Solar Energy Generating Systems

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"SEGS" redirects here. For the airport with that ICAO code, see Seymour Airport.
Solar Energy Generating Systems
Solar Plant kl.jpg
Part of the 354 MW SEGS solar complex in northern San Bernardino County, California.
Country United States
Location Mojave Desert
Coordinates 35°01′54″N 117°20′53″W / 35.0316°N 117.348°W / 35.0316; -117.348Coordinates: 35°01′54″N 117°20′53″W / 35.0316°N 117.348°W / 35.0316; -117.348
Status Operational
Commission date 1984
Owner(s) NextEra Energy Resources
Solar farm
Type CSP
CSP technology Parabolic trough
Site area 1,600 acres (647.5 ha)
Power generation
Nameplate capacity 354
Capacity factor 21%
Annual generation 662

Solar Energy Generating Systems (SEGS) in California, with the combined capacity from three separate locations at 354 megawatts (MW, 474,700 hp), is now the world's second largest solar thermal energy generating facility, after the commissioning of the even larger Ivanpah facility in 2014. It consists of nine solar power plants in California's Mojave Desert, where insolation is among the best available in the United States. SEGS I–II (44 MW) are located at Daggett (34°51′45″N 116°49′45″W / 34.86250°N 116.82917°W / 34.86250; -116.82917), SEGS III–VII (150 MW) are installed at Kramer Junction, and SEGS VIII–IX (160 MW) are placed at Harper Lake (35°02′N 117°21′W / 35.033°N 117.350°W / 35.033; -117.350).[1] NextEra Energy Resources operates and partially owns the plants located at Kramer Junction and Harper Lake.

Plants' scale and operations[edit]

The plants have a 354 MW installed capacity. The average gross solar output for all nine plants at SEGS is around 75 MWe a capacity factor of 21%. In addition, the turbines can be utilized at night by burning natural gas.

NextEra claims that the solar plants power 232,500 homes (during the day, at peak power) and displace 3,800 tons of pollution per year that would have been produced if the electricity had been provided by fossil fuels, such as oil.[2]

The facilities have a total of 936,384 mirrors and cover more than 1,600 acres (647.5 ha). Lined up, the parabolic mirrors would extend over 229 miles (369 km).

As an example of cost, in 2002, one of the 30 MW Kramer Junction sites required $90 million to construct, and its operation and maintenance cost was about $3 million per year (4.6 cents per kilowatt hour).[3] With a considered lifetime of 20 years, the operation, maintenance and investments interest and depreciation triples the price, to approximately 14 cents per kilowatt hour.[citation needed]

Principle of operation[edit]

Sketch of a Parabolic Trough Collector

The installation uses parabolic trough, solar thermal technology along with natural gas to generate electricity. About 90% of the electricity is produced by the sunlight.[citation needed] Natural gas is only used when the solar power is insufficient to meet the demand from Southern California Edison, the distributor of power in southern California.

Mirrors[edit]

The parabolic mirrors are shaped like a half-pipe. The sun shines onto the panels made of glass, which are 94% reflective, unlike a typical mirror, which is only 70% reflective. The mirrors automatically track the sun throughout the day. The greatest source of mirror breakage is wind, with 3,000 mirrors typically replaced each year. Operators can turn the mirrors to protect them during intense wind storms. An automated washing mechanism is used to periodically clean the parabolic reflective panels.

Heat transfer[edit]

The sunlight bounces off the mirrors and is directed to a central tube filled with synthetic oil, which heats to over 400 °C (750 °F). The reflected light focused at the central tube is 71 to 80 times more intense than the ordinary sunlight. The synthetic oil transfers its heat to water, which boils and drives the Rankine cycle steam turbine,[4] thereby generating electricity. Synthetic oil is used to carry the heat (instead of water) to keep the pressure within manageable parameters.

Individual locations[edit]

The SEGS power plants were built by Luz Industries,[4][5] and commissioned between 1984 and 1991. After Luz Industries' bankruptcy in 1991 plants were sold to various investor groups as individual projects, and expansion including three more plants was halted.[citation needed]

Kramer Junction employs about 95 people and 45 people work at Harper Lake.

