City Council Workshop Agenda Item #1 November 16, 2015 Municipal Services Facility Fuel Source On August 24th staff provided the City Council with an update on the Municipal Services Facility. Part of the update was discussion of the fuel source for the facility. The City’s Climate Action Plan provides guidance that City facilities should move away from #2 heating oil as a heating source. Through the design process a number of fuel sources were looked at for initial and long-term maintenance costs, annual fuel costs and environmental impact. At the workshop, much of the conversation was around the potential incorporation of a biomass plant to heat the facility, with natural gas being a close second alternative. During the August presentation, staff did not have a good sense that Unitil would be able to schedule an extension of their gas main from Evans Street to the new facility on Highland Avenue. Over the last month Unitil has been working closely with the City and new information/willingness has come from Unitil making the potential use of natural gas stronger. In September staff learned estimates for a biomass plant range between 1.4 and 1.6 million. The initial construction budget developed allocated $300,000 for the heating plant for the new facility. Our conversations, over the last month, with Unitil have led to a cost share in the extension of the gas main up Highland Avenue. With the demand that Unitil is experiencing from residents in the Highland Avenue neighborhoods, Unitil is now willing to extend the gas main if the City resurfaces the trench. The City just recently paved a good portion of Highland where the gas line would be installed. The cost estimate for this remediation work is estimated at $35,000. With the recent information from Unitil, a better handle on what a biomass facility would cost, the payback and the cleanliness of gas vs. biomass with regards to air emissions, staff is recommending the use of natural gas for the new facility. SMRT Architects will accompany staff in providing an overview of the facility’s heating system. Attached I have provided documentation on greenhouse gas emissions and air emissions for the two types of heating systems. ___________________________ City Manager

9

ENVIRONMENTAL IMPACTS

Air Emissions

As the number of biomass heating systems in schools and public buildings increase, there is increased concern about the emissions from biomass systems and air quality. The emissions from wood-fired boilers are different from emissions of natural gas, propane or oil boilers. A number of these components are air pollutants and are discussed below. Boiler emissions are typically measured in pounds of pollutant per million British thermal units (a million British thermal units is the amount of heat energy roughly equivalent to that produced by burning 8 gallons of gasoline, or 121 lbs of dry woodchips).

In terms of health impacts from wood combustion, particulate matter (PM) is the air pollutant of greatest concern. Particulates are pieces of solid matter or very fine droplets, ranging in size from visible to invisible.

Relatively small PM, 10 micrometers or less in diameter, is called PM10. Small PM is of greater concern for human health than larger PM, since small particles remain air-born for longer distances and can be inhaled deep within the lungs. Particulate matter exacerbates asthma, lung diseases and increases mortality among sensitive populations.

Increasingly, concern about very fine particulates (2.5 microns and smaller) is receiving more attention by health and environmental officials for the same reasons. Work investigating wood and pellet boiler emissions of very fine particulates is ongoing.

Based on air emissions tests performed on small scale wood-chip fired boilers, typical 2-3 million Btu input units without particulate control systems produce 0.12 – 0.15 lbs/MMBtu/hr of PM10.

Oxides of sulfur (SOx), oxides of nitrogen (NOx), carbon monoxide (CO), and volatile organic compounds (VOCs) are other air pollutants of concern emitted during fuel combustion. Modern wood systems emit more SO2 than natural gas, but have less than 2% the SO2 emissions of fuel oil and about 50% the SO2 emissions of propane. Wood, propane and fuel oil combustion have similar levels of NOx emissions. All fuel combustion processes produce carbon monoxide (CO). The level produced by wood combustion depends very much on how well the system is tuned. Wood combustion produces significantly more CO than oil, natural gas and propane. This, in addition to PM, is a good reason to make sure the facility is fitted with the best available controls and that the stack is tall enough to disperse any remaining emissions away from ground level.

However, CO emissions from burning wood are of relatively minor concern to air quality regulators, except in areas like cities that have high levels of CO in the air from automobile exhaust.

10

Figure 1 This table is from the Resource Systems Group report titled Air Pollution Control Technologies for Small Wood-fired Boilers (2001). VOC, discussed here, are one component of total organic compounds (TOC) shown in the table above.

Volatile organic compounds (VOC) are one component of total organic compounds (TOC) shown in the table above. VOCs are a large family of air pollutants, some of which are produced by fuel combustion. Some are toxic and others are carcinogenic. In addition, VOCs elevate ozone and smog levels in the lower atmosphere, causing respiratory problems. Both wood and oil combustion produce VOCs – wood is higher in some compounds and oil is higher in others. VOC emissions can be minimized with good combustion practices.

Control Devices for PM

As described above, fine particulate matter is the pollutant of greatest concern with regard to wood systems. Even with the greater climate change benefits of wood energy, the PM2.5 issue needs to be considered as the regulatory framework is changing The National Ambient Air Quality Standard for PM2.5 has recently been changed, with the standard becoming tighter. The region of Grafton, New Hampshire is expected to be in compliance with the revised standards based on EPA designations. The AP42 uncontrolled PM emission factor (EPA accepted measurement of emissions) is 0.29 lb/MM Btu for wet wood, which can be reduced to 0.20 lb/ MMBtu by installing mechanical collector. Some uncontrolled small wood-fired boilers of modern design with a gasifier or staged combustion have uncontrolled emission rates of between 0.1 and 0.2 lb/MM Btu. No emissions control device will be required for this project at normal operating conditions. However, because of the variability of fuel and combustion conditions manufacturers will not guarantee these emission rates.

