developed to address such measures. Atlanta’s Better Buildings Challenge spearheads energy efficiency measures in large commercial buildings and both the continuation and extension of this program has the potential to provide large energy savings.
• Increase the energy efficiency of existing residential buildings, and related equipment and appliances. Residential energy usage in Atlanta is high in comparison to other U.S. cities with comparable climates. To provide the benefits of reduced energy use across all the residences of Atlanta is likely to require a combination of programs. Georgia Power has a program to help residential customers identify opportunities for energy efficiency, and also provides some rebates for energy efficiency upgrades. Supporting and extending this program, as well as finding additional avenues to residential energy savings, can directly benefit the citizens of Atlanta as well as help reduce the city’s overall greenhouse gas emissions.
• Reduce greenhouse gas emissions from the generation of electricity. This can be achieved by Atlanta citizens and businesses by purchasing green power from the electric utility, by developing on-site renewable electricity generation systems, by fuel-switching at the building scale, and by developing on-site combined cooling, heat and power systems. Reduced emissions can be achieved by the electric utility by shifting electricity production toward sources with lower greenhouse gas emissions, including natural gas, nuclear, biomass, landfill gas, wind, and solar power.
4 • Reduce the emissions from driving. Although Atlanta has a great deal of traffic congestion, and
driving makes a significant contribution to greenhouse gas emissions, Atlanta’s electricity usage is so high that transportation makes a relatively small contribution to greenhouse gas emissions within the city limits. Nevertheless, reducing the emissions from driving can make an important contribution to reducing greenhouse gas emissions in Atlanta, and can also provide air quality benefits, reduce congestion, and potentially other benefits as well. Reduced driving emissions can be achieved by Atlanta citizens and businesses by reducing the number of passenger vehicle miles traveled, with a shift towards walking, biking or taking transit, through the purchase of low-emitting vehicles, and living in mixed-use in-town developments.
As described in the body of the report, near-term cost effective actions in these categories can provide a basis for substantial reductions in Atlanta’s greenhouse gas emissions while providing substantial improvements in quality of life and the overall attractiveness of Atlanta. The citizens, businesses and city government of Atlanta directly control individual energy usage, the energy efficiency of the equipment purchased, and the infrastructure developed. However, actions taken at the state and federal level and by the private sector outside of Atlanta will set the baseline for efficiency and clean energy. To a substantial extent, greenhouse gas emissions in Atlanta can be expected to fall due to actions already initiated by state and federal government and by the private sector:
• proposed federal standards will increase average fuel efficiency for cars and light trucks; • new appliances and equipment - refrigerators, washing machines, computers, air conditioners, etc. -
are becoming increasingly energy efficient; • the state of Georgia has committed to ensuring 90% building energy code compliance by 2017,
increasing the energy efficiency of new buildings and renovations; and • two new nuclear power plants are being built in Georgia, which will produce large amounts of
electricity with low greenhouse gas emissions. These and other factors suggest that cars, houses, electricity and equipment will be increasingly efficient in the coming years. With thoughtful and effective policy and citizen action, Atlanta can ensure that it benefits from these trends. Taking into account expected population growth and economic growth in Atlanta, and assuming a moderate level of activity to increase energy efficiency and reduce greenhouse gas emissions, we project that Atlanta could reduce its greenhouse gas emissions 15% by 2020 and 30% by 2030 compared to a 2010 baseline. Greater reductions are definitely possible, particularly with greater energy efficiency improvements, but must be tempered with the potential for not achieving such goals if little or no action is taken. Along with this report we provide a spreadsheet to allow for examination of the results of greater or lesser progress in greenhouse gas emission reduction. In addition to reducing greenhouse gas emissions, Atlanta can take action to reduce the impact of higher temperatures and lower water availability. Measures can include use of reflective roofing and pavement, planting trees to increasing shade and vegetative cover, reducing waste heat emissions, and greater water use efficiency. The analysis and policy options discussed in the body of the report are meant to provide a starting point for discussion, policy development and action. This document will be revised and updated; suggestions are welcome.
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Acknowledgements This material is based upon work supported by the Department of Energy under Award Number(s) EE0000801. Additional support was provided by matching funds from the Georgia Institute of Technology, funds from the Anderson Interface Natural Systems Chair in the School of Industrial and Systems Engineering at Georgia Tech, and pro bono contributions from Perkins+Will. We would like to thank the many engineers, modelers, and energy experts who have provided input and comment to this study, including Bill Hosken, Denise Quarles, Aaron Bastian and Jean Pullen of the City of Atlanta for their continuing feedback and support; Mandy Mahoney of the Southeast Energy Efficiency Alliance for support of the 2008 greenhouse gas emissions inventory of City of Atlanta operations, Georgia Power for data on electricity consumption, AGL for data on natural gas consumption, Cassie Branum of Perkins+Will for assistance with GIS analysis for the greenhouse gas emissions inventory, John Bracey of Southface for discussion of building energy efficiency options, and Sustainable Atlanta for supporting numerous discussions with stakeholders.
Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government, nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
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Contents
1. Executive Summary
2. Greenhouse Gas Emissions in Atlanta
3. Greenhouse Gas Reductions for Commercial and Residential Buildings
4. Greenhouse Gas Reductions for Transportation
5. Adaptation and Resilience in Atlanta
6. Quantitative Goals for Greenhouse Gas Emissions Reductions
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2. Greenhouse Gas Emissions in Atlanta 2.1 Introduction to Greenhouse Gases Life on earth is based on carbon; plants and animals store energy from the sun in carbon-containing molecules, and when they die, their remains are fossilized over long periods of time. Fossil fuels, including coal, natural gas, and petroleum, are the fossilized remains of ancient plants and animals, formed millions of years ago. When these fossil fuels are combusted during use – to make electricity in power plants or to fuel our cars, trucks, and planes, or to heat houses or power factories – the carbon and hydrogen atoms combine with oxygen (O2) to make carbon dioxide (CO2) and water (H2O) and are released to the atmosphere. The equations below show the basic transformation of coal, natural gas and petroleum.
Coal CH + 5/2 O2 à CO2 + ½ H2O Natural gas CH4 + 2 O2 à CO2 + 2 H2O Petroleum C8H18 + 25/2O2 à 8 CO2 + 9 H2O
Carbon dioxide, because the energy levels of its molecular bonds overlap with the energy from the sun, tends to trap energy from the sun. Other molecules also have this effect, water being the most important; the Earth has enjoyed the warming effect of water and small amounts of carbon dioxide for millions of years. As the sun warms the Earth, energy is radiated back into the atmosphere and beyond in the form of long wave radiation. Carbon dioxide, because of its energy levels, absorbs long wave radiation from the Earth, trapping energy that would have otherwise left the atmosphere. Other molecules, such as methane, chlorofluorocarbons and water also have this effect. Historically, the amount of greenhouse gases have been naturally regulated and buffered by forests and oceans. Now, however, the amount of carbon dioxide in the atmosphere is increasing rapidly, because of our use of fossil fuels that would have otherwise been “locked” in the earth’s crust; we are releasing carbon dioxide much more quickly than the Earth can assimilate it. Although the exact changes in climate are difficult to predict, current emissions are approaching and may have already passed levels that can induce substantial changes to our climate. This study focuses on evaluating current greenhouse gas emissions from the City of Atlanta, projecting potential future emissions, and evaluating options for reducing greenhouse gas emissions. In this report, we include direct greenhouse gas emissions from combustion of petroleum and natural gas and other activities within Atlanta, as well as greenhouse gas emissions from the generation of the electricity that is used in Atlanta [1]. Jet fuel dispensed at Hartsfield-Jackson Atlanta International Airport is discussed separately.1
1 This is a “scope 2” analysis, consistent with protocols developed by the World Resources Institute and ICLEI for community greenhouse gas emissions inventories, including electricity produced outside the city, although not including the emissions from all the products and services consumed in Atlanta.
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2.2 Emissions Sources
2.2.1. Electricity
Figure 1, of electricity consumption by sector within the city limits of Atlanta illustrates that over two-thirds of electricity is used commercially, one-quarter is used in residences, and that slightly less than one-tenth is used in industry and by the Atlanta Airline Terminal Corporation (AATC) combined.2 MARTA electricity consumption accounts for approximately 1% of total consumption and is included in the commercial sector data. Figure 1: Proportion of 2010 electricity consumed by sector
Table 1 and Figure 2 display monthly electricity use in Atlanta. Note that residential electricity use shows the most variation over the year and peaks in the summer, corresponding to summer air conditioning. The commercial sector electricity use is more stable because it has a larger base load (computers, lighting, equipment) and because large buildings tend to require year round cooling.
2 Electricity in Atlanta is provided by Georgia Power, which provided the data for 2009 and 2010 electricity usage (kWh) disaggregated by county, ZIP code and customer type (commercial, industrial, residential and MARTA). Since the city limits do not correspond to ZIP code boundaries, we used geographic information system analysis (GIS) to determine the proportion of each ZIP code’s land area that is within city limits. Outside of the city limits, electricity is provided by a number of providers in addition to Georgia Power; full data from these providers is not currently available.
Residential 24%
Commercial 68%
Industrial 6%
AATC 2%
10 Table 1: 2010 Monthly electricity consumption by sector
Consumption (GWh)
Residential Commercial Industrial AATC Total
January 228 560 48 18 854 February 198 505 45 15 764
March 177 481 45 15 718 April 140 489 45 17 690 May 141 501 46 19 707 June 198 556 47 20 822 July 243 603 47 21 914
August 263 619 52 24 957 September 225 568 49 20 862
October 156 494 44 17 710 November 134 473 44 17 668 December 188 529 44 16 777
Annual 2,292 6,378 554 220 9,444
Figure 2: Monthly electricity consumption by sector for 2009 and 2010
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Figure 3 shows total electricity use in Atlanta for the year of 2010. In comparison to the top five area codes in Atlanta, 30303 has the smallest population size of approximately 5,934 persons but the most electricty usage. In the top five area codes from the graph above, 30303, 30308, and 30318 all are located in the heart of Atlanta. The zipcode 30318, with the second hightest electricity usage, is also the tenth largest city in the state of Georgia. Both area codes 30309 and 30305, the third and fourth cities with the highest electicity use, have a population size greater than 20,000.
Figure 4: Residential electricity use by ZIP code in Atlanta
Figure 4 tracks residential electricity usage in each zipcode for the city of Atlanta. Area codes 30318, 30305, and 30309 have population sizes 49,336, 22,999, and 21,845 respectively for the year 2010. In comparison to Figure 3 the graph shows a correlation of larger population size to higher residential electricity usage as predicted.
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Figure 5: Residential electricity consumption per person, by ZIP code.
Figure 5 shows residential electricity use per person in each ZIP code. The average electricity use per person ranges in intensity by nearly a factor of four, from about 3000 kWh per person per year in 30313, to 9000 kWh per person per year in 30305, and 11,600 kWh per person per year in 30327.
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13 2.2.2. Natural Gas Figure 6 show natural gas use in Atlanta by sector. Just over half of natural gas is used in residences for space heating, water heating, and cooking.3 A little less than half of natural gas use is in commercial buildings. There are some industrial facilities in Atlanta using natural gas, corresponding to about 2% of total consumption, and a small amount used at the Atlanta airport (AATC).
Figure 6: Proportion of natural gas consumption by sector, September 2009 to August 2010
3 Atlanta Gas Light (AGL) provided natural gas consumption (ccf and therms) data disaggregated by county, zip code, and customer type (commercial and residential) for Atlanta and for much of the Atlanta metropolitan area (MSA) from January 2004 through August 2010, as well as industrial consumption for September 2009 to August 2010. As for the electricity data, GIS was used to determine the percentage of each ZIP codes’ land area that is within city limits. This percentage was applied to the total consumption for the ZIP code. Data for ZIP codes with less than 0.6% of their area within the city limits were not provided; this accounts for less than 0.0005% of the total land area of the city.
Commercial 42.6%
Residential 54.6%
Industrial 2.3%
AATC 0.5%
14 Table 2 and Figure 7 show that natural gas consumption peaks in the winter. Figure 7 shows natural gas consumption data from January 2004 to December 2010. Also shown, with the dashed line, are heating degree days, a measure of weather variation. The chart shows that, as expected, more natural gas is used when we experience colder winters.
Table 2: Monthly natural gas usage (million therms)
Residential Commercial AATC Total Sep-09 2.0 1.7 0.00 3.6 Oct-09 2.4 2.4 0.02 4.8 Nov-09 3.3 4.9 0.04 8.2 Dec-09 5.6 9.8 0.14 15.5 Jan-10 9.6 17.2 0.24 27.1 Feb-10 8.0 15.0 0.22 23.2 Mar-10 8.7 13.2 0.05 22.0 Apr-10 3.9 5.5 0.00 9.3 May-10 2.6 2.3 0.00 5.0 Jun-10 2.3 1.8 0.00 4.0 Jul-10 2.5 1.6 0.00 4.1 Aug-10 8.8 1.5 0.00 10.3 Total 59.7 76.7 0.71 137.1
Figure 7: Monthly natural gas consumption by sector and heating degree days in Atlanta
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Figure 8: Commercial natural gas use in Atlanta, 2004-August 2010 (million therms per year)
Figure 9: Residential natural gas use per person by ZIP code in Atlanta, 2010
Figure 9 shows per-person residential natural gas use by ZIP code in Atlanta for 2010. Multiplying the number of people in each ZIP code by the amount of natural gas used per person yields the amount of natural gas used by all residents in that ZIP code, as shown in Figure 10. ZIP code 30318 with 49,700 people used an average of 161 therms per person per year, ZIP code 30305 with 23,000 people used 321 therms per person per year, and ZIP code 30327 with 14,000 people used 511 therms per person per year.
Figure 10: Residential natural gas consumption in Atlanta by ZIP code, 2010
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Figure 11 shows residential natural gas consumption in Atlanta by ZIP code from 2006 through August 2010. Some of the changes over time reflect the weather patterns over these years as shown in Figure 7; the data fluctuations may also indicate changes in building stock or efficiency improvements.
Figure 11: Residential natural gas use in Atlanta by ZIP code (million therms per year), for 2004 through August 2010
2.2.3 Gasoline and other Transportation Fuels
Calculating the greenhouse gas emissions from ground transportation within a city can be done from estimates of vehicle-miles traveled, data on local fuel sales, or from proportional scaling of state, provincial, or regional data. The vehicle-miles traveled approach is generally preferred [3], and that is the approach taken here. The Atlanta Regional Commission has estimated that 5,390 million vehicle miles were traveled within the city limits of Atlanta in 2005.4 Overall vehicle miles traveled in the Atlanta metropolitan region have remained constant from 2004 through 2009 [4]. In the absence of more recent estimates, we extrapolate the 2005 data to assess current vehicle-miles traveled. A fuel economy of 20 miles per gallon corresponds to the combined 4 This estimate was developed by Guy Rousseau of the Atlanta Regional Commission, using both model output and traffic count data, for a “screenline” analysis of a rectangle approximating the Atlanta city limits.