SEGS plant history and operational data (1985-1990)
Plant Year
built
Location Net turbine
capacity
Field
area
Oil
temperature
Gross solar production
of electricity (MWh)
(MW) (m²) (°C) 1985 1986 1987 1988 1989 1990
SEGS I 1984 Daggett 14 82,960 307 19,261 22,510 25,055 16,927 23,527 21,491
SEGS II 1985 Daggett 30 165,376 316 25,085 23,431 38,914 43,862 39,156
SEGS III 1986 Kramer Jct. 30 230,300 349 49,444 61,475 63,096 69,410
SEGS IV 1986 Kramer Jct. 30 230,300 349 52,181 64,762 70,552 74,661
SEGS V 1987 Kramer Jct. 30 250,500 349 62,858 65,280 72,449
SEGS VI 1988 Kramer Jct. 30 188,000 390 48,045 62,690
SEGS VII 1988 Kramer Jct. 30 194,280 390 38,868 57,661
SEGS VIII 1989 Harper Lake 80 464,340 390 114,996
SEGS IX 1990 Harper Lake 80 483,960 390 5,974
Total production (MWh) 19,261 47,595 150,111 244,937 353,230 518,487
Sources: Solargenix Energy,[6] KJC Operating Company,[7] IEEE,[8] NREL[9][10]
SEGS plant history and operational data (1991-2002)
Gross solar production
of electricity (MWh)
Plant 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 average 1998–2002 Total
SEGS I 20,252 17,938 20,368 20,194 19,800 19,879 19,228 18,686 11,250 17,235 17,947 17,402 16,500 331,550
SEGS II 35,168 32,481 36,882 36,566 35,853 35,995 34,817 33,836 33,408 31,207 32,497 31,511 32,500 549,159
SEGS III 60,134 48,702 58,248 56,892 56,663 64,170 64,677 70,598 70,689 65,994 69,369 66,125 68,555 995,686
SEGS IV 64,600 51,007 58,935 57,795 54,929 61,970 64,503 71,635 71,142 63,457 64,842 70,313 68,278 1,017,283
SEGS V 59,009 55,383 67,685 66,255 63,757 71,439 75,936 75,229 70,293 73,810 71,826 73,235 72,879 1,014,444
SEGS VI 64,155 47,087 55,724 56,908 63,650 71,409 70,019 67,358 71,066 68,543 67,339 64,483 67,758 878,476
SEGS VII 58,373 46,940 54,110 53,251 61,220 70,138 69,186 67,651 66,258 64,195 64,210 62,196 65,048 834,986
SEGS VIII 102,464 109,361 130,999 134,578 133,843 139,174 136,410 137,905 135,233 140,079 137,754 138,977 137,990 1,691,773
SEGS IX 144,805 129,558 130,847 137,915 138,959 141,916 139,697 119,732 107,513 128,315 132,051 137,570 125,036 1,594,852
Total 608,960 538,458 613,798 620,358 628,674 676,091 674,473 662,631 636,851 652,835 657,834 662,542 654,539 8,967,123
Sources: Solargenix Energy,[11] KJC Operating Company,[7] IEEE,[8] NREL[10][12]
SEGS plant history and operational data (2003-2012)
Net solar production
of electricity (MWh)
Plant 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 average 2003–2012 Total
SEGS I[13] 6,913 8,421 6,366 5,559 - 10,705 9,033 10,648 11,164 11,666 8,048 80,475
SEGS II[14] 11,142 14,582 13,375 7,547 5,445 28,040 18,635 22,829 26,198 25,126 17,292 172,919
SEGS III[15] 59,027 64,413 56,680 51,721 59,480 69,012 62,971 60,029 61,350 56,877 60,156 601,560
SEGS IV[16] 58,100 62,006 56,349 52,439 59,799 69,338 63,563 63,084 57,684 62,414 60,478 604,776

Harper Lake[edit]

SEGS VIII and SEGS IX, located at 35°01′54″N 117°20′53″W / 35.0316°N 117.348°W / 35.0316; -117.348 (SEGS VIII and IX), are the largest solar thermal power plants individually and collectively in the world.[17] They were the last, the largest, and the most advanced of the nine plants at SEGS, designed to take advantage of the economies of scale. Construction of the tenth plant in the same locality was halted because of the bankruptcy of Luz Industries. Construction of the approved eleventh and twelfth plants never started. Each of the three planned plants had 80 MW of installed capacity.[18] Abengoa Solar recently constructed the 280MW Mojave Solar Project (MSP) adjacent to thee SEGS VIII and SEGS IX plants.[19] The MSP uses concentrating solar thermal technology as the SEGS projects.

