Solar After Dark: BrightSource Adding Molten Salt Storage for Power Plants

Developer of Mojave Desert solar tower projects to develop proven storage option.

1 min read
Solar After Dark: BrightSource Adding Molten Salt Storage for Power Plants

BrightSource Energy announced yesterday the launch of SolarPLUS, a combination of its solar tower technology and a way to store the power it generates using molten salts. Storage of solar energy has long been a sticking point, given that a solar plant can't generate power when the sun isn't shining.

Molten salt storage has been proven in other countries in recent years, as described by our own Peter Fairley in a story on the Andasol 1 plant in Spain. Like the Spanish facility, BrightSource will use a combination of sodium nitrate and potassium nitrate in its system. Basically, the salts are heated during the day when the sun is shining using a heat exchanger, and the process is reversed at night when power is needed but no sun is available.

BrightSource's solar technology involves the solar tower concept, in which a huge array of thousands of mirrors -- known as heliostats, because they track the sun across the sky -- concentrates the sun's rays on to a centralized tower. Inside the tower, steam is generated from the heat, and the steam is used to run a turbine just as in a standard power plant. The molten salt storage will allow the turbines to turn after dark. Though possible to keep them turning all night, the company says a two- to six-hour window is optimal. BrightSource is currently building the Ivanpah Solar plant in the Mojave Desert, a 392-megawatt project that has generated controversy for its use of public lands and the potential environmental harm involved.

(Image via BrightSource Energy)

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This Dutch City Is Road-Testing Vehicle-to-Grid Tech

Utrecht leads the world in using EVs for grid storage

10 min read
This photograph shows a car with the words “We Drive Solar” on the door, connected to a charging station. A windmill can be seen in the background.

The Dutch city of Utrecht is embracing vehicle-to-grid technology, an example of which is shown here—an EV connected to a bidirectional charger. The historic Rijn en Zon windmill provides a fitting background for this scene.

We Drive Solar

Hundreds of charging stations for electric vehicles dot Utrecht’s urban landscape in the Netherlands like little electric mushrooms. Unlike those you may have grown accustomed to seeing, many of these stations don’t just charge electric cars—they can also send power from vehicle batteries to the local utility grid for use by homes and businesses.

Debates over the feasibility and value of such vehicle-to-grid technology go back decades. Those arguments are not yet settled. But big automakers like Volkswagen, Nissan, and Hyundai have moved to produce the kinds of cars that can use such bidirectional chargers—alongside similar vehicle-to-home technology, whereby your car can power your house, say, during a blackout, as promoted by Ford with its new F-150 Lightning. Given the rapid uptake of electric vehicles, many people are thinking hard about how to make the best use of all that rolling battery power.

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