How much usable energy do wind turbines produce? It is a question that perplexes engineers and frustrates potential users, especially on windless days. A study published this month in the International Journal of Exergy provides a formula for answering this vexing question.

Abolfazl Ahmadi and Mehdi Ali Ehyaei of the Department of Mechanical Engineering, at Iran University of Science and Technology-Arak Branch, in Arak, have investigated the “exergy” of wind power. Exergy is a term from thermodynamics that measures that the energy a system that is available to do work.

Wind is one of the oldest renewable energy resources. Fan blades atop a tall capture the wind’s energy and convert it to useful power at ground level. Modern turbines, of course, take this notion of wind power one stage further and produce electricity to drive equipment elsewhere. A single wind turbine can vary in size from a few kilowatts for small residential applications to more than 5 megawatts for industrial scale electricity generation.

Ahmadi and Ehyaei point out that wind turbines have to compete with many other energy sources, primarily fossil fuels but also other renewable energy sources such as solar and biomass technology. As such, a wind turbine has to be cost effective in order to be environmentally effective.

Turbine design must meet load requirements and produce energy at a minimal per dollar cost. In order to address this cost issue, performance characteristics such as power output versus wind speed or versus rotor angular velocity must be optimized. Exergy analysis looks at the “quality” of the energy produced by a system. To be viable, there is little point in producing intermittent power at wildly varying levels, as this feeds only low-quality energy into the power supply system.

Read more . . .

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Tags: capture the wind, electricity generation, exergy, Innovation, quality energy, renewable energy resources, renewable energy sources, turbine design, usable energy, vexing question, wind turbine, wind turbines, windless days

This entry was posted on Monday, June 22nd, 2009 at 10:38 am and is filed under Innovation, Project Energy, Science Digest / Science Daily. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.