It’s not working and its promoter blames the Spanish company.

It opened to great fanfare as one of the most innovative renewable energy projects in the United States. Ten years later, it has only enchanted airplane passengers flying over the Nevada desert. This is the Crescent Dunes fiasco.

10,347 mirrors in the desert. The 110 MW Crescent Dunes has more than ten thousand mirrors that concentrate sunlight onto a 200-metre central tower. It was the second solar thermal power plant with molten salt storage after Spain’s Gemasolar. But it was built on a six-times larger scale, with the intention of storing up to 1.1 GWh of energy and providing flexible power to 100,000 people.

But the ambitious project, built between 2011 and 2013 in Tonopah, halfway between Las Vegas and Reno, never lived up to its promise.

A multi-million dollar waste. The project was promoted by California-based SolarReserve. Its price tag: about $1 billion, financed by investors like Warren Buffett and Citigroup with loans guaranteed by the U.S. government.

Crescent Dunes was born out of an agreement to supply NV Energy, a Nevada electric company, with 100 percent of the electricity it produced for 25 years. 500,000 megawatt hours a year, day and night, thanks to 10 hours of molten salt storage. But the power never arrived, or it arrived at an exorbitant price.

Bankrupt. In 2019, NV Energy sued SolarReserve for breach of contract and terminated the power purchase agreement. The cost of running the plant and paying employees eventually made the project unviable after losing its only customer, leading to the plant’s closure.

Crescent Dunes investors pulled out of the project and also sued SolarReserve for capital mismanagement. The following year, Crescent Dunes filed for bankruptcy, confirming what had been brewing since its opening: the biggest renewable energy fiasco in the history of the United States. The plant was taken over by the government in a foreclosure.

They point to a Spanish company. After the project was abandoned, Bill Gould, co-founder of SolarReserve, blamed the failure on Spanish company ACS Cobra, the co-owner and designer of the power plant, accusing it of designing a faulty storage tank.

Despite the allegations, SolarReserve has not filed a lawsuit against the Spanish company, a former subsidiary of Banco Santander and the ACS group headed by Florentino Perez. The Crescent Dunes salt tank failed because it was too big. High temperature differences cause greater expansion, which increases the compressive forces. With very large diameters, the probability of failure due to cyclic loading increases many times over.

Inefficient technology. Solar thermoelectric power (CSP) has not gained the same widespread adoption as photovoltaic power due to its high initial cost and lack of advances in thermal storage. Instead of solar panels converting light into electricity, these plants use heliostats that chase the sun with their mirrors, concentrating the light into a mixture of molten salts.

Molten salts store thermal energy at temperatures between 290 and 565 degrees Celsius. This energy can be used on demand to heat water and produce steam; the steam, in turn, drives a turbine to generate electricity. It has its advantages (it’s flexible, whereas photovoltaics are intermittent), but it was an outdated system when Crescent Dunes opened in 2015.

The plant is now managed by ACS. Crescent Dunes failed not only because of the problems with the salt deposit. The plant can produce electricity, but at a very high price: $135 per MWh, while the photovoltaic solar farm offers prices below $30 per MWh.

Despite everything, the debt was suspended with a $200 million payment. Crescent Dunes reopened in 2021 under ACS management and a new contract with NV Energy. It produced 80,236 MWh last year.

Image | BLM Nevada

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