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17 passenger car and light truck fleet [5]. The AATC consumed 18,000 gallons of diesel fuel in 2010. The data implies a gasoline consumption of 270 million gallons per year.5
2.2.4. Other Sources of Greenhouse Gas Emissions
Other sources of greenhouse gases include fugitive emissions from the use of refrigerants, methane releases from landfills, and nitrous oxide emissions from soils; estimates are given below. There are also emissions from the use of propane, kerosene, fuel oil, and any other uses of fossil fuels not included above. Refrigerants: Refrigerants are used in refrigerators and air conditioners. Small amounts can leak into the air through normal system use and system maintenance. They are occasionally spilled or otherwise released illegally. Although the amount of refrigerants released is small, the climate effect of these molecules is much larger than that of an equivalent mass of carbon dioxide. In addition, smaller amounts of similar substances are released through use of aerosols, foams, solvents, and fire protection chemicals. The US Environmental Protection Agency (EPA) reported that in 2010 the United States emitted 112 million tonnes of CO2 equivalent in this category, or 0.37 tonnes CO2 equivalent per capita [6]. Applying this per capita measure to Atlanta, the emissions for Atlanta from the use of refrigerants are 157,000 tonnes CO2 equivalent.6 Landfills: Landfills emit methane resulting from the decomposition of organic matter in an anaerobic environment. Methane is a potent greenhouse gas. City-‐owned landfills alone are estimated to have a CO2 equivalent emission of approximately 90 thousand metric tons per year as of 2010 [7]. Additional landfills or other sources with the city limits, including the Chambers-‐Bolton Road landfill, the Southern States Bolton Road landfill, and the Watts Road landfill, will increase this number [8]. Nitrogen Fertilizers: Nitrous oxide is released from soils and from water that contains nitrogen, and is strongly correlated with the use of nitrogen-containing fertilizers. Based on an upper bound estimate of lawn area and recommended fertilization rates, we estimate nitrogen use in fertilizers of about 1,700 tonnes per year, and a corresponding nitrous oxide emission equivalent to about 10,000 tonnes of CO2 per year. Greenhouse Gases from Products and Services: Key categories are food, water, and cement [9]. Estimates of emissions attributable to these categories may be included in future updates of this study.
2.3 Greenhouse Gas Emissions The emissions factors used to calculate the carbon dioxide emissions are shown in Table 3.
Table 3: Carbon Dioxide Emissions Factors
Source CO2 Emissions Factor Electricity 0.65 kg/kWh7
Natural Gas 5.22 kg/therm
5 5390/20=269.5 6 We use tonne to refer to a metric ton, equal to 1000 kg or 2205 lbs. 7 Emissions factor estimate from Georgia Power for 2010.
18 Transportation Fuel 8.85 kg/gallon8
Jet Fuel 9.57 kg/gallon The total CO2 emissions by source shown in Table 4 and Figure 12 show that within the city limits of Atlanta electricity is the largest CO2 emission source, accounting for nearly two-thirds of the 9.6 million tonnes emitted per year. With a population of 420,000 as of 2010 this amounts to 23 tonnes of CO2 per person. Figure 13 shows a pie chart of Atlanta’s CO2 emissions by source. Figure 14 shows that Atlanta’s greenhouse gas emissions pattern closely tracks its energy use.
Table 4: Atlanta CO2e emissions by source, 2010 (million tonnes)
Source Emissions Electricity 6.2 Natural Gas 0.74 Transportation Fuels 2.4 Refrigerants 0.21 Landfills 0.09 Fertilizer 0.01
Total 9.6
Figure 12: Atlanta greenhouse gas emissions (CO2e) by source
Figure 13: Atlanta greenhouse gas emissions (CO2e) by source
8 Based on 8.80 kg CO2/gallon unleaded gasoline and 10.1 kg CO2/gallon diesel, assuming 95% of consumption was unleaded gasoline [10].
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Figure 14: Atlanta energy use and greenhouse gas emissions (CO2e) by source
2.4. Discussion This report addresses emissions within the city limits of Atlanta. It does not include emissions from the entire metropolitan area, and thus presents only a partial picture of metropolitan Atlanta’s overall greenhouse gas
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20 impact. Notwithstanding, these data provide some insight into Atlanta’s current status with respect to greenhouse gas emissions, and potential avenues for emission reductions. Greenhouse gas emissions from electricity depend on the fuel used to make electricity. Generally, electricity from coal fired power plants emits more greenhouse gases for a given energy output than electricity derived from natural gas. Nuclear power has no direct greenhouse gases. In Atlanta, greenhouse gas emissions from electricity production can be expected to fall over time as Georgia Power converts Plant McDonough from coal to natural gas, and when the planned new nuclear power reactors at Vogtle are completed and begin production in 2016-2017. Atlanta’s energy use and greenhouse gas emissions can be compared to those of other US cities that have completed comparable assessments. The US Census estimated the 2010 population of Atlanta to be 420,000 [2]. On this basis, the 9.6 million metric tonnes per year of emissions correspond to 23 metric tonnes per person per year in Atlanta. Figure 15 compares Atlanta’s greenhouse gas emissions from buildings and transportation with emissions from like sources in other cities [9]. Figure 15: Greenhouse Gas Emissions of Selected Cities (tonnes per person per year), showing building energy use and surface
transportation only. Atlanta data are from this study; the other data are from Hill and Ramaswamy [9]
While CO2 emissions are comparable among the cities represented in Figure 15, the CO2 emissions from buildings in tonnes per year is a much higher than the other averages. To further explore Atlanta’s greenhouse gas emissions, energy use and the building stock can be compared to those in the cities shown in Figure 15. Amongst these cities, Austin has the closest match in terms of weather patterns. Figure 16 illustrates similar residence sizes in all the cities, as is the number of people per household. However, the amount of electricity used per square foot is higher in Atlanta than in other major cities. The annual residential electricity consumption in Atlanta, 5,500 kWh per person, is slightly less than the Georgia average of 5,900 kWh per person.9 9 In Atlanta there has been some uncertainty about the accuracy of the US Census estimates of the Atlanta propulation; in 2009 the American Community Survey estimated Atlanta’s population to be 540,000. If the Atlanta population were 540,000 then the residential electricity use per person would be 5500 kWh/person, which is closer to the state average. Another possible contributor to the high per person electricity consumption is unfilled housing; the electricity consumption of unoccupied residences, such as empty apartments, is included in the residential total. Our overall assumption is that the data on both residential electricity consumption and population are correct, indicating a high residential electricity consumption in Atlanta.
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21 Figure 16: Average residence size, residential electricity use per square foot, and people per household for selected
US cities. Atlanta data are from this study; data for other cities from Hill and Ramaswamy [9]
Figure 17 shows commercial electricity use per square foot of floor space, and also shows sales per square foot. The figure shows that Atlanta’s sales per square foot are fairly strong, higher than Austin, Minneapolis and Denver although lower than Portland and Seattle; these differences may reflect structural differences in uses of commercial space; not all commercial space is used for retail activities. Nevertheless, all of the comparison cities use 20 kWh/ft2 or less, but Atlanta uses 51 kWh/ft2, more than twice as much as other cities.
Figure 17: Commercial electricity use per square foot in several US cities, and sales per square foot. Atlanta data from this study; data for other cities from [9] and other sources
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Addendum
Hartsfield-Jackson Atlanta International Airport
The greenhouse gas emissions from an airport can be categorized and allocated in many ways. Hartsfield-Jackson Atlanta International Airport lies partially within city limits and is partially within the operational control of the City government. The City does not have direct control over operations but can indirectly influence operations by setting contract terms with airlines, management and vendors. Hartsfield-Jackson Atlanta International Airport reported that 982 million gallons of jet fuel were dispensed in 2010 [11]. As shown in Figure 18 and 19, CO2 emissions from the fuel dispensed at the airport is more than from all the electricity used in Atlanta. Energy is also used in the airport buildings and by ground transport vehicles at the airport. In 2010, the Atlanta Airlines Terminal Corporation (AATC) consumed 220 GWh of electricity, 0.76 million therms of natural gas, 32,000 gallons of jet fuel, and 18,000 gallons of diesel fuel used in boilers and generators.
Figure 18: CO2e emissions by source in Atlanta including the airport
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Figure 19: Atlanta greenhouse gas emissions (CO2e) by source including jet fuel for aircraft
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24
References [1] Greenhouse Gas Protocol. World Resources Institute and World Business Council for Sustainable Development, 2011. [2] U.S. Census Bureau, “Population Finder -‐ American FactFinder.” http://factfinder.census.gov/servlet/SAFFPopulation. [Accessed: 24-‐Jun-‐2011]. [3] A. Ramaswami, T. Hillman, B. Janson, M. Reiner, and G. Thomas, “A Demand-Centered, Hybrid Life-Cycle Methodology for City-Scale Greenhouse Gas Inventories,” Environmental Science & Technology, vol. 42, no. 17, pp. 6455-6461, 2008. [4] Transportation Fact Book 2010. Atlanta Regional Commission, 2010. [5] S. C. Davis, S. W. Diegel, and R. G. Boundy, Transportation Energy Data Book: Edition 29. United States Department of Energy, 2010. [6] Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2010. US Environmental Protection Agency, 2012. Table 4-89. http://www.epa.gov/climatechange/ghgemissions/usinventoryreport.html [Accessed 6-‐Jun-‐2013] [7] US EPA 2010. 2010 Greenhouse Gas Emissions from Large Facilities. http://ghgdata.epa.gov/ghgp/main.do#/facility/?q=atlanta&st=GA&fid=&lowE=0&highE=23000000&&g1=1&g2=1&g3=1&g4=1&g5=1&g6=1&g7=1&s1=1&s2=1&s3=1&s4=1&s5=1&s6=1&s7=1&s8=1&s9=1&s301=1&s302=1&s303=1&s304=1&s305=1&s306=1&s401=1&s402=1&s403=1&s404=1&s601=1&s602=1&s701=1&s702=1&s703=1&s704=1&s705=1&s706=1&s707=1&s708=1&s709=1&s710=1&s711=1&s801=1&s802=1&s803=1&s804=1&s805=1&s901=1&s902=1&s903=1&s904=1&s905=1&ss=&so=0&ds=E&yr=2010 [Accessed 6-‐Jun-‐2013] [8] US EPA 2012. Landfill Methane Outreach Program. http://www.epa.gov/lmop/projects-‐candidates/index.html#map-‐area [Accessed 6-‐Jun-‐2013] [9] T. Hillman and A. Ramaswami, “Greenhouse Gas Emission Footprints and Energy Use Benchmarks for Eight U.S. Cities,” Environmental Science & Technology, vol. 44, no. 6, pp. 1902-1910, Mar. 2010. [10] US Environmental Protection Agency, “Emission Facts: Average Carbon Dioxide Emissions Resulting from Gasoline and Diesel Fuel.” http://www.epa.gov/oms/climate/420f05001.htm. [Accessed 6-‐Jun-‐2013] [11] Hartsfield-‐Jackson Atlanta International Airport. Sustainable management plan. November 30, 2011. http://www.atlanta-‐airport.com/docs/Airport/Environmental/Sustainable%20Management%20Plan.pdf [Accessed 6-‐Jun-‐2013]
25
3. Greenhouse Gas Reductions for Commercial and Residential Buildings
3.1. Projections of Future Energy Use and Greenhouse Gas Emissions from Atlanta As shown in Figure 20 below, electricity use in buildings is the largest source of greenhouse gas emissions in Atlanta. The use of natural gas is also a major contributor to greenhouse gas emissions. Commercial buildings play the biggest role in electricity consumption while residential buildings consume the second highest amount.
Figure 20. Atlanta greenhouse gas emissions 2010
Over the past decade in Georgia, electricity consumption per person has been rising slightly for residential and commercial use and falling for industrial use (Figure 21). On the basis of this history of per-person electricity consumption in Georgia, the constant per person electricity consumption is used to project electricity consumption in Atlanta. It should be recognized that a range of factors could affect future Atlanta electricity consumption such as the increased use of electronic equipment including data centers, the potential increased use of electric vehicles, etc. The projections made here are meant to be a reasonable basis for evaluating options for energy efficiency and reductions in greenhouse gas emissions and should not be interpreted as a prediction. Estimates for population growth in Georgia and in the Atlanta metropolitan region are for about a 37% increase by 2030. This value is the average of the projection from the U.S. Census Bureau and the State of Georgia, and is also consistent with projections made by the Atlanta Regional Commission for the Atlanta metropolitan
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26 region. In the absence of an estimate for growth published by the City of Atlanta, we consider a 37% population growth, as a baseline for projection, not as a prediction. If this increase in population held true, and if residential, commercial, and industrial energy consumption all increase proportionally, then there would be a 37% increase in energy use in Atlanta’s buildings by 2030, under a “business as usual” scenario.
Figure 21. Georgia electricity consumption per person for residential, commercial and industrial sectors, in MWh/capita/year. Data from US DOE EIA (2012).
Choi and Thomas (2012) have calculated the expected greenhouse gas emissions from electricity production in Georgia. Under a business as usual scenario, with no federal greenhouse gas policy and no renewable electricity standard in Georgia, the greenhouse gas emissions per kilowatt-hour (kWh) generated are expected to decrease over time. This is due to a combination of increased total electricity consumption, the gradual substitution of coal by lower-emitting natural gas, and by the start-up of new nuclear reactors at Plant Vogtle expected by 2017. Figure 22. Projected future GHG emissions per kilowatt-‐hour in Georgia. Based on Choi and Thomas (2012). These
changes are due to expected increased electricity generation from nuclear and natural gas plants in Georgia.