Currently, the four most common air pollution control devices used to reduce PM emissions from wood-fired boilers are mechanical collectors (cyclones and core separators), wet scrubbers, electrostatic precipitators (ESPs), and fabric filters. Such devices can reduce PM emissions by 70 to 99.9%. Core separators and water scrubbers of size suitable for boilers in the size ranges recommended for the Grafton County complex are not commercially available in US.

Multicyclones

Multicyclones or multiple tube cyclones are mechanical separators that use the velocity differential across the cyclone to separate particles. Cyclones are less efficient collectors than multicyclone. A multicyclone uses several smaller diameter cyclones to improve efficiency. Overall efficiency ranges from 65% to 95% but multicyclones, like cyclones, are more efficient in collecting larger particles

11

and their collection efficiency falls off at small particle sizes. The AP42 lists multicyclone controlled emission rates that indicate a control efficiency of 73% for PM10 when the uncontrolled emission rate is 0.71 lb/MMBtu. The resulting multicyclone controlled emission rate is 0.19 lb/MMBtu. When the uncontrolled emission rate is as low as 0.1 to 0.2 lb/MM Btu the overall control efficiency will be lower. Some combustion units could meet an emission level of 0.1 lb/MM Btu with a multicyclone.

Electrostatic Precipitators (ESP)

Electrostatic precipitators (ESPs) are widely used for the control of particulates from a variety of combustion sources including wood combustion. An ESP is a particle control device that employs electric fields to collect particles from the gas stream on to collector plates from where they can be removed. There are a number of different designs that achieve very high overall control efficiencies. Control efficiencies typically average over 98% with control efficiencies almost as high for particle sizes of 1 micrometer or less. Overall ESPs are almost as good as the best fabric filters. For small boilers two designs were considered; a dry electrostatic precipitator and a wet electrostatic precipitator. The systems are basically similar except that wet electrostatic precipitators use water to flush the captured particles from the collectors. The advantage of dry systems is that they may have a lower capital cost and reduced waste disposal problems. Wet systems may be less expensive to operate and are probably slightly more efficient at capturing very small particles that may include toxic metals. Fabric Filters or Baghouses

With the correct design and choice of fabric, particulate control efficiencies of over 99% can be achieved even for very small particles (1 micrometer or less) by fabric filters or baghouses. The lowest emission rate for large wood-fired boilers controlled by fabric filters reported is 0.01 lb/MMBtu. Operating experience with baghouses on larger wood-fired boilers indicates that there is a fire risk, due to caking of the filters with unburned wood dust. It is possible to control or manage this risk by installation of a mechanical collector upstream of the fabric filter to remove large burning particles of fly ash (i. e. "sparklers”). A cyclone-baghouse combination reduces the fire risk.

BERC recommends the installation of a cyclone and baghouse combination. The cyclone is generally included at part of the standard manufacturer supplied equipment. A cyclone and properly sized stack are sufficient to keep air emissions below state permitting thresholds. BERC recommends the additional installation of a baghouse to biomass systems in nursing home and public buildings (like the Grafton county complex) because of the particular vulnerability of senior citizens to health impacts from fine particulates released by wood combustion. The use of these advanced controls also ensures the project is serving as a model demonstration of the best system possible. The cost of both a cyclone and bag house has been included in the economic analysis. BERC is actively engaged in this on-going discussion and will continue to recommend changes in combustion techniques and pollution control options as appropriate based on the state of the scientific information.

SUSTAINABILITY

OFFICE

JULIE A. ROSENBACH

Sustainability Coordinator

MEMORANDUM TO: Rick Towle, Parks, Recreation, & Waterfront Director Jim Gailey, South Portland City Manager

FROM: Julie Rosenbach, Sustainability Coordinator

DATE: October 7, 2015

SUBJECT: Biomass fuel GHG impacts What are the impacts of emissions to the City using the biomass technology? How does this compare with other forms of fuel we discussed at our workshop with the City Council? We recommended a biomass wood chip heating system for the new Municipal Services Facility because it is more sustainable and more in line with our Climate Action Plan than the fossil fuel alternatives.

We recognize that biomass is not a carbon neutral fuel. What is in question is the extent to which these emissions contribute to climate change.

What we do know is that burning fossil fuels unavoidably increases the amount of carbon in the atmosphere resulting in climate change. But this outcome is not inevitable with the burning of biomass. The impact of biomass CO2 emissions on climate change ultimately depends on the efficiency of the heating system, the management of the forests from which the biomass is harvested, and the amount of forest feedstock that grows in place of what was consumed.

Therefore ensuring the sustainability of the biomass feedstock used is key to ensuring the sustainability of the fuel.

