2.1.1 NEPA and CEQA Requirements for Project Alternatives

Both NEPA and CEQA require that a reasonable range of alternatives to the Proposed Action be considered that could feasibly meet the objectives of the Proposed Action as defined in the purpose and need for the Project described in Section [40 CFR 1502.14(a) and CEQA Guidelines Section 15126(d)]. CEQA guidelines also advise that the range of potential alternatives to the proposed project shall include those that could feasibly accomplish most of the basic purposes of the project and could substantially lessen one or more of the significant effects [CEQA Guidelines Section 15126(d)(2)]. The range of alternatives required is governed by a “rule of reason” (i.e., only those feasible alternatives necessary to permit a reasoned choice need be considered). Reasonable alternatives are those that are practical or feasible based on technical and economic considerations [46 Fed. Reg. 18026 (March 23, 1981), as amended, 51 Fed. Reg. 15618, April 25, 1986].

2.1.2 Project Alternatives Development and Selection Process

Project Alternatives were formulated and developed during scoping and were refined throughout the EIS/EIR process. A range of alternatives was developed that would meet the primary project objectives described in Section 1.3 and that would also be responsive to concerns raised during public scoping (see Section 1.10.3).

Considerations used by CEGC to develop the Proposed Action included: Development of a geothermal-powered electrical generation project using geothermal resources from CEGC’s federal geothermal leases CA12370, CA12371, CA12372, CA13803, CA21933, and CA2500; Use of an electrical power generation technology suitable to the geothermal resources that exist within the identified CEGC leases; Development of a geothermal production and injection wellfield within reasonably accessible surface and subsurface portions of the identified CEGC leases; Location of the geothermal wellfield in areas of the identified CEGC leases with a high probability for successfully encountering commercially suitable geothermal resources during well drilling; Location of the power plant site in a centrally located part of the wellfield development area to minimize pipeline distances and resulting heat loss from the produced geothermal fluid; Location of well pads and the power plant site on relatively flat topography reasonably accessible to existing roads; and Development of a project that would be technically viable, economically feasible, and would minimize adverse environment effects.

These same criteria and other agency management directions were taken into consideration during the development of the range of alternatives by the agencies.

It is also an assumption of the Proposed Action and each of the other action Project Alternatives that a preferred utility corridor from the Medicine Lake Highlands (MLH) to the existing BPA Malin-Warner transmission line east of Highway 139 would be selected by the USFS as the result of an earlier proposal for geothermal development on the MLH (i.e., the Fourmile Hill Geothermal Development Project). The pending decision on the Fourmile Hill Project includes a range of utility corridors (see Section 2.2.5.1). The preferred alternative identified in the Final EIS/EIR prepared for the Fourmile Hill Project is for a Northern Utility Corridor (transmission line segments A3, B1, and C2) (BLM et al. 1998). It is assumed that the transmission line corridor selected by the USFS for the Fourmile Hill Project would be accessible from a power plant site within the Telephone Flat Project wellfield area via an interconnection tie in transmission line (see Section 2.2.5). If the Fourmile Hill Project is not constructed, then the entire 21-mile transmission line from the Telephone Flat Project power plant site to the BPA Malin-Warner transmission line would be constructed originating with an interconnection transmission line route to a tie in point with the agency preferred Northern Utility Corridor as part of the Telephone Flat Project.

Alternatives to the Proposed Action were selected to reduce potentially significant effects of the Project with respect to visibility of the Project facilities; potential conflicts with residential and developed recreation use areas adjacent to Medicine Lake from Project-generated noise, traffic, malodors, or other temporary or intermittent intrusions; and potential effects of the Project on regional groundwater hydrology. Each of the Project Alternatives selected has the capacity to substantially reduce one or more of these potentially significant effects of the Proposed Action.

2.2 Proposed Action

CEGC submitted a Plan of Operations (POO) for Development and Production and a POO for Utilization and Disposal to the BLM for constructing, operating, and maintaining a 48 MW (gross), dual flash, geothermal power plant and wet cooling tower, associated geothermal production and injections wells, well pads, roads, interconnected geothermal fluid pipelines, and accompanying segments of a 230-kV transmission line (CEGC 1997 and 1997a). This project, known as the Telephone Flat Geothermal Development Project (Project), would be located within the Glass Mountain Unit of the Glass Mountain Known Geothermal Resource Area (KGRA) on the Modoc National Forest (see Figure 1.1.1). The geothermal fluid supplies and wellhead reserves have been projected by CEGC to be sufficient for at least 50 years and the Project is expected to continue for at least that long.

