Ivanpah Solar Power Facility

Ivanpah Solar Electric Generating System
Looking north towards Ivanpah Facility's eastern boiler tower from Interstate 15.
Location of Ivanpah Solar Electric Generating System in California
Country	United States
Location	near Ivanpah, San Bernardino County, California
Coordinates	35°34′N 115°28′W / 35.57°N 115.47°W / 35.57; -115.47Coordinates: 35°34′N 115°28′W / 35.57°N 115.47°W / 35.57; -115.47
Status	Operational
Construction began	2010
Commission date	2014[1][2]
Construction cost	$2.2 billion
Owner(s)	NRG Energy BrightSource Energy Google
Solar farm
Type	CSP
CSP technology	Solar power tower
Heliostats	173,500
Site area	3,500 acres (1,420 ha)[3]
Power generation
Make and model	Siemens SST-900
Nameplate capacity	Ivanpah 1 has a total capacity of 126 MW and Ivanpah 2 and 3 are both 133 MW each. Planned: 392 MW gross, 377 MW net[4]
Capacity factor	31%
Annual generation	1,000 GW·h
Website ivanpahsolar.com

The Ivanpah Solar Electric Generating System is a concentrated solar thermal plant in the California Mojave Desert, 64 km (40 miles) southwest of Las Vegas, with a gross capacity of 392 megawatts (MW).^[5] It deploys 173,500 heliostats, each with two mirrors, focusing solar energy on boilers located on three centralized solar power towers.^[5] Unit 1 of the project was connected to the grid in September 2013 in an initial sync testing.^[6] The facility formally opened on February 13, 2014,^[1] and it is currently the world's largest solar thermal power station.^[7][8]

The project was developed by BrightSource Energy and Bechtel.^[9] It cost $2.2 billion; the largest investor in the project is NRG Energy, a power generating company based in Princeton, New Jersey, that has contributed $300 million. Google has contributed $168 million.^[10] In 2010, the project was scaled back from the original 440-megawatt (590,050 hp) design, to avoid building on the habitat of the desert tortoise.^[11]

In November 2014, Associated Press reported that the plant was producing only "about half of its expected annual output". The California Energy Commission issued a statement blaming this on "clouds, jet contrails and weather".^[12]

Description

Aerial photograph of Ivanpah Solar Power Facility

Power tower #2 of the Ivanpah Solar Electric Generating System under construction. The heliostat mirrors on the truck are awaiting installation.

View of Ivanpah Solar Electric Generating System from Yates Well Road. The Clark Mountain Range can be seen in the distance.

Ivanpah Solar Electric Generating System with all three towers under load, Feb 2014. Taken from I-15.

The Ivanpah Solar Electric Generating System consists of three solar thermal power plants on a 4,000 acres (1,600 ha) tract of public land near the Mojave Desert and the California—Nevada border in the Southwestern United States.;^[13] this is near Interstate 15 and north of Ivanpah, California.^[14] The site is visible from adjacent Mojave National Preserve, Mesquite Wilderness, and Stateline Wilderness.^[14]

The facility consists of fields of heliostat mirrors focusing sunlight on receivers located on centralized solar power towers. The receivers generate steam to drive specially adapted steam turbines. For the first plant, the largest ever fully solar-powered steam turbine-generator set was ordered, using a 123-megawatt (165,000 hp) Siemens SST-900 single-casing reheat turbine.^[15] Besides steam-turbine generators Siemens supplied instrumentation and control systems.^[16] Final approval was gained in October 2010.^[17] On October 27, 2010, California Governor Arnold Schwarzenegger, Interior Secretary Ken Salazar, and other dignitaries gathered in the Mojave Desert to officially break ground on the project.^[5] The project generated controversy because of the decision to build it on ecologically intact desert habitat.^[18]

The project has received a $1.6 billion loan guarantee from the U.S. Department of Energy.^[19] The total cost of the project is about $2.18 billion.^[20] The facility has contracts to sell about two-thirds of the power generated at Ivanpah to PG&E, and the rest to SCE.^[21][22][23]

The largest investor in the project is NRG Energy, a generating company based in Princeton, N.J., that has put in $300 million.^[10] The project has also received an investment of $168 million from Google,^[24] but in November 2011, Google announced that they would no longer invest in CSP due to the rapid price decline of photovoltaics, and stopped its research on the project.^[25][26][10]

Awards

In August 2014, Ivanpah was awarded the "Plant of the Year" award from POWER Magazine.^[27] In February 2012, Ivanpah was awarded the CSP (Concentrating Solar Power) Project of the Year by Solar Power Generation USA.^[28]

Power towers

The facility's three towers.

The Ivanpah plants use BrightSource Energy's "Luz Power Tower 550 technology" (LPT 550):

The LPT 550 solar system produces electricity the same way as traditional power plants – by creating high temperature steam to turn a turbine. BrightSource uses thousands of mirrors called heliostats to reflect sunlight onto a receiver being developed by Riley Power Inc. filled with water that sits atop a tower. When the sunlight hits the receiver, the water inside is heated and creates high temperature steam. The steam is then piped to a conventional turbine, which generates electricity.^[23]

Additionally, "the power towers have 'receiver units' at their top on which the mirror fields focus their reflected light. During operation, these receiver units become extremely hot, such that they glow and appear brightly lit.... Because they are high above the ground, these glowing receiver units will be a visible distraction to persons at many of the KOPs [Key Observation Points], including travelers utilizing I-15."^[14]

According to the State of California Energy Resources Conservation and Development Commission Opening Briefs regarding this project, "the project itself is visually imposing. It would cover roughly 4,000 acres (1,600 ha), most of which would be covered with mirror fields. The panoramic expanse of mirror arrays would present strong textural contrast with the intact, natural character of the desert floor [and] would rise to a height of roughly 459 feet [140 m]; an additional 10 to 15 feet [3–5 m] above that height would consist of lighting to meet Federal Aviation Administration (FAA) requirements."^[14]

Ivanpah Solar Power Facility Online  Ivanpah's eastern tower online. Note the sunlight glare on either side of the boiler.  One of the three towers of the Ivanpah Solar Power Facility.