Biomass vs. Natural Gas In August we recommended a biomass wood chip heating system for the new Municipal Services Facility because it is more sustainable and more in line with our Climate Action Plan than fossil fuels. Though the economics have changed, the environmental costs and benefits have not. Below is a summary of the environmental issues associated with both biomass and natural gas as the stated alternative. Greenhouse gas emissions Biomass

In recent years scientists have challenged the unqualified categorization of biomass as a carbon neutral fuel. In fact a recent Massachusetts study revealed that certain types of biomass, such as harvesting and burning whole trees to generate electricity, can actually produce more greenhouse gases (GHG) than coal. But biomass represents a broad category of feedstocks used for heat and power generation, some of which are ultimately beneficial to the environment and others that may cause more harm than good.i The impact of biomass GHG emissions ultimately depends on the efficiency of the system, the type of feedstock that is used, and the management of the forests from which the biomass is harvested. Therefore ensuring the sustainability of the biomass feedstock used is key to ensuring the sustainability of the fuel. The authors of the Massachusetts biomass study concluded that there is a beneficial role for biomass under EPA's Clean Power Plan (CCP) if the feedstock used meets strict environmental and emissions accounting criteria, which they call “low-risk.”

Examples of low-risk bioenergy include biomass waste that otherwise ends up in a landfill and decays, forest residues that would otherwise be burned in piles in the field, and byproducts such as sawdust and wood chips from timber processing. All of these “waste and residue” materials are likely to result in instant greenhouse gases emissions therefore using them for energy and offsetting fossil fuels is the smart and low-risk choice. EPA has already indicated these resources are very likely to be approved under state plans for CPP compliance.ii

With a relatively efficient heating system, energy fueled by wood waste and timber harvest residues (tops and branches) has the potential to reduce carbon emissions within a short time.iii AS you will see below in Maine we are well-situated to use these feedstocks.

SUSTAINABILITY

OFFICE

JULIE A. ROSENBACH Sustainability Coordinator

Natural gas

Natural gas is the cleanest burning of all fossil fuels. It emits 30% fewer greenhouse gases than oil when combusted. And graphically, far fewer emissions than biomass. But natural gas is a non-renewable fuel. Supply cannot be replaced for millennia and the carbon dioxide and methane released from burning natural gas unequivocally cause climate change. To note, greenhouse gas emissions calculations only account for combustion of fuels at the plant. Extraction and supply is not factored in. So, simply comparing the GHG emissions numbers is not the full story. Significant leakage problems during extraction and distribution of natural gas through pipelines emit huge quantities of methane, a much more potent GHG, into the atmosphere. By some accounts these leaks could put natural gas on par with coal in terms of carbon intensity.iv Maintenance & Air pollution Biomass

Biomass requires more maintenance than fossil fuel systems. Ash bins must be emptied and the boiler needs to be cleaned regularly. Wood chip systems also require more space to store bulky fuel, and steady use requires a continuous supply of wood chips to be trucked in. In terms of air pollution, the greatest concern of biomass systems is particulate matter (PM). This concern can be mitigated by installing technology controls to capture the fine particles from the stack. Wood chip boilers with this type of advanced emissions controls are relatively non-polluting. They meet EPA standards and produce no visible emissions or odors like woodstoves. Biomass is also non-toxic and biodegradable, and the ash can be spread on lawns, gardens, and the woods. Natural gas

Natural gas is widely available and is not disruptive. It burns very efficiently producing very low levels of SOX , NOX, and soot when burned. This means gas burning equipment tends to maintain its operating efficiency throughout the heating season and requires little maintenance making it no fuss. Economy & Geography

Biomass

Biomass is a local, renewable resource. Maine is the country’s most heavily forested state (90%), and even with a robust wood-based economic sector, the amount of forested land has remained steady since the 1980s. Furthermore, the net growth of tree volume currently exceeds harvests annually.v Biomass fuel is also playing a growing role in building our local economy. With the decline of the paper industry, sustainable feedstocks for wood chips and pellets is widely available. An expanding supply chain that includes loggers, pellet mills, and wood stoves/boiler retailers has been established. Dollars spent on wood products stay in the state and region, and biomass derived from wood waste and non-lumber quality wood is a productive use of a low-grade waste product. Maine is uniquely well suited to use biomass fuel because we have a significant amount of forest residue to tap into. Below is an image of the amount of forest residue available nation-wide from the National Renewable Energy Laboratory (NREL). Large sources of forest residue are shown in red.

This comprises unused portions of trees, cut or killed by logging and left in the woods and the unutilized volume of trees cut or killed during logging operations. The dataset illustrates 65% of logging residues and 50% of other removals which is the portion that could be collected as biomass. The remaining portion is to be left on the field to maintain ecological functions.vi

Natural Gas

Natural gas lines are expected to expand across Maine. Though natural gas is a cheaper and easier heating fuel than oil, which Maine has been heavily reliant on, it is neither local nor sustainable in the long run. Aside from its contribution to climate change, the great unknown with natural gas is the extent of the environmental risks associated with hydraulic fracturing "fracking" which include:

• Water pollution from runoff of fracking chemicals • Companies are not required to disclose the chemicals they use • Water can bring up adsorbed underground toxins including arsenic • Fracking has been linked to earthquakes • Leaks have contaminated drinking water

Cost savings & Price stability Biomass

Biomass is a low cost fuel and the cost of biomass has been extremely stable over the past decade compared with fossil fuels. Statistics show that inflation has little effect on the cost of wood chips. However biomass has a high capital cost. In this case it is a $1.6million investment. The current low price of natural gas plus the new lower cost estimate to extend the gas line to the site makes the expected return on this investment as currently modeled undesirable.

