The Texas Commission on Environmental Quality on March 25 posted to its website a notice of intent to approve an air permit application for new generating capacity at a power plant of Golden Spread Electric Cooperative.
Golden Spread applied in July 2014 for issuance of Air Quality Permit 109148 and Prevention of Significant Deterioration (PSD) Air Quality Permit PSDTX1358M1.
Golden Spread Electric Cooperative (GSEC) owns and operates Antelope Elk Energy Center, a generating facility in Hale County made up of one General Electric 7F 5-Series combustion turbine-generator (CTG, currently under construction) and 18 quick start Wärtsilä engines (currently authorized via TCEQ Standard Permit Registration No. 91644), located near Abernathy, Texas.
GSEC is proposing to build three additional new CTGs at Antelope Elk Energy Center. GSEC expects the new facility to provide primarily peaking and intermediate power needs in a highly cyclical operation. The new units at Antelope Elk Energy Center will each be a new GE 7F 5-Series gas turbine operated in a simple cycle application, rated at a maximum output of 202 MW with a maximum design capacity of 1,941 million British thermal units per hour (MMBtu/hr). Each turbine will operate a maximum of 4,572 hours per year. Supply air will be compressed by the integral 14-stage compressor. Natural gas fuel will be combusted in GE’s Dry Low Nitrogen Oxide (DLN) 2.6 combustion systems and the combustion exhaust gases will power the 3-stage expansion turbines. The turbines are air-cooled, and evaporative air coolers are also used for inlet air cooling during summer peak ambient air temperatures.
Each new GE aero-derived turbine can achieve efficiency greater than 38.7% and produce up to 202 MW in cold weather and nominally 190.1 MW in peak summer. During normal startup, the turbine will achieve 50% capacity load in 30 minutes and thereafter operate at design emission limits.
The control technology review for simple cycle natural-gas fired turbine generators greater than 25 MW showed two control options that achieved the highest levels of control: lean burn technology with Selective Catalytic Reduction (SCR) emitting 2 parts per million by volume, dry (ppmvd) NOx corrected to 15% oxygen (O2); or DLN combustors with a maximum NOx emission rate of 9 ppmvd at 15% oxygen. GSEC proposes to use DLN.
The notice said: “GSEC has requested authorization to operate each unit up to 4,572 hours per year. TCEQ practice has been to require reduced hours (typically 2,500 per year) for simple cycle turbines at higher NOx levels such as proposed by GSEC. However, GSEC is constructing these three turbines in order to supply 600 MW that it is obligated to provide under its requirements contracts with its 16 distribution member system to supply their power requirements. The amount of generation needed was estimated from member load growth and expiring power purchase agreements with Xcel Energy. (Xcel served notice of termination of its contract with GSEC and will cease all sales to GSEC over a period of years ending in 2019.) Because these turbines provide backup to significant sources of wind generation, the timing of which is unpredictable, the turbines need to be authorized to operate about 4,500 hours per year. Fewer authorized hours per year would constitute a redefinition of the source / project.”