The Project would occur in three defined phases: Wellfield development and site construction activities (construction); Commercial electrical power generation operations (operations); and Decommissioning and site restoration activities (decommissioning).

The Project construction phase is the first phase of the Proposed Action. Previously approved exploration well drilling and testing would continue through the 1999 drilling summer season. Assuming a timely Project approval, construction of new facilities would be expected to start about mid- to late-1999 and would be expected to be completed by late-2001; this would include drilling, constructing and testing additional production wells, installing the electrical transmission line, improving and constructing access roads, and constructing the geothermal power plant, pipelines, and ancillary facilities.

The operation phase would begin when the power plant begins commercial generation of electrical power. Project activities that would occur during this phase would include production of geothermal fluid, injection of spent fluid, power plant operations and maintenance, well servicing activities, replacement well drilling, and maintenance of pipeline and transmission line.

At the end of the operation phase, the decommissioning phase would occur. This phase would include well abandonment, removal of surface facilities, and site restoration activities. This phase would continue for approximately 2-3 years.

2.2.1 Project Location

The proposed geothermal power plant, well pads, and fluid pipelines would be located within portions of Federal geothermal leases CA12370, CA12371, and CA12372 within the Glass Mountain Unit of the Glass Mountain KGRA and the Modoc National Forest. The proposed power plant site would be located in Section 18 within an approximately 8.41 square mile area that defines the Telephone Flat Project Participating Area, located in Sections 7, 8, 9, 16, 17, 18, 19, and 20 T43N, R4E; and Sections 13 and 24 T43N, R3E, MDB&M, Siskiyou County, California (see Figure 1.1.4). Previous geothermal exploration activities in the vicinity of the Project were discussed in Section 1.8.2, and geothermal exploration well pads that currently exist within the Project wellfield area and are shown on Figure 1.1.6.

2.2.2 Site Access and Roads

2.2.2.1 Access

The Project site would be accessed by several existing paved and gravel-surfaced arterial roads and many gravel surfaced collector roads. The main access route to the wellfield and power plant from the east would be Primary Forest Route 97 (a.k.a. Modoc County Road 97 or Road 97), also known as the Tionesta-Black Mountain Road. This main access road is a paved two-lane arterial providing access from California State Highway 139 near Tionesta. Arterial access roads from the south (Primary Forest Route 49 and west (Primary Forest Route 15) would also be expected to be seasonally used to access the Project site. Several existing gravel-surfaced roads cross the wellfield, proposed power plant site and transmission line route. Figure 2.2.1 shows the location of the existing roads in the wellfield area to be used by the Project. Year-round access to the power plant is proposed. This would require plowing snow-covered sections of Primary Forest Route 97 and the secondary power plant and wellfield access roads during the winter months (see Section 2.2.4.6).

2.2.2.2 Road Construction

The access road from Road 97 to the power plant and all well pad access roads would be improved to a USFS all weather gravel road standard (see Figure 2.2.2). Figure 2.2.4 shows the approximate location of the new, reconstructed and improved roads for the Project power plant site and wellfield. Approximately 0.6 miles of new road construction would be necessary and approximately 5.2 miles of former logging roads and 4-wheel drive trails would need to be reconstructed by widening, improving drainage, and improving the surface with gravel. Approximately 1 mile of Forest Road 43N53 and 0.8 miles of Forest Road 43N21 would have the surface improved with additional gravel. The maintenance roads in the pipeline and transmission line corridors used for construction that are not primary access routes would be allowed to revegetate (see Figure 2.2.3).

Any road gravel or other road materials necessary for improvement or repair of existing roads or site construction would be obtained from existing road material pits with the concurrence of the USFS. Water would be used as necessary to control dust during road construction and maintenance.