Natural Gas

Natural gas has a much lower capital cost to install, and the fuel cost is currently relatively cheap (close to par with biomass). However there is much more price volatility with natural gas. With the major shift to natural gas in the Northeast, demand has superseded pipeline capacity. New pipelines are being built to ease expected price spikes, but there remains the potential for continued volatility especially concerning regulatory risk as government moves to force extraction companies to clean up their act which will increase production costs and consumer prices. i Conservation Law Foundation webpage (http://www.clf.org/our-work/clean-energy-climate-change/renewable-energy-and-transmission/biomass-energy) ii Emily McGlynn, Thomas Buchholz, John Gunn, David Saah, Brian Kittler, "Opinion Low-risk Bioenergy Can Be A Critical Climate Solution" August 10, 2015 (http://www.ecosystemmarketplace.com/articles/opinion-low-risk-bioenergy-can-be-a-critical-climate-solution) iii NRDC blog February 4, 2014 (http://switchboard.nrdc.org/blogs/slyutse/tackling_climate_change_means.html) iv Peter Moskowitz "New report estimates enough natural gas is leaking to negate climate benefits " The Guardian June 24, 2015 (http://www.theguardian.com/environment/2015/jun/24/natural-gas-leaks-methane-environment) v The North East State Foresters Association The Economic Importance of Maine's Forest-Based Economy 2013 (http://digitalmaine.com/cgi/viewcontent.cgi?article=1005&context=for_docs) vi National Renewable Energy Laboratory (NREL) Biofuels Atlas (https://maps.nrel.gov/biofuels-atlas/#/?aL=chXUF-%255Bv%255D%3Dt%260gBHTu%255Bv%255D%3Dt%260gBHTu%255Bd%255D%3D1&bL=groad&cE=0&lR=0&mC=42.06560675405716%2C-90.263671875&zL=4) *For fuel procurement - use Innovative Natural Resource Solutions to identify wood chip sources in our area and write specifications for sustainable feedstock (Forest Guild report Forest Biomass Retention and Harvesting Guidelines for the Northeast)

City of South Portland Municipal Public Services Project

Greenhouse Gas Emissions

Fuel MMBTUs

GWP GWP

OIL 6,471 73.96 kg 3 g 25 0.08 kg 0.6 g 298 0.179 kg 480,208 1,058,858 529 15,883

NATURAL GAS 5,851 53.06 kg 1 g 25 0.03 kg 0.1 g 298 0.03 kg 310,780 685,270 343 10,279

PROPANE 5,978 62.87 kg 3 g 25 0.08 kg 0.6 g 298 0.179 kg 377,373 832,107 416 12,482

BIOMASS 6,875 93.8 kg 7.2 g 25 0.18 kg 3.6 g 298 1.073 kg 653,488 1,440,941 720 21,614

Fuel MMBTUs

GWP GWPAnthropogenic

eCO2 (lb)

Biogenic

eCO2 (lb)

Anthropogenic

eCO2 (tons)

Biogenic

eCO2 (tons)

OIL 6,471 163.082 lb 3 g 25 0.17 lb 0.6 g 298 0.394 lb 1,058,858 0 529 0

NATURAL GAS 5,851 116.997 lb 1 g 25 0.06 lb 0.1 g 298 0.066 lb 685,270 0 343 0

PROPANE 5,978 138.628 lb 3 g 25 0.17 lb 0.6 g 298 0.394 lb 832,107 0 416 0

BIOMASS 6,875 206.829 lb 7.2 g 25 0.4 lb 3.6 g 298 2.366 lb 18,992 1,421,949 9 711

Notes:

1. EPA emissions factors April 2014 (http://www.epa.gov/climateleadership/inventory/ghg-emissions.html)

(CO2x1,000)+(CH4x25)+(N2Ox298)= grams of eCO2

1 kilogram x 2.205 = 1 pound / 2,000 = 1 short ton

CO2 eCO2 eCO2

CH4 N2O

CH4 N2O

eCO2 eCO2

Totals

eCO2

(kgs)

eCO2

(pounds)

eCO2

(tons)

over 30 yrs

eCO2

(tons)

Emissions Factors1

CO2

Emissions Factors1 Totals

0

100

200

300

400

500

600

700

800

OIL NATURAL GAS PROPANE BIOMASS

Biogenic eCO2 (tons)

Anthropogenic eCO2 (tons)

GHG Emissions (eCO2 in tons per year)

$0

$1,000,000

$2,000,000

$3,000,000

$4,000,000

$5,000,000

$6,000,000

0 5 10 15 20 25 30

TOTA

L C

OST

(IN

ITIA

L C

OST

+ C

UM

ALA

TIV

E O

PER

ATI

NG

CO

ST)

YEARS OF OPERATION

TOTAL ESTIMATED COST OVER NEXT 30 YEARS (2014-15 Fuel Price w/ Yearly Fuel Price Increase)

Natural Gas - 0%

Natural Gas - 2.25%

Natural Gas - 4.25%

Wood Chip Boiler - 0%

Wood Chip Boiler - 2.25%

$0

$1,000,000

$2,000,000

$3,000,000

$4,000,000

$5,000,000

$6,000,000

Natural Gas - 0% Natural Gas - 2.25% Natural Gas - 4.25% Wood Chip Boiler - 0%

Wood Chip Boiler - 1%

Wood Chip Boiler - 2.25%

TOTA

L C

OST

IN

30

YEA

RS

TYPE OF BOILER

TOTAL ESTIMATED COST IN 30 YEARS (2014-15 Fuel Price w/ Yearly Fuel Price Increase)

