Credit: By Fred Ward | Monadnock Ledger-Transcript | Tuesday, January 12, 2016 | (Published in print: Tuesday, January 19, 2016) | www.ledgertranscript.com ~~
We all want clean, cheap, reliable electric energy. And there is plenty of clean energy available in the winds that come and go over New Hampshire. However, converting this intermittent energy source into electricity is not easy. There are engineering, aesthetic, environmental and political problems. And, there is an additional problem, purely economic. It applies not only to Antrim Wind Energy, but to any proposed industrial wind facility, or IWF, in the state of New Hampshire.
An intermittent power source like a wind turbine will generate between zero percent and 100 percent of its maximum power, depending on the wind speed. A wind turbine of 3 Mw rated power, with an efficiency of about 33 percent, will actually produce between zero Mw and 3 Mw, with an average power output of 1 Mw. The difference between its 3 Mw maximum power, and its 1 Mw average power, is a factor of three, the inverse of its 1/3 efficiency.
In order to reach the legislated mandate of 25 percent average renewable power by 2025, wind would have to contribute at least 10 of the 25 percent. This would require at least 500 3 Mw turbines, averaging 500 Mw, but actually generating between 0 Mw and 1,500 Mw, at least occasionally. If all the turbines spun randomly, they would generate about 500 Mw most of the time. However if winds made them spin together, near 1500 Mw surges would be a frequent occurrence. This raises a critical question. How well do the winds harmonize the spin of different IWFs all over New Hampshire or New England? And send 1,500 Mw surges to the ISO-NE electric grid? The meteorological question is simple. How well harmonized are the wind speeds at various weather stations throughout New Hampshire or New England?
Wind data are available from weather stations from Caribou in northern Maine to Bridgeport in southwest Connecticut and from Albany, New York, just over the western border of New England, to Portland, Maine and Providence, Rhode Island on our easterly boundary.
Analysis of these National Weather Service data, publicly available for many decades, shows very clearly that the winds all over New England are highly harmonized. When the winds are strong in one part of New England, they are generally strong over all of New England, and when the winds are light in one area they are generally light all over New England. And since the station-to-station winds become increasingly harmonized with increasing altitude, this harmonization will be even higher for the winds blowing over 2,000-foot hills and ridges.
The net of this analysis is that for wind power to provide even 10 of the 25 percent legislatively mandated average renewable power, these synchronized wind facilities will actually have to generate between 0 percent and 30 percent of our average power.
To put this 30 percent in perspective, a single nuclear, hydro or coal plant, or Northern Pass, generates less than 30 percent of our average power. This highlights how these large wind surges would raise havoc with the ISO-NE grid. A scan of the New England wind data shows that large wind-generated electric surges would hit the ISO-NE grid once or twice each week, and last many hours.
If this problem weren’t already insurmountable, the topography and meteorology of New Hampshire add an additional, and large, problem. The only feasible locations for IWFs are over the tops of our isolated hills and elevated ridges.
The winds that blow at 2,000 feet over New Hampshire hills and ridges reach their maximum at night, with lesser winds in the daytime. This means that these large surges will be inflicted on the ISO-NE grid at night, when demand for electric power is at a minimum.
There is no obvious solution to this problem, and it indicates that wind is not a viable source of electric energy in New Hampshire. The wind power industry should be required to offer a solution before any more wind facilities are approved in New Hampshire.
Meteorologist Fred Ward lives in Stoddard; he holds bachelor, master’s and PhD degrees from Massachusetts Institute of Technology.