El Centro Generating Station Unit 3

Imperial Irrigation District (IID) proposes to replace an existing steam-generating unit within the site of the existing El Centro Generating Station (ECGS) located in El Centro, Imperial County, California. The El Centro Unit 3 Repower Project would be owned and operated by IID. The Unit 3 repower will continue to serve the growing electrical load demands of the region.

The Unit 3 repower will replace an existing boiler with a General Electric Frame 7EA dry low NOx combustion turbine generator and heat recovery steam generator to supply steam to the existing steam turbine generator. The generator output from the Unit 3 repower will be stepped-up to transmission system voltage and interconnected to the existing IID El Centro Switching Station also located within the ECGS property. Most of the existing Unit 3 plant systems will continue to be used with only minor modifications. The Unit 3 repower will increase the existing Unit 3 generating capacity by 84 MW from 44 MW to 128 MW.

The new combustion turbine generator step-up transformer will interconnect with the existing 92-kV portion of the El Centro Switching Station via an overhead line approximately 2,350 feet long and 50 to 80 feet high. The interconnection facilities are entirely within the existing El Centro Switching Station and adjacent areas within the EGCS property.

The Unit 3 repower will interconnect to the existing Southern California Gas Company high pressure gas metering station located on the existing ECGS property. The connection will occur via two existing pipelines running south from the Gas Company's Niland regulating station to the ECGS. Minor modifications at the ECGS site will be performed to support the proposed project including changes to the metering station for increasing the flow of high-pressure gas through the station serving the new Unit 3 combustion turbine.

Annual water consumption for the Unit 3 repower is expected to be approximately 1,125 acre-feet. The existing ECGS uses raw water from IID's Dogwood surface canal Gate 54B for cooling tower make-up. An existing demineralization system treats the raw water to provide high quality make-up water. These existing systems will be used to meet the expected water requirements for the proposed project. IID also proposes to eliminate the discharge from the entire ECGS and dispose of the wastewater to a deep injection well system, consisting of two Class I non-hazardous wastewater deep injection wells approximately 2,000 feet below ground surface. These wells will be located on the ECGS property.