The Geothermal Public Power Line (GPPL)

Docket Nos. 84-NOI-1, 86-AFC-2

NOI Approval on August 13, 1985

AFC Withdrawn by Applicant and Terminated by the Commission on February 18, 1992

Staff Counsel: Dick Ratliff

Hearing Officer: Stan Valkosky

Presiding Member: Chairman Charles Imbrecht


Project Summary


The Geothermal Public Power Line (GPPL) was conceived by the municipal utilities in the early 1980s during a time of great optimism regarding the geothermal area of Sonoma and Lake Counties known as the geysers. Projections indicated an overall potential of 2,700-3,000 MW for the Geysers Known Geothermal Resource Area (KGRA), in which the municipal utilities were building a large number of powerplants, with a collective generating capacity of 1000 megawatts (MW), to achieve energy independence by taking the place of purchased federal and PG&E power.

Geothermal power had become the CEC’s most successful preferred technology during the late 1970s and early 1980s, with a total of twelve powerplants ultimately certified in the geysers KGRA, making it the world’s largest geothermal field. Geothermal, followed later by natural gas-fired cogeneration, was the Energy Commission’s chosen alternative to the large coal and nuclear plants long favored by utilities.

In the midst of this continuing boom, the municipal utilities felt they could not afford to rely upon the PG&E transmission system to carry power from their present and future plants out of the geysers. Dependence upon PG&E transmission meant physical and economic constraints that were unacceptable to the municipals, given their view of PG&E’s hostility to municipal power. The only way to safeguard their geothermal-derived power was to have a major new transmission line owned and operated by the municipal utilities themselves.

The Sacramento Municipal Utility District (SMUD), the Northern California Power Agency (NCPA), the Modesto Irrigation District (MID), and the City of Santa Clara (collectively known as the "Joint Owners") thus joined forces to propose their own 1,000 MW capacity transmission line out of the geysers. Construction was scheduled to begin in 1986, with use of the line anticipated by January 1988.

The timing could not have been worse for the municipals. PG&E managed to license and build its own new 2,600 MW geysers transmission line from the geysers by the mid 1980s (Geysers 16, Docket No. 79-AFC-5). PG&E would have a surplus of transmission capacity out of the geysers. As the GPPL always lagged behind PG&E’s project in the regulatory approval process, it was doomed to failure.

Following a lengthy Notice of Intention (NOI) phase at the Energy Commission, the GPPL Application for Certification (AFC) was under review when the geysers steam supply began to show a major decline. The steam supply estimates had been wrong. The Geysers KGRA could not support the geothermal plants already built, let alone the many projects once on the drawing board. Many existing geothermal plants had to close or cut back production, and all future geysers geothermal projects were canceled.

GPPL no longer had any reason to exist. After countless years of work on their ambitious project, GPPL was withdrawn by the Joint Owners. Municipal power would continue to forever be carried out of the geysers on the PG&E transmission system.


The Joint Owners filed GPPL as a stand-alone transmission line, not appurtenant to any specific geothermal facility. Thus, unlike the Geysers 16 transmission line, which was part of an NOI-exempt powerplant AFC, GPPL had no NOI exemption.

NOI Alternative Routes and Termination Points

The GPPL NOI, filed on January 17, 1984, became a complex and exhaustive open planning process that lasted eighteen months. (By statute, an NOI should take only 12 months.) While an NOI requires applicant submittal of at least three alternatives, the Joint Owners and CEC staff ended up presenting presented multiple combination options, amounting to 38 possible transmission line corridor routings, running through nine counties. All the different routes terminated at either the Williams Substation in Colusa County or the Elverta Substation in Sacramento County. Applicant's preferred alternative included 13.5 miles of "collector" transmission line and 55.7 miles of transmission line to a termination point at Williams.

Transmission lines are an unpopular land use to begin with, considered unsightly or worse. Proper notice to affected landowners and communities was necessary. GPPL became what the NOI decision called at page 5 "perhaps the most widely publicized regulatory event in Commission history." With so many alternative routes running in all directions, GPPL produced massive opposition throughout large sections of northern California. Urban, rural, and agricultural interests all fought against GPPL.

Regardless of some applicant/CEC staff stipulations, virtually every possible subject was disputed by anti-GPPL intervenors or the CEC staff. The intervenors wanted GPPL somewhere else, away from them. More alternative transmission line routes were suggested, including CEC staff’s proposal for a new termination point at PG&E’s Vaca-Dixon Substation in Solano County.

