1 11.5 EAST MORMON MOUNTAIN 2 3 4 11.5.1 Background and Summary of Impacts 5 6 7 11.5.1.1 General Information 8 9 The proposed East Mormon Mountain SEZ is located in Lincoln County in southern 10 Nevada (Figure 11.5.1.1-1). The SEZ has a total area of 8,968 acres (36 km2). In 2008, the 11 county population was 4,643, while adjacent Clark County to the south had a population of 12 1,879,093. The towns of Mesquite and Bunkerville are approximately 13 mi (21 km) southeast of 13 the SEZ; the larger, Mesquite, had a population of approximately 9,300 at the 2000 Census. The 14 Las Vegas metropolitan area is approximately 62 mi (100 km) to the southwest of the SEZ. 15 16 The nearest major road access to the proposed SEZ is I-15, which runs southwest– 17 northeast approximately 11 mi (18 km) to the southeast of the East Mormon Mountain SEZ. The 18 UP Railroad passes about 20 mi (32 km) west of the SEZ; the closest railroad stop is in Moapa, 19 approximately 25 mi (40 km) to the southwest. The nearest public airport is the Mesquite 20 Airport, a small airport in the vicinity of the SEZ near I-15. The nearest airport with scheduled 21 passenger service is the St. George Municipal Airport, 43 mi (69 km) to the northeast in 22 St. George, Utah. 23 24 A 500-kV transmission line is adjacent to the southeast corner of the SEZ; there are two 25 additional transmission lines within designated corridors adjacent to the site. It is assumed that 26 an existing transmission line could potentially provide access from the SEZ to the transmission 27 grid (see Section 11.5.1.2). 28 29 Applications for ROWs that have been submitted to the BLM include eight pending solar 30 projects, three pending authorizations for wind site testing, and two authorized projects for wind 31 site testing that would be located within 50 mi (80 km) of the East Mormon Mountain SEZ. 32 These applications are discussed in Section 11.5.22.2.1. There are currently no ROW 33 applications for solar projects within the SEZ. 34 35 The proposed East Mormon Mountain SEZ is located in the Lower Virgin River Valley. 36 The Mormon and East Mormon Mountains and Tule Spring Hills are located to the northwest of 37 the SEZ, and the Beaver Dam Mountains (in Utah and Arizona) are to the northeast. The Muddy 38 Mountains and Black Mountains are to the southwest; the Southern Virgin Mountains and Virgin 39 Mountains (Arizona) are to the southeast. 40 41 The proposed East Mormon Mountain SEZ and other relevant information are shown in 42 Figure 11.5.1.1-1. The criteria used to identify the SEZ as an appropriate location for solar 43 energy development included proximity to existing transmission lines or designated corridors, 44 proximity to existing roads, a slope of generally less than 2%, and an area of more than 45 2,500 acres (10 km2). In addition, the area was identified as being relatively free of other types 46 of conflicts, such as USFWS-designated critical habitat for threatened and endangered species, 47 ACECs, SRMAs, and NLCS lands (see Section 2.2.2.2 for the complete list of exclusions). Draft Solar PEIS 11.5-1 December 2010 1 2 FIGURE 11.5.1.1-1 Proposed East Mormon Mountain SEZ Draft Solar PEIS 11.5-2 December 2010 1 Although these classes of restricted lands were excluded from the proposed East Mormon 2 Mountain SEZ, other restrictions might be appropriate. The analyses in the following sections 3 evaluate the affected environment and potential impacts associated with utility-scale solar energy 4 development in the proposed SEZ for important environmental, cultural, and socioeconomic 5 resources. 6 7 As initially announced in the Federal Register on June 30, 2009, the proposed East 8 Mormon Mountain SEZ encompassed 7,418 acres (30 km2). Subsequent to the study area 9 scoping period, the boundaries of the proposed East Mormon Mountain SEZ were altered 10 somewhat to facilitate the BLM’s administration of the SEZ area. Some higher slope areas 11 internal to and at the borders of the site were added to the SEZ; particularly significant was the 12 addition of the Toquop Wash area to acreage. Although included in the SEZ, these higher slope 13 areas would not likely be utilized for solar facilities. Additionally, borders with irregularly 14 shaped boundaries were adjusted to match the section boundaries of the Public Lands Survey 15 System (PLSS) (BLM and USFS 2010c). The revised SEZ is approximately 1,550 acres 16 (6.3 km2) larger than the original SEZ area as published in June 2009. 