Transcript Document

1
The Effects of Greenhouse Gas
Limits on Electric Power System
Dispatch and Operations
Miaolei Shao ([email protected])
Ward Jewell ([email protected])
Department of Electrical and Computer Engineering
Wichita State University
PSERC Tele-Seminar
September 2nd, 2008
2
Greenhouse Gas (GHG) Emissions &
Electric Power Industry
• United States is the source of 1/4 of the world’s GHG emissions.
• Electric power industry accounts for 38 percent of the nation’s overall
carbon dioxide (CO2) emissions and one-third of the overall U.S. GHG
emissions.
• 39 states have or are developing State Action Plans specially targeting
GHG emission reductions.
-- Regional Greenhouse Gas Initiative (RGGI)
-- California Assembly Bill 32 (AB 32)
3
Electric Power System Features That
Impact CO2 Emissions
• CO2 emission factors by type of fuel
• Unit thermal efficiency
• Regional generation mix
• Electricity demand
• Transmission constraints
4
CO2 Emission Factors (EF) by Type of
Fuel (lb CO2/MBtu)
Coal
EF
Oil
EF
Gas
EF
Bituminous
205
Distillate oil
161
Natural gas
117
Subbituminous
213
Jet fuel
156
Propane
139
Lignite
215
Kerosene
159
Anthracite
227
Petroleum coke
225
Residual
174
Source: S. Goodman, M. Walker, “Benchmarking air emissions of the 100 largest electric power
producers in the united states – 2004”, Apr. 2006
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CO2 Emission Factors (EF) by Type of
Fuel (Cont.)
P1 = 400 MW
G1 (400 MW coalfired generation unit)
Bus 1
Bus 2
800 MW Load
400 MW
Two-bus, two-generator
power system
P2 = 400 MW
G2 (400 MW gasfired generation unit)
CO2 emission factor is 215 lbs/Mbtu for
coal and 117 lbs/Mbtu for gas.
(346  198) tons / h
 0.68 tons / MWh
800 MW
Heat rate data of 400 MW fossil fired generation units came from “A. J. Wood, B. F. Wollenberg, Power Generation,
Operation, and Control, John Wiley & Sons, 1996.”
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Unit thermal Efficiency and CO2 Emissions
G1 (400 MW coal-fired
generation unit)
Efficiency
(400 MW)
Efficiency + 1%
Efficiency + 3%
Efficiency (%)
37.9%
38.9%
40.9%
CO2 emissions (tons/h)
345.5
336.7
320.2
CO2 emission reduction (%)
N/A
-2.5%
-7.3%
Efficiency + 1%
Efficiency + 3%
G2 (400 MW gas-fired
generation unit)
Efficiency
(400 M)
Efficiency (%)
35.9%
36.9%
38.9%
CO2 emissions (tons/h)
198.5
193.1
183.2
CO2 emission reduction (%)
N/A
-2.7%
-7.7%
One kilowatt hour (kWh) has a thermal equivalent of approximately 3412 Btu.
7
Regional Generation Mix & CO2 Emissions
P1 = 400 MW
Bus 1
G1 (400 MW coalfired generation unit)
Bus 2
600 MW Load
400 MW
P2 = 200 MW
Two-bus, two-generator
power system
P1 = 400 MW
G1 (400 MW coalfired generation unit)
Bus 1
G2 (400 MW gasfired generation unit)
Bus 2
600 MW
600 MW Load
P2 = 0 MW
P3 = 200 MW
G3 (400 MW coalfired generation unit)
Two-bus, three-generator
power system
G2 (400 MW gasfired generation unit)
Regional Generation Mix & CO2 Emissions
(Cont.)
527
450
(G2)
(G1)
450 tons / h
 0.75 tons / MWh
600 MW
(G3)
(G1)
527 tons / h
 0.88 tons / MWh
600 MW
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9
Electricity Demand & CO2 Emissions
Load L (MW)
800
Load-duration curve
600
400
Hours load equals or
exceeds L MW
Bus 2
P1 = 400 MW
G1 (400 MW coalfired generation unit)
Bus 1
400 MW Load
600 MW Load
800 MW Load
400 MW
P2 = 0 MW
P2 = 200 MW
Two-bus, two-generator
power system
P2 = 400 MW
G2 (400 MW gasfired generation unit)
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Electricity Demand & CO2 Emissions (Cont.)
CO2 emission amounts (tons/h)
346 tons / h
 0.87 tons / MWh
400 MW
450 tons / h
 0.75 tons / MWh
600 MW
544 tons / h
 0.68 tons / MWh
800 MW
CO2 emission rates (tons/MWh)
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Transmission Constraints & CO2 Emissions
P1 = 400 MW
Bus 1
G1 (400 MW coalfired generation unit)
Bus 2
600 MW Load
400 MW
P2 = 200 MW
400 MW maximum
transmission capability
between bus 1 and bus 2
P1 = 300 MW
G1 (400 MW coalfired generation unit)
Bus 1
G2 (400 MW gasfired generation unit)
Bus 2
300 MW
300 MW maximum
transmission capability
between bus 1 and bus 2
600 MW Load
P2 = 300 MW
G2 (400 MW gasfired generation unit)
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Transmission Constraints & CO2 Emissions (Cont.)
