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Balance of power: Wind fluctuations complicate energy distribution through grids

When temperatures rose into the triple digits in the Pacific Northwest last week, breaking local heat records, electricity use also skyrocketed. Most grids can handle such events, but there was a problem in this case, Reuters reported. Just as A-C demand went up, winds slowed to nearly a halt. The calm air wasn’t turning turbines, a growing component of the region’s suite of energy sources. 

Electricity operators are learning more about how fluctuating winds complicate energy distribution in a region that is becoming more dependent on wind power. For instance, over the course of just one hour this June, energy generated from wind farms on the eastern end of the Columbia River Gorge jumped 1,000 megawatts—or “enough to power some 680,000 homes,” reported the Seattle Post-Intelligencer. To balance out the rise, operators had to quickly divert water around hydroelectric dams—the region’s primary power source—to keep the system from overloading. When the winds calmed again, operators could let the water flow back through. (A secondary issue arises here: whereas holding water behind dams creates more potential energy for use after winds die, it is harmful for fish trying to make their way down river.)

But last week, while the hot air stood still, water levels in the rivers also dropped—putting extra strain on a system that continues to rely more heavily on water than wind for its power.

The wind-generating capacity within the 15,238 square miles controlled by the federal Bonneville Power Administration, including the farms on the Columbia River Gorge, is now at 2,105 megawatts—up from 25 in 1998. “It’s enough to power two cities the size of Seattle,” according to the Seattle PI. And this capacity is expected to nearly triple in size within four years.

When wind’s contributions to the grid were small compared to more traditional—and consistent—energy sources, its natural unpredictability was not an issue. As wind power’s contribution has grown, however, wind’s erratic nature comes to the fore. The BPA estimates the system will no longer have enough flexibility to adjust for wind variability by 2011.

Scientists are currently looking into options to help mitigate the issues that arise with what should be a very good thing—a growth in clean, renewable energy. One strategy getting a lot of attention is better wind forecasting. The U.S. Department of Energy is currently collaborating with INESC Porto, a research institution in Portugal, on a project to reduce the margins of error in forecasts from 20 to 15 percent.

Meanwhile, the BPA will add 16 wind-monitoring stations and will soon schedule power realignments on the half hour rather than the hour. “The more accurately we can forecast, the less reserves we have to have and that will lower the cost,” Kim Randolph, a BPA power operation specialist told the Seattle PI.

Lower costs will appeal to consumers; fewer riparian traffic jams might please the fish.

Picture of wind turbine by ianmunroe via Flickr

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