Kenetech machines have experienced difficulties in extreme weather. Two 33M-VS turbines being tested by the New York utility, Niagara Mohawk, experienced serious problems because of cold weather, according to the utility. The turbines produced only 400,000 kWh between them for the year ended November 28 (Windpower Monthly, January 1994). This low production was partly because the turbines were shut down for most of December and February and winter is the windy season at the site. Major retrofitting was needed, says Gerry Rockower of Niagara Mohawk.
The liquid inside the cooling system for the electronics froze, he says, and the units over-heated and shut down. One was replaced with air cooling and the other with an improved liquid cooling system. In addition, the lubricants and grease posed problems in the cold weather, at times 35 degrees Fahrenheit below zero, he says. Additional heaters were installed. There were problems with the anemometers freezing too, he says.
Rockower stresses the turbines are test machines and not commercially operating models. "These are all the things you learn testing in the field and not in the laboratory. We're not apologetic about the performance of these turbines," he says. He notes that from December 1992 to February 1993, they produced 25,300 kWh, or 8,433 kWh a month. But from December 1993 to February, they produced 117,150 kWh or 39,050 a month -- five times as much, he says.
Problems could yet be posed by lightning, he adds. The area sees some 6000 strikes in an average summer. "We don't know the effect of lightning yet," he says. "We hope it won't hit. But we need to know the effect if they do."