Solar Energy Generating Systems

"SEGS" redirects here. For the airport with that ICAO code, see Seymour Airport.
Solar Energy Generating Systems

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°WCoordinates: 35°01′54″N 117°20′53″W / 35.0316°N 117.348°W
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
Units operational 936,384
Nameplate capacity 354 MW
Capacity factor 21%
Annual generation 662 GWh

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), 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).[1] NextEra Energy Resources operates and partially owns the plants located at Kramer Junction and Harper Lake.

Plants' scale and operations

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.

Principle of operation

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. 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

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

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

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.

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 I1984Daggett1482,96030719,26122,51025,05516,92723,52721,491
SEGS II1985Daggett30165,376316 25,08523,43138,91443,86239,156
SEGS III1986Kramer Jct.30230,300349 49,44461,47563,09669,410
SEGS IV1986Kramer Jct.30230,300349 52,18164,76270,55274,661
SEGS V1987Kramer Jct.30250,500349 62,85865,28072,449
SEGS VI1988Kramer Jct.30188,000390 48,04562,690
SEGS VII1988Kramer Jct.30194,280390 38,86857,661
SEGS VIII1989Harper Lake80464,340390 114,996
SEGS IX1990Harper Lake80483,960390 5,974
Total production (MWh)19,26147,595150,111244,937353,230518,487
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 I20,25217,93820,36820,19419,80019,87919,22818,68611,25017,23517,94717,40216,500331,550
SEGS II35,16832,48136,88236,56635,85335,99534,81733,83633,40831,20732,49731,51132,500549,159
SEGS III60,13448,70258,24856,89256,66364,17064,67770,59870,68965,99469,36966,12568,555995,686
SEGS IV64,60051,00758,93557,79554,92961,97064,50371,63571,14263,45764,84270,31368,2781,017,283
SEGS V59,00955,38367,68566,25563,75771,43975,93675,22970,29373,81071,82673,23572,8791,014,444
SEGS VI64,15547,08755,72456,90863,65071,40970,01967,35871,06668,54367,33964,48367,758878,476
SEGS VII58,37346,94054,11053,25161,22070,13869,18667,65166,25864,19564,21062,19665,048834,986
SEGS VIII102,464109,361130,999134,578133,843139,174136,410137,905135,233140,079137,754138,977137,9901,691,773
SEGS IX144,805129,558130,847137,915138,959141,916139,697119,732107,513128,315132,051137,570125,0361,594,852
Total608,960538,458613,798620,358628,674676,091674,473662,631636,851652,835657,834662,542654,5398,967,123
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

SEGS VIII and SEGS IX, located at 35°01′54″N 117°20′53″W / 35.0316°N 117.348°W, 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

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) 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.

Daggett

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

Accidents and incidents

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

References

  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. ↑ 4.0 4.1 "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). "IEEE May Technical Meeting" (PDF). Las Vegas, Nevada: Solargenix Energy. p. 10. |chapter= ignored (help)
  7. ↑ 7.0 7.1 7.2 Frier, Scott (1999). "Parabolic Trough Workshop" (PDF). Ontario, California: KJC Operating Company. |chapter= ignored (help)
  8. ↑ 8.0 8.1 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). "Trough Technology - Algeria" (PDF). NREL. p. 9. |chapter= ignored (help)
  10. ↑ 10.0 10.1 Solar Electric Generating Station IX
  11. ↑ Cohen, Gilbert (2006). "IEEE May Technical Meeting" (PDF). Las Vegas, Nevada: Solargenix Energy. p. 10. |chapter= ignored (help)
  12. ↑ Price, Hank (2002). "Trough Technology - Algeria" (PDF). NREL. p. 9. |chapter= ignored (help)
  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