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27 3.2. The Opportunity for Improvement Commercial Energy Use For opportunity for improvement, commercial energy is considered first because it represents the largest source of greenhouse gas emissions in Atlanta. A number of studies have evaluated the energy efficiency potential in the commercial sector in the southeast region of the U.S. Chandler and Brown (2009), in a review of studies evaluating the potential for energy efficiency, conclude that the energy efficiency potential for the South’s commercial sector is 14% of the regional commercial energy consumption forecast. In a study of the Appalachian region, Brown et al. (2009) showed 22% energy efficiency potential for the commercial sector. In a broader study, McKinsey and Company (2009) showed a commercial energy efficiency potential for the South of 32%. In their book “Toward Zero Carbon: The Central Chicago DeCarbonization Plan” authors Adrian Smith and Gordan Gill project that select major renovations have the potential to save 30-40% in pre-1975 buildings and 15-25% in post 1975 buildings. While the savings may vary for Atlanta, the Chicago study suggests that older buildings may have substantial opportunities for improvement. In another study, Brown et al. (2010) used the National Energy Modeling System to evaluate two specific potential energy efficiency policies for the commercial sector in the southeast: aggressive commercial appliance standards, and incentivizing HVAC retrofits. The commercial equipment standards policy focuses on space heating, space cooling, water heating, ventilation, cooking, lighting, refrigeration, office equipment (PCs), office equipment (non-PCs) and miscellaneous equipment. Lighting is the largest consumer of energy in most commercial buildings. Rosenquist et al. (2005) have noted that potential energy savings from commercial sector standards have a greater net present value than those from the residential sector. The commercial equipment standards policy considered by Brown et al. results in a 17% reduction in commercial energy consumption between 2010 and 2030. The net present value of the costs are an estimated $26 billion for the southeast as a whole, and the net present value of the benefits are $109 billion, for a benefit to cost ratio of 4.6. The HVAC retrofit policy results in a 3% reduction in commercial energy consumption between 2010 and 2030. This modeled policy provided incremental cost incentives of up to 30% for efficient retrofits. The net present value of the costs are an estimated $8.5 billion for the southeast as a whole, and the net present value of the benefits are $21 billion, for a benefit to cost ratio of 2.4. Taken together, these studies suggest that a 20% reduction in commercial building energy use by 2030 is ambitious but feasible. This level of reduction is consistent with the Better Building Challenge, currently underway in Atlanta and discussed later. Greater reductions may be feasible through combinations of measures and innovative programs. There are financing mechanisms that can reduce the cost and increase the financial viability of building energy retrofits. Property Assessed Clean Energy (PACE) financing allows municipalities to offer bonds to investors and loan these funds to consumers and businesses for energy retrofits. What makes it unique is that the loan is attached to the property rather than to the individual. In 2010, Georgia enacted legislation (HB 1388) authorizing local governments to create PACE financing programs. Georgia has authorized the expansion of “business improvement districts” to allow county, city, or town development authorities to provide financing for the installation of renewable energy systems, energy efficiency or conservation improvements, and water efficiency or conservation improvements to residential, commercial, industrial, and other qualifying property. The future implementation of this mechanism may improve the feasibility and affordability of energy efficiency upgrades. Example of an Atlanta Commercial Energy Retrofit As an example of the potential costs and benefits of commercial energy efficiency in Atlanta, Southface Energy Institute developed energy efficiency retrofit options for an Atlanta commercial building. The specific building was a 15-year-old 10,000 square foot office building, with a heating set point of 71°F and a cooling set point of
28 74°F. Annual energy use in the all-electric building is 134,000 kWh per year at a cost of $18,600. Overall, this is a relatively efficient building; its annual electricity use of 13 kWh per square foot is low compared to the Atlanta average and even low compared to commercial energy use in the other cities considered in Chapter 2. The following eight options were analyzed10:
1. Upgrade of heating cooling and ventilation (HVAC) to more efficient system. Every air conditioner is assigned an efficiency rating known as its “seasonal energy efficiency ratio” (SEER), which is the total cooling output (in BTUs) divided by the total energy input in kWh. An upgrade from SEER 10 to SEER 15 in a typical Atlanta office building costs $14,000 and would save 8,750 kWh/year;
2. Reducing air leakage costs $5,800 and would save 7,010 kWh/year; 3. Increasing the efficiency of lighting (retrofitting standard T8 fluorescent lights with high performance (HP) T8
lights costs $10,500 and would save 10,093 kWh/year; 4. Improved thermostat controls costs $1,200 and would save 4,413 kWh/yr; 5. Replacing fluorescent lights with compact fluorescent lights (CFLs) costs $250 and would save 3,121 kWh/yr; 6. Point-of-use (POU) instantaneous water heating costs $2,000 and would save 2,277 kWh/year; 7. Motion sensors, to turn off lights when no one is in the room, costs $1,400 and would save 1310 kWh/year; 8. Computer sleep mode implementation costs $100 and would save 1,032 kWh/year. (There is no purchase
required, the $100 is a conservative estimate of the labor cost for someone to select the energy efficiency option on each computer in the building.)
These measures, if all implemented, would reduce electricity use in the building by 28%. If the most expensive option, the HVAC upgrade, were not implemented, the energy savings would be 22%. Note that all of these measures are technology improvements and none involve changes in behavior or temperature setpoints. These measures would provide additional opportunities for energy savings. Each of these measures involves some upfront cost and provides energy savings for the life of the equipment. Evaluation of the cost effectiveness of each measure will depend on the investment time frame – how many years of energy savings to consider – and the time value of money, which takes into account upfront costs with accumulated savings over time. One way to think about the costs is to look at the simple payback, which is the number of years of savings needed to pay back the investment cost without considering issues such as the time value of money or interest rates on loans. This simple payback is shown in Figure 23. The figure shows that two of the measures – changing incandescent light bulbs to compact fluorescents, and adjusting (turning on) the sleep mode settings on computers so that they use less power when not in use – are completely paid for in less than one year, and continue to provide savings for years to come. On the other hand, replacing the air conditioning system with a more efficient one takes more than ten years to “pay for itself” in this example. Note that the air conditioner upgrade and all other equipment changes are for replacement of working equipment; if equipment is replaced when it is broken, or if initial purchases are for highly efficient systems, then the additional cost of energy efficiency is much less. The comparatively high cost of replacing major equipment underscores the benefit of installing very efficient equipment each time a new system is required.
10 We thank John Bracey of Southface for providing these estimates.
29
Figure 23. Simple payback time for energy efficiency investments in a typical commercial building in Atlanta. The
payback time is the number of years of energy savings required to equal the amount invested, without consideration of the time value of money, interest costs, or other issues.
Another way to think about commercial building energy efficiency retrofits is in terms of the “interest rate” provided by the energy savings investment. Figure 24 shows that these range from 8% for the more efficient air conditioning system to 150% for changing the light bulbs. This chart helps to illustrate that even though some of these energy efficiency investments may take years to pay for themselves, the return on investment may be attractive.
Figure 24. Effective interest rates for energy efficiency investments in a typical commercial building in Atlanta.
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Figure 25. Energy savings for energy efficiency investments in a typical commercial building in Atlanta as a function of
the cumulative amount invested.
Figure 25 shows the cumulative energy savings from all of the measures for the commercial building. This figure underscores that although the replacement of incandescent lights, and adjustment of computer sleep mode are very cost effective energy efficiency actions that pay for themselves in less than a year, even taken together these actions reduce overall building energy use by less than 5%. To get more significant energy savings, more changes are needed, such as installation of programmable thermostats, reduction of air leaks, replacement of the water heater, installation of more efficient fluorescent lights, and installation of motion sensor controls for lighting. To illustrate the overall cost of these energy efficiency measures in a way that can provide insights for other buildings, both larger and smaller, the cost is shown as the percentage of annual energy costs for the building. Overall, the figure shows that, implementing all of the energy efficiency measures involves an expenditure of a bit more than two years of energy expenditures (219% for all of the measures including the new air conditioning system) and achieves an annual energy saving of nearly 30% (28.4%). From a more general perspective, staff of Perkins+Will’s Atlanta office estimated the energy savings that might be generated by measures to increase energy efficiency in commercial buildings in Atlanta.
1. Behavioral change: turning lights and equipment off, utilizing operable windows, appropriate seasonal dress for comfort, etc. (energy saving = 2 to 3%).
2. Building operations – night-time setbacks, building equipment load management (energy saving = 5 to 10%)
3. Lighting upgrades and controls/sensors (energy saving = 5 to 10%). 4. Plug load strategies - efficient computers and equipment (energy saving = 2 to 5%).
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31 5. Retro-Commissioning (energy saving = 10 to 12%). 6. Envelope improvements – windows, insulation, air sealing, moisture management (energy saving = 2 to
5%). 7. Mechanical systems upgrades for heating, ventilation and air conditioning (energy saving = 10 to 12%). 8. Reflective roofing and window films (energy saving = 2 to 3%). 9. Add renewable energy (energy saving = 1 to 2% of total energy).
Residential energy use While commercial energy use is the largest source of greenhouse gas emissions in Atlanta, residential energy use is also a significant contributor. Moreover, residential energy is often under the direct control of Atlanta’s residents, and reduced energy use can save money as well as provide environmental benefits. Example of an Atlanta Residential Energy Retrofit Southface Energy Institute also developed an example of an Atlanta residential retrofit, based on a 30-year-old 1100 square foot house with three bedrooms and two baths. The measures considered are as follows:
1. A programmable thermostat would cost $250 to install and save, if used correctly, $204 per year. 2. Upgrading incandescent light bulbs to compact fluorescent light bulbs would cost $100 and save $27 per year. 3. Duct sealing would cost $750 and would save $179 per year. 4. Installing wall insulation (to R13) would cost $3000 and save $330 per year. 5. Installing attic insulation (to R38) would cost $1000 and save $77 per year. 6. Reducing air leaks (air sealing to reduce leakage by about 50%) would cost $2000 and save $124 per year. 7. Installing R-19 insulation in the crawl space would cost $750 and save $39/year. 8. Installing a high efficiency (SEER 16) heat pump for both heating and cooling would cost $12500 and save $656
per year. 9. Upgrading the gas-fired water heating system from a 59% efficient system to a 67% efficient system would cost
$800 and save $39 per year. 10. Sealing the crawl space with R-10 wall would cost $800 and save $39 per year. 11. Upgrading the gas-fired water heating system from a 59% efficient system to a 82% efficient tankless system
would cost $1500 and save $55 per year. 12. Installing new energy star appliances would cost $1200 and save $31 per year. 13. Installing a new efficient (SEER 16) air conditioner would cost $10,000 and save $237 per year. 14. Installing a radiant barrier in the attic would cost $2000 and save $34 per year. 15. Installing new energy efficient windows, with the heat transfer U value of 0.32 and solar heat gain coefficient
(SHGC) of 0.27, would cost $10,000 and save $132 per year. 16. Installation of a 1 kW (peak electricity production) rooftop solar photovoltaic system would cost $7500 and save
$93/year. 17. Installation of a solar hot water system would cost $8800 and save $59 per year. 18. Installation of a reflective roof would cost $10,000 and save $17 per year.
Note that this list does not include any behavioral change or any change in the temperature settings of the house, other than the programming of the thermostat. Behaviorial changes and changes in the temperature to reduce summer air conditioning and winter heating can provide additional energy savings at low to no cost. Figure 26 shows the simple payback time for each of these potential energy efficiency upgrades. The figure shows that several of the measures pay for themselves in a few years, but that quite a few measures take more than 10 years to pay for themselves. This underscores the importance of installing high efficiency
32 systems when they need to be replaced, because it is more cost effective than replacing working systems with new ones.
Figure 26. Simple payback times for energy efficiency upgrades for a house in Atlanta. The chart shows payback
periods up to twenty years; upgrades shown with + have longer than 20 year payback times.
Figure 27 shows the effective interest rate for investment in residential energy efficiency. The figure shows that there are a number of efficiency investments that have effective interest rates of around 5% or more; these returns may be of interest to many homeowners. These measures include sealing the crawl space, insulating the crawl space, reducing air leaks, adding insulation to the walls and the attic, and sealing ducts, as well as investments in more energy efficient equipment such as a more efficient water heater, a heat pump, transition from incandescent lights to compact fluorescent lights, and installation and use of a programmable thermostat.
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33
Figure 27. Effective interest rate from energy efficiency upgrades for a sample residence in Atlanta. Interest rates are
only shown out to 20% although those shown actually have higher values.
Figure 28. Energy savings for energy efficiency investments in a typical house in Atlanta as a function of the amount
invested.
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34 Figure 28 shows the cumulative savings from the lowest cost residential efficiency improvements. The figure shows that with a programmable thermostat, conversion from incandescent lights to compact fluorescent lights, and duct sealing, an annual energy savings of about 20% can be achieved, with a one-time expenditure of about 50% of total annual energy costs. Costs of energy efficiency and renewable energy options will vary and can be expected to fall over time. As emphasized above, the costs shown here are for retrofitting a house that does not need repair and in which all the equipment is in working order. Replacing broken or end-of-life equipment with highly efficient equipment will result in much less net cost for energy efficient improvements. In this analysis, the renewable energy options are more expensive than many energy efficiency options. For the solar photovoltaic system, the full cost including installation was estimated to be $7500 for a 1 kW system; this amounts to $7.50 per installed watt. There is currently substantial effort underway to reduce the costs of residential solar photovoltaic systems to $1.50 per installed watt, supported by the U.S. Department of Energy. Nor does this estimate take into account various renewable energy incentives. For those homeowners and building-owners choosing renewable energy systems, this analysis underscores the benefits of maximizing energy efficiency efforts before or concurrent with installation of renewable energy systems. For a more efficient building, a greater proportion of the energy requirements can be supplied by an investment in renewable energy generation. Very Efficient Commercial Buildings in Atlanta There are a number commercial buildings examples in Atlanta that demonstrate the feasibility of efficiency. Perkins+Will: 1315 Peachtree St. Atlanta, GA 30309 Among a host of other energy efficient features, the Perkins+Will building highlights an example of “combined cooling, heat, and power” (CCHP) in a commercial building. The generation and distribution of electricity from the power grid can be very inefficient; roughly 30-35% of the energy in the source fuel (coal for example) makes it to power outlets in the form of electricity, mostly due to heat loss at the power plant. By generating power on-site through a tri-generation system, waste heat is captured and used for both heating and cooling using an adsorption chiller, thereby achieving much greater efficiencies than grid-sourced electricity generation. In addition, the switch to natural gas as a primary fuel source to generate roughly 40% of building electricity reduces greenhouse gas emissions that would be generated from the combustion of coal – a primary fuel for local power plants. The building remains connected to the grid and relies on grid electricity when there is not much need for heating or cooling. When heating or cooling is needed, however, the tri-generation system satisfies the demand and also produces electricity. This flexibility has contributed to 58% cost reduction and 68% greenhouse gas reduction at the Perkins+Will Atlanta offices.
35
© 2011, Michelle Litvin © Eduard Hueber / archphoto.com
Figure 29. The 1315 Peachtree St tri-‐generation system includes the above pictured absorption chiller designed to cool water by utilizing a silica gel media and the “waste” heat from two microturbines. Made in Athens, GA, this
absorption chiller is one of only a few in operation in the southeast and one of approximately 12 in the United States at the time of this report.
Southface Eco Office: 241 Pine Street NE Atlanta, GA 30308 The Southface Eco Office, located in downtown Atlanta, is a three-story commercial structure that serves as an office, training, and demonstration facility. At 10,100 square feet, it is the same size as 74% of American commercial buildings. It uses 84% less water and 50% less energy than a comparable, code-built facility. The south side of the building has motorized window louvres to reduce heating from the sun in the summer and to promote heat gain from the sun in winter. There are also solar shades on the south-facing windows. The roof is constructed of reflective white pavers. The building is designed for daylighting, has a photovoltaic system on the roof, energy star appliances, and many other energy efficient features. Both in-person and online (http://www.southface.org/onlinetour/) tours are available (Southface 2012).
Figure 30. Southface Eco Office, 241 Pine Street NE, Atlanta (Southface 2013) Energy Institute)
Carbon Neutral Energy Solutions Laboratory – Georgia Tech Georgia Tech’s Carbon Neutral Energy Solution Laboratory, opened in 2012, seeks zero net external energy. The building makes extensive use of daylighting, highly efficient lighting, a high-performance building envelope, natural ventilation, energy recovery, solar thermal desiccant recovery for humidity reduction, solar
36 photovoltaics, a ground-source heat pump chiller/boiler with chilled beams and radiant slab, and a trombe wall for passive solar heating. The building is stretched along the east-west axis, providing long north and south facades. By design, no artificial light will be required during daylight hours, and lights will be turned off when the lab is not in use. Lighting controls are multi-tiered to allow for fully lighting an individual workspace without lighting unoccupied areas. Light tubes bring daylight to internal areas of the building. To conserve energy used for heating and cooling, the acceptable temperature range of the facility has been expanded, with greater air circulation and ventilation to maintain comfort. The building also has a roof rainwater collection system for on-site grey water and site irrigation (Georgia Tech 2012).
Interface Showroom: 75 Fifth Street, NW Suite 110 Atlanta, GA 30308 The Interface Showroom is a 7,000 ft2 commercial office and retail space in downtown Atlanta. As a single tenant (2% of total) within a larger building, this project demonstrates what is possible when a project does not have complete control over all parameters of design and construction. As a pilot project, it was awarded the first ever LEED Platinum rating in the LEED Commercial Interiors Rating System (LEED CI).