Maintenance

Fuel Cost

Initial Cost

$0

$500,000

$1,000,000

$1,500,000

$2,000,000

$2,500,000

$3,000,000

$3,500,000

Natural Gas - 0% Natural Gas - 2.25% Natural Gas - 4.25% Wood Chip Boiler - 0%

Wood Chip Boiler - 1%

Wood Chip Boiler - 2.25%

TOTA

L C

OST

IN 2

0 Y

EAR

S

TYPE OF BOILER

TOTAL ESTIMATED COST IN 20 YEARS (2014-15 Fuel Price w/ Yearly Fuel Price Increase)

Maintenance

Fuel Cost

Initial Cost

11/13/2015

Cost includes major equipment only.

System:

Description Estimated Size

Total

Material

Cost

Total

Installed

Cost

1 @ 4000 MBH $600,000 $900,000

(Messersmith)

Boiler Room/Storage Bin Includes MEP $418,000 $418,000Trenching $10/LF $25,000 $25,000

Underground Pex Piping $58/lf 4", $27/lf 2" $64,750 $65,157

Underground sprinkler $56/lf $14,000 $14,407

Underground Electrical $18,850 $22,620

Shoulder Season Boiler (LP) Viessman 2xCM2-620 $105,293 $105,293

Contingency 20% of Building Cost $83,600 $83,600

Total $1,329,493 $1,634,077

System:

Description Estimated Size

Total

Material

Cost

Total

Installed

Cost

Condensing Boilers 2 @ 2000 MBH $105,294 $210,587

(Viessman 2xCM2-620)

Bring NG to Site -$ $0

Total $105,294 $210,587

Probable Estimate of Cost

Natural Gas Boiler

Wood Chip (1 @ 4000 MBH)

Wood chip boiler including

controls and fuel delivery

system

System

Initial CostYearly Operating

Cost (1)

Yearly

Maintenance

Cost

Total Yearly Cost

(Maint. &

Operating)

5 Year Total Cost

(1)

10 year Total

Cost (1)

20 year total

cost (1)30 Year Total Cost

Simple Payback

(years)

Natural Gas - 0% $210,587 $92,856 $3,314 $96,170 $691,439 $1,172,291 $2,133,995 $3,095,699 0.00

Natural Gas - 2.25% $210,587 $92,856 $3,314

Natural Gas - 4.25% $210,587 $92,856 $3,314

Wood Chip Boiler - 0% $1,634,077 $40,441 $8,858 $49,300 $1,880,575 $2,127,072 $2,620,067 $3,113,062 30.37

Wood Chip Boiler - 1% $1,634,077 $40,441 $8,858

Wood Chip Boiler - 2.25% $1,634,077 $40,441 $8,858

Notes: 1. Operating cost using today's fuel price only. Inflation for fuel prices are unpredictable and unknown.

Year Natural Gas - 0% Natural Gas - 2.25%

Natural Gas -

4.25%

Wood Chip Boiler -

0%

Wood Chip

Boiler - 1%

Wood Chip

Boiler - 2.25%

0 $210,587 $210,587 $210,587 $1,634,077 $1,634,077 $1,634,077

1 $306,758 $306,758 $306,758 $1,683,377 $1,683,377 $1,683,377 Fuel Cost Maintenance Cost

2 $402,928 $405,017 $406,875 $1,732,676 $1,733,080 $1,733,586 $2,785,691 $99,420

3 $499,099 $505,413 $511,105 $1,781,976 $1,783,193 $1,784,726 $3,918,100 $99,420

4 $595,269 $607,994 $619,625 $1,831,275 $1,833,718 $1,836,817 $5,430,755 $99,420

5 $691,439 $712,807 $732,616 $1,880,575 $1,884,659 $1,889,881 $1,213,235 $265,750

6 $787,610 $819,905 $850,269 $1,929,874 $1,936,022 $1,943,939 $1,406,742 $265,750

7 $883,780 $929,338 $972,781 $1,979,174 $1,987,809 $1,999,015 $1,706,426 $265,750

8 $979,950 $1,041,158 $1,100,358 $2,028,473 $2,040,026 $2,055,130

9 $1,076,121 $1,155,420 $1,233,217 $2,077,773 $2,092,676 $2,112,309

10 $1,172,291 $1,272,178 $1,371,582 $2,127,072 $2,145,765 $2,170,575 Fuel Cost Maintenance Cost

11 $1,268,462 $1,391,488 $1,515,686 $2,176,372 $2,199,295 $2,229,953 $1,857,128 $66,280

12 $1,364,632 $1,513,409 $1,665,774 $2,225,671 $2,253,272 $2,290,467 $2,313,194 $66,280

13 $1,460,802 $1,637,998 $1,822,099 $2,274,971 $2,307,701 $2,352,143 $2,837,923 $66,280

14 $1,556,973 $1,765,315 $1,984,928 $2,324,270 $2,362,585 $2,415,008 $808,824 $177,167

15 $1,653,143 $1,895,423 $2,154,536 $2,373,570 $2,417,929 $2,479,088 $890,474 $177,167

16 $1,749,314 $2,028,384 $2,331,212 $2,422,869 $2,473,739 $2,544,411 $1,007,451 $177,167