Economic impact

BrightSource estimated that the Ivanpah facility would involve some 1,000 jobs at the peak of construction, 86 permanent jobs, and total economic benefits of $3 billion.^[21][23]

Elected San Bernardino County Supervisor Brad Mitzelfelt, who represents most of the California Mojave Desert stated that the "project would create jobs for mostly Las Vegas and electricity for mostly San Francisco".^[29]

The project received a $1.6 billion loan guarantee from the United States Department of Energy.^[30] The estimated construction costs for the project ($5,561.00 per KW) fall between the construction costs for coal and nuclear power plants, according to Synapse Energy Economics,^[31][32] but this does not account for the less favorable capacity factor of solar power.

It was reported in November 2014 that the investors in the plant were applying for a $539 million federal grant to pay off their federal loan.^[33]

Performance

The steam plant is designed for 28.72% gross efficiency.^[3]

The local irradiance near this area is about 7.4 kW·h/m²/day^[34][35] (annual average) for a total solar energy flow in the visible spectrum of 2,717 kW·h/m² yearly or 2.717 MW·h/m² yearly.

A claimed capacity factor of 31.4%^[35] implies that the plant will operate for 365 days * 24 hours * 31.4% = 2751 hours/year. At 377 MW (net nameplate capacity) constant power, this means a generation of 377 MW * 2751 hours/year = 1,037,127 MW·h/year rounding up to 1.04 TW·h/year.

One heliostat mirror is a 75.6 square feet (7.02 m²) reflecting surface,^[36] for a total of 151.2 square feet (14.05 m²) per heliostat. Total plant heliostat reflecting surface results in 173,500 heliostats * 14.05 m²/heliostat = 2,437,144 m². Based on irradiance, the intercepted solar energy flow is 2.717 MW·h/m²/year * 2,437,144 m² = 6,621,720 MW·h yearly. Thermal yield, after taking into consideration reflection, transmission, radiation and absorption losses, is about 55%, resulting in a thermal power input to the steam turbines of 6,621,720 MW·h * 55% = 3,641,946 MW·h_th. Resulting expected energy output is 3,641,946 MW·h_th * 28.72% efficiency = 1,045,967 MW·h/year, rounding up to 1.05 TW·h/year. Lack of published performance data is causing speculation that the plant is not meeting expectations, but it's probably too early to tell.^[37]

Environmental impacts

The Ivanpah installation is estimated to reduce carbon dioxide emissions by more than 400,000 tons annually. It was designed to minimize impacts on the natural environment compared to some photovoltaic solar facilities because the use of heliostats does not require as much grading of the land.^[28] However, the facilities are fenced off to keep some terrestrial wildlife out, and initial studies indicate that birds face the risk of collision with the heliostat mirrors or from burning in solar flux created by the mirror field.^[38][39]

The Ivanpah Solar power project was built on 6 square miles of public land in the northeastern Mojave Desert.^[40] Project construction was temporarily halted in the spring of 2011 due to the suspected impacts on desert tortoises.^[41] Although, construction resumed when the United States Fish and Wildlife Service (USFWS) found the project was not likely to jeopardize the endangered desert tortoise.^[42] BrightSource also installed fencing to keep wildlife out of the area.^[43] In 2010, the project was scaled back from the original 440-megawatt (590,050 hp) design, to avoid building on the habitat of the desert tortoise.^[11]

In 2012, the National Parks Conservation Association (NPCA) issued a report on the project, citing water concerns, damage to visual resources, and impacts on important desert species. In order to conserve scarce desert water, LPT 550 uses air-cooling to convert the steam back into water. Compared to conventional wet-cooling, this results in a 90 percent reduction in water usage. The water is then returned to the boiler in a closed process.^[23] Many desert tortoises found on the site were relocated to other parts of the Mojave Desert; however, environmentalists raised concerns that relocated tortoises were more likely to die due to the stresses involved.^[44][45]

During the trial of the plant in September 2013, 34 dead birds were found at the plant, 15 of which had heavily burned feathers, which staff at the plant referred to as "streamers" because they were burned in flight by the intense radiation from the heliostat mirrors.^[46] From February through June 2014, a team of biologists monitoring the number of bird deaths reported a total of 290.^[47] According to a USFWS report in April 2014, 141 birds were collected at Ivanpah in October 2013 and 47 of the deaths were attributed to solar flux.^[48] According to a report by the Associated Press, "Ivanpah might act as a 'mega-trap' for wildlife, with the bright light of the plant attracting insects, which in turn attract insect-eating birds that fly to their death in the intensely focused light rays."^[49] Possible bird kill mitigation strategies are being considered, such as using proven, environmentally safe technologies such as avian radars and LRADs to keep birds away from the site, covering ponds to discourage waterbirds from loitering, and clearing additional land around the plant to make it less attractive and more visible to birds in flight.^{[46][50][51][52]}

Another potential issue that has been reported is the effect of mirror glare on airplane pilots.^[53]

See also

• List of solar thermal power stations
• SEGS
• Solar power plants in the Mojave Desert
• Blythe Solar Power Project

References

External links

• Ivanpah Solar Power Facility website
• Brightsource energy official website
• Ivanpah Solar Electric Generating System