2.2.3 Geothermal Wellfield

The geothermal wellfield would be comprised of production and injection wells located on well pads spatially separated within the Project wellfield area to optimize field development. An estimated 10-12 production wells would be initially required to provide geothermal resource to the power plant, and an estimated 3-5 injection wells would be initially required to return spent geothermal fluid, condensate fluids, and cooling tower blowdown to the geothermal reservoir. Four well pads (87-13, 68-8, 46-8 and 31-17) were earlier constructed in the Project wellfield area under previously approved exploration plans of operation. Three existing geothermal exploration wells were drilled on three of the constructed well pads, including: wells 68-8, 31-17 and 87-13, and have been incorporated into the Proposed Action. Two additional well pads (56-18 and 13-18) were also approved for construction in the Project wellfield area as part of the previously approved 1995 Plan of Exploration (POE) for exploration drilling in the Glass Mountain Unit Area. Although approved, these well pads have not been constructed. The 4 existing well pad locations and the two approved exploration well pad locations have been incorporated into the Proposed Action. Twelve additional new well pads have been proposed for a total of 18 existing and alternative well pad locations in the Proposed Action (see Figure 2.2.5). Not all of the well pads would be expected to be constructed. The well pad locations and orientation would be subject to changes of up to about 200 feet in distance in any given direction to avoid any potential site specific environmental resource conflicts that may be identified.

The actual number and location of production and injection well sites to be used during the Project would depend on the results of drilling, testing, and the response of the geothermal reservoir. The expected startup production well sites would be: 16-18, 13-18, 52-18 (or 51-18), and 56-18; and the expected startup injection well sites would be: 68-8, 72-17, and 15-16. Well sites 46-8, 84-7 and 31-17 could be either production or injection well sites, depending on Project needs. Existing well 87-13 is proposed to be used as an observation well. The existing and proposed Project well pads and preliminary designation of the pads as either production or injection well sites is provided in Table 2.2.1. The other identified well pad locations would be used if supplemental production or injection is required as “make-up” over the life of the Project.

Table 2.2.1: Existing and Proposed Well Pads

Existing Wells and Pads
Well Number	Location	Pad Designation	Status/Commentsa
46-8	Section 8, T43N, R4E	Production or Injection	Pad constructed, no wells, existing pad size 250’ x 350’, maximum area cleared 300’ x 500’
68-8	Section 8, T43N, R3E	Injection	Pad constructed with existing well, existing pad size 200’ x 250’, maximum area cleared 400’ x 400’
87-13	Section 13, T43N, R3E	Observation	Pad constructed with existing well, proposed sump closure, existing pad size 200’ x 200’, no plans for pad expansion
31-17	Section 17, T43N, R4E	Production or Injection	Pad constructed with existing well, existing pad size 250’ x 300’, maximum area cleared 300’ x 500’
Previously Approved Exploration Wells, Pads Not Constructed
Well Number	Location	Pad Designation	Status/Commentsa
13-18	Section 18, T43N, R4E	Production	Approved, not constructed, maximum area cleared 400 x 600’
56-18	Section 18, T43N, R4E	Production	Approved, not constructed, maximum area cleared 300’ x 400’
Proposed New Well Pads
Well Number	Location	Pad Designation	Status/Commentsa
26-7	Section 7, T43N, R4E	Make-up Production	Proposed new well pad, maximum area cleared 400’ x 400’
84-7	Section 7, T43N, R4E	Production or Injection	Proposed new well pad, maximum area cleared 400’ x 400’
64-8	Section 8, T43N, R4E	Make-up Injection	Proposed new well pad, maximum area cleared 400’ x 400’
73-13	Section 13, T43N, R3E	Make-up Production	Proposed new well pad, maximum area cleared 400’ x 400’
15-16	Section 16, T43N, R4E	Injection	Proposed new well pad, maximum area cleared 400’ x 400’
26-17	Section 17, T43N, R3E	Make-up Production	Proposed new well pad, maximum area cleared 300’ x 400’
72-17	Section 17, T43N, R4E	Injection	Proposed new well pad, maximum area cleared 400’ x 400’
16-18	Section 18, T43N, R4E	Production	Proposed new well pad, maximum area cleared 400’ x 600’
25-18	Section 18, T43N, R4E	Make-up Production	Proposed new well pad, maximum area cleared 400’ x 600’
51-18	Section 18, T43N, R4E	Production	Proposed new well pad, maximum area cleared 400’ x 600’
52-18	Section 18, T43N, R3E	Production	Proposed new well pad, maximum area cleared 400’ x 600’
83-18	Section 18, T43N, R4E	Make-up Production	Proposed new well pad, maximum area cleared 400’ x 600’
a The maximum pad size would be the largest well pad constructed at the respective locations. The maximum pad size would be 300’ x 500’ working surface built within a 400’ x 600’ cleared area. Multiple-well production well pads would be the largest cleared areas (400’ x 600’) and single-well pads with anticipated construction constraints being the smallest well pads within smaller cleared areas.