Non-linear objectives in mechanism design Shuchi Chawla University of Wisconsin – Madison FOCS 2012.
WaterImplicaonsofCO 2&Emission&Performance&Standards&for ... · WaterImplicaonsofCO 2...
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Water Implica-ons of CO 2 Emission Performance Standards for Fossil FuelFired Power Plants Shuchi Tala-, Haibo Zhai, and Granger Morgan Department of Engineering and Public Policy, Carnegie Mellon University, Pi<sburgh PA BACKGROUND Understanding water demand in the context of carbon regula6on policies and the mandate to begin using carbon capture systems is essen6al to future energy genera6on planning. The impacts of emission performance standards (EPS) recently proposed by U.S. Environmental Protec6on Agency (US EPA) to regulate CO 2 emissions from coal and natural gas plants have not been quan6fied. Currently, it is known that the addi6on of 90% carbon capture systems will lead to a nearly doubling of water use, however specific changes in water use to adhere to the proposed regula6on are not known. Research Objec-ves 1) Inves6gate plant level changes in water use for fossil fuel fired power genera6on systems with adherence to the proposed emissions performance standard 2) Explore changes in water use from the impact of plant design as well as policy choices 3) Evaluate the uncertainty in water use from the EPS 4) Understand the water management policy implica6ons. The proposed EPS is as following [2]: • New Coal Units (PC & IGCC): 1,100 lb CO2/MWh gross over a 12opera6ng month period, or 1,0001,050 lb CO2/MWh gross over a 7year period • NGCC units: 1,000 lb CO2/MWh gross for larger units or 1,100 lb CO2/MWh gross for smaller units METHODS The Integrated Environmental Control Model, developed by Carnegie Mellon University and the Na6onal Energy Technology Lab, was the main tool u6lized to conduct this analysis [3]. We first established base case PC and NGCC power plants without carbon capture, and a PC plant in compliance with the proposed EPS. We then conducted a large scale sensi6vity analysis to look at a range of factors affec6ng water use in fossil fuel power plants with an EPS measure in place. We then assessed uncertainty through the use of IECM’s uncertainty func6onality. [1] Freshwater Use by U.S. Power Plants: Electricity’s Thirst for a Precious Resource, UCS (2011) hbp://www.ucsusa.org/assets/documents/clean_energy/ew3/ew3freshwaterusebyuspowerplants.pdf [2] US EPA: hbp://www2.epa.gov/carbonpollu6onstandards/2013proposedcarbonpollu6onstandardnewpowerplants [3] IECM: hbp://www.cmu.edu/epp/iecm/ RESULTS Base cases Three power plant base cases were analyzed: supercri6cal pulverized coal (PC), supercri6cal PC with CCS to meet the EPS, and an NGCC plant. Plant Design Sensi-vity PC plant type, coal type, and cooling system type all significantly contribute to determining carbon removal efficiency and overall water use. An example of such sensi6vity is below, illustra6ng the varia6ons that occur based on changes in plant type. Cooling system type has the largest effect on overall water use, however plant type and coal type have larger effects on the carbon removal efficiencies and water use from the carbon capture system. Compliance Timing Sensi-vity The EPS allows for choice between a 12 and 84month opera6ng period, with 6ghter regula6ons for the laber. An analysis was conducted to determine if 1) there would be a significant difference in water 2) how long a plant would be able to wait before installing and u6lizing 90% carbon capture to meet the standard and 3) if this would cause significant differences in water use. We thank the Center for Climate and Energy Decision Making and the Department of Engineering and Public Policy at Carnegie Mellon University, for their support of this work. Sensi-vity to Policy Choices NGCC plants fall within compliance of the EPS. Only if more stringent measures were put in place would NGCC plants need to install CCS. Subsequent NGCC and PC consump6on intensi6es are shown below. The net vs. gross dis6nc6on in the policy is an important one. Requiring capture on a net basis, leads to a 10% increase in the carbon removal efficiency and subsequent higher