Hybrid Power Plants Can Help Industry Go Green

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http://www.aftau.org/site/News2?page=NewsArticle&id=15477

Hybrid Power Plants Can Help Industry Go Green

Thursday, November 3, 2011

TAU researchers develop affordable solar option for power plants

Hybrid cars, powered by a mixture of gas and electricity, have become a practical way to "go green" on the roads. Now researchers at Tel Aviv University are applying the term "hybrid" to power plants as well.

Most power plants, explains Prof. Avi Kribus of TAU's School of Mechanical Engineering and its innovative new Renewable Energy Center, create power using fuel. And solar thermal power plants — which use high temperatures and pressure generated by sunlight to produce turbine movement — are currently the industry's environmentally-friendly alternative. But it's an expensive option, especially when it comes to equipment made from expensive metals and the solar high-accuracy concentrator technology used to harvest solar energy.

Now, a new technology Prof. Kribus has developed combines the use of conventional fuel with the lower pressures and temperatures of steam produced by solar power, allowing plants to be hybrid, replacing 25 to 50 percent of their fuel use with green energy. His method, which will be reported in a future issue of the Solar Energy Journal, presents a potentially cost-effective and realistic way to integrate solar technology into today's power plants.

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Instead, with his graduate student Maya Livshits, Prof. Kribus is developing an alternative technology, called a steam-injection gas turbine. "We combine a gas turbine, which works on hot air and not steam, and inject the solar-produced steam into the process," he explains. "We still need to burn fuel to heat the air, but we add steam from low-temperature solar energy, approximately 200 degrees centigrade." This hybrid cycle is not only highly efficient in terms of energy production, but the lowered pressure and heat requirements allow the solar part of the technology to use more cost-effective materials, such as common metals and low-cost solar collectors.

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