Solar Energy Generating Systems

Solar Energy Generating Systems
Part of the 354 MW SEGS solar complex in northern San Bernardino County, California.
Map
CountryUnited States
LocationMojave Desert
Coordinates35°01′54″N 117°20′53″W / 35.0316°N 117.348°W / 35.0316; -117.348
StatusOperational
Construction began1983
Commission date1984
Owner(s)NextEra Energy Resources
Solar farm
TypeCSP
CSP technologyParabolic trough
Collectors936,384
Site resource2,725 kWh/m2/yr
Site area1,600 acres (647.5 ha)
Power generation
Units operational2
Units decommissioned7
Nameplate capacity160 MW
Capacity factor19.2%
Annual net output539 GW·h (2015)
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Solar Energy Generating Systems (SEGS) is a concentrated solar power plant in California, United States. With the combined capacity from three separate locations at 354 megawatt (MW), it was once the world's second largest solar thermal energy generating facility, until the commissioning of the even larger Ivanpah facility in 2014. It consisted 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) were located at Daggett (34°51′45″N 116°49′45″W / 34.86250°N 116.82917°W / 34.86250; -116.82917); they have been replaced with a solar photovoltaic farm.

SEGS III–VII (150 MW) were installed at Kramer Junction (35°00′43″N 117°33′32″W / 35.01194°N 117.55889°W / 35.01194; -117.55889); all five SEGS have undergone demolition.

SEGS VIII–IX (160 MW) are located at Harper Lake (35°01′55″N 117°20′50″W / 35.03194°N 117.34722°W / 35.03194; -117.34722). NextEra Energy Resources operates and partially owns the plants located at Kramer Junction. On January 26, 2018, the SEGS VIII and IX at Harper Lake were sold to renewable energy company Terra-Gen, LLC.

A tenth plant (SEGS X, 80 MW) had been in construction and SEGS XI and SEGS XII had been planned by Luz Industries, but the developer filed for bankruptcy in 1992, because it was unable to secure construction financing. The site of SEGS X was later licensed for a solar photovoltaic farm, Lockhart Solar PV II.

Most of the thermal facilities were retired by 2021, and photovoltaics were built on the same sites.

Plants' scale and operations

Before retirement and replacement of SEGS I-VII with solar photovoltaics, the plants had a 354 MW net (394 MW gross) installed capacity. The nameplate capacity, which operating continuously, would dеliver the samе net power output, coming only from the solar source was around 75 MWe, representing a 21% capacity factor. In addition, the turbines could be utilized at night by burning natural gas.

NextEra claimed in 2009 that the solar plants could power 232,500 homеs (during the day, at peak power) and displace 3,800 tons of pollution pеr year that would have been produced if the electricity had been providеd by fossil fuels, such as oil.

The facilities had a total of 936,384 mirrors and cover more than 1,600 acres (647.5 ha). Lined up, the parabolic mirrors would have extended 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). 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

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

The parabolic mirrors are shaped like quarter-pipes. The sun shines on glass panels, 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. The term "field area" is assessed as the actual collector area.

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, 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, and commissioned between December 20, 1984 and October 1, 1990. 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.[citation needed]