17 $1,845,484 $2,164,262 $2,515,255 $2,472,169 $2,530,017 $2,611,004

18 $1,941,654 $2,303,122 $2,706,979 $2,521,468 $2,586,770 $2,678,896

19 $2,037,825 $2,445,032 $2,906,711 $2,570,768 $2,644,002 $2,748,116 Fuel Cost Maintenance Cost

20 $2,133,995 $2,590,061 $3,114,791 $2,620,067 $2,701,718 $2,818,695 $928,564 $33,140

21 $2,230,165 $2,738,278 $3,331,573 $2,669,367 $2,759,922 $2,890,662 $1,028,450 $33,140

22 $2,326,336 $2,889,756 $3,557,427 $2,718,666 $2,818,620 $2,964,049 $1,127,854 $33,140

23 $2,422,506 $3,044,567 $3,792,740 $2,767,966 $2,877,816 $3,038,888 $404,412 $88,583

24 $2,518,677 $3,202,787 $4,037,912 $2,817,265 $2,937,516 $3,115,212 $423,104 $88,583

25 $2,614,847 $3,364,492 $4,293,364 $2,866,565 $2,997,724 $3,193,053 $447,915 $88,583

26 $2,711,017 $3,529,761 $4,559,531 $2,915,864 $3,058,445 $3,272,447

27 $2,807,188 $3,698,675 $4,836,870 $2,965,164 $3,119,685 $3,353,428

28 $2,903,358 $3,871,314 $5,125,854 $3,014,463 $3,181,449 $3,436,031

29 $2,999,529 $4,047,763 $5,426,980 $3,063,763 $3,243,742 $3,520,294

30 $3,095,699 $4,228,107 $5,740,762 $3,113,062 $3,306,569 $3,606,253

Notes: 1. Operating cost using annual % fuel increase: NG=2%, LP = 4.7%, Oil=8.7%,

ESTIMATED PAYPACK (2014-15 Fuel Prices)

COST IN 30 YEARS

COST IN 20 YEARS

COST IN 10 YEARS

TOTAL COST ESTIMATE - CUMALATIVE YEAR TO YEAR

System: Woodchip Boiler

Description

Hours Per

/QTY

Occurrences

per year

In house

$/hr.

Out

house

$/hr.

In-house

Cost per

Year

Out-

house

Cost per

Year

Daily Maintenance 0.33 365 25 0 $3,042 $0

Weekly Maintenance 0.42 52 25 0 $542 $0

Monthly Maintenance 2.00 12 25 0 $600 $0

Semi-annual 3.00 2 25 0 $150 $0

Yearly 1.00 1 25 0 $25 $0

Spring Shutdown 1.00 1 0 2500 $0 $2,500

Bi-Yearly Certification 1.00 0.5 0 1000 $0 $500 $1000 every other year

Refactory Repair 1.00 0.1 0 15000 $0 $1,500 $15000 every 10 years

Sub Total = $4,358 $4,500

Total Yearly Maint. Cost = 8,858$

System: NG Boilers (Two Boilers)

Description

Hours Per

/QTY

Occurrences

per year

In house

$/hr.

Out

house

$/hr.

In-house

Cost per

Year

Out-

house

Cost per

Year

Annual boiler service 8.00 2 0 100 $0 $1,600

Major Repair 2.00 0.143 0 6000 $0 $1,714 Assumes $6000 every 7 years per boiler

Sub Total = $0 $3,314

Total Yearly Maint. Cost = $3,314

Probable Estimate of Yearly Maintenance Cost

Natural Gas Wood Chips

Estimated BTU Output (10^5 BTU) (2) 55,000.0 55,000.0

Equipment Efficiency 94.0 80.0

BTU Output (10^5 BTU) 58,510.6 68,750.0

$/THERM ($/(10^5 BTU)) 1.587 0.588Yearly Operating Cost (1) 92,856.4 40,441.2

$52,415 $0

130% 0%

Notes: 1. Cost include fuel consumption costs only. Maintenance and operating cost not included

2. Fuel cost estimate using simple algebraic equations and estimates on anticipated heating loads. An energy model was not performed

Fuel Unit Cost Units $/Therm Unit Conversion Notes

NATURAL GAS (1) $15.87 $/MCF $1.59 10 THERM/MCF

Wood Chips (2) $60.00 $/TON $0.59 10,200,000 BTU/TON 5100 BTU/lb (40%MC)

2. Fuel cost based on estimate from Messersmith.

3. Average annual increase over last 10 heating seasons

500%

Estimated Fuel Cost - 2014-15 Fuel Prices

Notes: 1. 2014-15 Heating Season Average based on http://www.eia.gov/dnav/ng/hist/n3020me3m.htm

ADDITIONAL OPERATING COST

(RELATIVE TO LOW COST)

Probable Estimate of Yearly Fuel Cost (2014-15 Fuel Prices)

System

Initial CostYearly Operating

Cost (1)

Yearly

Maintenance

Cost

Total Yearly Cost

(Maint. &

Operating)

5 Year Total Cost

(1)

10 year Total

Cost (1)

20 year total

cost (1)30 Year Total Cost

Simple Payback

(years)

Natural Gas - 0% $210,587 $54,366 $3,314 $57,680 $498,986 $787,385 $1,364,182 $1,940,979 0.00

Natural Gas - 2.25% $210,587 $54,366 $3,314

Natural Gas - 4.25% $210,587 $54,366 $3,314

Wood Chip Boiler - 0% $1,634,077 $40,441 $8,858 $49,300 $1,880,575 $2,127,072 $2,620,067 $3,113,062 169.86

Wood Chip Boiler - 1% $1,634,077 $40,441 $8,858

Wood Chip Boiler - 2.25% $1,634,077 $40,441 $8,858

Notes: 1. Operating cost using today's fuel price only. Inflation for fuel prices are unpredictable and unknown.