450
412
Transmission congestion help
reduce system CO2 emissions?
(G2)
(G2)
(G1)
(G1)
450 tons / h
 0.75 tons / MWh
600 MW
412 tons / h
 0.69 tons / MWh
600 MW
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CO2 Emission-incorporated Cost Model
Input-output function
H fuel _ ij (Pi )  ki 0  ki1Pi  ki 2 Pi 2
Fuel cost function
Ffuel _ ij (Pi )  C j (ki 0  ki1Pi  ki 2 Pi 2 )
CO2 emission cost function
FCO2 _ ij (Pi )  CCO2  ef j  (ki 0  ki1Pi  Ki 2 Pi 2 )
Fuel-emission cost function
Ffe _ ij ( Pi )  Ffuel _ ij (Pi )  FCO2 _ ij (Pi )
 (C j  CCO2  ef j )(ki 0  ki1Pi  ki 2 Pi 2 )
Fossil-fired Generation Units’ Cost Variation
Due to CO2 Emissions
4
4
x 10
2.2
2
2
1.8
1.8
1.6
1.6
1.4
1.4
Costs ($/h)
Costs ($/h)
2.2
1.2
1
0.6
0.6
0.4
0.4
0.2
0.2
0
0
300
400
Output, P (MW)
G1 (400 MW coalfired generation unit)
• Coal price is 1.90 $/MBtu
• CO2 emission factor of coal
is 215 lb/MBtu
• Gas price is 3.80 $/MBtu
• CO2 emission factor of gas is
117 lb/MBtu
• CO2 price is 30 $/ton
1
0.8
200
x 10
1.2
0.8
100
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Fuel costs
100
200
300
400
Output, P (MW)
G2 (400 MW gasfired generation unit)
CO2 emission
costs
Fuel-emission
costs
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Breakeven Price of CO2
Coal price is 1.90 $/MBtu
Coal CO2 emission factor is 215 lb/MBtu
Gas CO2 emission factor is 117 lb/MBtu
• Gas price is 3.8 $/MBtu
• Gas price is 5.7 $/MBtu
• Breakeven price of CO2 is around 50 $/ton
• Breakeven price of CO2 is around 100 $/ton
CO2 Emission-constrained ac
Optimal Power Flow (OPF)
Objective function
Ng
F
Equality constraints
Inequality constraints
i 1
Ng
fe _ ij
i 1
P  P
i 1



( Pi )   Ffuel _ ij ( Pi )  FCO2 _ ij ( Pi )
Ng
i
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Load
 PLoss
Pi  Pi  Pi
Ng
Q  Q
i 1

Ek  Ek  Ek
i
Load
 QLoss
Qi  Qi  Qi
 k   k   k


MVAmn
 MVAmn  MVAmn
Linear Programming
Software used in this research: PowerWorld Simulator
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IEEE Reliability Test System (RTS)
• 24 buses
• 38 transmission lines and
transformers.
• a total load of 2850 MW
• a total generation capacity
of 3405 MW
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Simulation Cases and Description
Case
#
Description
Fuel Prices ($/MBtu)
Coal
Gas
Oil
System
Load (MW)
1
Medium fuel price and
normal system load
1.88
9.09
12.00
1995
2
High fuel price and
normal system load
1.95
12.74
16.37
1995
3
Medium fuel price and
peak system load
1.88
9.09
12.00
2850
4
High fuel price and peak
system load
1.95
12.74
16.37
2850
Simulation Results of Case 1
Power Output (MW)
1200
70 $/ton
180 $/ton
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280 $/ton
1000
800
Coal
600
Gas
400
Oil
200
Nuclear
• At CO2 price of 70 $/ton, coal and gas
power generation start to shift.
• At CO2 price of 180 $/ton, gas power
generation almost equals coal power
generation.
Hydro
0
0
50
• At CO2 price of 280 $/ton, major
shifting process is finished.
100 150 200 250 300 350 400 450
1000
800
600
400
200
0
400000
320000
240000
160000
80000
0
0
50 100 150 200 250 300 350 400 450
CO2 Price ($/ton)
Total CO2 Emissions (tons/hr)
CO2 Emission Costs ($/hr)
Fuel Costs ($/hr)
Fuel-Emission Costs ($/hr)
Costs ($/h)
Total CO2 Emissions (tons/h)
CO2 Price ($/ton)
• CO2 emissions decrease from 928
tons/h at CO2 price of 0 $/ton to 514
tons/h at CO2 price of 280 $/ton, a 44.6%
reduction.
