New Concentrating Solar Tower Is Worth Its Salt with 24/7 Power

A California firm is converting sunlight to heat and storing it in molten salt so it can supply electricity when the wind is calm or the sun isn’t shining

By Knvul Sheikh on July 14, 2016

The facility is touted as being the first solar power plant that can store more than 10 hours of electricity, which translates into 1,100 megawatt-hours, enough to power 75,000 homes.

“We can ramp up electricity generation for utilities based on the demand. We can turn on when they want us to turn on and we can turn off when they want us to turn off,” SolarReserve CEO Kevin Smith says.


The 110-megawatt Crescent Dunes Solar Energy Facility in Nevada is the first utility-scale concentrating solar plant that can provide electricity whenever it’s needed most, even after dark. Credit: SolarReserve

Deep in the Nevada desert, halfway between Las Vegas and Reno, a lone white tower stands 195 meters tall, gleaming like a beacon. It is surrounded by more than 10,000 billboard-size mirrors focusing the sun’s rays on its tip. The Crescent Dunes “concentrating solar power plant” looks like some advanced communication device for aliens. But the facility’s innovation lies in the fact that it can store electricity and make it available on demand any time—day or night.

Crescent Dunes, the flagship project of Santa Monica–based firm SolarReserve, has achieved what engineers and proponents of renewable energy have struggled with for decades: providing cheap, commercial-scale, non–fossil fuel electricity even when winds are calm or the sun is not shining. The facility is touted as being the first solar power plant that can store more than 10 hours of electricity, which translates into 1,100 megawatt-hours, enough to power 75,000 homes. “We can ramp up electricity generation for utilities based on the demand. We can turn on when they want us to turn on and we can turn off when they want us to turn off,” SolarReserve CEO Kevin Smith says.

The trick is to have all those mirrors heat up a massive tank fullof sodium and potassium nitrates that are pumped up to the top of the tower. There the molten salt can reach temperatures as high as 565  degrees Celsius. When electricity is needed, the hot salt is used to boil water and produce high-temperature, high-pressure steam, which turns turbines that generate electricity. The rest of the time, the molten salt can be stored in another insulated tank on the ground.

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