Year Natural Gas - 0% Natural Gas - 2.25%

Natural Gas -

4.25%

Wood Chip Boiler -

0%

Wood Chip

Boiler - 1%

Wood Chip

Boiler - 2.25%

0 $210,587 $210,587 $210,587 $1,634,077 $1,634,077 $1,634,077

1 $268,267 $268,267 $268,267 $1,683,377 $1,683,377 $1,683,377 Fuel Cost Maintenance Cost

2 $325,947 $327,170 $328,257 $1,732,676 $1,733,080 $1,733,586 $1,630,971 $99,420

3 $383,627 $387,324 $390,656 $1,781,976 $1,783,193 $1,784,726 $2,293,976 $99,420

4 $441,306 $448,756 $455,567 $1,831,275 $1,833,718 $1,836,817 $3,179,608 $99,420

5 $498,986 $511,497 $523,094 $1,880,575 $1,884,659 $1,889,881 $1,213,235 $265,750

6 $556,666 $575,574 $593,352 $1,929,874 $1,936,022 $1,943,939 $1,406,742 $265,750

7 $614,345 $641,019 $666,454 $1,979,174 $1,987,809 $1,999,015 $1,706,426 $265,750

8 $672,025 $707,861 $742,522 $2,028,473 $2,040,026 $2,055,130

9 $729,705 $776,133 $821,682 $2,077,773 $2,092,676 $2,112,309

10 $787,385 $845,866 $904,066 $2,127,072 $2,145,765 $2,170,575 Fuel Cost Maintenance Cost

11 $845,064 $917,094 $989,810 $2,176,372 $2,199,295 $2,229,953 $1,087,314 $66,280

12 $902,744 $989,850 $1,079,057 $2,225,671 $2,253,272 $2,290,467 $1,354,333 $66,280

13 $960,424 $1,064,168 $1,171,957 $2,274,971 $2,307,701 $2,352,143 $1,661,552 $66,280

14 $1,018,103 $1,140,084 $1,268,663 $2,324,270 $2,362,585 $2,415,008 $808,824 $177,167

15 $1,075,783 $1,217,634 $1,369,340 $2,373,570 $2,417,929 $2,479,088 $890,474 $177,167

16 $1,133,463 $1,296,854 $1,474,154 $2,422,869 $2,473,739 $2,544,411 $1,007,451 $177,167

17 $1,191,143 $1,377,781 $1,583,281 $2,472,169 $2,530,017 $2,611,004

18 $1,248,822 $1,460,455 $1,696,906 $2,521,468 $2,586,770 $2,678,896

19 $1,306,502 $1,544,915 $1,815,219 $2,570,768 $2,644,002 $2,748,116 Fuel Cost Maintenance Cost

20 $1,364,182 $1,631,200 $1,938,420 $2,620,067 $2,701,718 $2,818,695 $543,657 $33,140

21 $1,421,861 $1,719,352 $2,066,715 $2,669,367 $2,759,922 $2,890,662 $602,139 $33,140

22 $1,479,541 $1,809,413 $2,200,323 $2,718,666 $2,818,620 $2,964,049 $660,338 $33,140

23 $1,537,221 $1,901,426 $2,339,468 $2,767,966 $2,877,816 $3,038,888 $404,412 $88,583

24 $1,594,901 $1,995,435 $2,484,385 $2,817,265 $2,937,516 $3,115,212 $423,104 $88,583

25 $1,652,580 $2,091,484 $2,635,321 $2,866,565 $2,997,724 $3,193,053 $447,915 $88,583

26 $1,710,260 $2,189,620 $2,792,531 $2,915,864 $3,058,445 $3,272,447

27 $1,767,940 $2,289,889 $2,956,281 $2,965,164 $3,119,685 $3,353,428

28 $1,825,619 $2,392,340 $3,126,850 $3,014,463 $3,181,449 $3,436,031

29 $1,883,299 $2,497,021 $3,304,527 $3,063,763 $3,243,742 $3,520,294

30 $1,940,979 $2,603,983 $3,489,615 $3,113,062 $3,306,569 $3,606,253

Notes: 1. Operating cost using annual % fuel increase: NG=2%, LP = 4.7%, Oil=8.7%,

ESTIMATED PAYPACK (Nov. 2015 Fuel Prices)

COST IN 30 YEARS

COST IN 20 YEARS

COST IN 10 YEARS

TOTAL COST ESTIMATE - CUMALATIVE YEAR TO YEAR

System: Woodchip Boiler

Description

Hours Per

/QTY

Occurrences

per year

In house

$/hr.

Out house

$/hr.

