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Navajo Generating Station is a 2250 megawatt coal-fired powerplant located on the Navajo Indian Reservation, near Page, Arizona, United States. This plant provides electrical power to customers in Arizona, Nevada, and California. It also provides the power for pumping Colorado River water for the Central Arizona Project, supplying about 1.5 million acre feet (1.85 km3) of water annually to central and southern Arizona. As of 2013 permission to operate as a conventional coal-fired plant is anticipated until December 22, 2044.〔 The Navajo Generating Station is the United States of America's third largest emitter of carbon dioxide.〔(【引用サイトリンク】url=http://www.npr.org/2015/06/25/417430662/how-a-historical-blunder-helped-create-the-water-crisis-in-the-west )〕 ==History== In the 1950s and 1960s, there was a need for new electric generation in the Southwest to supply power to growing populations in southern California, Arizona and Nevada. The US Bureau of Reclamation also needed a large source of power for running the pumps of the planned Central Arizona Project (CAP). A number of power projects were initially considered to fill these needs, most notably Bridge Canyon and Marble Canyon hydroelectric dams on the Colorado River. However, the proximity of the proposed dams to the Grand Canyon raised opposition, initially from the National Park Service and then more vigorously from a coalition of environmental groups which promoted construction of a thermal or nuclear power plant as an alternative. As a result, the proposed dams were abandoned in favor of the Navajo Power Project, consisting of the Navajo Generating Station (NGS) along with the Kayenta mine, Black Mesa & Lake Powell (BM&LP) Railroad, and of 500 KV transmission lines. The site selected for the new power plant was about six miles (10 km) east of Glen Canyon Dam and three miles (5 km) south of Lake Powell on of land leased from the Navajo Nation. The site was close to a source of competitively priced fuel and a reliable source of surface water for cooling. The nearby city of Page and U.S. Highway 89 provided existing infrastructure to support construction and operation of the project. The contract for engineering and construction was awarded to Bechtel Corporation, which began construction on the site in April, 1970. Generating units 1, 2, and 3 were completed in 1974, 1975, and 1976 respectively at a total cost of about $650 million. Between 1977 and 1990, following Clean Air Act amendments for assessing and protecting visibility in national parks and wilderness areas, the EPA, Salt River Project and other entities cooperated in visibility studies to assess possible effects that NGS emissions might have on those areas. The series of studies culminated in the Winter Haze Intensive Tracer Experiment (WHITEX) and the Navajo Generating Station Visibility Study (NGSVS). Those studies indicated that controlling SO2 emissions might improve winter visual range in the Grand Canyon by 2% to 7%, which prompted the EPA to propose a rule requiring NGS to reduce SO2 emissions by 70%. NGS and environmental groups, however, negotiated an approach that would achieve a greater degree of improvement at lower cost. They agreed to, and recommended a requirement of a 90% reduction in SO2 emissions based on an annual average, with installation to be completed in 1999. The EPA accepted the recommendation and implemented those conditions in its final rule. The technology selected for flue gas desulfurization was wet SO2 scrubbing with forced oxidation. Stone & Webster, the architect-engineering firm for the scrubber project, began construction in 1994 and completed the work on Units 3, 2, and 1 in 1997, 1998, and 1999 respectively. The cost of the scrubber project was about $420 million. During spring overhauls in 2003 through 2005, the electrostatic precipitators were completely gutted and rebuilt for reliability and optimum performance. The original collecting plates and weighted wire electrodes were replaced with improved collecting plates and rigid discharge electrodes. Control equipment was replaced with upgraded automatic voltage controls and rappers. In 2007, an analysis of nitrogen oxide (NOx) emissions and control options was conducted for SRP in support of Clean Air Act regional haze reduction efforts, although there were no (NOx) reduction requirements on NGS at the time. The analysis concluded that Low NOx burners with separated overfire air (SOFA) would provide the best available retrofit technology (BART) alternative in accordance with EPA BART guidelines. 〔 〕 Consequently, the plant voluntarily installed low NOx-SOFA burners on units 3, 2, and 1 during eight-week outages in February through March 2009, 2010, and 2011 respectively. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Navajo Generating Station」の詳細全文を読む スポンサード リンク
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