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Energy Storage

Published on June 6th, 2014 | by Tina Casey

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Low Cost Concentrating Solar Power System Leverages Calcium Energy Storage

June 6th, 2014 by  


A new project at the Southern Research Institute is in the works that could shoot low cost concentrating solar power from an also-ran to a major player in the competitive energy marketplace. The research effort is a $1.05 million project funded partly by the Energy Department under President Obama’s SunShot Initiative. It is part of a broader program aimed at developing high-temperature thermochemical energy storage systems for CSPs.

low cost concentrating solar power

Year of CSP (cropped) courtesy of US DOE

Energy Storage And Low Cost Concentrating Solar Power

For those of you new to the topic, concentrating solar power (CSP) plants are based on the concept that it is more efficient to literally concentrate raw solar energy in one place before converting it to useful forms of energy, rather than converting it directly to electricity through an array of photovoltaic cells.

The concentrating part is accomplished with mirrors, most familiarly in the form of parabolic troughs or flat heliostats. Typically, the solar energy is transferred to a fluid such as molten salt or a specialty oil. The transfer medium is then circulated to a generating station, where it boils water for a steam turbine to generate electricity.

That’s where the competitive aspect of low cost concentrating solar power part comes in. Once the solar energy is transferred from the mirrors into heat energy, it could be stored in that form for several hours. The storage feature provides CSP plants with the ability to time-shift their electricity generation into peak hours when grid rates are higher.

That, in turn, boosts the value of the CSP supply relative to other forms of energy in the grid mix.

The Southern Research Institute CSP Project

One key goal for low cost concentrating solar power is to find the most efficient fluid or other energy storage platform. The Southern Research Institute (SRI) project consists of a high temperature solar thermal storage system that uses a calcium-based sorbent.

The technology was originally researched for use in carbon capture for coal fired power plants, so we’re intrigued to see it transferred to a zero-emission facility.

According to SRI, the calcium angle takes CSP storage up to the next level. First of all, it can operate at up to 900 degrees Celsius, compared to only 550 degrees for a molten salt system. That higher storage operating temperature enables the development of next-generation, high-efficiency solar energy conversion systems.

The SRI team also estimates that the calcium-based system will cost only about one-fourth as much as the latest molten salt system.

 

Not to rub salt in the wound (sorry!), but according to SRI their calcium system has a much smaller footprint than molten salt, taking only about one-sixth of the size to store the same amount of energy.

SunShot And Low Cost Concentrating Solar Power

SunShot actually got its start under the Bush Administration, and under the Obama Administration it has become the Energy Department’s signature program for pushing the cost of solar power down to a competitive level with fossil fuels.

The SRI research project is funded by a $836,697 DOE grant, with SRI chipping in $209,175. It’s part of a $10 million CSP advanced storage tech package that DOE announced back in May as part of its Year of Concentrating Solar Power festivities celebrating “a true CSP Renaissance in America.”

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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



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