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In March 2011, the National Renewable Energy Laboratory published a new national wind resource assessment for winds at 80 meters above ground level, as well as new state-level 80 m wind maps.
Renewable Energy World magazine celebrated this achievement with this article here.
This new assessment showed a good deal more wind energy generation capacity available at 80m and 100m, the new "standard" size for large scale wind turbines, including the popular American-made General Electric models.
The new map was drawn up on the basis of important new studies in wind shear by Dennis Elliot of NREL, among others. The national findings are similar to what we have been finding here in Maine when we measure the wind with taller anemometer towers.
Maine wind power development companies have probably known or at least guessed at this information for some time. They generally use two or three 60m or even 80m anemometer towers when scoping out a large-scale wind farm, and they have data from the anemometers on the turbines themselves once constructed, and so would have begun to know about the higher wind speeds and wind shears beginning in 2007/2008, after Mars Hill was constructed.
But wind power development companies don't like to give out anemometer results. If a competitor or a power purchaser knows the capacity factor of a given turbine or wind farm, they can closely estimate the costs of production, and underbid the development company for power.
A development company that develops a site with a high capacity factor, but then can keep that information secret, makes more money per unit, sometimes several more cents/KWh.
The information was not therefore publicly available until NREL released it this spring. I began to guess at this information a couple of years ago when the results of our own 60 meter tower study in Thorndike, Maine revealed unexpectedly high wind shears, and when the Beaver Ridge and Vinalhaven plants were brought online and turned out to create more sound nuisance than expected, and to produce more power than expected. Both of these are suggestive of high wind shear and higher wind speeds at turbine hub height than would be suggested based on the old 50 meter wind map. Discussions with the operators of Beaver Ridge and Vinalhaven supported the hypothesis.
The new NREL wind map is yet further confirmation.
This is good news for Maine's energy independence prospects, and bad news for Maine's anti-wind activist groups.
The important implications for Maine wind power include:
1) There's a lot more wind energy onshore in the state than previously thought, and wind turbines on favorable sites will be more profitable than previously thought.
However, wind power development companies have probably known this for some time.
All these being equal, it means that many sites would be profitable without the federal subsidies currently available. Were the subsidies to be removed, some Maine wind power development would likely still go ahead.
(All this explains the strong continued commercial interest in developing onshore wind power in the state, despite some public resistance. And remember, fossil fuels are also heavily subsidized, and protected from lawsuits and environmental regulation.)
2) Accessing this wind energy will require taller turbines, with associated difficulties in planning, transportation, and protecting viewsheds
3) Maine wind turbines will generally produce more noise than we would have expected a few years ago, because of the new wind shear estimates. Noise modeling for wind farms will have to be adjusted based on the new data
Here's the new resource assessment based on the new wind map:
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