Figure 31. Interface Showroom, 75 5th St. NW, Atlanta GA (Interface 2013)
Daylight, efficient lighting, and lighting controls such as occupancy sensors reduce electricity use for lighting in the space by up to 30% and Energy Star appliances and equipment are used throughout. The Showroom underwent fundamental building systems commissioning to ensure that the systems operate as intended. Within the lease agreement, and supported by sub-metering installed in the project, the utilities are paid by the tenant, thereby providing an additional incentive for energy efficiency.
In addition to energy saving features, the Showroom location is supported by access to public transportation, storage space for bicycles, and showers with changing areas. Such amenities can further reduce carbon impacts associated with employee commutes as they support the use of alternative transportation options (Interface 2012).
Atlanta Better Buildings Challenge Buildings
Through the Atlanta Better Buildings Challenge (http://www.atlantabbc.com/), the City of Atlanta is working with the business and nonprofit community on comprehensive energy upgrades for downtown buildings, with the goal of improving energy performance at least 20% by 2020. The program began with a benchmarking initiative for Atlanta's 400 block downtown area, including City Hall, the Civic Center, and other landmark downtown buildings. Project partners are now working with banks, funds, energy service companies, and others to enable substantive retrofits of buildings from the university, healthcare, municipal, and commercial sectors. Enrolled buildings participating in substantive retrofits have a combined 21 million square feet of space, with broader participation expected from buildings that actively monitor and manage their energy use.
37 The number of participating buildings is growing and as of July 2012 includes the Atlanta Civic Center, Americas Mart, GSA Summit Building, Embassy Suites Centennial Olympic Park, Georgia Dome, Georgia World Congress Center, 330 Marietta Street, Technology Square Research Building, Ponce City Market, Epsten Group, CNN Center and Omni Hotel, 55 Allen Plaza, the Turner Building, Centennial Research Building, 10 Peachtree Place (AGL Resources), Morehouse School of Medicine Hugh M. Gloster Building, Georgia Tech Allen Lamar Sustainable Education Building, Spelman College Science Building, Fulton County Government Center, Fulton County Lewis R. Slaton Courthouse, Georgia Power Company Headquarters, Georgia State University One Park Place, Georgia Pacific Center, 260/270 Peachtree, Hartsfield-Jackson Atlanta International Airport, The Coca-Cola Company North Avenue Tower, Centennial Tower, 100 Peachtree Street, Suntrust Plaza and Garden Offices, Clark-Atlanta University Sage-Bacote Hall, Hyatt Regency Atlanta, St. Luke’s Episcopal Church, Centennial Park West Condominiums, Peachtree Center, and Philips Arena.
3.3. Policy Options for Reducing Greenhouse Gas Emissions from Buildings Atlanta Detailed discussion of goals and options for reducing overall greenhouse gas emissions in Atlanta are provided in Chapter 5. Below we discuss policies specifically aimed at reducing energy use and greenhouse gas emissions in buildings. Energy Efficiency Policies According to 2010 estimates from the U.S. Energy Information Administration, approximately 75% of the American built environment will be either new construction or renovated by 2035. This is based on the total U.S. building stock and accounts for yearly estimations for demolition (0.6% annually), renovation (1.8% annually), and new construction (an additional 1.8% annually). By the year 2035, approximately three-‐quarters (75%) of the built environment will be either new or renovated. Considering the projected renovation and new construction, the questions of “how to” or “when” to update buildings in Atlanta becomes less a concern of isolated financing for energy improvements, and elevates the leverage that building codes and policy can have in meeting the City’s carbon reduction targets. With effective building energy codes in place, a considerable portion of the built environment could contribute to the City’s carbon reductions as a matter of course. The following energy efficiency and renewable energy policies can be implemented at the local level and have the potential o support substantial improvements in energy efficiency: increasing energy efficiency in existing commercial and residential buildings, increasing adoption of energy efficient appliances and equipment, enforcement of Georgia’s 2011 building energy code, and adoption of new energy codes in coming years. These are discussed below. • Increase efficiency in existing commercial buildings.
- The Better Buildings Challenge encourages energy efficiency improvements in commercial buildings in Atlanta through public recognition and educational resources to improve efficiency. This program targets 20% reduction in energy use by 2020. Continued support of this program would enable substantial efficiency improvements in Atlanta.
- Additional building efficiency policies could include low or no-interest loans for Energy Star equipment, tax credits for purchases of energy efficient equipment, and a revolving loan fund for energy efficiency projects that would be paid back from energy savings. The City of Atlanta has established a revolving loan fund for internal City energy projects.
- Retrocommissioning, a commissioning process for existing buildings that seeks to improve how building equipment and systems function together, can improve energy performance. Retrocommissioning should be completed before energy conservation measures are implemented. By tuning the performance of existing buildings, energy, greenhouse gas and maintenance savings can be realized. Retrocommissioning can have a payback time of less than one year.
38 • Increase energy efficiency in existing residential buildings.
- Rebates of up to $2200 for residential energy efficiency improvements are available from Georgia Power (Georgia Power 2012). Programs are available for both single-family and multi-family homes, and are available for both whole-house upgrades and for individual improvements.
- Atlanta’s residential weatherization rebate program, SHINE, has been operating for more than a year. The program provides City of Atlanta homeowners up to $3,500 in rebates towards qualifying improvements including duct and air sealing, insulation improvement, caulking, weather-stripping, replacement of doors and windows, and high efficiency domestic hot water heaters. Building from the experience with SHINE, Atlanta can extend and strengthen its weatherization programs. • Increase adoption of efficient appliances and equipment (commercial and residential). Incentives can take the form of a utility backed trade-in program, a city or state tax holiday on the purchase of efficient energy star appliances, as well as education and resource sharing. Appliance rebates are available from Georgia Power for Energy Star freezers and for Energy Star room air conditioners, as well as rebates for refrigerator recycling, and reduced prices on compact fluorescent lights at participating retailers (Georgia Power 2012).
• Enforce the existing 2011 building energy code. In 2011, the state of Georgia adopted one of the strongest building energy codes in the nation. Georgia’s building energy code meets and exceeds the current international standard, the 2009 International Energy Conservation Code, IECC 2009. However, compliance with the code has not yet been achieved, particularly among the large numbers of contractors and builders in the residential sector. Southface and Sustainable Atlanta have estimated the energy savings that can be achieved by implementation of Georgia’s 2011 Building Energy Code, in comparison with current average practice. Several categories of buildings are considered, both residential and commercial, both new buildings and major renovations. Overall, implementation of the 2011 building energy code provides an energy savings of about 10% for new buildings, compared to current practice, and about 6% for major renovations (Burk et al. 2012). The state of Georgia has set a goal of 90% building energy code compliance by 2017. Atlanta could set a goal of full and immediate compliance with the 2011 building energy code for all new commercial and residential buildings and all major renovations.
• Adopt the 2012 IECC building energy code, including amendments developed by the U.S. Department of Energy, EC 147 for commercial buildings and EC 13 for residential buildings. Building energy codes are being continuously strengthened. Because buildings are the major source of greenhouse gas emissions in Atlanta, and because buildings are in effect legacy projects, ensuring that new buildings and major renovations meet high efficiency standards is key to reducing emissions in Atlanta. Georgia’s building energy code already exceeds the IECC 2009 code by requiring blower door and duct tests, which are the most challenging aspects of the recently released 2012 IECC code. Thus, Atlanta is already in a good position to be able to take a leadership position in building energy efficiency by adopting the remaining aspects of the 2012 IECC code that are not already in the 2011 Georgia code. The 2012 building code will increase energy efficiency of new buildings by 30% compared to current practice (U.S. DOE 2011). The EC 147 code for commercial buildings includes two major energy saving components. The first is a requirement for high performance cool roofs in the southern part of the U.S. These high performance reflective roofs can reduce building cooling, particularly for low-rise buildings, and also reduce the urban heat island effect (U.S. DOE 2012). Georgia has long had a leading code on cool roofs, putting Atlanta and all of Georgia in a strong position to adopt EC 147. The second major EC 147 component offers designers three approaches to increasing energy efficiency: more efficient lighting, more efficient HVAC (heating, ventilation, and air conditioning) or use of renewable energy. These three options allow designers flexibility when considering the building site, construction methods, environmental conditions, and costs while improving the bottom line efficiency of the building.
39 For residential buildings, EC 13 requires pressure testing of residential buildings to ensure that they have been air-sealed properly. While a significant advance at the national and international level, Georgia’s 2011 building energy code already includes this provision, making EC 13 adoption a smaller step for Georgia than for other states (U.S. DOE 2012). In addition, EC13 includes new provisions designed to significantly reduce energy and water wasted in typical piping systems. EC13 encourages hot-water distribution systems with short runs of small-diameter pipes and require insulation on longer, higher-volume piping. The impact of this aspect of EC13 would be significant. Approximately 25-35% of energy use in a home is consumed by heating water; reducing the amount of hot water stranded in pipes after the water-using fixtures or appliances are turned off could reduce the energy costs associated with heating water by up to 10%. And, residents will spend less time waiting for hot water to reach faucets and showers. Also, the EC13 proposal includes increased R-values in many thermal envelope assemblies, requires more efficient windows and skylights, and reduces allowable duct leakage rates (U.S. DOE 2012). • Encourage buildings that substantially exceed energy code requirements. Near-term incentives for buildings to meet or exceed the IECC 2012 code, including EC 13 or EC 147 as appropriate, would provide a basis for evaluating the adoption of this code in Atlanta. Incentives could include permitting expedition, exemptions, or relaxation of some requirements. In addition to energy efficiency, additional design elements can help reduce the City’s environmental impact including efficient use of water and materials, light colored paving, reduced parking, and promotion of alternative transportation. • Promote Sub-metering and advanced metering. Sub-meters can incentivize energy upgrades made by tenants in leased space. Sub-metering enables tenants to realize the benefits of purchasing efficient office equipment and promoting behavioral change in their organizations, thereby contributing to the City’s goals. Without sub-metering, there is little incentive for building tenants to promote efficiency as they do not realize any economic benefits. Such a strategy also enables efficient spaces to better compete under green leasing terms, be readily compared to other spaces, enables businesses to monitor their progress and investments, supports performance contracting, and can contribute to qualification for LEED certification.
• Energy use disclosure for large buildings. Energy use disclosure for large buildings provides a baseline for identifying opportunities for energy efficiency and for measuring progress. Energy use disclosure is a low-cost mechanism for encouraging energy efficiency. Building energy use disclosure is mandatory in New York City, Washington DC, Austin, Texas, Washington State, the European Union, and Australia. Many large commercial buildings in Atlanta are participating in the Better Buildings Challenge; as part of that program they disclose their energy use to the US Department of Energy.
• ASHRAE, the building engineering society that focuses on building systems, energy efficiency, indoor air quality, and sustainability within the building industry, is based in Atlanta. They have developed a building energy labeling program, the Building Energy Quotient (bEQ) for commercial buildings (ASHRAE 2012). This program allows building owners to understand and identify opportunities for energy savings, and also provides a means for tenants to find energy efficient buildings. Coupling a labeling system such as bEQ with energy use disclosure could provide additional benchmarks for building owners and tenants to compare options for energy savings and to promote energy efficiency.
40 • Green Leases. Green leases are a mechanism to recognize energy benefits and upgrades in the
market and throughout the commercial leasing process. Green lease efforts can span site selection, development of green guidelines for development, drafting and negotiation of lease language, etc.(Green Lease Library 2012).
Leadership and Education In addition to direct measures to improve energy efficiency, the City of Atlanta can support energy efficiency through leadership and education. • Energy Efficiency Information.
• Georgia Power provides an online energy check-up service. Both residential and commercial customers can receive recommendations for energy efficiency based on their actual energy use (Georgia Power 2012). By supporting and providing recognition for these resources, Atlanta can encourage energy efficiency for Atlanta’s residents and businesses.
• The City of Atlanta can foster change towards sustainability and greenhouse gas reductions through the compilation and dissemination of pertinent information to citizens. By providing citizens enhanced access to information ranging from recycling through home energy efficiency, the City can enable change at low cost. In addition, resources for developers and private sector stakeholders can be provided, such as grant opportunities, tax benefit information, green lease information, building energy code information, and LEED and other certification program links. This platform could also be used to raise awareness and inform executives of the benefits of conservation and efficiency measures. Non-governmental organizations in Atlanta, including Sustainable Atlanta and Southface, may be able to support or lead this effort.
• LEED certification for City-owned facilities. LEED – which standards for Leadership in Energy and Environmental Design – is a building certification program administered by the U.S. Green Building Council (U.S. Green Building Council 2012). The City of Atlanta currently requires LEED Silver for all new construction and major renovations of City-owned buildings. By pursuing LEED, the city commits to a position of leadership and transparency. Atlanta could go further in this direction, seeking LEED Gold certification for large new City-owned facilities, and/or by seeking the LEED Existing Buildings: Operations & Maintenance (EBOM) certification for existing City-owned facilities. It covers topics ranging from energy and water use, to green procurement, green cleaning, food services, and landscape management. Many operational practices require education of employees about sustainable behavior and can empower city employees to embrace the city’s environmental goals to make positive change for all citizens. Production of low greenhouse gas electricity • Increase production and use of renewable energy. Georgia Power customers can purchase electricity from renewable sources. For an extra 3.5¢ per kWh, purchased in 100 kWh blocks, customers buy biomass-derived electricity, primarily from the DeKalb landfill gas electricity generation station. Or, for an extra 5¢ per kWh, bought in 100 kWh blocks, customers can purchase electricity from a combination of the DeKalb landfill and solar energy generated in Georgia. • Work with energy utilities and the Georgia Public Service Commission (PSC) to develop an energy plan that reduces greenhouse gas emissions and increases energy efficiency. Greenhouse gas emissions from electricity can be reduced through a number of means: from transition from coal to natural gas, production of electricity from zero and low carbon sources such as solar, wind, biomass, and nuclear power, and from capture and sequestration of carbon dioxide. Energy efficiency programs are required by the PSC; the effectiveness and extent of these programs could be increased. Georgia Power offers a number of demand-side management
41 programs; the City of Atlanta could work with Georgia Power to support and extend these programs and increase their effectiveness in Atlanta. • Reduce potential barriers and provide incentives for distributed generation: on-site co- and tri-generation of power. Conventional energy plants see upwards of 60% energy loses through the stacks in the form of heat. When considered with another 5-10% transmission loss, grid energy is nearly 70% inefficient when it gets to the consumer. By generating energy on-site using natural gas as a base fuel, electricity can be generated and the associated heat could be captured for direct use or utilized in a heat recovery chiller to generate cool water. There are, however, numerous barriers to implementation of CHP. These include high upfront costs, low electricity rates for industry and other large consumers, input-based emissions standards (e.g. air pollution standards that don’t account for the air emissions benefits of electricity production by CHP), utility monopoly regulations, grid access regulations and net metering regulations (Brown et al. 2011).
• Promote residential and commercial renewable power installations. • In other states, renewable electricity companies can own and maintain solar panels or other equipment
on the consumer’s property, providing a mechanism for financing and maintaining renewable electricity generation. Such agreements are commonly referred to as power purchase agreements (PPAs) and reflect a model of build, own and operate. Currently in Georgia, under the Georgia Territorial Electric Service Act, homeowners or businesses can buy and install solar panels or other devices to produce electricity for their own use, but they are not allowed to rent panels from a third party, buy the power generated from a third party, or sell the power generated to a third party. This means that the business models that have been developed in other states by the renewable energy industry cannot be used in Georgia; new models need to be developed. In Atlanta, renewable electricity could be supported by mechanisms such as PACE financing to allow capital costs of renewable electricity equipment to be associated with the building.
