- Docket Number
- 110 MW
- Sonoma County
- Steam Turbine
- Project Status
- Operational (Geothermal)
- Project Type
- Application for Certification
The Socrates Geothermal project (Unit 18) is in Sonoma County near the Sonoma/Lake County line, in the Geysers Known Geothermal Resource Area along the ridgeline of the Mayacamas Mountains with moderately steep terrain, approximately 15 miles west of the town of Cobb. Unit 18, originally known as Pacific Gas & Electric Company’s (PG&E) Geysers Unit 18 Geothermal Project was certified by the California Energy Commission (CEC) in May 1980 and began commercial operation in November 1982.
Unit 18 is a dry-steam geothermal plant and was designed to provide up to 110 MW; however, due to reduced steam pressures, the plant currently supplies approximately 50 megawatts of base-load electricity to northern California's power grid. The major structures of the proposed facility are a turbine building, cooling tower, electrical switchyard, and a hydrogen sulfide abatement facility. The turbine building would house the steam turbine generator and other associated equipment required for electrical power production. The mechanical draft cooling tower would dissipate to abate hydrogen sulfide (H2S) emissions using a Stretford System which scrubs heat from the H2S from the vent gas stream from the condenser and catalytically oxidizes the gas to eliminate Sulfur.
In April 1999, the CEC granted a transfer of ownership of Socrates Geothermal (Unit 18), the former PG&E Geysers Unit 18 Geothermal Project to Geysers Power Company, LLC, a wholly owned subsidiary of the Calpine Corporation.
Modification of Compliance Plan to Add Approved Change to AQ-55, Not in Docket, 03/25/1983, Order No. 83-0325, Commission approval to modification of condition of certification AQ-55 in the project Compliance Plan.
Approval of Requested Changes to Verifications for Conditions of Certification, Not in Docket, 03/23/1995, Staff approval of verification changes for Conditions of Certification Air Quality 2-1 subparts 16 and 58.
Commission Order Approving Ownership Transfers, TN 11773, 04/22/1999, Order No. 99-0414-01b, Commission approval of ownership transfer from PG&E to Geysers Power Company.
Approval of Petition to Use Reclaimed Wastewater and Approval of Verification Changes, TN 31109, 03/12/2004, Staff approval of the use of reclaimed municipal wastewater at the six Calpine Geysers geothermal power plants as well as revision of the reporting requirements in the condition of certification verifications.
Approval of Requested Changes to Verifications for Conditions of Certification, Not in Docket, 03/23/1995, Staff approval of verification change to condition of certification AQ 1-2, subparts 16 and 58.
Authorization for Calpine to Obtain Demolition Permits from Sonoma and Lake Counties for Demolition, TN 206306, 11/19/2015, Staff approval for Calpine to obtain and implement county-issued demolition permits to abate fire damage to structures at Geysers 16, 18, and 20.
Expedited Processing Pursuant to Executive Order B-36-15, TN 206740, 11/23/2015, Executive Director approval of emergency reconstruction activities to include the repair, reconstruction, and/or replacement-in-kind of the cooling tower damaged in the Valley Fire.
Expedited Processing Pursuant to Executive Order B-36-15, TN 207191, 01/05/2016, Executive Director approval of expedited processing pursuant to Executive Order B-36-15 directing staff to to docket the ATC, and incorporate these provisions into the Energy Commission's Unit 18 Final Decision.
Resolution Approving (DCBO) services for fire system recommissioning activities at the Geysers facilities, TN 230277, 10/18/2019, Resolution No. 19-1014-04, Approval of Agreement 700-19-003 with NV5, Inc. for a $0 contract to provide delegate chief building official services for fire system recommissioning activities at the Geysers facilities.
Commission Order Approving to Replace Temporary Portable Emergency Diesel Engines at the Quicksilver, Socrates, and Grant Geothermal Power Plants, TN 226128, Order No. 18-1210-02, Commission approval to make identical modifications at each of the facilities with stationary permanent to replace temporary portable emergency diesel engines emergency diesel engines for the cooling tower wet-down systems to aid in fire prevention at the Quicksilver, Socrates, and Grant geothermal power plants.
Resolution Approving (DCBO) services for fire system recommissioning activities at the Geysers Facilities, TN 230279, 10/18/2019, Resolution No. 19-1014-04, Approval of Agreement 700-19-003 with NV5, Inc. for a $0 contract to provide delegate chief building official services for fire system recommissioning activities at the Geysers facilities.
Order Approving Settlement for Fire Protection System at the Six Geyser Facilities, TN 235700, 11/19/20, Order No. 20-1116-02, Commission approval of the Settlement Agreement and changes to the conditions of certification and direct the Executive Director to execute the Settlement Agreement on behalf of the CEC.
Attention: Non-hypertext items above will need to be requested from the Compliance Project Manager, along with the document TN number, if provided above.
Power Plant Certification and Exemption Processes
As required by the Warren-Alquist Act, the Energy Commission monitors projects under its jurisdiction throughout construction, operation, and closure to ensure compliance with the conditions of certification imposed for approving the projects.