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. (more…)

Xtreme Concentrated Solar Power: if a magnifying glass is like lightning to ants, this would be their atomic bomb.

We already know that concentrated solar power (CSP) is shaking things up in the solar industry. A subset within the industry is turning up the heat. “Extreme” Concentrated solar magnifies intense sunlight onto a solar cell, at temperatures that could melt it, to boost efficiency for less money.

The holy grail of renewable energy is not just efficiency but competitive pricing. Most consumers don’t want to wait 5-10+ years to earn back their investment in energy savings, assuming that they can afford solar. Never mind the added value of generating some of your own energy. Utility-scale facilities hinge not only on cost, but infrastructure. If you build your solar/wind farm in the desert, transmission lines may not come out to meet you. So when someone claims to have a cheap, efficient solar technology, people pay attention.

Extreme Concentrated Solar stands out because it claims to be affordable and very efficient. Unlike solar-thermal (CSP), which utilizes the heat of the sun, this technology still converts light into power (photo voltaic). So many solar companies have attempted to reduce cost by rising to industrial scale, but this method takes the opposite approach. XCPV (extreme concentrated photo voltaic) uses very small solar panels combined into a module design, and modules are infinitely scalable. (more…)

One of the most common arguments against large-scale use of renewable energy is that it cannot produce a steady, reliable stream of energy, day and night. Ausra Inc. does not agree. They believe that solar thermal technology can supply over 90% of grid power, while reducing carbon emissions.

“The U.S. could nearly eliminate our dependence on coal, oil and gas for electricity and transportation, drastically slashing global warming pollution without increasing costs for energy,” said David Mills, chief scientific officer and founder of Ausra.

You may be wondering, how will we have electricity at night or during cloudy weather?
Will we use large banks of batteries or burn candles?

The ability to utilize solar thermal technology after the sun sets is made possible by a storage system that is up to 93% efficient, according to Ausra’s executive vice president John O’Donnell. (more…)

What if you could produce clean solar energy night and day, rain or shine, and never hit the bank for a single P.V. solar panel? Photo voltaic panels can be pricey, so the solar industry is always trying to lower costs and boost efficiency in the quest to compete with coal. One fast-growing, cost-effective solar technology uses heat to generate energy 24 hours a day, and it can store energy without batteries. In this post I’m going to investigate solar-thermal technologies.

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. (more…)