Title: The Effects of Greenhouse Gas Limits on Electric Power System Dispatch and Operations
1The Effects of Greenhouse Gas Limits on Electric
Power System Dispatch and Operations
1
Miaolei Shao (mxshao_at_wichita.edu) Ward Jewell
(ward.jewell_at_wichita.edu) Department of
Electrical and Computer Engineering Wichita State
University
PSERC Tele-Seminar September 2nd, 2008
2Greenhouse Gas (GHG) Emissions Electric Power
Industry
2
- United States is the source of 1/4 of the worlds
GHG emissions. - Electric power industry accounts for 38 percent
of the nations 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)
3Electric Power System Features That Impact CO2
Emissions
3
- CO2 emission factors by type of fuel
- Unit thermal efficiency
- Regional generation mix
- Electricity demand
- Transmission constraints
4CO2 Emission Factors (EF) by Type of Fuel (lb
CO2/MBtu)
4
Source S. Goodman, M. Walker, Benchmarking air
emissions of the 100 largest electric power
producers in the united states 2004, Apr. 2006
55
CO2 Emission Factors (EF) by Type of Fuel (Cont.)
Bus 1
Bus 2
P1 400 MW
800 MW Load
G1 (400 MW coal-fired generation unit)
400 MW
P2 400 MW
Two-bus, two-generator power system
G2 (400 MW gas-fired generation unit)
CO2 emission factor is 215 lbs/Mbtu for coal and
117 lbs/Mbtu for gas.
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.
66
Unit thermal Efficiency and CO2 Emissions
One kilowatt hour (kWh) has a thermal equivalent
of approximately 3412 Btu.
77
Regional Generation Mix CO2 Emissions
Bus 1
Bus 2
P1 400 MW
600 MW Load
G1 (400 MW coal-fired generation unit)
400 MW
P2 200 MW
Two-bus, two-generator power system
G2 (400 MW gas-fired generation unit)
Bus 1
Bus 2
P1 400 MW
600 MW Load
G1 (400 MW coal-fired generation unit)
600 MW
P2 0 MW
P3 200 MW
Two-bus, three-generator power system
G2 (400 MW gas-fired generation unit)
G3 (400 MW coal-fired generation unit)
88
Regional Generation Mix CO2 Emissions (Cont.)
527
450
(G3)
(G2)
(G1)
(G1)
99
Electricity Demand CO2 Emissions
Load L (MW)
800
Load-duration curve
600
400
Hours load equals or exceeds L MW
Bus 2
400 MW Load
600 MW Load
Bus 1
P1 400 MW
800 MW Load
G1 (400 MW coal-fired generation unit)
400 MW
P2 0 MW
P2 200 MW
P2 400 MW
Two-bus, two-generator power system
G2 (400 MW gas-fired generation unit)
1010
Electricity Demand CO2 Emissions (Cont.)
CO2 emission amounts (tons/h)
CO2 emission rates (tons/MWh)
1111
Transmission Constraints CO2 Emissions
Bus 1
Bus 2
P1 400 MW
600 MW Load
G1 (400 MW coal-fired generation unit)
400 MW
P2 200 MW
400 MW maximum transmission capability between
bus 1 and bus 2
G2 (400 MW gas-fired generation unit)
Bus 1
Bus 2
P1 300 MW
600 MW Load
G1 (400 MW coal-fired generation unit)
300 MW
P2 300 MW
300 MW maximum transmission capability between
bus 1 and bus 2
G2 (400 MW gas-fired generation unit)
1212
Transmission Constraints CO2 Emissions (Cont.)
Transmission congestion help reduce system CO2
emissions?
450
412
(G2)
(G2)
(G1)
(G1)
1313
CO2 Emission-incorporated Cost Model
Input-output function
Fuel cost function
CO2 emission cost function
Fuel-emission cost function
1414
Fossil-fired Generation Units Cost Variation
Due to CO2 Emissions
- 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
Fuel costs
CO2 emission costs
Fuel-emission costs
G1 (400 MW coal-fired generation unit)
G2 (400 MW gas-fired generation unit)
1515
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
- Breakeven price of CO2 is around 50 /ton
- Gas price is 5.7 /MBtu
- Breakeven price of CO2 is around 100 /ton
1616
CO2 Emission-constrained ac Optimal Power Flow
(OPF)
Objective function
Equality constraints
Inequality constraints
Linear Programming
Software used in this research PowerWorld
Simulator
17IEEE Reliability Test System (RTS)
17
- 24 buses
- 38 transmission lines and transformers.
- a total load of 2850 MW
- a total generation capacity of 3405 MW
1818
Simulation Cases and Description
19Simulation Results of Case 1
19
70 /ton
180 /ton
280 /ton
- 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. - At CO2 price of 280 /ton, major shifting
process is finished.
- 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.
20Simulation Results of Case 1 (Cont.)
20
70 /ton
180 /ton
280 /ton
21Simulation Results
21
70 /ton
180 /ton
280 /ton
130 /ton
270 /ton
410 /ton
Case 2
Case 1
22Simulation Results (Cont.)
22
80 /ton
180 /ton
130 /ton
260 /ton
Case 4
Case 3
23Conclusions
23
- 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.
24Future Research
24
PSERC Project M21 Technical and Economic
Implications of Greenhouse Gas Regulation in a
Transmission Constrained Restructured Electricity
Market
Academic Team Members Ward Jewell (lead),
Wichita Shmuel Oren, UC Berkeley Chen-Ching Liu,
University College Dublin Yishu Chen, UC Merced
Industry Team Members 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
25Thank You
25