Northern Calif. Power Agency (NCPA) Geothermal Project No. 3 (NCPA 3)

Docket No. 81-AFC-3

Certification Granted on December 29, 1982

Staff Counsel: Catherine Johnson

Hearing Officer: Stan Valkosky

Presiding Member: Commissioner Gene Varanini

Project Summary


AFC Filing and Data Adequacy

The Northern California Power Agency (NCPA) filed an AFC for Geothermal Project No. 3 on November 6, 1981. The original filing was for a single 55 MW unit, with a second 55 unit to follow in the future. (This second unit was presented as a 55 MW amendment on August 3, 1982.) The initial AFC was found to be data adequate by the Energy Commission effective December 2, 1981.

Geysers Overview and Project Description

Geothermal power was the CEC’s most successful preferred technology during the late 1970s and early 1980s, with twelve powerplants certified in the Geysers Known Geothermal Resource Area (KGRA) of Lake and Sonoma Counties, making it the world’s largest geothermal field. Geothermal, followed later by cogeneration, was the Energy Commission’s chosen alternative to the large coal and nuclear plants long favored by utilities.

PG&E had pioneered in the geysers, but the municipal utilities, and then the qualifying facilities (QFs) all wanted their share. Projections indicated that a vast potential existed for additional geothermal plants, with no end in sight. This boom would collapse later in the 1980s as the geothermal steam unexpectedly began to decline.

The municipal utilities, such as NCPA, were strongly motivated to build their own power plants in the geysers, as a substitute for purchasing power from PG&E. In their quest for energy independence, NCPA #3 was one of many geothermal facilities proposed by the municipal utilities during the geysers boom period. It was located in northeast Sonoma County, right at the Lake County border, approximately 70 miles north of San Francisco. The land was owned by the Federal Bureau of Land Management (BLM), and leased to Shell California Production Incorporated (SCPI), NCPA’s steam supplier.

The closest residential communities were Anderson Springs, about 2 miles to the northeast, and Middletown, about 5 miles east of the site.

Steam Sufficiency Hearings

Under Public Resources Code section 25540.2(a), a 12-month geothermal AFC, without an NOI, can be reviewed by the Energy Commission only if, at the outset of the proceeding, the applicant can reasonably demonstrate that the site is capable of providing geothermal resources in commercial quantities.

The original 55 MW proposal had its steam sufficiency hearing on December 7, 1981. NCPA, CEC staff, and the Division of Oil and Gas all agreed that the site had sufficient steam to operate the facility for the planned 30-year period. The Committee concurred.

After the AFC was amended to become a 2-unit, 110 MW plant, a second steam sufficiency hearing was held on September 14, 1982, resulting in a finding of adequate steam for the full project for an anticipated life of 25 years.

Disputed Issues

There were two adjudicated issues in this proceeding. The first involved a CEC staff transmission line engineering concern regarding the most efficient NCPA tapline interconnection configuration with the PG&E system. The Committee resolved this highly technical matter by generally supporting NCPA’s chosen configuration, slightly modified.

In Socioeconomics, NCPA resisted having to mitigate impacts to overcrowded Lake and Sonoma County school districts that would be caused by the enrollment of new students who were the children of applicant’s workforce. The Geysers powerplant boom was bringing a large increase of construction workers (plus their children) to the area, and the schools were having trouble coping. The Lake and Sonoma County School Districts, as intervenors, called for a mitigation requirement, joined by the CEC staff. Such mitigation was first established in the South Geysers case (Docket No. 81-AFC-2), a precedent followed in Occidental Geothermal (Docket No. 81-AFC-1).

The Presiding Member’s Report supported a mitigation requirement, while preferring that NCPA reach its own settlement agreements with the school districts that would establish a reasonable amount of compensation for each new student attributable to NCPA #3. NCPA subsequently negotiated a settlement with the districts, ending the adjudication. The Committee and Commission congratulated the parties, and imposed conditions of certification requiring NCPA to abide by the settlements, also prohibiting construction until final, fully executed mitigation agreements had been submitted to the CEC. (Socioeconomics Conditions of Certification 1-3, page 96 of the decision.)


At the December 29, 1982 Business Meeting, NCPA’s Geothermal Project No. 3 was certified without any remaining contested issues.

NCPA No. 3 was constructed and began operating in 1985.