- Docket Number
- 250 MW
- Stanislaus County
- Combined Cycle
- Project Status
- Operational (Natural Gas-Fired)
- Project Type
- Application for Certification
The Walnut Energy Center (WEC) located on 18 acres within a 69-acre parcel in an industrially zoned area, about 4 miles west of the downtown portion of the City of Turlock, Stanislaus County. The site is located southeast of the intersection of West Main Street and South Washington Road.
WEC is a nominal 250-megawatt gas-fired, combined-cycle power plant consisting of two General Electric Frame 7EA combustion turbine generators equipped with dry, low oxides of nitrogen combustors; two heat recovery steam generators; one condensing steam turbine generator; a de-aerating surface condenser; a five-cell mechanical-draft cooling tower; and associated support equipment. Additional components include an advanced water treatment facility, administration and control building, emission control equipment, storage tanks, parking area, and one or more stormwater detention ponds.
WEC’s 2004 CEC Decision approved the use of potable water from the City as an interim supply, or “bridge supply,” for cooling, steam cycle make up and also as a back-up supply until the wastewater treatment plant was able to produce recycled water. Once recycled water was made available, potable water was permitted for use as a back-up source of water in the event of a short-term interruption in recycled water delivery. The use of potable water as a back-up supply after the bridge supply period was limited to 51 acre-feet per year (afy), calculated using a 5-year rolling average. Operation of WEC requires up to 1,800 afy of water, approximately 98 percent of which is used for cooling purposes.
On January 19, 2005, the California Energy Commission (CEC) approved a Post-Certification Amendment (PCA) to replace potable water as its bridge water supply with lower quality ground water from two wells drilled into the upper aquifer; to allow use of potable water for construction instead of upper aquifer well water from TID’s WPP and substation.
On July 27, 2005, the CEC approved a PCA (TN 36090) to modify the number and locations of the bridge and backup plant water supply wells and changes the definition of the “bridge period".
In August 27, 2013, the Energy Commission approved a PCA (TN 200536) to amend soils and water condition of certification to allow for additional back-up water supply.
Power Plant Certification and Exemption Processes
As required by the Warren-Alquist Act, the Energy Commission monitors Commission-certified energy projects throughout construction, operation, and closure to ensure compliance with the conditions of certification imposed by the Commission’s Final Decision for approving the projects.