EPA’s Proposed Standards of 

Performance for Greenhouse Gas 

Emissions from New Stationary Sources

June 2014

1
Golden Spread Electric Cooperative, 

Inc.

 Mission: To Provide Excellent Service to our Distribution 

Members by Creating Opportunities, Cultivating Cooperation, and 

Navigating Industry Risks

 Headquarters: Amarillo, Texas

 Serves:

o Full Requirement Service to sixteen Electric Distribution 

Cooperatives (Members) 

o Members serve 223,000 Member Consumers and 24% of the 

geographic area of Texas along with the Oklahoma Panhandle

o Member Service Areas are located in Electric Reliability Council 

of Texas (ERCOT) and Southwest Power Pool (SPP)

o 2013 Member Peak Demand – 1,547 MW

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Impacts of Proposed NSPS on Natural 

Gas-Fired Combustion Turbines

 BSER for gas-fired combustion turbines 

based on natural gas combined cycle (NGCC) 

technology:

o Large unit limit is 1,000 lbs CO2/MWh 

o Small unit limit is 1,100 lbs CO2/MWh 

 Applies to a unit that is “constructed for the purpose 

of supplying, and supplies, one-third or more of its 

potential electric output and more than 219,000 

MWh net-electrical output to a utility distribution 

system on a 3 year rolling average basis.”

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Summary of Major Points

 Restricting SC operation to no more than 33% over 

a three year period may result in higher GHG 

emissions, where the requirement results in greater 

curtailment of renewable resources

o Fast ramping SCs support renewables more efficiently 

than combined cycle

 Market forces will naturally restrict the dispatch of 

SC units. 

 To support renewable energy generation, EPA 

should exempt SC units from its Proposed NSPS for 

EGUs.

4
Golden Spread’s Strategy

 Golden Spread is pursuing a strategy to 

combine its natural-gas fired “fast-start” SCs 

with the abundant wind generation in its 

region to produce “virtual baseload 

generation” that is reliable.

 Because of its unique location, Golden Spread 

is “tip of the spear” on this issue. 

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 Golden Spread is located in area with high renewable 

potential.

 ERCOT and SPP are completing significant transmission 

grid upgrades, enabling increased renewable integration.

 Golden Spread serves loads in two electric grids (SPP and 

ERCOT) which are not synchronously connected.

 Golden Spread is developing generation resources which 

will be able to connect to either grid.

Factors Affecting Renewable Potential

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Fast Start

 SPP defines a “fast-start” resource as one 

that can be started, synchronized and inject 

energy within ten minutes of notification.

o A modern SC unit can be at 70% load in 10 

minutes and 100% load in approximately 11 

minutes.

o Advanced CC units can be at 75% of combustion 

turbine capacity in 10 minutes and 100% load in 

approximately 2 1/2 hours, from a cold state.

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U. S. Wind Speeds

8
Renewable Energy in ERCOT

9
SPP and ERCOT Transmission Map

10
Golden Spread Member Service Territories

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 Single Generation Plant

 Vertically Integrated Electric Utility

 Electric Grid

 Independent System Operator (ISO) Coordinated Market

 ISO Market with Utility Scale Renewable Integration

 ISO Market with Distributed Generation and Demand 

Response

U.S. Electric Market Evolution

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 Steam Electric Station (Natural Gas, Coal Nuclear)

11, 600 BTU/kwh

 Combined Heat and Power (Natural Gas Cogeneration)

 Combined Cycle (Natural Gas fired)

7,000 BTU/kwh

 Simple Cycle (Natural Gas)

9,000 BTU/kwh

U. S. Generation Technology Evolution

13
ERCOT Wind Development

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Renewable Generation Patterns

ERCOT Load vs. Actual Wind Output

Renewable 

Generation Units 

typically 

experience daily 

cycles, with wind 

generation 

resources often 

peaking out of sync 

with peak 

consumer electric 

demands and solar 

resources peaking 

during the 

daytime. 

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ERCOT Monthly Wind Output

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SPP Dispatch Mix

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 In the early morning hours of June 7th, ERCOT experienced a 

wind generation reduction of approximately 5,000 

Megawatts*. 

 ERCOT total wind generations dropped by about half of its 

total peak, which exceeded the output of all four nuclear 

generation units currently operational within ERCOT. 

