Burning high in the sky, he sits and watches us, just doing his job. Wearing an ironic pair of sunglasses, he keeps us warm during the day, bronzes our skin by the beach, and makes earth inhabitable. He does quite a bit for us, despite his dwelling 93 million miles away. But with concerns over the climate rising faster than the temperature, the Department of Energy is calling on him to play a bigger role.

With the costs of energy walking a tight rope, and an economy struggling to recover itself after a fall, the Department of Energy turned once more to Mr. Sun. Solar energy has been a good idea for a while, but because it can’t be stored, and because it only produces during part of the day, it can’t make the impact that many think it should.

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Greenpeace calculates that the exploitation of less than 1% of the total solar thermal potential of the sun would be enough to stabilise the world climate through massive carbon dioxide reductions. Some large scale technologies must become viable to even approach this level.

One’s first thought on solar energy is often the photo voltaic systems (PV) that convert sunlight directly into electricity. These small systems seem to have real potential, especially in areas that lack grid based electricity. However, PV material is expensive and has, to date, not found application as a mainstream alternate energy source.

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Launched by doctoral candidates Amy Mueller and Matt Orosz, the MIT project aims to bring cheap and eco-friendly energy to parts of the world that are now off the grid. The focus of their efforts: Lesotho, in southern Africa, where many people now get their energy from highly polluting diesel generators.

The students’ alternative comes in the form of solar energy. Not the expensive, photovoltaic-dependent kind, but the affordable and easy-to-harness concentrating solar kind. Their energy generator uses a parabolic trough to concentrate the sun’s energy to heat water to provide steam energy as well as hot water.

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The evolution of industrial power has been largely a story of utility. Societies adopted the most productive means of producing power, irrespective of all other concerns. Wind and water power may have been cheaper and cleaner, but with available technology were far less productive ways of making stuff.  Hence, they were abandoned in favor of fossil fuels. 

This is why, even after the energy trials and tribulations of the 1970s and the spikes in prices since, FFs still hold sway. Renewables just never quite had the reliable and sustained punch of the power we could generate by setting things on fire.

Yet present-day advances in solar promise to turn that model on its head. This time, we start with one of the cleanest fuels available – sunlight – and learn how to use it as productively as possible.        

Keep an eye on concentrating solar power (CSP), which has the potential to give fossil fueled power plants a run for their (and our) money in the near future.

This solar technology has the audacity, the unmitigated gall, to produce electricity long after the sun has gone down. What, you may ask, are these upstarts trying to do? Compete with coal and natural gas?

Pretty much.

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A Colorado company has unveiled what they call the highest performance, lowest cost utility-scale solar power system of any kind for generating electricity. The SkyTrough, by SkyFuel cuts the cost of its parabolic trough concentrator by 35% compared to other commercially available systems, largely because of a mirrored polymer which replaces the heavy glass used in other solar parabolic trough collectors.

>>More on concentrating solar power at CleanTechnica

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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?

The report, “On the Rise; Solar Thermal Power and the Fight Against Global Warming,” touts the multiple benefits of solar thermal power that the U.S. has barely begun to tap. One, it’s a clean source of energy that could replace other power sources that generate greenhouse gases and worsen climate change. Two, by storing thermal energy, it can generate electricity even when the sun isn’t shining. And ,three, it’s wildly abundant in the U.S., offering way more clean energy than we currently use on a daily basis.

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We have featured Concentrated Solar Power several times in this space, so it was nice to see that the Science section of the New York Times is finally starting to cover large-scale solar thermal plants used for generating electricity. (An article on SkyStream wind turbines is in the same section!)

The great news about solar thermal “Power Towers” is that they are able to store solar energy, which has always been a problem before. How does a solar “Power Tower” work?

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