- Docket Number
- 110 MW
- Sonoma County
- Steam Turbine
- Project Status
- Operational (Geothermal)
- Project Type
- Application for Certification
Northern California Power Agency (NCPA) Geothermal Plant No. 2 (NCPA-2) (formerly NCPA-3) is located near the town of Anderson Springs, in Sonoma County, on federally owned lands in the Geysers Known Geothermal Resource Area (KGRA). The federal lands are administered by the Bureau of Land Management and the Minerals Management Service.
NCPA-2 is a 55-megawatt (MW) generating geothermal facility consisting of two 55 MW turbine generators; multiple cell, double flow, mechanically induced draft cooling towers; a transmission switchyard, adjacent to the turbine generator building, containing a 13.8 kilovolt to 230 kV step-up transformer; and, a hydrogen sulfide (H2S) abatement system. Primary treatment will be through a Stretford system, in which H2S is scrubbed from the vent gas stream and catalytically oxidized to elemental sulfur. NCPA will use a hydrogen peroxide secondary H2S abatement system to further reduce emissions to an acceptable level.
NCPA-2 was initially designed and operated as a 110-MW facility comprised of two steam turbines units (units 3 and 4). However, due to the current steam field degradation, there is only enough steam to operate a single 55 MW steam turbine. Unit 4 was modified to accept the reduced new steam conditions. In April 2010, NCPA-2 put unit 3 in a non-operational state, which is not physically connected to the switchyard or grid. In 2014, NCPA-2 demolished and removed the cooling tower associated with unit 3. The current output for the facility is only 55 MW.
Currently, NCPA-2 is testing the existing fire protection system, including the deficient fire detection alarms, with a plan to make functional changes to the existing fire systems.
- Order Approving Amendment of Air Quality Determination of Compliance Condition No. 2, Not in Docket, 01/18/1989, Order No. 89-0118-01b, Commission approval to allow operation under conditions of July 26, 1988 Northern Sonoma County Air Pollution Control District Protocol Agreement.
- Notice of Determination for Approval to Replace an Existing Hydrogen Peroxide Tank, TN 206722, 11/20/2015, Staff approval to replace existing 13,000-gallon hydrogen peroxide tank at NCPA 2, with similarly sized carbon steel tanks.
- Notice of Determination for Approval to Install a New Sulfur Processing Building and Transfer Existing Equipment, TN 221943, 12/12/2017, Staff approval to replace and lower the height of its sulfur processing building, part of the facility’s Stretford hydrogen sulfide (H2S) abatement system.
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 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.