water use. Uncertainty Uncertainty of the water use was assessed by looking at cumula6ve probability distribu6ons of plant water use for a 500 MW net Super PC plant with and without CCS to meet the EPS (a). We then looked at the cumula6ve distribu6on of added water use based by using the noCCS plant output as the input distribu6ons (b). We found that 95% ranges from 238258 tonnes/hour – an increase of approximately 30.4%. DISCUSSION Water use from carbon regula6on policies will have large effects on water use, however it can be decreased through the use of adap6ve strategies to limit it as much as possible. As standards become more and more stringent, more water will be required to generate the same amount of power from fossil fuel powered genera6on. Source: UCS [1] 0% 10% 20% 30% 40% 50% Sub Cri6cal Super Cri6cal Ultra Cri6cal CO2 Removal Efficiency (%) Plant Type 0 0.5 1 1.5 2 2.5 3 3.5 Sub Cri6cal Super Cri6cal Ultra Cri6cal Water Use Intensity (m^3/ MWh) Plant Type Consump6on Withdrawal 0 200 400 600 800 1000 1200 1400 1600 1800 1 2 3 4 5 6 7 8 9 101112 CO2 Emission Rate (lb/MWh gross) Deployment Time of CCS (nth month) No/90% Capture 40% Capture 0 0.25 0.5 0.75 1 230 240 250 260 270 Cumula-ve Probability Added Water Consump-on from CCS (tonnes/hr) (b) 0 0.25 0.5 0.75 1 750 900 1050 1200 1350 Cumula-ve Probability Plant Water Consump-on (tonnes/hr) (a) CCS (40% Capture) No CCS Variable Results Plant Type Super PC Super PC NGCC EPS (1100 lb/MWhg) No Yes No Gross output (MW) 536 578 557 Net output (MW) 500 500 542 Net plant efficiency 38.2% 32.8% 50.1% CO 2 removal efficiency 40% Emissions rate (lb/MWhg) 1687 1097 782 Consump6on Intensity (m 3 /MWh) 1.63 2.13 .67 Withdrawal Intensity (m 3 /MWh) 2.33 3.06 .89 Type 90% Capture (months) Consum Intensity Withdr Intensity Avg Annual Consump Avg Annual Withdr 12 months 4.75 2.10 3.00 6.9 E6 9.8 E6 84 months 36.1 2.14 3.05 7.0 E6 10 E6 Consistent 0 2.13 2.64 7.0 E6 8.7 E6 0 0.5 1 1.5 2 2.5 3 1500 1100 800 500 300 Water Consump-on Intensity (m^3/ MWh) Emissions Performance Standard (lbMWhgross) PC NGCC
Transcript of WaterImplicaonsofCO 2&Emission&Performance&Standards&for ... · WaterImplicaonsofCO 2...
Water Implica-ons of CO2 Emission Performance Standards for Fossil Fuel-‐Fired Power Plants
Shuchi Tala-, Haibo Zhai, and Granger Morgan
Department of Engineering and Public Policy, Carnegie Mellon University, Pi<sburgh PA
BACKGROUND Understanding water demand in the context of carbon regula6on policies and the mandate to begin using carbon capture systems is essen6al to future energy genera6on planning. The impacts of emission performance standards (EPS) recently proposed by U.S. Environmental Protec6on Agency (US EPA) to regulate CO2 emissions from coal and natural gas plants have not been quan6fied. Currently, it is known that the addi6on of 90% carbon capture systems will lead to a nearly doubling of water use, however specific changes in water use to adhere to the proposed regula6on are not known. Research Objec-ves 1) Inves6gate plant level changes in water use for fossil fuel-‐
fired power genera6on systems with adherence to the proposed emissions performance standard
2) Explore changes in water use from the impact of plant design as well as policy choices
3) Evaluate the uncertainty in water use from the EPS 4) Understand the water management policy implica6ons. The proposed EPS is as following [2]: • New Coal Units (PC & IGCC): 1,100 lb CO2/MWh gross over a
12-‐opera6ng month period, or 1,000-‐1,050 lb CO2/MWh gross over a 7-‐year period
• NGCC units: 1,000 lb CO2/MWh gross for larger units or 1,100 lb CO2/MWh gross for smaller units
METHODS The Integrated Environmental Control Model, developed by Carnegie Mellon University and the Na6onal Energy Technology Lab, was the main tool u6lized to conduct this analysis [3]. We first established base case PC and NGCC power plants without carbon capture, and a PC plant in compliance with the proposed EPS. We then conducted a large scale sensi6vity analysis to look at a range of factors affec6ng water use in fossil fuel power plants with an EPS measure in place. We then assessed uncertainty through the use of IECM’s uncertainty func6onality.