17 18 19 11.5.1.2 Development Assumptions for the Impact Analysis 20 21 Maximum solar development of the East Mormon Mountain SEZ is assumed to be 80% 22 of the SEZ area over a period of 20 years, a maximum of 7,174 acres (29 km2). These values are 23 shown in Table 11.5.1.2-1, along with other development assumptions. Full development of the 24 East Mormon Mountain SEZ would allow development of facilities with an estimated total of 25 26 TABLE 11.5.1.2-1 Proposed East Mormon Mountain SEZ—Assumed Development Acreages, Solar MW Output, Access Roads, and Transmission Line ROWs Assumed Distance Area of Total Acreage Maximum Distance to and Capacity Assumed and Assumed SEZ Output Nearest State, of Nearest Transmission Distance to Developed for Various U.S., or Existing Line ROW Nearest Acreage Solar Interstate Transmission and Road Designated (80% of Total) Technologies Highway Line ROW Corridord 8,968 acres and 797 MWb and I-15 Adjacent, 0 acres and 0 mi 7,174 acresa 1,435 MWc 11 mid,e 500 kV 80 acres a To convert acres to km2, multiply by 0.004047. b Maximum power output if the SEZ were fully developed using power tower, dish engine, or PV technologies, assuming 9 acres/MW (0.04 km2/MW) of land required. c. Maximum power output if the SEZ were fully developed using solar trough technologies, assuming 5 acres/MW (0.02 km2/MW) of land required. d BLM-designated corridors are developed for federal land use planning purposes only and are not applicable to state-owned or privately owned land. e To convert mi to km, multiply by 1.609. Draft Solar PEIS 11.5-3 December 2010 1 797 MW of electrical power capacity if power tower, dish engine, or PV technologies were used, 2 assuming 9 acres/MW (0.04 km2/MW) of land required, and an estimated 1,435 MW of power if 3 solar trough technologies were used, assuming 5 acres/MW (0.02 km2/MW) of land required. 4 5 Availability of transmission from SEZs to load centers will be an important consideration 6 for future development in SEZs. The nearest existing transmission line is a 500-kV line that runs 7 adjacent to the SEZ. It is possible that this existing line could be used to provide access from the 8 SEZ to the transmission grid, but the 500-kV capacity of that line would likely be inadequate 9 for 797 to 1,435 MW of new capacity (a 500-kV line can accommodate approximately the load 10 of one 700-MW facility). At full build-out capacity, it is likely that new transmission and/or 11 upgrades of existing transmission lines would be required to bring electricity from the proposed 12 East Mormon Mountain SEZ to load centers; however, at this time the location and size of such 13 new transmission facilities are unknown. Generic impacts of transmission and associated 14 infrastructure construction and of line upgrades for various resources are discussed in Chapter 5. 15 Project-specific analyses would need to identify the specific impacts of new transmission 16 construction and line upgrades for any projects proposed within the SEZ. 17 18 For the purposes of analysis in the PEIS, it was assumed that the existing 500-kV 19 transmission line which runs adjacent to the proposed SEZ, could provide initial access to the 20 transmission grid, and thus no additional acreage for transmission line access was assessed. 21 Access to the existing transmission line was assumed, without additional information on whether 22 this line would be available for connection of future solar facilities. If a connecting transmission 23 line were constructed in the future to connect facilities within the SEZ to a different off-site grid 24 location from the one assumed here, site developers would need to determine the impacts from 25 construction and operation of that line. In addition, developers would need to determine the 26 impacts of line upgrades if they were needed. 27 28 I-15 lies 11 mi (18 km) to the south of the proposed East Mormon Mountain SEZ. 29 Assuming construction of a new access road to reach I-15 would be needed to support 30 construction and operation of solar facilities, approximately 80 acres (0.3 km2) of land 31 disturbance would occur (a 60-ft [18.3-m] wide ROW was assumed). 32 33 34 11.5.1.3 Summary of Major Impacts and SEZ-Specific Design Features 35 36 In this section, the impacts and SEZ-specific design features assessed in Sections 11.5.2 37 through 11.5.21 for the proposed East Mormon Mountain SEZ are summarized in tabular form. 38 Table 11.5.1.3-1 is a comprehensive list of impacts discussed in these sections; the reader may 39 reference the applicable sections for detailed support of the impact assessment.