Crescent Dunes Solar Energy Project

File:Boden 000298 172859 518225 4578 (36776425306).jpgs at Crescent Dunes]]

In late September 2011 Tonopah Solar Energy received a $737 million loan guarantee from the United States Department of Energy (DOE) and the right to build on public land.{{cite news |last1=Chris Martin |last2=Nic Querolo |title=A $1 Billion Solar Plant Was Obsolete Before It Ever Went Online |url=https://www.bloomberg.com/news/articles/2020-01-06/a-1-billion-solar-plant-was-obsolete-before-it-ever-went-online |access-date=5 February 2020 |work=Bloomberg |date=6 January 2020 |quote=Harry Reid, then the Senate majority leader and senior senator from Nevada, cleared the way for the company to build on public land}} The capital stack included $170,000,000 in EB-5 investment through SolarReserve/ACS Cobra partner CMB Regional Centers.{{Cite web|url=https://www.cmbeb5visa.com/project/group-ix-crescent-dunes-solar-reserve/|archive-url=https://web.archive.org/web/20170328195137/https://www.cmbeb5visa.com/project/group-ix-crescent-dunes-solar-reserve/|url-status=dead|archive-date=2017-03-28|title=Group IX – Crescent Dunes|website=www.cmbeb5visa.com|access-date=2017-03-27}}{{Cite web|url=https://www.cmbeb5visa.com/project/group-xi-crescent-dunes-acs-cobra/|archive-url=https://web.archive.org/web/20170328020133/https://www.cmbeb5visa.com/project/group-xi-crescent-dunes-acs-cobra/|url-status=dead|archive-date=2017-03-28|title=Nhóm XI – ACS Cobra|website=www.cmbeb5visa.com|access-date=2017-03-27}} Under a power purchase agreement 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.{{cite news |url= http://www.greentechmedia.com/articles/read/doe-closes-two-solar-loans-just-before-the-deadline/ |title= DOE Races Against the Clock: Two Solar Loans Closed, Seven More to Go |first= Eric |last= Wesoff |date= 29 September 2011 |publisher= Greentech Media |access-date= 29 September 2011}}

Ground was broken on the project in September 2011.{{cite news |url= http://www.lvrj.com/news/nevada-solar-project-to-get-737-million-federal-loan-guarantee-130713818.html |title= Nevada solar project to get $737 million federal loan guarantee |first= Steve |last= Tetreault |date= 28 September 2011 |work= Las Vegas Review-Journal |access-date= 29 September 2011 }} 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.{{cite news |url=http://www.power-technology.com/projects/crescent-dunes-solar-energy-project-nevada/ |title=Crescent Dunes Solar Energy Project, Nevada, United States of America |newspaper=Power Technology |access-date=29 December 2016}} It began operation in September 2015,{{cite web |url=http://www.nrel.gov/csp/solarpaces/project_detail.cfm/projectID=60 |title=Crescent Dunes Solar Energy Project |author=National Renewable Energy Laboratory |date= 10 November 2015 }} but went off-line in October 2016 due to a leak in a molten salt tank. The owners warned the EPC about flaws in the salt tank foundations (and other matters) with formal comments lodged on the record in March 2012 progress meeting with DOE and its engineer present (the lender did not voice any objection). It returned to operation in July 2017.{{cite web |url=https://www.reviewjournal.com/business/energy/nevada-solar-plant-back-online-after-eight-month-outage/ |title=Nevada solar plant back online after eight-month outage |author=Las Vegas Review-Journal |date= 21 July 2017 }}

The plant having last produced power in April 2019, 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, SolarReserve then raised the possibility of the project filing for bankruptcy, which subsequently happened.{{Cite web|url=https://pv-magazine-usa.com/2019/10/07/will-doe-take-the-crescent-dunes-solar-project-into-bankruptcy/|title=Will DOE take the Crescent Dunes solar project into bankruptcy?|date=October 7, 2019|website=pv magazine USA}}[https://www.bloomberglaw.com/public/desktop/document/SolarReserveCSPHoldingsLLCvsTonopahSolarEnergyLLCDocketNo20190791?1570209807 SOLARRESERVE CSP HOLDINGS vs.TONOPAH SOLAR ENERGY, LLC - Docket No.2019-0791] SolarReserve also filed a lawsuit, claiming that the Department of Energy was 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. An interim outcome in this regard was that SolarReserve took down its website and was believed to have ceased operations permanently.