• Utilize landfill methane from the multiple Atlanta-area landfills and wastewater treatment facilities. Methane has a global warming potential that is many times greater that CO2. Landfills emit methane that is generated from anaerobic decomposition of garbage. By flaring methane, the global warming potential is reduced to that of carbon dioxide. A preferred option to flaring the methane is to utilize it for power generation, direct use in industry, or for vehicle fuel. An example is the Dekalb County Seminole landfill, where electricity is produced from landfill methane and a project is underway to capture and covert landfill methane into fuel for county vehicles. Another example is the installation of the combined heat and power system installed at RM Clayton Water Reclamation Center that generates electricity from biogas that was previously flared.
References Architecture2030, 2011. Solution: The Building Sector. http://architecture2030.org/the_solution/buildings_solution_how ASHRAE 2012. Building Energy Quotient. http://www.buildingeq.com/index.php/building-energy-quotient-beq Brown, Marilyn A., John A. “Skip” Laitner, Sharon “Jess” Chandler, Elizabeth D. Kelly, Shruti Vaidyanathan, Vanessa McKinney, Cecelia “Elise” Logan, and Therese Langer. 2009b. Energy Efficiency in Appalachia: How much more is available, at what cost, and by when? Appalachian Regional Commission and Southeast Energy Efficiency Alliance. Brown, M. A., Gumerman, E., Sun, X., Baek, Y., Wang, J., Cortes, R., Soumonni, D., 2010. Energy Efficiency in the South. Southeast Energy Efficiency Alliance, Atlanta, GA. www.seealliance.org/se_efficiency_study/full_report_efficiency_in_the_south.pdf
42 Brown, M. A., M. Cox, P. Baer, Reviving Manufacturing with a Federal Cogeneration Policy. Working Paper #67, School of Public Policy, Georgia Institute of Technology, 2011. http://www.spp.gatech.edu/faculty/workingpapers/wp67.pdf Burke, D., Arora, S., Bracey, J., Curtis, O., David, C., Lindsley, S., Monroe, M., Roberts, S. Benefits from Effective Energy Code Implementation in the City of Atlanta. Sustainable Atlanta and Southface. February 2012. http://www.sustainableatlanta.org/ and http://www.southface.org/ Chander, J. S. and Brown, M.A., 2009. Meta-Review of Efficiency Potential Studies and Their Implications for the South. Working Paper 51, School of Public Policy, Georgia Institute of Technology. http://www.spp.gatech.edu/faculty/workingpapers/wp51.pdf Choi, D. G., Thomas, V. M., An Electricity Generation Planning Model Incorporating Demand Response, Energy Policy 42: 429-441, 2012. http://dx.doi.org/10.1016/j.enpol.2011.12.008 Georgia Department of Natural Resources (2000). GIS Database of Solid Waste Landfills within the State of Georgia Permitted through December 1999. Department of Natural Resources, Environmental Protection Division, Geologic Survey Branch: Atlanta, GA. Georgia Department of Industry Trade and Tourism (1996). 1996 Georgia Manufacturing Directory. Department of Industry Trade and Tourism: Atlanta, GA. Georgia Institute of Technology, 2012. Carbon Neutral Energy Solutions Laboratory. http://www.space.gatech.edu/planning/assets/PlnFile_0_20091110103111.pdf Georgia Power, 2012. Home Energy Improvement Program. http://www.georgiapower.com/residential/energy.asp Georgia Power, 2012. Energy Check-up. http://www.georgiapower.com/earthcents/residential/energy-checkup-online.asp?wt.ac=rlp_banner_onlineaudit_20120515 Interface, 2012. Tour Our Showrooms. http://www.interfaceflor.com/default.aspx?Section=3&Sub=7# Makres, E. et al. 2012. The Role of Local Governments and Community Organizations as Energy Efficiency Implementation Partners: Case Studies and a Review of Trends. American Council for an Energy Efficient Economgy, and MIT Energy Efficiency Strategy Project. McKinsey and Company, 2009. Unlocking Energy Efficiency in the U.S. Economy. Institute for Energy Research, 2010. http://www.instituteforenergyresearch.org/state-regs/pdf/Georgia.pdf Georgia 2010, Georgia 2030: Population Projection, Office of Planning and Budget, Report, www.opb.state.ga.us/media/12444/georgia%20population%20projections%20-%20march%202010.pdf Green Lease Library, 20120. http://www.greenleaselibrary.com Levin, T., Thomas, V. M., Lee, A. J. State-Scale Evaluation of Renewable Electricity Options: The Role of Renewable Electricity Credits and Carbon Taxes, Energy Policy 39(2): 950-960, 2011. http://dx.doi.org/10.1016/j.enpol.2010.11.020
43 Rosenquist, et,al. 2005. “Energy Efficiency Standards for Equipment: Additional Opportunities in the Residential and Commercial Sectors.” http://www.clasponline.org/files/EnergyPolicy-AdditionalOpportunities_aug05.pdf Southface, 2012. Southface Eco Office. http://www.southface.org/about/campus/eco-office Smith, I., Gill, G. 2011. Toward Zero Carbon: The Chicago Central Area DeCarbonization Plan. Images Publishing Dist Ac. US Census Bureau 2005, Interim Projections of the Total Population for the United States and States, http://www.census.gov/population/projections/SummaryTabA1.pdf US DOE, EIA, 2010. Trends in Residential Natural Gas Consumption. ftp://ftp.eia.doe.gov/pub/oil_gas/natural_gas/feature_articles/2010/ngtrendsresidcon/ngtrendsresidcon.pdf US DOE 2011. Building Energy Codes Program. http://www.energycodes.gov/status/2012_Final.stm US DOE, 2012. 30/30 Vision – Goal in Site. Building Energy Codes Program. http://www.energycodes.gov/status/30-30vision.stm US DOE, EIA, 2012. State Energy Data System. Georgia. http://www.eia.gov/state/seds/seds-states.cfm?q_state_a=GA&q_state=Georgia U.S. Green Building Council, 2012. http://www.usgbc.org/
44
4. Greenhouse Gas Reductions for Transportation
Summary
• We project that, with expected population growth and the implementation of the proposed federal vehicle fuel
efficiency standards, greenhouse gas emissions from surface transportation in Atlanta will fall about 18%
between 2010 and 2030.
• Vehicle efficiency regulation is addressed at the federal level; the greatest opportunities for Atlanta further to
reduce transportation greenhouse gas emissions are in the area of reducing vehicle miles traveled.
• Reducing travel and traffic in Atlanta will also save time, reduce fuel costs for consumers, and increase the
attractiveness of Atlanta.
• Measures to reduce vehicle travel include increasing the availability and convenience of transit, focusing
development in locations with transit opportunities, increasing the cost of parking, and increasing the viability
and attractiveness of walking and biking throughout Atlanta.
4.1. Introduction
Transportation in Atlanta includes the cars and other light duty vehicles that drive in and through Atlanta,
subway trains, buses, the freight trucks and trains that travel within and through Atlanta, and bicycles,
motorcycles, and walking – all the ways that people and goods move in and through Atlanta. Transportation in
Atlanta is part of transportation throughout the entire Atlanta metropolitan region, including air transport
through the Atlanta Hartsfield Jackson International airport, as well as traffic on the interstate highways and rail
systems that run through Atlanta.
The Atlanta Regional Commission has long experience with studying and modeling transportation in the
Atlanta metropolitan region; they have estimated 5.4 billion vehicle miles per year are traveled within the city
limits of Atlanta; this is what we use as a basis for our transportation assessment. To place this into context, the
entire 20-county Atlanta metropolitan region, with a 2010 population of 5.1 million people, has an estimated 61
billion vehicle miles traveled per year (Olivares 2010).
When gasoline or diesel fuel is consumed by cars, trucks or buses, the carbon molecules in the fuel, in
combination with oxygen from the air, are converted through the combustion reaction and water to carbon
dioxide and released through the tailpipe to the atmosphere. The equations below show this in words (first
45 equation) and in chemical form using octane (C8H18) as a representative gasoline molecule. These carbon
dioxide emissions are the greenhouse gas emissions from the transportation sector.11
Gasoline + Oxygen èCarbon Dioxide + Water
C8H18 + 12.5O2 è 8CO2 + 9H2O
The equations above represent an idealized picture of the combustion of petroleum fuels. In addition to the
carbon dioxide and water emissions, there are also small amount of nitrous oxide emissions – NO and NO2 –
formed from the nitrogen in the air and the small amounts in the fuel, some emissions of particulates
particularly from diesel engines, and some emissions of carbon monoxide (CO) and volatile organic compounds
(VOCs). All of these contribute to urban air pollution and have effects on health.
Making estimates of the average fuel efficiency of vehicles, we have derived an estimate of greenhouse
gas emissions from transportation in Atlanta, which comes to about 2.4 million metric tons, 22% of Atlanta’s
greenhouse gas emissions (Borin et al. 2012). This number does not include greenhouse gas emissions from the
jet fuel used at the Hartsfield Jackson International Airport, and does not include transportation outside of the
city limits. For Georgia as a whole, transportation accounts for 36% of greenhouse gas emissions (EIA 2010).
4.2. Estimate of Future Emissions from Transportation in Atlanta
How will transportation in Atlanta change over time? The greenhouse gas emissions from transportation
can be thought of as the product of the number of vehicle miles per person, and the emissions per mile. The
number of vehicle miles per person will depend on the future population of Atlanta, the future population of the
Atlanta metropolitan region, and changes in driving habits, patterns of development and availability of
transportation options.
In the 20-county region, per-person vehicle miles traveled rose from 17 miles per day to a peak of nearly
23 miles per day in 2003 and then declined to less than 21 miles per day as of 2007. The increase in vehicle
miles traveled during the 1990s is attributed to development increasingly far from the city center; the
subsequent decrease has been attributed to shorter trips in outer regions and to increased development in activity
centers and transportation corridors (Olivares 2010).
The Atlanta Regional Commission has projected that the population in the 20-county region will
increase by 40% between 2005 and 2030, and that vehicle miles traveled will increase at a faster rate than
population, with a resulting estimate of a more than 50% increase in vehicle miles traveled between 2005 and
11 There are other contributors to the climate impact of transportation, all small in Atlanta compared to all the CO2 emissions from gasoline and diesel fuel combustion – MARTA subway trains run on electricity, which has its own greenhouse gas emissions; refrigerants in vehicle air conditioners have a greenhouse gas impact if they leak into the atmosphere; diesel trucks and trains emit particulates which can have a climate effect, etc.
46 2030 (Olivares 2010). However, as shown in figure 4.1, in the overall Atlanta metropolitan region, vehicle
miles traveled per person per day rose during the 1990s, were basically constant from 2000 to 2005, and
decreased thereafter.
Figure 4.1. Vehicle miles traveled per person per day. Source: Texas Transportation Institute, 2009
Urban Mobility Report. As cited by Olivares (2010).
For the purpose of developing a baseline for future greenhouse gas emissions in Atlanta, we estimate that the
population of the city of Atlanta will increase at the rate projected for the entire state of Georgia, and that, in the
absence of new polices, the vehicle miles traveled per person will remain constant. With a projected population
increase of 37% between 2010 and 2030 in Georgia, this provides us with an estimated 37% increase in vehicle
miles traveled in Atlanta by 2030, as a baseline estimate.
Proposed federal fuel efficiency standards, expected to be adopted in late 2012, will reduce fuel use per vehicle
mile traveled. The proposed fleet-wide fuel economy standard is 49.6 mpg for model year (MY) 2025, as
measured using the National Highway Traffic Safety Administration (NHTSA) method (The White House
2011). Since the standard applies to new vehicles, and many older vehicles can be expected to remain on the
road, we conservatively estimate an average on-road vehicle fleet fuel efficiency of 40 miles per gallon by
2030. This is a substantial improvement over the current average in the Atlanta metropolitan area of 17 miles
per gallon (Olivares 2010).
Figure 4.2 shows our calculation of the energy use of the vehicle fleet.
47
Figure 4.2 Projection of fuel efficiency of cars and light trucks under the proposed fuel efficiency
standards. The dashed lines show new cars and new light duty trucks, the solid lines show the average stock of
cars in use, including new and remaining older cars (Choi 2012).
To model the future fuel efficiency of the entire U.S. light-duty vehicle (LDV) fleet, we use the proposed fleet-
wide fuel economy standard of 49.6 mpg for model year (MY) 2025, as measured using the National Highway
Traffic Safety Administration (NHTSA) method (The White House 2011). The NHTSA 49.6 mpg standard
determines the Corporate Average Fuel Economy (CAFE) standard and does not include many of the incentive
multipliers included in the EPA standard (Federal Register 2011). Therefore, the NHTSA standard is closer to
actual vehicle fuel economy and is used for this study. The standard projects a distribution of sales of vehicle
footprints and types (i.e. truck vs. car). Since the standards apply to individual vehicle footprints and type,
rather than the fleet as a whole, should actual sales not match the projected distribution, fleet-wide fuel
economy may not match the 49.6 mpg overall standard.
We use the proposed model year (MY) 2017-2025 standard and assume vehicle sales are distributed as
projected to develop the reference case. For the market share of new light-duty vehicle technology for 2025 we
use projections from the US EPA and the NHTSA (EPA 2010)12, which is that EVs reach 10% market share by
2025, as our base EV adoption scenario.
12Based on the current rule for 2012-‐16, the report developed four fuel economy scenarios: 47, 51, 56 and 62 mpg as measured by the EPA until 2025, and projected that the market share of fully electric vehicles among new vehicles in 2025 will reach 10%with an emphasis on EVs
0
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New Car Stock Car Stock Light-‐Duty Truck New Light-‐Duty Truck
48
Starting from 2008 sales figures (AEO 2011), of which 53% and 47% of LDV sales are cars and light-duty
trucks respectively, the market share of cars is projected by the EIA to gradually increase to about 64% by
2030. SUVs and vans are projected to comprise 64% and 11% respectively of light-duty truck sales. With the
projections of the future light duty vehicle sales and stocks, we project the number of vehicles scrapped13 each
year.
Combining the projected 37% growth in vehicle miles traveled in Atlanta with the projected 35% improvement
in vehicle fuel efficiency results in a projected 11% decrease in fuel use from transportation between 2010 and
2030, in the baseline scenario.
Adoption of low emission biofuels, mandated by the federal Renewable Fuel Standard (RFS2), can reduce
greenhouse gas emissions further (EISA 2007). The renewable fuel standard requires production of 10.5 billion
gallons of cellulosic biofuel, with 60% reduction in greenhouse gas emissions compared to gasoline, and 15
billion gallons of advanced biofuel, with 50% reduction in greenhouse gas emissions compared to gasoline, and
4.5 billion gallons of renewable fuel with 20% reduction in greenhouse gas emissions compared to gasoline.
The overall renewable fuel portion in transportation fuels is expected to be 7% (US DOE 2010). As a result, the
greenhouse gas emissions from gasoline will fall by 3.6%, per gallon of gasoline, by 2020. Although the
program does not currently extend beyond 2022, here we assumed continuation of the program to bring the
greenhouse gas emission reduction to 4% by 2030.