* ERCOT’s all time wind output of 10,296 MW occurred on 3/26/2014

ERCOT Wind Event June 7, 2014

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 Golden Spread operates two types of quick start generation 

units:

o Reciprocating Engines 

o Simple Cycle Combustion Turbines 

 SPP “Integrated Marketplace” began March 1

st, 2014

o Estimated to reduce consumer costs by $100 million annually.

o Improve market efficiencies

o Golden Spread’s Wartsila (Reciprocating Engine) units have 

increased their starts from approximately 200 starts/month to 

approximately 1,200 starts/month following the new market 

implementation. 

Golden Spread Quick Start Usage

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Wartsila Quick Start Generation Units

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GE 7FA 5 Series Combustion Turbine

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 Golden Spread’s Panhandle Wind Ranch operates in the 

Southwest Power Pool and has curtailed the output of the 

wind turbine generation.

 2013 Operations

o Actual Production 48% capacity, Potential Production 56% capacity

 2014 Jan – May Operations

o Actual Production 46% capacity, Potential Production 62% capacity

Golden Spread Wind Curtailment

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 Dispatchable generation units need to be cycled on 

and off more frequently to maintain grid reliability 

and accommodate variable renewable generation 

output.

 Operating dispatchable units at minimum output 

levels may force renewable units to curtail their 

output to maintain system reliability.

 Conventional combined cycle start-up time

 New design combined cycle start-up time

Combined Cycle vs. Simple Cycle

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Golden Spread Sample Grid

Fall/Spring Day in the Electric Power Market with High Wind and High CC Capacity

Hour 

Ending Demand Wind Nuclear Coal Gas SC Gas CC 2X2 

Gas 

1X1

Max Wind 

Potential

Wind 

Curtailed

1 2700 450 250 1350 0 0 650 850 400

2 2700 450 250 1350 0 0 650 800 350

3 2700 450 250 1350 0 0 650 825 375

4 2700 450 250 1350 0 0 650 835 385

5 2700 450 250 1350 0 0 650 715 265

6 2900 500 250 1500 0 0 650 650 150

7 2975 450 250 1600 25 0 650 600 150

8 3125 475 250 1750 0 0 650 500 25

9 3265 315 250 1900 150 0 650 415 100

10 3485 385 250 2000 200 0 650 450 65

11 3475 325 250 2000 250 0 650 325 0

12 3700 350 250 2000 350 750 0 350 0

13 3775 345 250 2000 330 850 0 345 0

14 3915 300 250 2000 415 950 0 300 0

15 4090 265 250 2000 525 1050 0 265 0

16 4235 235 250 2000 675 1075 0 235 0

17 4500 200 250 2000 950 1100 0 200 0

18 4450 225 250 2000 860 1115 0 225 0

19 4135 300 250 2000 585 1000 0 300 0

20 3990 375 250 2000 315 1050 0 375 0

21 3650 415 250 1800 185 1000 0 415 0

22 3250 400 250 1600 50 950 0 400 0

23 2950 400 250 1500 0 800 0 525 125

24 2700 400 250 1350 0 0 700 675 275

Total CC CO2 emissions in lbs 19,540,000 

Total 

MWh 5,865 11,690 7,850 11,575 2,665

Total CT CO2 emissions in lbs 7,624,500 

Total Combined CO2 27,164,500 

Assumptions

Generation 

(MW)

Max 

Load 

Output 

(MW)

Minimum 

Load 

Output 

(MW)

Nuclear 250 250

Coal 2,000 1,350

SC 1,350 0

CC 2X1 1,600 750

CC 1X1 1,100 650

Wind 1,100 0

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Golden Spread Sample Grid

Fall/Spring Day in the Electric Power Market with High Wind and High SC Capacity

Assumptions

Generation 

(MW)

Max 

Load 

Output 

(MW)

Minimum 

Load 

Output 

(MW)