Kramer Junction[edit]

The reflectors at Kramer Junction site facing the western sky to focus the late afternoon sunlight at the absorber tubes partially seen in the picture as bright white spots.

This location (35°00′51″N 117°33′32″W / 35.0142°N 117.559°W / 35.0142; -117.559 (SEGS III–VII)) receives an average of 340 days of sunshine per year, which makes it an ideal place for solar power generation. The average direct normal radiation (DNR) is 7.44 kWh/m²/day (310 W/m²),[7] one of the best in the nation[citation needed].

Daggett[edit]

SEGS I and II are located at 34°51′47″N 116°49′37″W / 34.8631°N 116.827°W / 34.8631; -116.827 (SEGS I and II) and are owned by Cogentrix Energy (Carlyle Group).[20]

Accidents and incidents[edit]

In February 1999, a 900,000-US-gallon (3,400 m3) Mineral Oil storage tank exploded at the SEGS I (Daggett) solar power plant, sending flames and smoke into the sky. Authorities were trying to keep flames away from two adjacent containers that held sulfuric acid and sodium hydroxide. The immediate area of 0.5 square miles (1.3 km2) was evacuated.[21]

See also[edit]

References[edit]

  1. ^ The Energy Blog: About Parabolic Trough Solar
  2. ^ "Solar Electric Generating System" (PDF). Retrieved 2009-12-13. 
  3. ^ "Reducing the Cost of Energy from Parabolic Trough Solar Power Plants", NREL, 2003
  4. ^ a b "Solar thermal power generation". Solel Solar Systems Ltd. Archived from the original on 2008-06-01. Retrieved 2010-09-30. 
  5. ^ Alexis Madrigal (November 16, 2009). "Crimes Against the Future: The Demise of Luz". Inventing Green. Retrieved 30 September 2010. 
  6. ^ Cohen, Gilbert (2006). "Nevada First Solar Electric Generating System" (PDF). "IEEE May Technical Meeting". Las Vegas, Nevada: Solargenix Energy. p. 10. 
  7. ^ a b c Frier, Scott (1999). "An overview of the Kramer Junction SEGS recent performance" (PDF). "Parabolic Trough Workshop". Ontario, California: KJC Operating Company. 
  8. ^ a b Kearney, D. (August 1989). "Solar Electric Generating Stations (SEGS)". IEEE Power Engineering Review (IEEE) 9 (8): 4–8. doi:10.1109/MPER.1989.4310850. 
  9. ^ Price, Hank (2002). "Parabolic trough technology overview" (PDF). "Trough Technology - Algeria". NREL. p. 9. 
  10. ^ a b Solar Electric Generating Station IX
  11. ^ Cohen, Gilbert (2006). "Nevada First Solar Electric Generating System" (PDF). "IEEE May Technical Meeting". Las Vegas, Nevada: Solargenix Energy. p. 10. 
  12. ^ Price, Hank (2002). "Parabolic trough technology overview" (PDF). "Trough Technology - Algeria". NREL. p. 9. 
  13. ^ EIA Electricity Data Browser - SEGS I
  14. ^ EIA Electricity Data Browser - SEGS II
  15. ^ EIA Electricity Data Browser - SEGS III
  16. ^ EIA Electricity Data Browser - SEGS IV
  17. ^ Jones, J. (2000), "Solar Trough Power Plants", National Renewable Energy Laboratory. Retrieved 2010-01-04.
  18. ^ California Energy Commission - Large Solar Energy Projects
  19. ^ Abengoa Solar - The Mojave Solar Project
  20. ^ SUNRAY/SEGS
  21. ^ Storage Tank at Solar Power Plant in Desert Explodes; Immediate Area Is Evacuated