Both the Connect Atlanta Plan (2011) and the Atlanta Regional Commission’s White Paper on greenhouse gas
emissions from transportation (Olivares 2010) have made recommendations that can reduce greenhouse gas
emissions from Atlanta’s transportation system.
There are two main approaches to further reducing greenhouse gas emissions from transportation: reducing the
number of vehicle miles traveled per person, and reducing the emissions per mile. These are discussed in turn
below.
4.3. Reducing Emissions per Mile Traveled
under the 56 mpg scenario which is equivalent to 49.6 mpg as measured by the NHTSA. These standards will require the fleet to meet an estimated combined average emissions level of 250 g of CO2 per mile in 2016, equivalent to 35.5 mpg. 13Vehicles scrapped is calculated as the difference between the vehicle stock changes between current and next years, and the number of new vehicle sales.
49 Approaches to reducing emissions per mile traveled include more efficient vehicles, electric vehicles charged
with sufficiently low-emission electricity, other alternative fuel vehicles, and low-emission biofuels.
• More efficient vehicles: As mentioned above, proposed corporate average fuel efficiency standards at the
federal level will, if implemented, result in a significant increase in the fuel efficiency of the light-duty vehicle
fleet. These fuel efficiency standards include electric vehicles as one way that vehicle manufacturers can meet
the efficiency standards; the standards are based on vehicle size, with some vehicles more efficient than the
standards and some less, so that the standard can be met in the average. For example, for a compact car such as
a Honda Fit, the fuel economy target is 61.1 mpg by 2025; for a mid-size car such as a Ford Fusion the target is
54.9 mpg, and for a fullsize car such as a Chrysler 300 the target is 48 mpg (NHTSA 2012). To the extent that
Atlanta can adopt efficient vehicles more quickly or at a higher level than required, Atlanta’s emissions – and
fuel costs – will be lower.
• Electric vehicles: Although electric vehicles do not have tail-pipe emissions, they do use electricity; their
greenhouse gas emissions will depend on the greenhouse gas emissions of the electricity system. The
greenhouse gas emissions reduction from electric vehicles depends on many factors: under some scenarios the
emissions reduction could be small, depending on the relative utilization of coal; alternatively emissions
reductions could be more than 50% with greater use of renewables or nuclear power; the greenhouse gas
emissions depends not only on the electricity system itself, but also on the time of day that the vehicles are
charged; at night more coal and nuclear are available whereas during the day more natural gas would be used
for charging (Choi et al. 2012). For the purpose of this study we estimate a 50% reduction in greenhouse gas
emissions for electric vehicles compared to conventional vehicles. The US EPA projects that nationally, electric
vehicle sales will reach 10% market share by 2025. If Atlanta chooses to promote electric vehicles, Atlanta
might achieve an electric vehicle market share of 15% or greater. With 50% lower greenhouse gas emissions
per mile, this would correspond to a 7.5% lower greenhouse gas emissions from transportation. In addition to
passenger vehicles, medium duty delivery trucks are also well suited for electric technology (Lee et al. 2012).
• Biofuels: The state of Georgia, and the southeast in general, have substantial potential for production of
biofuels. These fuels generally include ethanol, which can be blended with gasoline or used directly in some
vehicles, and bio-diesel, which can be used in trucks and diesel cars. There are also other biofuels which may
be produced in greater quantities in the “next generation” of biofuels, including bio-butanol, which can be
blended more easily with gasoline, and diesel and jet fuel produced from cellulosic biomass. Recent
investments include LanzaTech’s purchase of Range Fuels’ Soperton facility, as well as BASF’s recent $30M
investment in Kennesaw-based Renmatix. LanzaTech’s pilot plant is for a hybrid gasification fermentation
50 technology, using industrial, forest and agricultural residues to make ethanol. Renmatix has a demonstration
plant in south Georgia which is making renewable sugars from woody biomass, with a current estimated
capacity of 1 million gallons per year. In Alabama, Coskata is developing a first commercial scale facility
which will use a hybrid gasification fermentation technology to convert forest biomass into ethanol. In
Tennessee, Dupont has an enzymatic hydrolysis plant that uses cellulosic biomass to produce ethanol, with a
current capacity of less than 1 million gallons per year. In Mississippi, Kior is developing a first commercial
scale plant for the pyrolysis of wood chips into drop-in refinery intermediates.
Up to levels of 10 to 15%, ethanol can be mixed with gasoline and dispensed with gasoline. In addition,
many US vehicles have flex-fuel capability, and can use ethanol at much higher concentrations. In Atlanta,
ethanol (E85, meaning 85% ethanol) is available at the following locations:
Table 4.1. Gas stations in Atlanta selling E85 ethanol to the public (US DOE 2010).
Chevron – GasXpress 548 Northside Dr
AM/PM BP 2193 Peachtree Rd NW
Chevron Food Mart 639 Morosgo Dr, Buckhead
GasXpress Exxon 202 Candler Rd
Chevron 2755 Clairmont Rd
Texaco Food Mart 4495 S Cobb Dr., Smyrna
As mentioned in the inventory chapter, while the Atlanta Hartsfield Jackson International Airport
(AHJIA) is not included in our main assessment of greenhouse gas emissions from Atlanta, there is a substantial
potential to substitute petroleum jet fuel with biomass-derived jet fuel (ATAG 2011). As the world’s busiest
airport by passenger volume, AHJIA could lead in the adoption of biofuel; other US airports are developing
biofuel programs. Moreover, as thermochemical approaches for making biofuel generally produce both jet fuel
(kerosene) and diesel fuel, substantial adoption of biofuel at AHJIA could provide biodiesel for Atlanta’s large
freight transport system.
4.4 Reduce Vehicle Miles Traveled
A number of studies have considered approaches to reducing commuting time and congestion in Atlanta. The
Connect Atlanta Plan (2011), Atlanta’s comprehensive transportation plan, recommends use of transit, walking,
bicycles, and congestion reduction, all of which can contribute to greenhouse gas emissions reductions. In
general, approaches to reducing the amount of driving include:
• measures to decrease the attractiveness of driving;
51 • measures to increase the availability and attractiveness of alternatives;
• measures to decrease the length or amount of transportation needed, including carpooling, high-
occupancy vehicle lanes, focusing development at activity locations (e.g. housing near jobs, or jobs near
housing), and teleworking,
These three types of measures are discussed below.
• Measures to decrease the attractiveness of driving: In principle, these could include higher fuel taxes, tolls,
congestion pricing, higher parking cost and reduced parking availability. Transportation fuel taxes are under the
control of the State of Georgia, and thus are not under City of Atlanta control. Toll roads, with Georgia 400 as
an example, work best on limited access roads, which in Atlanta are under the control of the Georgia
Department of Transportation.
Congestion or emissions pricing: Congestion pricing is an approach to reducing traffic. In this type of
system, roadway users that wish to enter the city of Atlanta would pay a congestion-charge, or toll. Given
Atlanta’s complex of roadways, such a system might be implemented with a transponder, such as the Easy-Pass
system. Pricing has been implemented in London, and resulted in 15% reduction in traffic and emissions
(Litman 2006). The Connect Atlanta Plan recommends that this type of system be considered after
transportation alternatives are more fully developed.
Parking: Parking has been identified as perhaps the single most important development issue influencing
transit ridership. According to the Connect Atlanta Plan, parking in Atlanta is among the cheapest of any urban
area in its class (Connect Atlanta 2011). Charging parking fees has been found to reduce employee vehicle trips,
and consequentially parking demand, by between seven and 30 percent, depending on price and availability of
alternatives (US EPA 2007). The Connect Atlanta Plan recommends that the City modify its parking
regulations to shift away from parking minimums and establish parking maximums in areas served by premium
transit. The Plan also recommends that the City consider policies such as decoupling parking from residential
development, allowing those who choose not to drive to avoid the cost of a mandatory parking space (Connect
Atlanta 2011).
The City of Atlanta has already developed a strategic parking management plan for the downtown
district. Key goals include reducing parking demand and improving the efficiency of the existing supply,
integrating parking management that supports greater use of transit, vanpools, carpools, flexible work
schedules, accessing improvements for bicyclists and pedestrians, and supporting a balanced, linked and
sustainable multimodal transportation system characterized by transit use and vibrant neighborhood businesses
and residential areas (City of Atlanta 2007).
Taxes on parking spaces is another approach to reducing parking demand. How parking is taxed
influences its effect. Per-space parking levies are a type of property tax on parking facilities; they are credited
52 with distributing costs broadly and encouraging parking facility owners to manage parking supply efficiently;
per-space parking levies are associated with reducing sprawl. In contrast, commercial parking taxes are a
special tax only on commercial parking spaces; they have been found to discourage the pricing of parking; that
is, owners of parking lots may simply make parking free to avoid the tax, and thus this type of tax may not be
effective in reducing traffic congestion or vehicle miles traveled (Litman 2011).
• Measures to increase the availability and attractiveness of alternatives: These include increasing transit options
(bus, light rail, subway) and increasing their convenience and attractiveness, increasing opportunities for and
attractiveness of biking (bike lanes, bike-share programs), increasing the opportunities for and attractiveness of
walking (sidewalks), and co-location of development with transit opportunities: These types of measures are
explained in detail in the Connect Atlanta Plan (2011).
• Bicycling. A broad range of measures can support biking in Atlanta. These include bike lane and bike
ramp projects, installation of bike racks, and more (Atlanta Bicycle Coalition 2012).
• Scooter and Motorcycle Parking. Another near-term, low cost way to decrease the energy intensity of
miles driven and the footprint required for parking within city limits is to increase the quantity and visibility of
scooter and motorcycle parking spots. Atlanta’s climate allows for year round two-wheeled travel. Scooters
and motorcycles require a smaller footprint for parking, require less fuel, and result in less damage to roads.
Motorcycles use approximately 43 to 56 miles per gallon and scooters achieve up to 100 miles per gallon (BTS
2012; Welsh 2008).
A number of cities have implemented scooter incentives; as these have not been widely discussed in
Atlanta they are reviewed here. Boston has divided six standard car spots to create 39 scooter or motorcycle
spots, with a meter rate of $0.25 per hour with no time limit. This is intended to give scooter and motorcycle
drivers opportunities similar to motor vehicle drivers and keeping them from parking illegally. The move also
supports Boston’s Green Initiatives program. Spots are labeled with green signs (City of Boston, 2009).
Cincinnati has implemented a Two-Wheeler Parking Program including a list and map of scooter and
motorcycle parking spots in their urban core. They note that two-wheeled vehicles cause less damage to
roads.14 Philadelphia lists the location of motorcycle and scooter metered spots on their website. The meter fee
is one-half the prevailing rate on the block. Prohibition of parking on sidewalks in such zones is strictly
enforced.15 Seattle allows multiple motorcycles and scooters to occupy single parking spots and has designate
100 parking spaces around the city for the exclusive use by motorcycles and scooter. They provide a Google
map of on-street parking locations.16 Columbus, Ohio allows multiple two-wheeled vehicles per metered spot.
Their Motorcycle, Moped and Motor Scooter Parking and Permits Program requires the purchase of a $50 14 http://www.cincinnati-‐oh.gov/twowheeler/ 15 http://philapark.org/motorcycles-‐scooters/ 16 http://www.seattle.gov/transportation/parking/motorcycleparking.htm
53 annual permit that allows two-wheeled drivers to park at any of the program’s designated locations. They
provide a map showing the locations available for parking (City of Columbus 2012). The New York
Motorcycle and Scooter Task Force aims to interact with agencies and lawmakers to promote laws, regulations,
and policies that improve the quality of life for all motorcycle and scooter riders and defend against actions
adverse to the motorized two-wheeled community. They claim 7 motorcycles can fit in the space allowed for a
single automobile and suggest barricading separate parking areas to avoid “touch parking” by automobile
drivers that would knock over motorcycles. Among their initiatives include supporting legislation to require the
DOT to develop a plan for motorcycle parking at muni-meters, where receipts must be displayed that can easily
be removed from a motorcycle.17
4.5. The Role of Population Density
With an area of 132 square miles and a 2010 population of 420,000, Atlanta has an average density of nearly five people per acre, or 3200 people per square mile. This density, while larger than the overall regional average of less than one person per acre, is low compared to other urban municipalities. Increasing density could afford Atlanta numerous opportunities that could benefit the city over the long term. Density may be one of the most critical components to having a successful and highly utilized transit system. An increase in density could increase transit utilization around current MARTA lines, both bus and train, and also could make the extension of older lines and construction of new lines more cost effective. A recent National Research Council literature review of the effect of urban form on transportation demand indicates that increase in density, or increases in land use diversity and improvements in urban design (e.g. locating housing and employment and other services together) on their own can have a modest effect on transportation demand; with an elasticity of about 7% the projected 37% increase in Atlanta’s population by 2030 could reduce projected transportation demand by about 2.6% (NRC 2009). However, by combining increased density, land use diversity and urban design with improved access to transit, the effects can rise to greater than 20% (Mashayekh et al. 2012; NRC 2009). This suggests that with a 37% population increase by 2030, in conjunction with improved transit access and mixed use development, Atlanta might be able to achieve about 7.4% reduction in expected transportation demand.
4.6 Policy Options
The types of policy options that can reduce greenhouse gas emissions from transportation include the following:
Decrease attractiveness of driving:
• Increase the cost of parking.
• Develop options for congestion pricing, access pricing, or tolls.
Decrease the length of trips required:
• Support development near transit stations
• Support commute alternatives (www.cleanaircampaign.org). 17 http://nymstf.org/Parking.htm
54 Increase attractiveness of alternatives:
• Plan development to promote transit use, biking and walking.
• Support carpooling, vanpooling, teleworking, and other programs to reduce transport demand.
• Increase use, availability, and attractiveness of public transportation.
• Support bicycle and pedestrian projects (improve sidewalks, crosswalks, bicycle lanes, and lighting) in
areas that will reduce number of vehicle trips. The City of Atlanta supported the ViaCycle program at Georgia
Tech, the first bike-sharing program in the southeast (https://gt.viacycle.com/).
Decrease emissions per mile traveled:
• Support electric vehicle infrastructure development and reduction of emissions from electricity;
• Support biofuel development, including fuel for light duty vehicles, trucks, and aircraft.
Develop relevant transportation measures and report trends regularly.
References
Air Transport Action Group (ATAG), 2011. Powering the Future of Flight: The Six Easy Steps to Growing a Viable Aviation Biofuels Industry. Atlanta Bicycle Coalition, 2012. http://www.atlantabike.org Atlanta Regional Commission, 2010. Taking the Temperature: Transportation Impacts on Greenhouse Gas Emissions in the Atlanta Region. Elaine Olivares, March. http://www.atlantaregional.com/File%20Library/Environment/Air/Climate%20change%20white%20paper%20-%20FINAL.pdf Batra, A., Carpenter, L., Estrada, E., Smith D., and Zurawski, J. (2010). Sustaining the City of Atlanta’s Division of Sustainability: Analysis of Potential Models of Revenue Generation. Emory Goizeta Business School, BUS532, Porf. Bradley Killaly. Brown, J. R. and G. L. Thompson (2008). The Relationship between Transit Ridership and Urban Decentralisation: Insights from Atlanta. Urban Studies 45 (5/6): 1119-1139. Bureau of Transportation Statistics (BTS), 2012. National Transportation Statistics, Table 4-11. Research and Innovative Technology Administration (RITA). http://www.bts.gov/publications/national_transportation_statistics/html/table_04_11.html Bomford, M. (2010). A Range of ‘Business As Usual’ Projections for KY Vehicle Miles Traveled to 2030. Transportation and Land Use Technical Work Group, Kentucky Climate Action Council, Frankfort, KY. Borin, S., Thomas, V. M., 2012. Atlanta Greenhouse Gas Emissions Inventory. Georgia Institute of Technology. Brownstone, D. and T. F. Golob (2009). "The impact of residential density on vehicle usage and energy consumption." Journal of Urban Economics 65(1): 91-98.