Nuclear 

250 250

Coal

2,000 1,350

SC 2,350 0

CC 2X1 1,000 375

CC 1X1 700 300

Wind 1,100 0

Hour 

Ending

Deman

d MW Wind Nuclear Coal

Gas 

SC

Gas CC 2 x 

2

Gas CC 1 

x 1

Max Wind 

Potential

Wind 

Curtailed

1 2700 800 250 1350 0 0 300 850 50

2 2700 800 250 1350 0 0 300 800 0

3 2700 800 250 1350 0 0 300 825 25

4 2700 800 250 1350 0 0 300 835 35

5 2700 715 250 1350 0 0 385 715 0

6 2950 650 250 1500 125 0 425 650 0

7 2975 600 250 1600 200 0 325 600 0

8 3125 500 250 1750 250 0 375 500 0

9 3265 415 250 1900 275 425 0 415 0

10 3485 450 250 2000 285 500 0 450 0

11 3475 325 250 2000 350 550 0 325 0

12 3700 350 250 2000 450 650 0 350 0

13 3775 345 250 2000 480 700 0 345 0

14 3915 300 250 2000 565 800 0 300 0

15 4090 265 250 2000 675 900 0 265 0

16 4235 235 250 2000 750 1000 0 235 0

17 4500 200 250 2000 1000 1050 0 200 0

18 4450 225 250 2000 975 1000 0 225 0

19 4135 300 250 2000 635 950 0 300 0

20 3990 375 250 2000 515 850 0 375 0

21 3650 415 250 1800 350 835 0 415 0

22 3250 400 250 1600 200 800 0 400 0

23 2950 525 250 1500 50 0 625 525 0

24 2700 675 250 1350 0 0 425 675 0

Total CC CO2 emissions in lbs 14,770,00 Total MWh 8,130 11,010 3,760 11,575 110 

Total CT CO2 emissions in lbs 10,569,000 

Total Combined CO2 25,339,000 

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 Modern US LMP electric markets optimize the output of 

generators by location every five minutes (or less). 

 Market design rewards economic operation of electric 

generation units and incents inefficient generation units to be 

mothballed and retired. 

 Generation units with the lowest variable costs will operate most 

often. Units with higher variable costs will generally operate less 

often. Generation units with longer start up times may not 

operate frequently, particularly if load fluctuates rapidly or if 

high levels of low cost, variable renewable resources are 

available in the wholesale marketplace. Generation units with 

high startup costs will operate less often, unless they have

extremely low variable operating costs. 

US Locational Marginal Priced 

Wholesale Electric Markets

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Golden Spread “Virtual Baseload”

 Simple Cycle + Wind Farm

 Approximate 4,500 BTU/kwh 

(assuming 50 % capacity factor 

for wind farm)

 600 lbs/CO2 per MWh

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Because wind power is quickly assuming a greater 

role in the country’s generation portfolio, resources 

must be in place to maintain grid stability and meet 

load when weather conditions are not conducive to 

wind energy production.

Combined Cycle units, due to their performance 

characteristics, do not supplement renewable 

technologies as well as Simple Cycle Combustion 

Turbines in all cases, especially in areas of high 

renewable integration. 

Summary

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Summary continued...

Forcing generators to install combined cycle units 

where simple cycle units are indicated and 

limiting the hours of operations from such 

flexible ramping resources will force curtailments 

of renewable generation (because less generation 

will be available to support grid stabilization). 

Because simple cycle units have high operating 

costs, they will be the last to be dispatched unless 

there is good reason to dispatch them out-ofmerit, such as to support grid reliability or the 

use of renewable resources.

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 To support renewable energy generation, EPA should 

exempt Simple Cycle units from its Proposed NSPS for 

EGUs.

o To facilitate their support of renewable energy 

resources

o Because simple cycle units are not big contributors 

to global warming pollutants

o Because the newest simple cycle units have high 

energy efficiencies

o Because their use is inherently limited by production 

economics

Conclusion

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 New Electric Generating Plants in Texas since 1995, PUCT (slide 9) 

http://www.puc.texas.gov/industry/maps/elecmaps/gentable.pdf

 ERCOT, System Planning, Monthly Status Report, April 2014 (slide 14) 

http://www.ercot.com/calendar/2014/06/20140605-ROS, page 11.

 SPP State of the Market Report, December 2013 – February 2014 (slide 17) 

http://www.spp.org/publications/SPP_MSOM_Report_2013_14_Winter.pdf, p. 

14. 

 Potomac Economics, Ltd. Independent Market Monitor, June 2013, ERCOT 2012 

State of the Market Report (slide 16) 

http://www.potomaceconomics.com/uploads/ercot_reports/2012_ERCOT_SOM_

REPORT.pdf, page 66.

 ERCOT News Release, 2014 March 28, “Wind generation output in ERCOT tops 

10,000 MW, breaks record” (slide 18) 

http://www.ercot.com/news/press_releases/show/26611

 GSEC comments filed with EPA, Docket No. EPA-HQ-OAR-2013-0495, (slide 24-26) 

http://www.regulations.gov/contentStreamer?objectId=09000064816ede96&dis

position=attachment&contentType=pdf

References

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