Pacific Gas and Electric Company (PG&E) is proposing to reinforce the Northern Geysers Power Line System by making additions to existing facilities at the northern and southern ends of the existing Geysers Unit 11-Fulton transmission line. The proposed facilities would be installed at the Geysers and Fulton sites, both located in Sonoma County, California. The purpose of the project is to meet the rising demand for electricity in Colusa, Lake, Mendocino and northern Sonoma counties, to which PG&E provides power.

PG&E currently operates two power line systems that are served by geothermal power generated at The Geysers: the Northern Geysers 115/60kV Power Line System and a 230kV transmission system. The Northern Geysers Power Line System serves customers in Colusa, Lake, Mendocino and northern Sonoma counties. The 230kV transmission line provides electric service in southern Sonoma and Napa counties.

Electricity demand in Colusa, Lake, Mendocino and especially, northern Sonoma counties has increased over the past several years (PG&E, 1998). PG&E has stated that the expected electrical load growth is the primary reason for reinforcement of the Northern Geysers Power Line System. Currently, the system is served by six geothermal plants (including PG&E’s Geysers Units 5, 6, 7 and 8) and the Eagle Rock Substation. A fifth unit (Geysers Unit 11) and other units are currently connected to the 230kV system. Power flow studies simulating area peak load conditions in 1998 indicate that transformer bank capacity overload and unacceptable low voltages would occur on the 115kV/60kV power line if an outage were to occur at Geysers Units 5 and 6 or if Geysers Unit 7 were temporarily or permanently taken out of service. Under such conditions, transformer and power line overloads could interrupt electrical service for customers in Colusa, Lake, Mendocino and northern Sonoma counties.

Location. PG&E’s proposed reinforcement of the Northern Geysers Power Line System would consist of new power lines at two existing facilities, located at the Geysers and Fulton Substation sites, and circuit breaker structures at the Geysers Eagle Rock Substation.

The Geysers site is located in the northern portion of the Known Geysers Resource Area (KGRA), approximately twelve miles south of Clear Lake (see Figure 1). The site includes Geysers Unit 11 and the Eagle Rock Substation. The KGRA is a developed area in the rural Mayacamas Mountains used for heavy industry, primarily geothermal power plants. The area includes substations, transmission lines, access roads and support facilities. As topography at the Geysers site is mountainous, facilities have been constructed in flat areas of constructed cut and fill at the site. The site is in a remote location that has no public access.

The Fulton site is located adjacent to U.S. 101 approximately two miles north of Santa Rosa and roughly one-half mile east of the community of Fulton (see Figure 1). The site contains the Fulton Substation, two 230 kV transmission lines and one 115kV power line. The general site vicinity is primarily defined as rural or suburban, with agricultural uses, disturbed grasslands and nearby vineyards.

Proposed Facilities. The project consists of two elements:

• the proposed installation of a 3,300-foot long, 115 kV loop that would connect Geysers Unit 11 and the existing Geysers Unit 11-Fulton line to the Eagle Rock Substation, and the addition of two 115 kV electric bays with two 115 kV line positions to the substation at the Geysers site;

• the relocation of the 11-Fulton line connection point from a 230 kV position to a 115 kV line position at the Fulton site (PG&E, 1998).

Geysers Site: The proposed 3,300-foot 115 kV double circuit power line would be constructed from the existing transmission tower south of Geysers Unit 11 to the Eagle Rock Substation at the Geysers site (see Figure 2). An existing transmission cross arm on the tower would be replaced with a butterfly cross arm that ties the power line from Unit 11 to the Eagle Rock Substation. The new 115 kV power line would be carried by five new tubular steel power poles, three of which would be up to 135 feet tall and two which would be up to 85 feet tall. A fiber optic communication cable would be strung between Unit 11 and the Eagle Rock Substation on existing wooden poles. Approximately 400 feet of new graded road would be created to provide access to two of the tubular steel pole sites for their construction and maintenance.