In-house

Cost per

Year

Out-

house

Cost per

Year

Daily Maintenance 0.33 365 25 0 $3,042 $0

Weekly Maintenance 0.42 52 25 0 $542 $0

Monthly Maintenance 2.00 12 25 0 $600 $0

Semi-annual 3.00 2 25 0 $150 $0

Yearly 1.00 1 25 0 $25 $0

Spring Shutdown 1.00 1 0 2500 $0 $2,500

Bi-Yearly Certification 1.00 0.5 0 1000 $0 $500 $1000 every other year

Refactory Repair 1.00 0.1 0 15000 $0 $1,500 $15000 every 10 years

Sub Total = $4,358 $4,500

Total Yearly Maint. Cost = 8,858$

System: NG Boilers (Two Boilers)

Description

Hours Per

/QTY

Occurrences

per year

In house

$/hr.

Out house

$/hr.

In-house

Cost per

Year

Out-

house

Cost per

Year

Annual boiler service 8.00 2 0 100 $0 $1,600

Major Repair 2.00 0.143 0 6000 $0 $1,714 Assumes $6000 every 7 years per boiler

Sub Total = $0 $3,314

Total Yearly Maint. Cost = $3,314

Probable Estimate of Yearly Maintenance Cost

$0

$1,000,000

$2,000,000

$3,000,000

$4,000,000

$5,000,000

$6,000,000

0 5 10 15 20 25 30

TOTA

L C

OST

(IN

ITIA

L C

OST

+ C

UM

ALA

TIV

E O

PER

ATI

NG

CO

ST)

YEARS OF OPERATION

TOTAL ESTIMATED COST OVER NEXT 30 YEARS (Nov. 2015 w/ Yearly Fuel Price Increase)

Natural Gas - 0%

Natural Gas - 2.25%

Natural Gas - 4.25%

Wood Chip Boiler - 0%

Wood Chip Boiler - 2.25%

$0

$1,000,000

$2,000,000

$3,000,000

$4,000,000

$5,000,000

$6,000,000

Natural Gas - 0% Natural Gas - 2.25% Natural Gas - 4.25% Wood Chip Boiler - 0%

Wood Chip Boiler - 1%

Wood Chip Boiler - 2.25%

TOTA

L C

OST

IN

30

YEA

RS

TYPE OF BOILER

TOTAL ESTIMATED COST IN 30 YEARS (Nov. 2015 Fuel Price w/ Yearly Fuel Price Increase)

Maintenance

Fuel Cost

Initial Cost

$0

$500,000

$1,000,000

$1,500,000

$2,000,000

$2,500,000

$3,000,000

Natural Gas - 0% Natural Gas - 2.25% Natural Gas - 4.25% Wood Chip Boiler - 0%

Wood Chip Boiler - 1%

Wood Chip Boiler - 2.25%

TOTA

L C

OST

IN 2

0 Y

EAR

S

TYPE OF BOILER

TOTAL ESTIMATED COST IN 20 YEARS (Nov. 2015 Fuel Price w/ Yearly Fuel Price Increase)

Maintenance

Fuel Cost

Initial Cost

11/13/2015

Cost includes major equipment only.

System:

Description Estimated Size

Total

Material

Cost

Total

Installed

Cost

1 @ 4000 MBH $600,000 $900,000

(Messersmith)

Boiler Room/Storage Bin Includes MEP $418,000 $418,000

Trenching $10/LF $25,000 $25,000

Underground Pex Piping $58/lf 4", $27/lf 2" $64,750 $65,157

Underground sprinkler $56/lf $14,000 $14,407

Underground Electrical $18,850 $22,620

Shoulder Season Boiler (LP) Viessman 2xCM2-620 $105,293 $105,293

Contingency 20% of Building Cost $83,600 $83,600

Total $1,329,493 $1,634,077

System:

Description Estimated Size

Total

Material

Cost

Total

Installed

Cost

Condensing Boilers 2 @ 2000 MBH $105,294 $210,587

(Viessman 2xCM2-620)

Bring NG to Site -$ $0

Total $105,294 $210,587

Probable Estimate of Cost

Natural Gas Boiler

Wood Chip (1 @ 4000 MBH)

Wood chip boiler including

controls and fuel delivery

system

Natural Gas Wood Chips

Estimated BTU Output (10^5 BTU) (2) 55,000.0 55,000.0

Equipment Efficiency 94.0 80.0

BTU Output (10^5 BTU) 58,510.6 68,750.0

$/THERM ($/(10^5 BTU)) 0.929 0.588

Yearly Operating Cost (1) 54,365.7 40,441.2

$13,925 $0

34% 0%

Notes: 1. Cost include fuel consumption costs only. Maintenance and operating cost not included

2. Fuel cost estimate using simple algebraic equations and estimates on anticipated heating loads. An energy model was not performed

Fuel Unit Cost Units $/Therm Unit Conversion Notes

NATURAL GAS (1) $9.29 $/MCF $0.93 10 THERM/MCF

Wood Chips (2) $60.00 $/TON $0.59 10,200,000 BTU/TON 5100 BTU/lb (40%MC)

2. Fuel cost based on estimate from Messersmith.

3. Average annual increase over last 10 heating seasons

Estimated Fuel Cost - Nov. 2015 Fuel Prices

Notes: 1. Fuel price based on Unitil November 2015 Fuel Rate: $2.992/MCF Delivery, $5.963/MCF Supply, $164.12 Montly Charge.

ADDITIONAL OPERATING COST

(RELATIVE TO LOW COST)

Probable Estimate of Yearly Fuel Cost (Nov. 2015 Fuel Prices)