On November 6, 2006, E&L Westcoast, LLC, (E&LW or "Applicant") a subsidiary of Competitive Power Ventures filed an Application for Certification (AFC) seeking approval from the California Energy Commission to develop the Colusa Generating Station (CGS). On December 13, 2006 the Commission accepted the AFC as complete, thus started the Commissions' formal review of the proposed CGS project.
The proposed CGS project is a 660-megawatt (MW) natural gas-fired, dry-cooled, combined-cycle electric generating facility. This project is in response to Pacific Gas & Electric's (PG&E) "Request for Offer" and a contract agreement signed with E&LW in 2006. The contract between PG&E and E&LW would transfer the ownership and operation of the proposed power plant to PG&E after completion of commissioning. The proposed CGS would be located in the unincorporated portion of Colusa County, approximately 14 miles north of the City of Williams and 4 miles west of Interstate I-5. The site is generally bounded by the Tehama-Colusa Canal to the west, the Glenn/Colusa County line to the north, the Glenn-Colusa Canal to the east, and Dirks Road to the southeast. The project would be located within a 31 acre portion of a 100-acre parcel site leased from the Holthouse Ranch. The power plant site access road, water supply intake access road and new transmission interconnection would require an additional 2.7 acres (Project Description Figures 1 & 2).
Grazing land surrounds the 100-acre leased area immediately to the west, north, and south. The nearest actively farmed land is located approximately one mile southeast of proposed project location. The PG&E Delevan natural gas compressor station and Cottonwood to Vaca-Dixon transmission corridor (230kV overhead electric lines) are located immediately to the east of the proposed project site (Project Description Figures 2 & 3).
Colusa County currently designates the project site as Agriculture-General and zones the site as Exclusive Agriculture. The Applicant has submitted applications to the Colusa County Planning and Building Department requesting a general plan amendment and rezone of the site to designations more consistent for an industrial use. Please see the Land Use section of this document for a discussion of the project's land use consistency with local land use plans.
The following are the major components of the power plant (Project Description Figures 4 & 5):
- two General Electric (GE) Power Systems Frame 7FA combustion gas turbine generators (CTGs) equipped with dry low NOx combustors designed for natural gas;
- two multi-pressure heat recovery steam generators (HRSGs) with duct burners and a selective catalytic reduction system (to be used with aqueous ammonia);
- one steam turbine-generator (STG) system with multi-cell air cooled condenser: and associated auxiliary system and equipment (i.e., lubrication oil system including oil coolers and filters, and generator coolers);
- a 1000, kW standby diesel generator for extended utility outages during maintenance and shutdowns;
- 12 new transmission towers with 4 double-circuit 230 kV lines interconnecting to the existing PG&E transmission system; and
- a 4 inch, 2,700 foot water pipeline providing water to the project from the Tehama Colusa Canal.
- an 8 inch, 1,500 foot natural gas pipeline from PG&E's Compressor Station.
The project would use air-cooled condenser ("dry") cooling technology for its operation, thereby significantly reducing the amount of water needed for plant operation when compared to other power plants that use evaporative cooling technology.
Output of the generators would be connected to step-up transformers and then to a new CGS switchyard that would connect to 12 new lattice transmission towers for the electrical tie in to PG&E's existing 230 kV transmission lines.
The project would also employ a zero-liquid discharge system where the water from the combustion turbine generator's evaporative coolers is recovered for reuse in the plant and the remaining salts are concentrated for disposal off site (06-AFC-9).
Natural gas would be supplied to the CGS site via a new 8 inch, 1,500-foot-long pipeline interconnected to the PG&E gas transmission system located east of the proposed project site. The pressure reducing/metering station would be located within the CGS facility. The pipeline tap would be located adjacent to the existing PG&E natural gas compressor station (Project Description Figure 4).
The project would require approximately 126 acre-feet of water per year. The Glenn-Colusa Irrigation District would provide water to the CGS, via Colusa County and the Tehama-Colusa Canal. The Central Valley Project provides water to the Glenn-Colusa Irrigation District. Construction of a new 4-inch diameter, 2,700-foot long water pipeline from the Tehama-Colusa Canal to the CGS site would be required (Project Description Figure 4).
As part of the CGS project, a new switchyard would be constructed immediately north of the power plant site, which would be operated by PG&E. Generation from the CGS would be delivered to PG&E's high voltage transmission grid (the 230 kV Cottonwood to Vaca-Dixon transmission corridor), located approximately 1,800 feet east of the proposed switchyard. The transmission interconnection would require approximately 12 new steel lattice transmission towers with 4, 230 kV double-circuit conductors to be installed between the PG&E right-of-way and the CGS switchyard. The structure heights vary from 100 to 125 feet depending on configuration of the site and terrain (Project Description Figure 4).
project construction and operation
If approved by the Energy Commission, E&LW proposes to initiate construction of the CGS in spring 2008 and be completed by spring of 2010, provided there are no delays. The onsite construction workforce would peak at 669 workers in April of 2009. Construction costs are estimated to be $450 to $500 million. Operation of the CGS will require 31 full-time permanent staff. The plant will be operated 7 days a week 24 hours a day.
Primary construction access would be from I-5 to Delevan Road to McDermott Road to Dirks Road, west to the project site adjacent to the existing PG&E gas compressor station. On the northeast side of the site, 43 acres of the 100-acre parcel will accommodate storage of construction materials, equipment, construction offices and parking which the Applicant proposes to restore and re-vegetate after construction is complete (Project Description Figure 3).
Road and Bridge construction
The Teresa Creek Bridge (on McDermott Road, 5/8-mile north of Delevan Road) cannot currently accommodate heavy construction truck traffic and is would be replaced by the Applicant. The new bridge would either be a clear span bridge or a prefabricated bridge. The bridge type selected is dependent upon the project schedule (Project Description Figure 3).
The Glen-Colusa Canal Bridge (Dirks Road west of I-5) cannot currently accommodate heavy construction or two-way truck traffic. The bridge was originally designed for 40-ton load, but currently rated for 20-ton loads. The new bridge will be a free-span steel beam and concrete structure approximately 100 feet long by 30 feet wide. The new bridge would allow for two-way unimpeded traffic flow. No piers will be constructed in the canal to support the bridge. This new bridge would be capable of handling the heaviest loads required for the construction and operation or the power plant (Project Description Figure 3).
Additionally, to accommodate the wide turning radii of some heavy construction vehicles, the Applicant proposes to widen the northeastern and southeastern corners of the intersection of Delevan and McDermott roads. The Applicant would grade and place gravel at these corners. This would require relocation of the stop sign and telephone conduit box currently located at the northeastern corner of the intersection (Project Description Figure 3).