Tonopah Solar Energy filed for bankruptcy on July 30, 2020. Pending the approval of the bankruptcy court, a $200 million settlement with the remaining debtors — Tonopah Solar Energy LLC and ACS Cobra — for the return of taxpayer dollars was also announced at the end of July 2020.{{Cite web|url=https://www.reviewjournal.com/news/politics-and-government/200m-settlement-announced-over-bankrupt-tonopah-solar-project-2084328/amp/|title = Tonopah solar project part of $200M settlement | Las Vegas Review-Journal| date=July 30, 2020 }} The amount is less than half of what taxpayers are owed on the outstanding $425 million of public debt.{{cite news| url = https://www.wsj.com/articles/energy-department-poised-to-lose-up-to-225-million-on-solar-project-bankruptcy-11596145244| title = Energy Department Poised to Lose Up to $225 Million on Solar Project Bankruptcy - WSJ| newspaper = Wall Street Journal| date = July 30, 2020}} Under the settlement agreement and as a function of subsequent repairs, restoration of the plant to power production and acquisition of new long-term customers, ACS Cobra is liable for an additional $100 million in otherwise suspended debt.{{Cite web|url=https://www.eenews.net/stories/1063659143|title = POLITICO Pro}}

File:Boden 000140 166043 510376 4578 (36643882391).jpg

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 {{convert|656|ft|adj=on}} tall solar power tower. Each heliostat is made up of 35 6×{{convert|6|ft|m}} mirror facets, yielding a heliostat overall usable area of {{convert|1245|sqft|sqm|1}}. Total solar field aperture adds up to {{convert|12882015|sqft|sqm|0}}. 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. The storage technology thus eliminated the need for any backup fossil fuels, such as natural gas. Melting about {{convert|70000000|lb|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.{{cite news |url=http://analysis.newenergyupdate.com/csp-today/markets/no-drama-solarreserve-commissions-worlds-largest-csp-tower-storage |title=No drama as SolarReserve commissions world's largest CSP tower with storage |first= Heba |last= Hashem |date= 4 April 2014 |work= CSP Today Business Intelligence |publisher= FC Business Intelligence Limited |access-date= 6 May 2014 }}

Crescent Dunes was the first large (110 MW) tower CSP with thermal storage. While storage tanks of trough CSP operate at {{convert|400|C}}, Crescent Dunes operated the storage tank at almost {{convert|600|C}}, while keeping {{convert|280|C}} as base (cold) temperature.

Higher temperatures differences result in a greater expansion of the tank floor, generating greater compressive forces around the floor plate. At very large diameters, as the big tank of Crescent Dunes, that resulted in a high probability of failure under cycling loading.{{cite web | url = https://www.solarpaces.org/vast-solar-has-a-fix-for-crescent-dunes-thermal-storage-tank-leak/ | title = In Tower CSP, thermal storage had issues at first | date = 4 April 2023 | website = www.solarpaces.org | access-date = 10 August 2023

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Crescent Dunes began operation in September 2015, but went off-line in October 2016 due to a leak in a molten salt tank. It returned to operation in July 2017. 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.{{Cite web|url=https://reneweconomy.com.au/solarreserve-still-falling-short-at-flagship-solar-tower-project-13928/|title=SolarReserve still falling short at flagship solar tower project|first=David|last=Leitch|date=February 8, 2018|website=RenewEconomy}}

