Crescent Dunes Solar Energy Project

The Crescent Dunes Solar Energy Project is a 110 megawatt (MW) net[3] solar thermal power project with 1.1 gigawatt-hours of energy storage,[1] located near Tonopah, about 190 miles (310 km) northwest of Las Vegas.[4][5] Crescent Dunes was the first concentrated solar power (CSP) plant with a central receiver tower and advanced molten salt energy storage technology from SolarReserve.

Crescent Dunes Solar Energy Project
Crescent Dunes Solar December 2014.JPG
CountryUnited States
LocationTonopah, Nye County, Nevada
Coordinates38°14′00″N 117°22′01″W / 38.2333°N 117.367°W / 38.2333; -117.367
Construction began2011 (2011)
Commission date2016[1]
Construction cost$0.975 billion
Owner(s)Tonopah Solar Energy, LLC (SolarReserve, LLC)
Solar farm
CSP technologySolar power tower
Collectors10347 × 115.72 m²
Total collector area296 acres (1,200,000 m2)
Site resource2,685 kW·h/m2/yr[2]
Site area1,670 acres (676 ha)
Power generation
Units operational1
Make and modelAlstom
Nameplate capacity110 MW
Capacity factor51.9% (planned)
20.3% (2018)
Annual net output196 GW·h over 1 year (2018), or 22.4 MW actual average output
Storage capacity1,100 MW·he
External links
WebsiteCrescent Dunes Crescent Dunes]] 
CommonsRelated media on Commons

Developed by SolarReserve and owned by Tonopah Solar Energy, The Crescent Dunes project was anticipated to cost less than $1 billion and was backed by a $737 million in U.S. government loan guarantees.[6] The plant suffered several technical problems, and substantially missed its intended 50% capacity factor, only achieving about a 20% capacity factor in 2018, resulting in lawsuits and changes of control.[7][8][9] The site has not produced power since April 2019 and its sole customer, NV Energy, subsequently terminated their contract.[10] Bloomberg reports that NV Energy wasn’t allowed to sever its agreement with the plant until after the DoE took over the shuttered plant in August 2019.[7][11] Since the ousting from Crescent Dunes operator (Tonopah Solar Energy) board, SolarReserve is believed to have ceased operations.[12]


In late September 2011 Tonopah Solar Energy received a $737 million loan guarantee from the United States Department of Energy (DOE) and [4] the right to build on public land.[13] The capital stack included $170,000,000 in EB-5 investment through SolarReserve/ACS Cobra partner CMB Regional Centers.[14][15][8] Under a power purchase agreement (PPA) between SolarReserve and NV Energy, all power generated by the Crescent Dunes project in the next 25 years would have been sold to NV Energy for $0.135 per kilowatt-hour.[6] For comparison, the average U.S. cost per kilowatt-hour in 2011 was $0.12, and in 2019 the cost has risen to $0.133, so NV Energy's deal was essentially market-rate and competitively neither high nor low.[16][17]

Ground was broken on the project in September 2011.[18] Construction terminated at the end of 2013, followed by several months of testing the plant systems. The project entered commissioning phase in February 2014 following completion of construction.[19] It began operation in September 2015,[20] but went off-line in October 2016 due to a leak in a molten salt tank. It returned to operation in July 2017.[21]

NV Energy—the project's sole customer—terminated its contract in October 2019 on the basis of the project having "failed to produce." Alleging a takeover of Tonopah Solar Energy by the DOE,[11] SolarReserve has raised the possibility of the project filing for bankruptcy.[22][23] According to the lawsuit, the Department of Energy is looking to appoint two new members to Tonopah Solar Energy’s board of managers, giving the appearance of the Energy Department in complete control of Tonopah directors which comprise the entirety of the Tonopah Board of Managers.[11]


The project's EPC Contractor was ACS Cobra, which carried out the engineering design, procured the equipment and materials necessary, and then constructed and delivered the facility to Tonopah Solar Energy. The project includes 10,347 heliostats that collect and focus the sun's thermal energy to heat molten salt flowing through an approximately 640-foot (200 m) tall solar power tower. Each heliostat is made up of 35 6×6 feet (1.8 m) mirror facets, yielding a heliostat overall usable area of 1,245 square feet (115.7 m2). Total solar field aperture adds up to 12,882,015 square feet (1,196,778 m2). The molten salt circulates from the tower to a storage tank, where it is then used to produce steam and generate electricity.

Excess thermal energy is stored in the molten salt and could be used to generate power for up to ten hours, including during the evening hours and when direct sunlight is not available.[4] The storage technology thus eliminated the need for any backup fossil fuels, such as natural gas. Melting about 70,000,000 pounds (32,000,000 kg) of salt took two months. Once melted, the salt stays melted for the life of the plant and is cycled through the receiver for reheating.[24]

Maximum actual energy output that accounts for maintenance (i.e., capacity factor) was re-estimated at 500 GWh annually,[25] though the highest producing year thus far, 2018, only attained 40% of that.


Crescent Dunes began operation in September 2015,[20] but went off-line in October 2016 due to a leak in a molten salt tank. It returned to operation in July 2017.[21] While its average monthly production was expected to exceed 40,000 MWh, as of May 2019 it never reached that value and only exceeded half of it during 9 months.[26]

Generation (MW·h) of Crescent Dunes Solar Energy[27]
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total
2015 1,703 1,831 0 3,534
2016 1,508 9,121 7,099 2,158 11,485 6,216 25,560 28,267 30,514 5,410 0 0 127,338
2017 0 0 0 0 0 0 9,420 9,192 13,666 9,263 488 0 42,029
2018 795 5,145 5,907 13,801 10,653 33,387 23,749 33,169 31,632 21,253 8,130 8,189 195,810
2019 12,889 14,431 20,041 2,807 0 0 0 0 0 0 0 50,168
Total (2015-2019) 418,879

The commissioning of a new fossil power plant, the technology of which is at the base of Crescent Dunes, requires a couple of years from the first grid connection to full production.[28][29]

As an example the Edwardsport production data, whose progression, skipping first partial year, is a 40% output the first full year, 57% the second full year, the next year the progression was stopped by a problem in October, but resumes with a 73% the fourth and next year. At Crescent Dunes, it was to be expected a similar progression, but the failure of the storage tanks in 2016, froze the commissioning.[30] Following that, first full production year was delayed to 2018, starting with a 40% (200 over 500) output.


