Geysers Unit 16

Geysers Unit 16
Name	Geysers Unit 16
Country	United States
Location	Lake County, California, Geysers (steam field)
Status	Decommissioned
Commissioning	1980s
Decommission	2010s
Owner	Calpine Corporation
Fuel	Geothermal steam
Type	Flash steam turbine
Capacity mw	11–20

Geysers Unit 16 is a geothermal power unit located within the Geysers (steam field) complex in Lake County, California, United States. The unit formed part of a cluster of plants operated by Calpine Corporation and associated partners, drawing steam from the Clear Lake Volcanic Field region and contributing to the California energy infrastructure mix. It played a role in regional power production, interacting with agencies such as the California Energy Commission and utilities like Pacific Gas and Electric Company.

Overview

Unit 16 was one of multiple modular units sited at the The Geysers development, situated near Clearlake Highlands, California and within the broader geological setting of the Mayacamas Mountains and Clear Lake. Designed as a small to medium-capacity flash-steam unit, it interfaced with nearby transmission assets linked to the California Independent System Operator grid and participated in Northern California power dispatch. Ownership and operational responsibility involved corporate entities such as Calpine Corporation and legacy operators including Pacific Gas and Electric Company predecessors.

History and Development

Development of Unit 16 occurred against a backdrop of mid-20th- and late-20th-century expansion at The Geysers, which itself traces earlier work by companies like Union Oil Company of California and research by institutions including Lawrence Berkeley National Laboratory and Stanford University. Permitting involved regional regulators such as the Lake County Planning Department and state oversight by the California Public Utilities Commission and the California Environmental Protection Agency. Financing and construction drew on capital markets influenced by energy policy changes during the Energy Policy Act of 1992 era and involved engineering firms with experience at projects like Mammoth Geothermal Plant and Salton Sea Geothermal Field operations.

Technical Specifications and Design

Unit 16 used flash-steam turbines supplied by industrial manufacturers that have also supplied equipment for plants such as The Geysers Unit 15 and internationally to projects in Iceland and the Philippines. The design incorporated downhole and surface infrastructure, including production wells tied to wellfields characterized in studies by United States Geological Survey and monitored by California Geological Survey. Auxiliary systems matched standards employed by entities such as International Electrotechnical Commission and manufacturers like Toshiba Corporation and Siemens. Steam gathering, separators, and condensers connected to cooling and reinjection systems modeled on reinjection programs observed at the Salton Sea and Krafla fields, and the unit interfaced with grid protection schemes used by Western Electricity Coordinating Council.

Operational History and Performance

During operation, Unit 16 contributed to baseload and peaking supplies, with performance tracked alongside neighboring units in reports by the California Energy Commission and operation logs maintained by Calpine Corporation. Its output fluctuated with steamfield pressures studied in academic work from University of California, Berkeley and operational adjustments mirrored strategies used at other geothermal sites like The Geysers Unit 18 and international analogs in New Zealand. Maintenance cycles followed industry practice described by organizations such as the Geothermal Resources Council, and the unit experienced typical issues including scaling, well decline, and thermal drawdown addressed through well workovers and reinjection programs documented in reports from Lawrence Livermore National Laboratory.

Environmental and Seismic Impacts

The environmental footprint of Unit 16 intersected with concerns raised by agencies including the California Environmental Protection Agency and monitoring by the United States Geological Survey. Emissions were primarily non-combustion steam flows regulated under frameworks influenced by the Clean Air Act and state air boards like the Bay Area Air Quality Management District. Water reinjection and usage practices were considered relative to studies on subsidence and induced seismicity by researchers affiliated with Stanford University and the U.S. Geological Survey, which evaluated correlations between reinjection at The Geysers and microseismicity observed in the Mayacamas Mountains. Wildlife and land use reviews referenced standards from the California Department of Fish and Wildlife and local conservation groups operating in the Clear Lake basin.

Decommissioning and Future Plans

Unit 16 was taken offline as part of fleet rationalization and declining steam availability, actions coordinated by Calpine Corporation and overseen by regulators including the California Energy Commission and Federal Energy Regulatory Commission. Decommissioning followed practices outlined by the Environmental Protection Agency and industry guidance from the Geothermal Resources Council, including well plugging, equipment removal, and site restoration consistent with Lake County reclamation policies. Future plans for the site have been considered in proposals involving binary-cycle retrofits similar to conversions at the Salton Sea and reinvigoration strategies promoted by research at Lawrence Berkeley National Laboratory and National Renewable Energy Laboratory, as well as potential community redevelopment in consultation with Lake County Board of Supervisors.

Category:Geothermal power stations in California Category:Buildings and structures in Lake County, California