New technique 'banks' wind farm energy

UNIVERSITY OF WISCONSIN-MILWAUKEE - A high-tech way of "banking" extra energy from high winds can improve wind power's ups and downs and make it more efficient, U.S. university researchers said.

The method uses an algorithm, or sequence of finite instructions, to take advantage of high winds and wind gusts, University of Wisconsin-Milwaukee electrical engineers and computer scientists said in the International Journal of Power Electronics.

The algorithm adjusts a wind turbine's rotor speed so that when wind speeds are greater than average, the rotor speeds up and stores the excess energy, they said.

This energy is then released when the wind power falls below average.

The approach ends any need for external batteries or capacitors to store electricity for bad days and the additional infrastructure and engineering they entail, the researchers said.

The method also captures wind energy more effectively and therefore improves wind farming's overall efficiency, potentially reducing the number of turbines required on a given wind farm, they said.

The United States has added more wind energy to its grid than any other country, growing 45 percent to 16.8 gigawatts in 2007 and is now the world's largest wind power producer, due in part to its better average winds.

U.S. wind-power capacity could reach 300 gigawatts — or 300 billion watts — by 2030, meeting a fifth of all U.S. electricity demand, the U.S. Department of Energy says.