NPR’s Alan Yu wrote an interesting article about Abengoa Solar. On Wednesday, Abengoa cranked up the world’s largest solar energy plant of its kind. What is newsworthy is not only its size — it powers 70,000 homes in Arizona — but the technology that enables it to store energy during the day and then generate power at night.
In a nutshell, so-called parabolic trough collectors capture the sun’s energy and use it to heat oil. The oil boils water, which in turn powers turbines that generate electricity.
And here is the interesting part: the oil can also transfer its heat to enormous tanks filled with salt. The salt retains that energy, and can heat the oil back up after the sun sets (or when demand for electricity increases beyond typical capacity), using it to complete the cycle described above.
When I first heard about Solyndra, a solar panel manufacturer in California’s Silicon Valley and mentioned in NPR’s article, I was puzzled by how it could possibly compete with manufacturers in China. Solyndra had a unique design for its solar collectors, but not as special as the technology developed by Abengoa. Clearly, any company hoping to succeed in the vast solar market must focus on bringing innovative technology to market. Energy storage, from typical computer batteries to tanks of salt, is on the minds of many R&D labs around the world.
Another substantial challenge for developers of solar energy installations is their use of water. Cooling of production plants can take hundreds of millions of gallons of water per year, and especially in sunny areas that are highly suitable to solar energy collection, water supply is often sparse.
Mr. Yu mentions that Abengoa has additional installations underway in California’s Mojave Desert and in South Africa.
According to Wikipedia, Abengoa Solar registered more than 112 CSP (concentrating solar power) and PV (photovoltaic technology) patent applications as of May, 2012. It has offices in San Francisco, CA, and is a subsidiary of Abengoa, SA, a multi-national corporation based in Seville, Spain.