The Committee established criteria under which various alternatives could be deleted or added. Ultimately, testimony was presented on the comparative advantages and disadvantages of nine different corridors, plus three potential termination points, all of which were exhaustively analyzed.

The Joint Owners argued for approval of their two proposed termination points, the Williams and Elverta Substations, both of which the Joint Owners would own and control. The Joint Owners opposed CEC staff’s alternative, termination at PG&E’s Vaca-Dixon Substation.

Weighing the relative environmental, engineering and economic merits of various corridors and termination points, the Committee found specific routes to both Williams and Vaca-Dixon which were acceptable. These approved transmission links and corridors were presented on Map 7, following page 157 of the Decision. Termination at the Elverta Substation and all other routes not indicated on Map 7 were disapproved. (Page 157 of the NOI Decision.) The Committee also established a set of conditions and informational requirements in each subject area which the AFC filing would have to meet.

NOI Demand Conformance

The Joint Owners based their need for GPPL upon assumptions that the geysers would soon quickly sustain a level of up to 3,000 MW, of which less than only about 2,000 MW had been built or licensed. The Committee was skeptical, even before the steam decline destroyed every steam supply assumption made about the geysers.

By 1985, PG&E had deferred new geysers projects due to a surplus of baseload capacity. With, geysers growth already slowing down, the Committee believed the Joint Owners had overstated the need for GPPL. (Page 43 of the NOI Decision.) However, neither the Warren-Alquist Act, nor the Electricity Reports of the day required any specific demand conformance finding for a transmission line NOI.

The Committee found "lack of a currently demonstrated need for the proposed project," (Page 47 of the NOI Decision), but this did not prevent NOI approval. The NOI Decision deferred demand conformance to the GPPL AFC, directing the Joint Owners to establish need for GPPL early in that proceeding, or face summary termination of the AFC. (Pages 47-50 of the NOI Decision.)

However, in the AFC itself, demand conformance proved too difficult a subject for any quick resolution to be possible.

NOI Approval

On August 13, 1985, the Energy Commission unanimously approved the GPPL NOI with its two possible termination points. Chairman Imbrecht disagreed with one specific condition requiring the AFC filing to include results from a joint transmission study being undertaken by the applicants, PG&E, and the U.S. Western Area Power Administration (WAPA). Commissioner Commons filed a one page Concurring Opinion indicating his preference for greater cooperation between public and private utilities in order to avoid building unneeded transmission lines.


The Joint Owners filed the GPPL Application for Certification on September 26, 1986, over a year after NOI approval. The transmission line would terminate at Williams, rather than the PG&E Vaca-Dixon Substation preferred by CEC staff. After supplemental filings, the Commission found it to be data adequate effective February 27, 1987.

The AFC was subject to numerous delays as CEC staff analyzed demand conformance as well as new alternatives proposed by intervenors and in addition to a host of potential adverse environmental impacts and engineering problems. CEC staff finally issued its Preliminary Staff Assessment (PSA) on February 22, 1989. However, that document did not include analyses in the three most difficult subject areas: biology, transmission line system evaluation, and demand conformance.

The Committee had spent much of the 1987-88 period trying to devise a demand conformance test for the GPPL AFC. The Committee now emphasized that negotiations between the Joint Owners and PG&E for a long-term transmission agreement would serve as both a potential alternative to GPPL and a factor to be considered in any need test. A GPPL demand conformance test was finally adopted by the Commission on July 7, 1988, although its contents would continue to be disputed by various parties into 1989.

By 1989, the geysers boom had ended and the major steam decline was becoming a reality. None of the new geothermal plants, upon which the Joint Owners based their need for GPPL, was going to be built. The Joint Owners and PG&E had commenced serious negotiations for a new transmission agreement that would provide for secure PG&E transmission of municipal geothermal power.

These negotiations led to the Joint Owners requesting that the GPPL AFC be continued. "Continuance" was another polite way of saying and meaning suspension of the proceeding. The first GPPL continuance was ordered on April 7, 1989. The fifth and last continuance was granted on September 5, 1990. Agreement was finally reached for PG&E to transmit municipal power out of the geysers as the permanent alternative to GPPL.

The Joint Owners requested withdrawal of the Geothermal Public Power Line AFC in a letter dated January 6, 1992. The Energy Commission formally terminated the GPPL AFC on February 18, 1992. Eight years had been spent on the failed GPPL effort.