55 City of Atlanta, Downtown Transportation Management Association. Downtown Parking Demand Management Action Plan. Feb 2007. City of Boston, 2009. Scoot and Motorcycle Parking. http://www.cityofboston.gov/parking/scooterandmotorcycle.asp City of Columbus, 2012. Scooter Moped Motorcycle Parking Permits. Department of Public Service. http://publicservice.columbus.gov/content.aspx?id=30827. Choi, D. G. Kreikebaum, F., Thomas, V. M, and Divan, D., 2012. Integration of EVs and Wind Power. Manuscript in preparation. Connect Atlanta Plan, 2011. http://web.atlantaga.gov/connectatlanta/connectatl09/Chapter_6.pdf EPA 2010, Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards for Model Years 2017-2025, Interim Joint Technical Assessment Report, Federal Register, 2011, 2017–2025 Model Year Light-DutyVehicle GHG Emissions and CAFE Standards: Supplemental Notice of Intent, Federal Register / Vol. 76, No. 153 / Tuesday, August 9, 2011, pp. 48758-48769 Energy Independence and Security Act, 2007. Energy Inforamtion Administraion, 2010. Georgia Carbon Dioxide Emissions from Fossil Fuel Consumption (1980 to 2007). US Department of Energy. EPA 2010, Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards for Model Years 2017-2025, Interim Joint Technical Assessment Report, Federal Register, 2011, 2017–2025 Model Year Light-DutyVehicle GHG Emissions and CAFE Standards: Supplemental Notice ofIntent, Federal Register / Vol. 76, No. 153 / Tuesday, August 9, 2011, pp. 48758-48769. Johnston, R. A., S. Gao, et al. (2005). Modeling Long-Range Transportation and Land Use Scenarios for the Sacramento Region, Using Citizen-Generated Policies. Davis, CA, University of California-Davis. Olivares, E. (2010). Taking the Temperature: Transportation Impacts on Greenhouse Gas Emissions in the Atlanta Region. Atlanta, GA, Atlanta Regional Commission. http://www.atlantaregional.com/File%20Library/Environment/Air/Climate%20change%20white%20paper%20-%20FINAL.pdf Lee, D. Y., Thomas, V. M., and Brown, M., 2012. Electric Urban Delivery Trucks: Lifecycle Assessment and Cost-Effectiveness. In preparation for submission to Environmental Science and Technology. Litman, T. (2006). London Congestion Pricing: Implications for Other Cities. London, UK, Victoria Transport Policy Institute. Litman, T. (2011) Parking Taxes: Evaluating Options and Impacts. Victoria Transport Policy Institute. http://www.vtpi.org/parking_tax.pdf MARTA (2009). BeltLine Corridor Environmental Study. Environmental Effects Report Public Hearing. Atlanta. Mashayekh, Y., Jaramillo, P., Samaras, C., Hendrickson, C. T., Blackhurst, M., MacLean, H. L., Matthews, H. S. Potentials for Sustainable Transportation in Cities to Alleviate Climate Change Impacts. Envir. Sci. Technol.
56 46(5): 2529-2537, 2012. National Highway Transportation Safety Administration (NHTSA), 2012. NHTSA and EPA Propose to Extend the National Program to Improve Fuel Economy and Greenhouse Gases for Passenger Cars and Light Trucks. http://www.nhtsa.gov/fuel-economy National Research Council (NRC), 2009. Special Report 298 – Driving and the Built Environment: The Effects of Compact Development on Motorized Travel, Energy Use, and CO2 Emissions. Transportation Research. Plug-in Georgia, 2011. Plug-in Georgia Charter, October 17 2011, http://www.plugingeorgia.com/pdf/plug-in_georgia_charter.pdf Ross, C., M. Meyer, et al. (2005). The Atlanta BeltLine: Transit Feasibility White Paper. Atlanta, Atlanta Development Authority. Studio, R. L. U. (2002). Alternative Land Use Futures - Metropolitan Atlanta 2025. Atlanta, Georgia Institute of Technology The White House, 2011, http://www.whitehouse.gov/the-press-office/2011/07/29/president-obama-announces-historic-545-mpg-fuel-efficiency-standard U.S. Environmental Protection Agency (EPA), 2006. Parking Spaces/Community Places: Finding the Balance through Smart Growth Solutions. January. U.S. Department of Energy (DOE) 2010. EPA Finalizes Regulations for the National Renewable Fuel Standard Program for 2010 and Beyond. http://www.epa.gov/oms/renewablefuels/420f10007.htm#7 US Department of Energy (DOE), 2010. Alternative Fuels and Advanced Vehicles Data Center. http://www.afdc.energy.gov/afdc/locator/stations/ U.S. Environmental Protection Agency (EPA), 2008. Reducing Urban Heat Islands: Compendium of Strategies. http://www.epa.gov/hiri/resources/compendium.htm Welsh, J. Born to be … Fuel Efficient. Wall Street Journal. May 21, 2008. http://online.wsj.com/article/SB121131620487908103.html Williams, J. H., DeBenedictis, A., Ghandadan, R., Mahone, A., Moore, J., Morrow, W. R., Price, S., and Torn, M. S. The Technology Path to Deep Greenhouse Gas Emissions Cuts by 2050: The Pivotal Role of Electricity. Science 335: 53-59.
57 5. Preparing for the Future: Adaptation and Resilience in Atlanta
Whereas climate mitigation primarily involves reducing our greenhouse gas emissions to reduce the risks associated with climate change, climate adaptation addresses how we can plan to cope with changes to our environment that may have already occurred, or are expected based on current trends. At its core, planning for climate adaptation asks the questions: -how is our climate changing? -how will those changes impact our way of life or the way things currently operate? -what can we do to best prepare ourselves, our plans, and our infrastructure to cope with those changes? A comprehensive planning effort to address risks, opportunities, vulnerabilities and resilience measures could enable the city to thrive in a changing climate (Stone et al. 2012). Planning for climate adaptation can take many forms and be addressed at multiple scales. One of the better known examples is of the Cape Hatteras Lighthouse in North Carolina that was moved inland a half mile because of existing and projected rises in sea level. In Atlanta, adaptation to climate change may include many options such as the promotion of rain barrel programs and green infrastructure to manage stormwater, high performance roofs, hardscape and vegetation requirements to reduce heat island effects, community engagement to help citizens take action and also support vulnerable populations. Also it is conceivable that Atlanta may be a “destination refuge” during catastrophic coastal flooding, as happened after Hurricane Katrina. In addition to its effect on transportation choices, the black asphalt of parking lots and other dark surfaces contributes to the urban heat island effect, increasing temperatures in Atlanta above those in nearby rural areas (Figure 5.1). By increasing the shading of parking lots, or providing reflective coatings, the heating effect of the parking lots could be reduced (Ben-Joseph 2012; Summers 2012; Stone et al. 2010). Overall the urban heat island effect makes Atlanta several degrees hotter than surrounding rural areas. Opportunities to reduce the urban heat island effect include tree planting, cool roofs, and other actions (US EPA 2008). A study from the Lawrence Berkeley National Laboratory projected that urban temperatures in Los Angeles could be reduced by approximately 3 °C (5 °F) after planting ten million trees, reroofing five million homes, and painting one-quarter of the roads at an estimated cost of US$1 billion, giving estimated annual benefits of US$170 million from reduced air-conditioning costs and US$360 million in smog related health savings (Rosenfeld et al. 1997). The scale of investment in Atlanta for a comparable program would be less than 10% of this amount; overall, however this analysis suggests a pay-back period of 6 years from energy savings alone, with additional greater savings from the health benefits of air quality improvements.
58
Figure 5.1. Urban heat island
Reflective Roofs: In 2011 the state of Georgia adopted one of the strongest building energy codes in the nation. Georgia’s building energy code meets and exceeds the current international standard, the 2009 International Energy Conservation Code, IECC 2009. The strength of Georgia’s current energy codes put Georgia in a strong position to be able to take a leadership role in adopting additional new code components. Georgia has long had a leading code on cool roofs, putting Atlanta and all of Georgia in a strong position to adopt an improved roof code. Reflective roofing has the advantage of both reducing the urban heat island effect outdoors, and reducing air conditioning requirements indoors, particularly for low-rise buildings. In addition to the new IECC 2012 code, discussed in chapter 3, there is a new code for commercial buildings, EC 147, which includes a requirement for high performance cool roofs in the southern part of the US. These high performance reflective roofs can reduce building cooling, particularly for low-rise buildings, and also reduce the urban heat island effect (US DOE 2012).
Figure 5.1. A 2003 aerial photograph of midtown Atlanta showing the 5th street bridge crossing I-85. Both white
roofs and black roofs can be seen, as well as one roof with vegetation and some trees in the parking lots.
59 As can be seen in Figure 5.1, reflective white roofs are already being adopted in Atlanta. As detailed in Chapter 3, installation of a reflective roof on a building that does not need a new roof is expensive. However, installation of a reflective roof as part of the re-roofing process, and on new buildings, is a cost effective measure that reduces urban heat island effect, and reduces the cooling requirements of the building. Figure 5.2 shows a flat reflective white roof, and a pitched reflective white roof, which are reported to provide about 15% and 10% reduction in air conditioner energy use, respectively (Rosenfeld 2011).
Figure 5.2 Flat reflective white roof and pitched reflective white roof
Not all reflective roofs are white. About half of the energy from the sun is in the infrared wavelengths, beyond the visible range. So-called “cool colored” roofs reflect more of this infrared energy than do standard-colored roofs. Figure 5.3 shows a pitched “cool colored” roof, reported to reduce air conditioner energy requirements by about 5%
Figure 5.3. Pitched “cool colored” roof.
Trees and Vegetation Trees and vegetation lower surface temperatures both through the shade they provide and through evapotranspiration (US EPA 2013). Also, trees and vegetation that shade buildings save energy, by directly reducing the requirements for air conditioning. Atlanta is already known for its abundance of tress. Recently,
60 the City of Atlanta has set a goal of providing 10 acres of greenspace per 1000 residents, and restoring the city’s tree canopy to 40 percent coverage (Atlanta Better Buildings Challenge 2013). Atlanta has a strong tree protection ordinance and the commitment to increase tree cover has the potential to contribute significantly to moderating temperatures in Atlanta, reducing storm water run off, reducing cooling loads, and beautifying the city. Cool Pavements Pavements that can reduce the urban heat island effect include those with high reflectance and those that are permeable. Options include concrete, which initially has a high solar reflectance, and microsurfacing, which is a thin sealing layer used for maintenance but which also has high solar reflectance. Conventional asphalt pavement can be modified with reflective materials. Other reflective pavements are used mainly in low traffic areas such as sidewalks and parking lots, include tree resins and colored asphalts (US EPA 2012). Non-vegetated permeable pavements have voids that allow for water drainage. In addition to improving temperature control, these pavements have substantial benefits in reducing storm water run-off. Vegetated permeable pavements provide a structure through which grass or other vegetation can grow (US EPA 2012). Examples include the City of Atlanta parking lot on the corner of Pryor Street and Memorial Drive, and the parking lot of the East Atlanta Library at 400 Flat Shoals Avenue. Green Roofs Vegetated roofs, or green roofs, increase the reflectance of the roof, provide outdoor cooling by increasing evapotranspiration, and by acting as insulators reduce both the heating and the cooling requirements of the building (US EPA 2012). There are numerous green roofs in Atlanta, including the Atlanta City Hall, the Woodruff Arts Center, the Georgia Tech Clough Undergraduate Learning Center, the Perkins+Will building, Implementation of any of these strategies will provide benefits at the building site. However, to achieve reductions in outdoor air temperatures, neighborhood and community scale implementation is needed. Adoption of strategies to increase tree cover, to adopt cool or green roofs, and to increase the reflectance or permeability of pavement for roads, parking lots, and sidewalks can have benefits for both outdoor temperatures, energy use, greenhouse gas emissions, stormwater management, and water quality. Implementation of these measures through code changes and ordinances could provide for gradual improvements at low cost, directly improving the resilience of Atlanta to summer-time heat and reducing the stress on its water resources. References Atlanta Better Buildings Challenge, 2013. City of Atlanta. http://www.atlantabbc.com/city-of-atlanta Ben-Joseph, Eran, 2012. ReThinking a Lot: The Design and Culture of Parking. MIT Press. http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=12874 Levinson, R. 2009. Cool Roof Q&A. Lawrence Berkeley National Laboratory. http://www1.eere.energy.gov/femp/pdfs/coolroof_qa.pdf Morsch, A. 2010. A Climate Change Vulnerability and Risk Assessment for the City of Atlanta, Georgia. Masters Thesis, Nicholas Institute for Environmental Policy Decisions, Duke University. http://dukespace.lib.duke.edu/dspace/handle/10161/2157 Rosenfeld, A., J. Romm; H. Akbari; A. Lloyd, 1997. Painting the Town White - and Green". http://web.archive.org/web/20070714173907/http://eetd.lbl.gov/HeatIsland/PUBS/PAINTING/
61 Rosenfeld, A. 2011. Ten Years at the Calif. Energy Commission & White Roofs to Cool your Building, your City and Cool the World. HaasExecEduc 4-6-11. Powerpoint presentation. www.ArtRosenfeld.org Stone, B., Hess, and Frumkin. 2010. Urban Form and Extreme Heat Events: Are Sprawling Cities More Vulnerable to Climate Change Than Compact Cities? Envir. Health Perspectives 118(10): 1425–1428. Stone, B. Vargo, J., Habeeb, D. 2012. Managing Climate Change in Cities: Will Climate Action Plans Work? Landscape and Urban Planning 107 (3): 263-271. Summers, C., 2012. Is there a worldwide parking problem? BBC News, April 30. http://www.bbc.co.uk/news/magazine-17271118. US DOE, 2012. 30/30 Vision – Goal in Site. Building Energy Codes Program. http://www.energycodes.gov/status/30-30vision.stm US EPA, 2012. Reducing Urban Heat Islands: A Compendium of Strategies. www.epa.gov/heatisld/mitigation US EPA 2013. Heat Island Effect. Trees and Vegetation. http://www.epa.gov/heatisld/mitigation/trees.htm
62
6. Goals for Greenhouse Gas Emissions Reductions Climate change is a global effect; emissions contribute to the overall global atmosphere. Because carbon dioxide stays in the atmosphere for a long time, the only way to reduce the atmospheric levels is through substantial reductions in the annual emissions. Globally, economic growth is pushing emissions up. In 2008 President-elect Obama pledged to cut US greenhouse gas emissions by 80% below 1990 emissions by 2050. In 2008 the UK government also pledged to reduce greenhouse gas emissions by 80% by 2050, in 2012 Japan also adopted the goal of 80% reductions by 2050. A number of cities have established greenhouse gas emission reduction goals. New York’s PlaNYC set an ambitious target of reducing the City government's GHG emissions by 30% below 2006 levels by 2017. In contrast, Chicago proposes a 25% reduction below 1990 levels in 2020 for new and significantly renovated buildings; this is a modest proposal as it only addressed new and significantly renovated buildings. The Mayor’s Climate Commitment, signed by Mayor Franklin, commits Atlanta to strive to achieve a 7% reduction from 1990 levels by 2012, the same target sought by the Kyoto Protocol. These goals are independent of population growth or economic development. Virtually all governments expect their populations and economies to grow; meeting greenhouse gas reduction goals will require even steeper reductions in per-person and per GDP emissions. Note that most of these goals are from the 1990 baseline. Atlanta’s first greenhouse gas emissions inventory was for the year 2010, so that is the most convenient baseline for emission reduction goals. Below we consider the potential for Atlanta to reduce greenhouse gas reductions by 2020 and 2030. Table 5.1 shows one scenario for future energy use and greenhouse gas emission reduction in Atlanta. It is not the only possible scenario; future energy use could be higher or lower and greenhouse gas emission reductions in different categories could be higher or lower; the specific values chosen are discussed below. The 2010 baseline column shows the greenhouse gas emissions in Atlanta as of 2010. The “Actions” column shows the types of actions that can reduce greenhouse gas emissions, in broad categories that could encompass a number of specific policies or activities. The 2020 and 2030 baseline emissions are based on a projected energy consumption growth of 37% in all categories by 2030. A 37% increase by 2030 mirrors projected population growth in the state of Georgia and in the Atlanta region. The per-person use of residential energy and use of gasoline has been fairly constant over the past decade in the Atlanta region and nationally; overall we consider this to be a reasonable baseline expectation of growth in energy use in Atlanta in the absence of actions that limit greenhouse gas emissions. However, Atlanta’s greenhouse gas emissions are driven by energy use in buildings. Since Atlanta may have larger-than-typical spare housing and spare commercial space that is nevertheless being heated and cooled while under-utilized, a 37% increase in population and an associated increase in commercial activity may not be accompanied by a 37% increase in residential and commercial floor space. That is, our baseline assumption of 37% growth in energy use by 2030 may be on the high side. In Table 5.2, we show how the greenhouse gas reduction goals could be met in a lower energy growth scenario, of 20% increase by 2030. Commercial Buildings Lower Carbon Electricity: The reductions shown here reflect completion of the new nuclear power plants at Vogtle, and calculation of the least cost electricity production for Georgia Power, showing some shift from coal to natural gas due to low natural gas prices (Choi and Thomas 2012). The reductions shown here do not include any changes in electricity generation for the purpose of reducing greenhouse gas emissions; it is only the
63 projected least-cost generation profile, which happens to show reductions over time. In Tables 5.1 and 5.2 these reductions are shown for all electricity-using sectors – commercial buildings, residential buildings, and industry. Table 5.1. Scenario for reducing greenhouse gas emissions in Atlanta under an expected growth scenario. Numbers are shown in both million tons of CO2-equivalent (M tons) and as percentage reductions.