Two 115 kV bay structures with two 115 kV line positions would be added to the easterly end of the Eagle Rock substation. The area is an open gravel-covered space located entirely within the existing substation fence. Each bay would be 35 feet high by 36 feet wide by 50 feet long and would be supported on approximately 11 concrete foundation footings which would be 18 inches by 18 inches by 5 feet deep. Each line position would contain a 115 kV circuit breaker, approximately 15 feet high by 13 feet wide by 8 feet long, and three 115 kV air disconnect switches. The line position would be mounted on a 6-foot by 6-foot concrete pad. Control wires in a plastic conduit would run between the existing control building and the proposed circuit breakers. Approximately 200 feet of the control wire would be placed in existing conduit and 100 feet would be placed in new conduit in a one foot wide by three foot deep trench.

Fulton Site: The project would include installing a new 115 kV line position at an existing 115 kV bay at the Fulton Substation. The line position would include a 115 kV circuit breaker and five 115kV air disconnect switches. The 115 kV circuit breaker would be mounted on a six foot by six foot concrete pad. Approximately 1,200 feet of 115 kV power line would be constructed to route the Geysers Unit 11-Fulton power line from the Fulton Substation to the new 115 kV line position within the substation. The line would be located entirely within the existing substation fence. The construction of the 115 kV line would require the installation of six new tubular steel poles, three of which would be 40 feet tall, and three of which would be 70 feet tall (see Figure 3).

Construction. Improvements at the Geysers site would be constructed over a 10 week period. Improvements at the Fulton site would be constructed over a period of 13 weeks. Existing roads would be used to transport materials on site. The project would involve the following construction:

• The new 115 kV bays and line positions would be added at the two existing substations.

• At the Fulton site, six new poles would be installed within the perimeter of the substation. At the Geysers site, access improvements would be required at the proposed locations of two of the 5 new poles to be installed, one located near the Eagle Rock Substation, the other at an intermediate pole site located approximately mid-way along the existing access road between Unit 11 and the Eagle Rock Substation. Approximately 400 feet of graded roads would be built to provide access for construction and maintenance of these 2 poles. After completion of these road improvements, the foundations for new tubular steel poles at both sites would be excavated and poured and new poles would be installed.

• Conductors would be strung on the new poles at both the Geysers and Fulton sites. Equipment for installing power line conductors would be placed at opposite ends of the new line sections. After installation of the tubular steel poles and conductors, all equipment would be tested and the line would be energized. Final tests would be run with the facilities energized.

• All construction-related debris would be removed from the sites and disposed at approved landfills.

All construction equipment, vehicles, personnel and staging areas would be accommodated at the existing substations. Construction is scheduled to begin March 1999 and anticipated to finish in June 1999. Construction crews would consist of a maximum of ten people. A substation crew would install the 115 kV line positions, a tower crew would install the tubular steel poles and a line crew would be responsible for stringing conductors. Additionally, a two-person road crew would be used for construction of the access roads at the Geysers site. Construction would not require crossing of any public roads or highways nor any stream crossings.

Although the Geysers Unit 11-Fulton line would be temporarily de-energized, PG&E does not expect electrical service interruptions to customers in the area during the construction (PG&E 1998).

The Geysers site is located in a remote unpopulated mountainous area within the KGRA. Surrounding uses include heavy industry, geothermal plants, substations, transmission lines, access roads and support facilities.

The Fulton site is surrounded by agricultural uses, vineyards, residential and commercial uses (see Figure 1). The site is bounded by Highway 101 to the northeast, River Road to the south and vineyards to the west and north. A residential area, consisting of approximately 12 homes, is located east of Highway 101, approximately 500 to 1,500 feet from the northeast corner of the site. Most of the homes are greater than 1,000 feet away from the site. A commercial bed-and-breakfast establishment is located southeast of the site, at the intersection of River Road and Barnes Road. A few commercial buildings are located west of the substation on River Road.

Pursuant to State Law, the California Public Utilities Commission (CPUC) is the permitting authority for the project.

A grading permit will be required from Sonoma County for the 400 feet of access roads.