Scoring high load factors -- Wind is worth it

A wind turbine at the 33.7 MW Tararua wind farm in New Zealand scored what could be a record capacity factor for a three month period at the beginning of this year, operating at maximum rated power for 65% of the time. Of the 51 Vestas 660 kW turbines at Tararua, only three of them had capacity factors below 57%, reports WindStats Newsletter, a sister publication to Windpower Monthly. For the whole of 2002, the wind farm recorded a load factor of 51.7%, meaning that winds are strong and steady enough at the site for the wind turbines to have operated at maximum output for more than half the year.

The Tararua capacity factor compares with an average load factor of around 80% for coal, gas and nuclear. While lower than that, the achievements at Tararua illustrate that wind power can produce significant amounts of power. The wind farm produced 0.4% of New Zealand's electricity last year.

Output projections from wind farms in Britain further illustrate that wind power production is significant, even if the wind does not blow all the time. The average capacity factor for 38 UK wind farms with a combined capacity of 258 MW is 33.1%.

Calculations of "capacity equivalents" for wind plant allow comparisons with thermal power stations. Adding 1000 MW of wind around Tararua would be equivalent to 612 MW of thermal plant, states WindStats, while 1000 MW of UK wind plant at typical locations would produce the same energy as just under 400 MW of thermal plant