Emission Categories Actions
2010 2020 2030
Base M tons
Base M
tons Reduction
% Reduction
M tons Base M tons
Reduction %
Reduction M tons
Buildings Commercial
5.19 6.15
7.11
Lower Carbon Electricity
18% -1.04
20% -1.42 More renewables
1% -0.06
5% -0.36
Enforce Building Energy Code
2% -0.10
3% -0.16 Commercial Energy Efficiency
20% -0.81
30% -1.60
Residential
2.35 2.79
3.22
Lower Carbon Electricity
18% -0.42
20% -0.64
More renewables
1% -0.02
5% -0.16 Enforce Building Energy Code
2% -0.053
3% -0.093
Residential Energy Efficiency 10% -0.23 30% -0.73 Transport 2.40 2.84 3.29 More Efficient Vehicles
16.5% -0.47
34% -1.12
Biofuels
5% -0.12
10% -0.22 Reduce VMT/Person/Day
15% -0.36
25% -0.49
Industrial Facilities 0.68 0.80 0.92 Lower Carbon Electricity
18% -0.14
30% -0.28
More renewables
1% -0.01
5% -0.05 Industrial Energy Efficiency 10% -0.06 20% -0.12 Refrigerants
0.21 0.25
0.29
Refrigerant management 10% -0.02
30% -0.09 Landfills 0.03 0.04 0.04 Fertilizer 0.01 0.01 0.01
Total 10.87 12.88 8.96 14.89 7.38
Goals
8.15
6.52
% Reduction 17.6% 32.1%
More Renewables: Atlanta could produce or use more renewable electricity than is already in the Georgia Power generation mix, through use of solar photovoltaics and solar hot water heaters, through buying blocks of additional renewables that are available through Georgia Power, through development of additional landfill gas sites, and through greater use of biomass energy. In addition, Georgia Power could potentially develop a renewables expansion program, or the state of Georgia could pass a Renewable Electricity Standard requiring some fraction of the electricity to be produced from renewable sources, as has been done in a number of other states. We have calculated that Georgia can produce 20% or more of its electricity from renewables, primarily from biomass, at low incremental cost (Levin, Thomas, and Lee 2010), not even taking into account the potential for lower prices for renewables in the future. In Tables 5.1 and 5.2 we posit additional renewable
64 energy production of 1% by 2020 and 5% by 2030. In Tables 5.1 and 5.2 these reductions are shown for all electricity-using sectors – commercial buildings, residential buildings, and industry. Table 5.2. Scenario for reducing greenhouse gas emissions in Atlanta under a slow growth scenario Numbers are shown in both million tons of CO2-equivalent (M tons) and as percentage reductions.
Emission Categories Actions
2010 2020 2030 Base M tons
Base M tons
Reduction %
Reduction M tons
Base M tons
Reduction %
Reduction M tons
Buildings Commercial
5.19 5.71
6.23
Lower Carbon Electricity
18% -0.97 20% -1.17 More renewables
1% -0.06 5% -0.31
Enforce Building Energy Code
2% -0.094 3% -0.142 Commercial Energy Efficiency
20% -0.66 20% -0.95
Residential
2.35 2.59
2.82
Lower Carbon Electricity
18% 0.39 20% -0.47
More renewables
1% -0.03 5% -0.14 Enforce Building Energy Code
2% -0.050 3% -0.066
Residential Energy Efficiency 10% -0.29 20% -0.44 Transport 2.40 2.64 2.88 More Efficient Vehicles
16.5% -0.44 34% -0.98
Biofuels
5% -0.11 10% -0.19 Reduce VMT/Person/Day
10% -0.22 20% -0.38
Industrial Facilities 0.68 0.74 0.81 Lower Carbon Electricity
18% -0.13
20% -0.16
More renewables
1% -0.01
5% -0.04 Industrial Energy Efficiency
10% -0.06
20% -0.12
Refrigerants 0.21 0.25 0.29 Refrigerant management 10% -0.02 20% -0.06 Landfills 0.03 0.04 0.04 Fertilizer 0.01 0.01 0.01
Total 10.87 11.98 9.22 13.09 7.46
Goals
8.15
6.52
% Reduction 15.2% 31.4%
Enforce Building Energy Code. The State of Georgia adopted a new energy code in 2011, that conforms with and exceeds the international 2009 International Energy Conservation Code (IECC) standard. An assessment by Southface and Sustainable Atlanta (Burk et al. 2012) indicates that about 80% of commercial builders and 50% of residential builders are already meeting the code in new buildings as of 2011; that study also estimated energy savings for the next five years from full compliance with the code for new buildings. We use their estimates here, projecting future building construction rates. Commercial Energy Efficiency: The City of Atlanta’s Better Buildings Challenge is challenging building owners to reduce their energy use 20% by 2020; this program is apparently successful and expanding. In Tables 5.1 and 5.2 we posit that by 2020, 80% of commercial buildings in Atlanta could reduce their energy use by 20%. By 2030 we posit significantly higher achievement in energy efficiency, with overall 30% reduction in
65 energy use in commercial buildings. Achieving a 30% reduction in energy use in commercial buildings is feasible and likely to be cost effective; however considerable effort may be needed to achieve broad participation. Policies for energy efficiency in commercial buildings include the Better Buildings Challenge, adoption of a stronger building energy code, and a range of polices and actions discussed in the Buildings chapter. Residential Buildings The actions that can reduce greenhouse gas emissions from residential buildings parallel those for commercial buildings. Building energy code compliance among residential builders is thought to be lower than among commercial builders, so policies to encourage code compliance may be especially appropriate. In addition, however, due to the large stock of existing residential structures, reducing greenhouse gas emissions from residential buildings will require improved energy efficiency in existing residences. In Tables 5.1 and 5.2 we posit a 10% improvement in energy efficiency in residential buildings by 2020. This is not a large reduction, particularly given the apparently high residential energy consumption in Atlanta. However, given the challenges of achieving broad participation in energy efficiency programs quickly, we posit a modest 10% improvement by 2020. For 2030 we posit a 30% efficiency improvement in Atlanta residences. A 30% reduction is technically feasible, particularly given the high current residential energy consumption, and is likely to be cost effective. However, achieving this reduction will require broad participation from the citizens of Atlanta and the owners of residential buildings. Partnership with Georgia Power, AGL and other organizations could help homeowners benefit from energy efficiency programs. Transportation More efficient vehicles. The new proposed federal fuel efficiency standards for cars and light trucks will provide a substantial improvement in energy efficiency; we have projected the implementation of these standards and the gradual adoption of new cars in Atlanta. This is what is shown under “more efficient vehicles”; no action beyond the new federal standards is included. Biofuels. Implementation of the federal renewable fuel standard (RFS2) will introduce substantial amounts of renewable fuel that have lower net emissions of greenhouse gases; these are the reductions included in the biofuel row of Tables 5.1 and 5.2. Reduce VMT (vehicle miles traveled) per person per day. Greenhouse gas emissions can be further reduced by reducing the average vehicle miles traveled per person per day. Here we posit a 10% reduction by 2020 and a 20% reduction by 2030; vehicle miles traveled per person per day in the Atlanta region has already been decreasing; this further decrease would put Atlanta in line with other large cities, and could be encourage through a range of policy measures from those encouraging transit use and ride-sharing to transit-focused development. Industrial Energy Use Although industrial energy use represents a small portion of overall energy use in Atlanta, it is likely that industrial energy efficiency measures can provide cost-effective ways to reduce emissions. We suggest that a 10% reduction by 2020 and a 20% reduction by 2030 is feasible Refrigerants and Other Emissions Sources New refrigerants are being introduced with lower greenhouse gas impacts, and we expect improved refrigerant management measures to somewhat reduce leakage of refrigerants. The other emissions sources listed, nitrogen fertilizers and landfill gas, are assumed to remain constant. Potential to Meet Goals
66 The scenarios shown in Tables 5.1 and 5.2 provide a decrease of more than 15% by 2020 and a decrease of more than 30% by 2030. The reductions shown in the tables illustrate the potential results of a moderate level of action; larger reductions could be achieved. Tables 5.1 and 5.2 are available as a spreadsheet to allow consideration of greater or lesser reductions in any of the categories. To repeat the recommendations of the Executive Summary, we provisionally suggest that the most effective measures for Atlanta can be described as follows:
• Increase the energy efficiency of existing commercial buildings, and all their equipment and appliances. Commercial energy use in Atlanta is high compared with other cities, and there may be numerous opportunities to save money by reducing energy use. Atlanta’s Better Buildings Challenge program is spearheading energy efficiency measures in large commercial buildings; continuation and extension of this program has the potential to provide large energy savings.
• Increase the energy efficiency of existing residential buildings, and all their equipment and appliances. Residential energy use in Atlanta is high compared to other cities. To provide the benefits of reduced energy use across all the residences of Atlanta is likely to require a combination of programs. Georgia Power has a program to help residential customers identify opportunities for energy efficiency, and also provides some rebates for energy efficiency upgrades. Supporting and extending this program, as well as finding additional avenues to residential energy savings, could directly benefit the citizens of Atlanta as well as help Atlanta reduce its greenhouse gas emissions.
• Reduce greenhouse gas emissions from electricity. This can be achieved by Atlanta citizens and businesses by purchasing green power from the electric utility, by developing on-site renewable electricity generation systems, and by developing on-site combined cooling, heat and power systems. Reduced emissions can be achieved by the electric utility by shifting electricity production toward sources with lower greenhouse gas emissions, including natural gas, nuclear, biomass, landfill gas, and solar power.
• Reduce the emissions from driving. Although Atlanta has a great deal of traffic congestion, and driving makes a significant contribution to greenhouse gas emissions, Atlanta’ electricity use is so high that transportation makes a relatively small contribution to greenhouse gas emissions within the city limits. Nevertheless, reducing the emissions from driving can make an important contribution to reducing greenhouse gas emissions in Atlanta, and can also provide air quality benefits, reduce congestion, and can potentially have other benefits as well. Reduced driving emissions can be achieved by Atlanta citizens and businesses by reducing the number of passenger vehicle miles traveled, with a shift toward walking, biking or taking transit instead of driving, and by buying and using vehicles with lower emissions, including highly efficient gasoline-powered vehicles, electric vehicles.
In addition to reducing greenhouse gas emissions, Atlanta can reduce the effect of climate change by increasing tree cover and vegetation and increasing use of reflective roofs and paving. • Increase Atlanta’s tree canopy to 40%. This is already a City of Atlanta goal; the increased tree canopy will have a cooling effect, and shaded buildings will require less air conditioning. • Promote adoption of more reflective roofing or green roofing, through demonstration projects, full implementation of the current building code requirements for reflective roofing, and consider adoption of the more advanced EC 147 reflective roof building code. • Promote adoption of pervious pavement or reflective pavement for roads, sidewalks, parking lots and other paved areas. Tracking Progress Toward Goals Atlanta can better achieve greenhouse gas emissions reductions if it can track its progress. Currently, data that would show Atlanta’s progress are not available to or tracked by the City. To track progress toward goals, the following information would be useful: • Annual data on electricity consumption by ZIP code in Atlanta, by residential, commercial and industrial categories. Georgia Power has provided these data for this study; continued data sharing would allow progress to be tracked.
67 • Annual data on green power purchases and generation by customers within Atlanta, by ZIP code and by commercial, residential, and industrial categories. • Annual data on natural gas consumption by ZIP code in Atlanta, by residential, commercial, and industrial categories, from AGL. AGL has provided these data for this study; continued data sharing would allow progress to be tracked. • Annual estimates of vehicle miles traveled in Atlanta, from the Atlanta Regional Commission. References Burke, D., Arora, S., Bracey, J., Curtis, O., David, C., Lindsley, S., Monroe, M., Roberts, S. Benefits from Effective Energy Code Implementation in the City of Atlanta. Sustainable Atlanta and Southface. February 2012. http://www.sustainableatlanta.org/ and http://www.southface.org/ Choi, D. G., Thomas, V. M., An Electricity Generation Planning Model Incorporating Demand Response, Energy Policy 42: 429-441, 2012. http://dx.doi.org/10.1016/j.enpol.2011.12.008 Levin, T., Thomas, V. M., Lee, A. J. State-Scale Evaluation of Renewable Electricity Options: The Role of Renewable Electricity Credits and Carbon Taxes, Energy Policy 39(2): 950-960, 2011. http://dx.doi.org/10.1016/j.enpol.2010.11.020
