Winter is No Friend to Green Power

Dec 26, 2008 - Deseret News (Salt Lake City)

Old Man Winter, it turns out, is no friend of renewable energy.

This time of year, wind turbine blades ice up, biodiesel congeals in tanks and solar panels produce less power because there is not as much sun. And perhaps most irritating to the people who own them, the panels become covered with snow, rendering them useless even in bright winter sunshine.

So in regions where homeowners have long rolled their eyes at shoveling driveways, add another cold-weather chore: cleaning off the solar panels.

"At least I can get to them with a long pole and a squeegee," said Alan Stankevitz, a homeowner in southeast Minnesota.

In January 2007, a bus stalled in the middle of the night on I- 70 in the Colorado mountains. The culprit was a 20 percent biodiesel blend that congealed in the freezing weather, according to John Jones, the transit director for the bus line, Summit Stage. (Biodiesel is a diesel substitute, typically made from vegetable oil, that is used to displace some fossil fuels.)

Winter may pose even bigger safety hazards in the vicinity of wind turbines. Some observers say the machines can hurl chunks of ice as they rotate.

"It's like you throw a plate out there and that plate breaks," said Ralph Brokaw, a cattle rancher in southeast Wyoming who has 69 wind turbines on his property. When his turbines ice up, he stays out of the way.

From the standpoint of generating power, winter is actually good for wind turbines, because it is generally windier than summer. In Vermont, for example, Green Mountain Power, which operates a small wind farm in the southeastern part of the state, gets more than twice the monthly production in winter as in August.

The opposite is true, however, for solar power. Days are shorter and the sun is lower in the sky during the winter, ensuring less power production.

Operators of the electrical grid do not worry much about the seasonal swings, because the percentage of production from renewable energy is still so low -- around 1 percent of the country's power comes from wind, and less from solar panels. But as renewable energy becomes a bigger part of the nation's power mix, the seasonable variability could become more of a problem.

Trey Taylor, the president of Verdant Power, which has put small turbines in the tidal East River in New York City and plans more for the St. Lawrence River in Canada, said that ice chunks could slide over one another "like a deck of cards," pushing ice below and harming turbines. That may rule out parts of otherwise promising sites like the Yukon River in Alaska, he said.