• The system fuel costs increase from
18595 $/h at CO2 price of 0 $/ton to
79255 $/h at CO2 price of 280 $/ton, a
326% increase.
Simulation Results of Case # 1 (Cont.)
Power Output (MW)
1200
70 $/ton
180 $/ton
280 $/ton
1000
800
Coal
600
Gas
400
Oil
200
Nuclear
Hydro
0
0
50
100 150 200 250 300 350 400 450
CO2 Price ($/ton)
20
21
Simulation Results
130 $/ton
1200
1200
1000
1000
800
Coal
600
Gas
400
Oil
200
Nuclear
Power Output (MW)
Hydro
0
0
50
Coal
600
Gas
400
Oil
200
Nuclear
Hydro
0
0
50
100 150 200 250 300 350 400 450
CO2 Price ($/CO2)
400000
800
320000
600
240000
400
160000
200
80000
0
50
100 150 200 250 300 350 400 450
CO2 Price ($/ton)
Total CO2 Emissions (tons/h)
CO2 Emission Costs ($/h)
Fuel Costs ($/h)
Fuel-Emission Costs ($/h)
Case # 1
Totoal CO2 Emissions (tons/h)
1000
Costs ($/h)
Total CO2 Emissions (tons/h)
CO2 Price ($/ton)
0
410 $/ton
800
100 150 200 250 300 350 400 450
0
270 $/ton
1000
400000
800
320000
600
240000
400
160000
200
80000
0
0
0
50
100 150 200 250 300 350 400 450
CO2 Price ($/CO2)
Total CO2 Emissions (tons/h)
CO2 Emission Costs ($/h)
Fuel Costs ($/h)
Fuel-Emission Costs ($/h)
Case # 2
Costs ($/h)
Power Output (MW)
70 $/ton 180 $/ton 280 $/ton
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Simulation Results (Cont.)
130 $/ton 260 $/ton
1400
1400
1200
1200
1000
Coal
800
Gas
600
Oil
400
Nuclear
200
Power Output (MW)
0
Coal
800
Gas
600
Oil
400
Nuclear
200
Hydro
0
1000
Hydro
0
0
50 100 150 200 250 300 350 400 450
50
100 150 200 250 300 350 400 450
CO2 Price ($/ton)
800000
1450
600000
1400
400000
1350
1300
200000
1250
0
0
50 100 150 200 250 300 350 400 450
Total CO2 Emission (tons/h)
1500
Costs ($/h)
Total CO2 Emission (tons/h)
CO2 Price ($/ton)
1500
800000
1450
600000
1400
400000
1350
1300
200000
1250
0
0
50 100 150 200 250 300 350 400 450
CO2 Price ($/ton)
CO2 Price ($/ton)
Total CO2 Emissions (tons/h)
CO2 Emission Costs ($/h)
Total CO2 Emissions (tons/h)
CO2 Emission Costs ($/h)
Fuel Costs ($/h)
Fuel-Emission Costs ($/h)
Fuel Costs ($/h)
Fuel-Emission Costs ($/h)
Case # 3
Case # 4
Costs ($/h)
Power Output (MW)
80 $/ton 180 $/ton
Conclusions
•
CO2 emissions from electric power industry are impacted by several power
system features; ignoring any of them will incur errors in analysis.
•
CO2 emission-constrained ac OPF is a powerful tool that considers all the
features that impact CO2 emissions from electric power generation.
•
CO2 emission-constrained ac OPF, which can be realized in commercial and
educational power system software or developed as stand-alone software, has
potential to be utilized for investigating and assessing the effects, including costs
and reliability, of GHG limits on electric power industry.
•
Simulation results indicate that the effects of GHG limits on electric power
system dispatch and operations are sensitive to several factors such as system
load levels, fuel prices etc.
•
In current high gas price situation, it is quite expensive to reduce CO2 emissions
by switching from coal power generation to gas power generation.
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Future Research
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PSERC Project M21: “Technical and Economic Implications of
Greenhouse Gas Regulation in a Transmission Constrained
Restructured Electricity Market”
Academic Team Members:
Industry Team Members:
Ward Jewell (lead), Wichita
Shmuel Oren, UC Berkeley
Chen-Ching Liu, University
College Dublin
Yishu Chen, UC Merced
Jim Price, CAISO
Mariann Quinn, Duke Energy
Floyd Galvan, Entergy
Mark Sanford, GE
Jay Giri, AREVA
Tongxin Zheng, ISO-NE
Ralph Boroughs, TVA
Robert Wilson, WAPA
Avnaesh Jayantilal, AREVA
Jerry Pell, DOE
Sundar Venkataraman, GE Energy
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Thank You