Sunday, September 24, 2006

The Difference Wind Makes

A press release this week from Green Mountain Power Co. (GMP), a Vermont-based electric utility, talked about the 10th anniversary of the installation of the first wind turbine at the company's Searsburg, Vt., wind farm. It included the following quote:

“The 11 turbines at GMP’s Searsburg plant have generated 110,000 megawatt-hours since they began operation in 1997, which is the equivalent of approximately 14,000 homes being powered by wind for a full year. Every kilowatt-hour generated by wind avoids a kilowatt-hour generated by another source, which on the New England grid is generally natural gas or oil fired during the peak periods when wind generation is at its height.” [emphasis added]

This is an important statement because one of the recent accusations being widely circulated by anti-wind individuals and groups is that wind (a) generates no net electricity, (b) does not offset other fuels and (c) therefore displaces no emissions.

It's a strange contention. About the only explanation I can think of for it is a weakness for conspiracy theories. In any event, GMP owns the wind farm and presumably knows what it is in fact doing. More information on the difference wind power makes can be found here.
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1 comment:

Tom Gray said...

Dear Mr. Smith:

YOUR STATEMENT, "Every kilowatt-hour generated by wind avoids a kilowatt-hour generated by another source,,," EXHIBITS A COMPLETE LACK OF UNDERSTANDING OF WINDPOWER GENERATION AND ELECTRIC GRID OPERATION.

An interesting assertion, since it is not my statement, it is a statement made by Green Mountain Power Co. (GMP), which has now been operating a wind farm--one that it owns--on its electric grid for almost 10 years.

THE DESIGNS OF WINDMILLS INSTALLED TODAY HAVE IMPROVED OVER THE YEARS, BUT REMAIN EXTRAORDINARILY DEFICIENT, PARTICULARLY IN REGARDS TO POWER STABILITY.

Thanks for the kudos, but the rest of your statement is wrong.

AT ANY GIVEN MOMENT, WINDMILLS CAN BE A BURDEN TO THE GRID, CONSUMING ENERGY AND IMPOSING A POWER FACTOR BURDEN. THIS HAPPENS WHENEVER THE WIND LULLS OR CHANGES DIRECTION, AND WHEN THE INTERNAL POWER CONSUMPTION EXCEEDS THE ACTUAL OUTPUT, SUCH AS WHEN THEY ARE OPERATING AT LOW WIND SPEEDS OR ARE NOT OPERATING AT ALL.

This is true of the first machines installed in California 25 years ago, but it is not true of those being installed today.

IT IS WORTH NOTING THAT THE WINDMILLS AT SEARSBURG ARE NOT NET METERED AS WOULD BE THE CASE IF AN HONEST ASSESSMENT OF POWER PRODUCTION WERE DESIRED. THE METERS REGISTER ONLY OUTGOING POWER, IGNORING POWER ACTUALLY CONSUMED BY THE WIND INSTALLATION. THIS OVERSTATES THE GREEN POWER PRODUCED TO THE ENRICHMENT OF THE POWER COMPANY.

Another interesting claim. I'll ask GMP to comment.

WINDPOWER IS HORRENDOUSLY WASTEFUL OF HUMAN AND NATURAL RESOURCES.

Hogwash.

IT IS UNRELIABLE, THEREFOR IT WILL NEVER REPLACE CONVENTIONAL POWER SOURCES.

I have addressed the reliability issue at some length elsewhere on this blog. I'll agree with you that wind is not the most efficient way to add new generating capacity to a utility system. Its primary value is that it dramatically reduces the environmental impacts of operating the system, from "cradle to grave"--from mining or drilling for fuel production (none required) to water and air pollution resulting (none).

WHEN WINDMILLS DO PRODUCE POWER, CONVENTIONAL POWER PLANTS MUST BE THROTTLED BACK. UNFORTUNATELY THIS DOES NOT MEAN FUEL IS SAVED IN PROPORTION TO THE WINDPOWER PRODUCED. IN MOST CASES, THROTTLING BACK POWER PLANTS CAUSES THEM TO RUN LESS EFFICIENTLY, THUS HYDROCARBONS ARE NOT SAVED PROPORTIONATELY.

This is actually true. It is also trivial--an effort to make a mountain out of a molehill.

I refer you to a report released earlier this year by the U.K. Energy Research Centre (UKERC), which convened an expert group that reviewed more than 200 studies on wind power integration and published an internationally peer-reviewed, comprehensive report on its findings (see release at http://www.ukerc.ac.uk/content/view/259/952 and full report at http://www.ukerc.ac.uk/content/view/258/852).

Here is what the UKERC had to say about your specific claim:

First, from the press release: "The output of fossil fuel plant will need to be adjusted more often to cope with fluctuations in wind output, but any losses this causes are small compared to overall savings in emissions." [emphasis added]

Second, from the study itself (p. 15): "Actual CO2 savings are dependant [sic] on what fossil fuel plant is displaced, reduced by efficiency losses in thermal plant affected by intermittency and additional use of reserve and response. As we show in Ch. 3, these losses are a small proportion of the energy provided. Links to other grids can mean that CO2 savings are ‘exported’ so might not be realised in the country of origin. But the CO2 savings are, within a few percentage points, directly linked to the energy that renewable stations generate." [emphasis added]

And finally, also from the study (p. 54): "The fuel savings not realised because of the reduced efficiency tend to increase as intermittent generation penetration level rises but the actual losses are generally small - up to the 20% penetration level, the studies present efficiency losses ranging between a negligible level and 7% (as a percentage of theoretical maximum fuel savings)." [emphasis added]

SINCE WINDMILLS ARE USUALLY LOCATED IN AREAS REMOTE FROM MAJOR LOADS, THERE IS MORE LINE LOSS IF THE WINDMILLS ACTUALLY PRODUCE ENOUGH POWER TO SERVE THOSE MAJOR LOADS.

Yes, and this is another trivial effect, particularly in New England where you are located and transmission distances are generally small. Additionally, because of the cost of new transmission lines, wind farm developers try to find locations that are close to existing lines.

AT LOW POWER PRODUCTION, THE POWER IS CONSUMED LOCALLY, IN WHICH CASE THE LOCAL POWER CONSUMERS BEAR THE BRUNT OF UNSTABLE POWER PRODUCTION.

This is a new one on me. I'll check with our in-house experts and see what they have to say.

TO SOME PEOPLE, WINDPOWER IS A WONDERFUL DREAM. TO THE WELL INFORMED, WINDPOWER IS A WASTEFUL NIGHTMARE.

Wind power is a "wasteful nightmare" only to those who make up their own facts and ignore credible, authoritative scientific and technical sources.

Regards,
Thomas O. Gray
American Wind Energy Association
www.awea.org
www.ifnotwind.org

3:46 PM

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