While adoption of solar energy steps up around the world, two key challenges remain: how to store the energy created during the day so it can be used through the night and how to dispatch the energy to where it is needed. Both of these problems may be solved by coupling molten salt with concentrating solar power (CSP), according to a June 26 article in Renewable Energy World.

You will recall from previous CleanTechnica postings that CSP technology concentrates the sun’s power to create steam, which turns a turbine to make electricity. But how did molten salt get into the picture?

“Terry Murphy, Chief Executive Officer for SolarReserve, who along with others helped develop the molten salt technology at Rocketdyne. ‘Molten salt is a heat storage medium that retains thermal energy very effectively over time and operates at temperatures greater than 1000°F, which matches well with the most efficient steam turbines. Second, it remains in a liquid state throughout the plant’s operating regime, which will improve long-term reliability and reduce operation and maintenance costs. And third, it’s totally ‘green,’ molten salt is a non-toxic, readily available material…..’”

Molten salt storage was a key component of the Solar Grand Plan, published in Scientific American in December 2007, which outlined a plan to supply 69% of U.S. electricity and 35% of its total energy by 2050. The Grand Plan, written by By Ken Zweibel, James Mason and Vasilis Fthenakis, proposes molten salt storage concentrating solar, among other proven technologies, and calls for an aggressive plan of government subsidies to allow solar energy to compete fairly with oil and other fossil fuels.

Related Posts on Solar Storage

Clean Energy Intro: Solar Thermal

Solar Power Goes to Extremes

Solar Thermal Electricity: Can It Replace Coal, Gas and Oil?

I ran across this article at The Oil Drum and thought it was too tasty to pass up. It describes a new design to help concentrated solar power (CSP) increase efficiency and reduce cost.

Here’s the problem: solar thermal collectors focus the sun’s heat onto a clear tube of fluid (see: Intro to Solar Thermal). The collectors generate the most energy when the sun’s rays are parallel with the tube of fluid.  Since the sun moves across the sky throughout the days and seasons, it only reaches this “sweet spot” certain hours each day. But, if the solar collectors could move to track the sun, their power output could increase dramatically. Keep in mind that CSP is one of the most efficient forms of solar power.

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It’s called “Concentrated Solar Power” or C.S.P. The idea is simple; no complex chemistry or fancy silicon wafers required. Glorified mirrors shaped like satellite dishes (or parabolic troughs) direct the sun’s rays towards a reservoir. The concentrated solar heat boils water into steam, and steam powers a turbine. When the water cools off it’s collected and cycled back through the system. The mirrors can even track the sun across the sky to maximize efficiency. Water is not the only fluid that can be used, but its unique properties have made it popular. More on that below.

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