SEGS plant history and operational data (1985-1990)
Plant Year
built
Location Turbine
capacity
Field
area
Oil
temperature
Gross solar production
of electricity (MWh)
Net (MW) Gross (MW) (m2) (°C) 1985 1986 1987 1988 1989 1990
SEGS I 1984 Daggett 14 14 82,960 307 19,261 22,510 25,055 16,927 23,527 21,491
SEGS II 1985 Daggett 30 33 190,338 316 25,085 23,431 38,914 43,862 39,156
SEGS III 1986 Kramer Jct. 30 33 230,300 349 49,444 61,475 63,096 69,410
SEGS IV 1986 Kramer Jct. 30 33 230,300 349 52,181 64,762 70,552 74,661
SEGS V 1987 Kramer Jct. 30 33 250,500 349 62,858 65,280 72,449
SEGS VI 1988 Kramer Jct. 30 35 188,000 390 48,045 62,690
SEGS VII 1988 Kramer Jct. 30 35 194,280 390 38,868 57,661
SEGS VIII 1989 Harper Lake 80 89 464,340 390 114,996
SEGS IX 1990 Harper Lake 80 89 483,960 390 5,974
Total 354 394 2,314,978 19,261 47,595 150,111 244,937 353,230 518,487
Sources: Solargenix Energy, KJC Operating Company, IEEE, NREL
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 16,500 348,950
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 32,500 571,696
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, KJC Operating Company, IEEE, NREL
SEGS plant history and operational data (2003-2014)
Net solar production
of electricity (MWh)
Plant 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 average 2003–2014 Total
SEGS I 6,913 8,421 6,336 5,559 0 10,705 9,033 10,648 11,164 11,666 9,403 8,583 8,203 98,431
SEGS II 11,142 14,582 13,375 7,547 5,445 28,040 18,635 22,829 26,198 25,126 23,173 7,611 16,975 203,703
SEGS III 59,027 64,413 56,680 51,721 59,480 69,012 62,971 60,029 61,350 56,877 56,824 54,407 59,399 712,791
SEGS IV 58,100 62,006 56,349 52,439 59,799 69,338 63,563 63,084 57,684 62,414 58,317 54,321 59,785 717,414
SEGS V 61,921 67,717 62,309 53,471 59,547 69,316 59,820 54,328 60,451 62,877 57,758 56,354 60,489 725,869
SEGS VI 50,504 53,618 51,827 45,076 65,832 67,156 62,750 63,576 59,327 56,082 52,539 50,547 56,570 678,834
SEGS VII 49,154 50,479 46,628 42,050 58,307 65,185 58,950 58,836 57,378 54,147 48,183 46,762 53,005 636,059
SEGS VIII 119,357 124,089 120,282 117,451 122,676 135,492 131,474 155,933 152,463 145,247 141,356 145,525 134,279 1,611,345
SEGS IX 115,541 123,605 120,915 117,310 122,699 150,362 139,756 163,899 160,506 164,203 154,082 147,883 140,063 1,680,761
Total 531,659 568,930 534,701 492,624 553,785 664,606 606,952 653,162 646,521 638,639 601,635 571,993 588,767 7,065,207
SEGS plant history and operational data (2015-2021)
Net solar production
of electricity (MWh)
Plant 2015 2016 2017 2018 2019 2020 2021 Total Total
1985–2021
SEGS I 12,562 dec. (PV) (PV) (PV) (PV) (PV) 12,562 459,943
SEGS II dec. dec. (PV) (PV) (PV) (PV) (PV) 0 775,399
SEGS III 52,073 46,582 44,115 43,849 38,242 0 dec. 224,861 1,933,518
SEGS IV 53,117 49,034 43,182 44,406 41,865 0 dec. 231,604 1,969,301
SEGS V 52,646 50,142 43,934 47,383 41,424 0 dec. 235,529 1,975,842
SEGS VI 46,937 40,923 36,380 34,262 0 0 dec. 158,502 1,715,812
SEGS VII 37,771 30,480 32,601 27,956 0 0 dec. 128,808 1,599,852
SEGS VIII 138,149 140,849 123,451 132,871 120,530 114,557 81,699 852,106 4,189,538
SEGS IX 145,863 142,867 131,268 137,564 124,375 122,045 116,013 919,995 4,161,294
Total 539,118 500,877 454,931 468,291 366,254 236,602 197,712 2,754,405 18,780,499
Starting 2017, SEGS I was replaced by PV system Sunray 2, and SEGS II by PV system Sunray 3

Harper Lake

Until Ivanpah Solar Power Facility was commissioned in 2014, SEGS VIII and SEGS IX, located at 35°01′55″N 117°20′50″W / 35.031815°N 117.347270°W / 35.031815; -117.347270 (SEGS VIII and IX) were the largest solar thermal power plants individually and collectively in the world. 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 would have had 80 MW of installed capacity. Abengoa Solar recently constructed the 280MW Mojave Solar Project (MSP) adjacent to the SEGS VIII and SEGS IX plants. The MSP also uses concentrating solar thermal trough technology.

Starting in February 2020, SEGS VIII no longer burned natural gas. The last production month was October 2021. SEGS IX stopped burning natural gas starting October 2020, except for January 2021.

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′48″N 117°33′38″W / 35.013218°N 117.560531°W / 35.013218; -117.560531 (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), one of the best in the nation[citation needed]. This was the location of SEGS II - VII, which were retired in 2019. As of 2021, they were going to be replaced with a new solar photovoltaic array called Resurgence I.

Daggett

SEGS I and II were 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 owned by Cogentrix Energy (Carlyle Group). SEGS II was shut down in 2014 and was replaced by Sunray 3 (EIA plant code 10438), a 13,8 MW photovoltaic system. SEGS I was shut down one year later and replaced by 20 MW PV system Sunray 2 (EIA plant code 10437). Sunray 2 and Sunray 3 started production in 2017 as per EIA data.

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.

See also


This page was last updated at 2023-11-27 17:28 UTC. Update now. View original page.

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