Wind farm near Manjeel, northwest Iran.

Two Iranian scientists have published a paper titled "Exergy analysis of a wind turbine" in International Journal of Exergy, in which they discuss their approach to improved exergy analysis of wind turbine performance, citing improvements of 20% in efficiency and about 80% decrease in "wasted" energy.

Exergy is a term, usually used in thermodynamics, which describes the amount of energy in a system which is capable of doing work. In other words, this is the amount of energy we have at our disposal from a wind turbine which we can use to generate electricity, or power some other process. Varying operational parameters dictate different amounts of exergy available, so wind speed difference has a direct effect on wind turbine output. Optimizing wind turbine performance to give maximum exergy for every regime of wind speed, would represent an ideal profile for wind turbine efficiency. According to Abolfazl Ahmadi and Mehdi Ali Ehyaei (Department of Mechanical Engineering, Iran University of Science and Technology-Arak Branch), a more in-depth analysis of the conversion process is needed for a more holistic approach in exergy calculations.

The scientists came up with a model which tells how a wind turbine's work potential can be lost. This in turn offers the ability to optimize three main parameters – cut-in speed, rated and furling wind speeds, providing maximum energy at any given wind speed, from the gentlest breeze, to a gale-force wind, and all within the safe operation parameters of the turbine.

Ahmadi and Ehyaei have carried out exergy analyses of wind turbines at two cities in Iran – Tehran and Manjeel. Tehran is slow wind area, whereas Manjeel is considered a windy area. Their new formula offers optimized values for wind turbine rotation speed, which can be changed depending on wind speed conditions.