Average wind speeds in Missouri are lower than reported on a state-produced wind map, said a University of Missouri atmospheric scientist. This finding may affect utilities and private investors planning to build wind turbines to provide clean, renewable energy. Lower-than-predicted wind speeds also may make it harder to meet goals set in 2008 by Missouri Proposition C ...to obtain a gradually increasing percentage of their energy from renewable sources.

COLUMBIA, Mo. - Average wind speeds in Missouri are lower than reported on a state-produced wind map, said a University of Missouri atmospheric scientist. This finding may affect utilities and private investors planning to build wind turbines to provide clean, renewable energy.

Lower-than-predicted wind speeds also may make it harder to meet goals set in 2008 by Missouri Proposition C, which requires investor-owned electric utilities to obtain a gradually increasing percentage of their energy from renewable sources.

In a two-year study, MU atmospheric scientist Neil Fox gathered data from 10 wind towers across the state. At 100 meters (230 feet) above ground level, the height at which wind turbines operate, wind speeds averaged between 0.1 and 1 meter per second slower than estimated on a wind map produced by the Missouri Department of Natural Resources (DNR).

"While this is not good news, on the positive side, it is better to know the genuine wind speed rather than overestimate things," Fox said. "To reach the targets of Prop C, we will need to use a range of renewable sources, and the amounts of each type of energy have to be based on accurate data."

The DNR wind map used measurements of ground-level wind speeds and other data to estimate wind speeds at turbine height, he said. "Characterizing how wind changes as we go up above the surface is actually very difficult. The standard equations that get used don't always work very well."

The strongest winds are in the northwest corner of the state. Fox said these sites appear to be the ones where the errors are smaller. "In northwest Missouri, where most wind farm development to date has taken place, we'd expect to see slightly less power generated than we might have thought before," he said. "Developers are not going to get quite the same return on their investment as they thought."

The disparity is worse in other parts of the state, though Fox said that wind power in those areas still has potential for niche applications. "There may be a role for smaller turbines, for personal or community-based power generation rather than these large wind farms that a utility company would build."

He noted that two years might be too short a time to establish a definitive climatology. The DNR wind map drew on data sampled over a 15-year period. Both data sets contain uncertainties calling for more investigation, he said.

"We may find that these last two years we've been measuring were the worst two years in history," Fox said. "Or we may find they were the best two years."

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