The first three months of 2019 (January, February and March) showed good progression, topping all previous monthly data, but in April the plant was shut down because the project's sole buyer, NV Energy, terminated the Power Purchase Agreement for failure to produce the contracted power production. The power generated also cost NV Energy about $135 per megawatt-hour, compared with less than $30 per MWh available from a new Nevada photovoltaic solar farm.[31][32] But the Tonopah solar project power is dispatchable whilst photovoltaic power is intermittent. It is inappropriate to compare intermittent generating technologies, like wind and solar, with dispatchable generating technologies like nuclear, gas combined cycle, and coal. Crescent Dunes project is more on the conventional type of generation.The difference between the noon low hourly prices and the evening high hourly prices, can be up to four orders of magnitude, if capacity payments for generating capacity available to supply power during peak hours is included.[33]


See alsoEdit


  1. ^ a b "Crescent Dunes 24-Hour Solar Tower Is Online". CleanTechnica. 22 February 2016. Retrieved 15 June 2016.
  2. ^ Crescent Dunes Solar Energy Project, National Renewable Energy Laboratory
  3. ^ "Crescent Dunes Solar Thermal Power Plant". Grupo COBRA. 2016. Archived from the original on 4 June 2016. Retrieved 26 May 2019.
  4. ^ a b c "Energy Department Finalizes $737 Million Loan Guarantee to Tonopah Solar Energy for Nevada Project" (Press release). Loan Programs Office (LPO), Dept. of Energy (DOE). 28 September 2011. Retrieved 2 July 2014.
  5. ^ "Crescent Dunes: Project Under Construction". Loan Programs Office (LPO), Dept. of Energy (DOE). 1 September 2015. Retrieved 17 January 2016.
  6. ^ a b Wesoff, Eric (29 September 2011). "DOE Races Against the Clock: Two Solar Loans Closed, Seven More to Go". Greentech Media. Retrieved 29 September 2011.
  7. ^ a b Solar Power - Solar Power Plant,
  8. ^ a b NV Energy sends termination notice to massive Tonopah solar project, developer accuses Energy Department of taking over
  9. ^ Future of Crescent Dunes solar plant near Tonopah appears bleak
  10. ^ Nye solar plant could be facing a crisis
  11. ^ a b c Schulz, Bailey (7 October 2019). Cook, Glenn (ed.). "Tonopah solar plant could end up in bankruptcy, developer says". Las Vegas: J. Keith Moyer. Archived from the original on 8 October 2019. Retrieved 26 February 2020. major decisions — such as bankruptcy proceedings — require a unanimous vote from the managers, the lawsuit alleges that the Energy Department can determine the fate of Tonopah Solar Energy without any representation of SolarReserve on the board
  12. ^ America’s Concentrated Solar Power Companies Have All but Disappeared
  13. ^ Chris Martin; Nic Querolo (6 January 2020). "A $1 Billion Solar Plant Was Obsolete Before It Ever Went Online". Bloomberg. Retrieved 5 February 2020. Harry Reid, then the Senate majority leader and senior senator from Nevada, cleared the way for the company to build on public land
  14. ^ "Group IX – Crescent Dunes". Retrieved 2017-03-27.[dead link]
  15. ^ "Nhóm XI – ACS Cobra". Retrieved 2017-03-27.[dead link]
  16. ^ The Price Of Electricity In Your State
  17. ^ Electricity rates by state – the U.S. average is 13.04 cents per kilowatt hour
  18. ^ Tetreault, Steve (28 September 2011). "Nevada solar project to get $737 million federal loan guarantee". Las Vegas Review-Journal. Retrieved 29 September 2011.
  19. ^ "Crescent Dunes Solar Energy Project, Nevada, United States of America". Retrieved 29 December 2016.
  20. ^ a b National Renewable Energy Laboratory (10 November 2015). "Crescent Dunes Solar Energy Project".
  21. ^ a b Las Vegas Review-Journal (21 July 2017). "Nevada solar plant back online after eight-month outage".
  22. ^ Will DOE take the Crescent Dunes solar project into bankruptcy?
  24. ^ Hashem, Heba (4 April 2014). "No drama as SolarReserve commissions world's largest CSP tower with storage". CSP Today Business Intelligence. FC Business Intelligence Limited. Retrieved 6 May 2014.
  25. ^ "Crescent Dunes". Archived from the original on 14 August 2017. Retrieved 17 October 2017.
  26. ^ SolarReserve still falling short at flagship solar tower project
  27. ^ "Crescent Dunes Solar Energy, Monthly". Electricity Data Browser. Energy Information Administration. Retrieved October 8, 2019.
  28. ^ Commissioning Phase
  29. ^ Building a Coal Fired Power Station
  30. ^ Salt leak shuts down Crescent Dunes Concentrated Solar Power plant
  31. ^ A $1 Billion Solar Plant Was Obsolete Before It Ever Went Online
  32. ^ NV Energy sends termination notice to massive Tonopah solar project, developer accuses Energy Department of taking over
  33. ^ Comparing the Costs of Intermittent and Dispatchable Electricity Generating Technologies

External linksEdit