[1] Freshwater Use by U.S. Power Plants: Electricity’s Thirst for a Precious Resource, UCS (2011) hbp://www.ucsusa.org/assets/documents/clean_energy/ew3/ew3-‐freshwater-‐use-‐by-‐us-‐power-‐plants.pdf [2] US EPA: hbp://www2.epa.gov/carbon-‐pollu6on-‐standards/2013-‐proposed-‐carbon-‐pollu6on-‐standard-‐new-‐power-‐plants [3] IECM: hbp://www.cmu.edu/epp/iecm/
RESULTS Base cases Three power plant base cases were analyzed: supercri6cal pulverized coal (PC), supercri6cal PC with CCS to meet the EPS, and an NGCC plant. Plant Design Sensi-vity PC plant type, coal type, and cooling system type all significantly contribute to determining carbon removal efficiency and overall water use. An example of such sensi6vity is below, illustra6ng the varia6ons that occur based on changes in plant type. Cooling system type has the largest effect on overall water use, however plant type and coal type have larger effects on the carbon removal efficiencies and water use from the carbon capture system.
Compliance Timing Sensi-vity The EPS allows for choice between a 12 and 84-‐month opera6ng period, with 6ghter regula6ons for the laber. An analysis was conducted to determine if 1) there would be a significant difference in water 2) how long a plant would be able to wait before installing and u6lizing 90% carbon capture to meet the standard and 3) if this would cause significant differences in water use.
We thank the Center for Climate and Energy Decision Making and the Department of Engineering and Public Policy at Carnegie Mellon University, for their support of this work.
Sensi-vity to Policy Choices NGCC plants fall within compliance of the EPS. Only if more stringent measures were put in place would NGCC plants need to install CCS. Subsequent NGCC and PC consump6on intensi6es are shown below.
The net vs. gross dis6nc6on in the policy is an important one. Requiring capture on a net basis, leads to a 10% increase in the carbon removal efficiency and subsequent higher water use. Uncertainty Uncertainty of the water use was assessed by looking at cumula6ve probability distribu6ons of plant water use for a 500 MW net Super PC plant with and without CCS to meet the EPS (a). We then looked at the cumula6ve distribu6on of added water use based by using the no-‐CCS plant output as the input distribu6ons (b). We found that 95% ranges from 238-‐258 tonnes/hour – an increase of approximately 30.4%. DISCUSSION Water use from carbon regula6on policies will have large effects on water use, however it can be decreased through the use of adap6ve strategies to limit it as much as possible. As standards become more and more stringent, more water will be required to generate the same amount of power from fossil fuel powered genera6on.
Source: UCS [1]
0%
10%
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Sub Cri6cal Super Cri6cal Ultra Cri6cal CO2 Re
moval Efficien
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)
Plant Type
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2.5 3
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Water Use In
tensity
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MWh)
Plant Type
Consump6on Withdrawal
0 200 400 600 800 1000 1200 1400 1600 1800
1 2 3 4 5 6 7 8 9 10 11 12
CO2 Em
ission
Rate (lb
/MWh-‐
gross)
Deployment Time of CCS (nth month)
No/90% Capture 40% Capture
0
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Cumula-
ve Proba
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Added Water Consump-on from CCS (tonnes/hr)
(b)
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0.75
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750 900 1050 1200 1350
Cumula-
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bility
Plant Water Consump-on (tonnes/hr)
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CCS (40% Capture)
No CCS
Variable Results
Plant Type Super PC Super PC NGCC
EPS (1100 lb/MWh-‐g) No Yes No
Gross output (MW) 536 578 557
Net output (MW) 500 500 542
Net plant efficiency 38.2% 32.8% 50.1%
CO2 removal efficiency -‐ 40% -‐
Emissions rate (lb/MWh-‐g) 1687 1097 782
Consump6on Intensity (m3/MWh) 1.63 2.13 .67
Withdrawal Intensity (m3/MWh) 2.33 3.06 .89
Type 90% Capture (months)
Consum Intensity
Withdr Intensity
Avg Annual Consump
Avg Annual Withdr
12 months 4.75 2.10 3.00 6.9 E6 9.8 E6
84 months 36.1 2.14 3.05 7.0 E6 10 E6
Consistent 0 2.13 2.64 7.0 E6 8.7 E6
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on In
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Emissions Performance Standard (lb-‐MWh-‐gross)
PC
NGCC