The commissioning of a new thermal plant requires up to four years to achieve 100% operating level, from the first grid connection to full production. 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.{{cite web |title=EuroTrough Helped Cut Ramp-Up Time of China's 100 MW Urat CSP |url=https://www.solarpaces.org/eurotrough-cut-ramp-up-in-china-100-mw-urat-csp%E2%80%A8

|website=www.solarpaces.org |publisher=SolarPACES |url-status= |archive-url=https://web.archive.org/web/20211219113434/https://www.solarpaces.org/eurotrough-cut-ramp-up-in-china-100-mw-urat-csp%E2%80%A8 |archive-date=19 December 2021 |access-date=8 February 2022 |quote=... thermal plants require up to four years to ramp-up to 100% operating level...}} At Crescent Dunes, it was to be expected a similar progression, but the failure of the storage tanks in 2016 froze the commissioning.{{Cite web|url=https://helioscsp.com/salt-leak-shuts-down-crescent-dunes-concentrated-solar-power-plant/|title=Salt leak shuts down Crescent Dunes Concentrated Solar Power plant|first=Jose|last=Santamarta}} 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.{{Cite news|url=https://www.bloomberg.com/news/articles/2020-01-06/a-1-billion-solar-plant-was-obsolete-before-it-ever-went-online|title=A $1 Billion Solar Plant Was Obsolete Before It Ever Went Online|newspaper=Bloomberg|date=January 6, 2020}} However, the Tonopah solar project power is dispatchable while photovoltaic power is intermittent. Levelized cost comparisons must include the capacity payments for generating capacity available to supply power during peak hours. By doing so, low-to-high hourly wholesale electricity prices have been shown to vary by up to four orders of magnitude.{{Cite web|url=https://www.researchgate.net/publication/227357598|title=(PDF) Comparing the Costs of Intermittent and Dispatchable Electricity Generating Technologies|accessdate=September 17, 2023}}{{Cite web |url=https://economics.mit.edu/files/6317 |title=MIT Economics |access-date=January 14, 2021 |archive-date=February 21, 2021 |archive-url=https://web.archive.org/web/20210221202324/http://economics.mit.edu/files/6317 |url-status=dead }}

In July 2021, the project restarted production.

CrescentDunes.jpg|2012 January – The solar tower under construction as seen from a commercial airliner. The eponymous Crescent Dunes are at lower right.

Crescent Dunes Solar December 2014.JPG|2014 December – Completed site as seen from a commercial airliner.

Crescent Dunes 2024.png|2024 August - Crescent Dunes Solar Energy Project as seen from commercial airliner

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{{Commons category|Crescent Dunes Solar Energy Project}}

• {{cite web

|url= http://www.solarreserve.com/en/global-projects/csp/crescent-dunes

|title= Crescent Dunes Solar Energy Project

|publisher= SolarReserve, LLC

|access-date= 28 April 2015

|archive-date= August 14, 2017

|archive-url= https://web.archive.org/web/20170814214605/http://www.solarreserve.com/en/global-projects/csp/crescent-dunes

|url-status= dead

}}

• {{cite web

|url= https://solarpaces.nrel.gov/crescent-dunes-solar-energy-project

|title= Crescent Dunes Solar Energy Project

|date= 20 January 2011 |work= Concentrating Solar Power Projects

|publisher= National Renewable Energy Laboratory (NREL), DOE

|access-date= 29 September 2011 }}

• {{cite web

|url= http://energy.gov/lpo/solarreserve-llc-crescent-dunes

|title= SolarReserve, LLC (Crescent Dunes)

|work= Projects |publisher= LPO, DOE

|access-date= 16 September 2014 }}

• {{cite web

|url= http://www.recovery.gov/arra/Transparency/RecoveryData/pages/recipientprojectsummary508.aspx?awardidsur=128618&awardtype=Loans

|title= American Recovery and Reinvestment Act (ARRA) Loans - Award Summary: Tonopah Solar Energy, LLC

|date= 21 September 2011

|publisher= Recovery.gov

|access-date= 2 July 2014

|archive-url= https://web.archive.org/web/20140714200723/http://www.recovery.gov/arra/Transparency/RecoveryData/pages/recipientprojectsummary508.aspx?awardidsur=128618&awardtype=Loans

|archive-date= 14 July 2014

|url-status= dead

}}

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