In times of low wind, or during maintenance, a wind turbine will consume a small amount of power to run computers, communications, hydraulics, yaw motors, heaters and radiator fans. When a turbine is generating, its power curve (or rated output) is net of power consumption, so it does not draw power from the grid at that time. Commercial scale wind turbines produce power 70-80% of the time, with output ranging from a small amount to the full rated capacity of the turbine. A typical wind turbine will produce 100 times more power than it consumes in a given month. Its consumption and peak load are very small. A 1.8 MW turbine may have peak load of 27kW, with a resting consumption of as low as 5 kW. Wind turbines are principally suppliers of power to the system, and any consumption is purely incidental. As such, wind turbines are not typical demand customers and should not be treated as other loads.

In this report we discuss some recent studies that have occurred in the United States since our previous work [2, 3]. The key objectives of these studies were to quantify the physical impacts and costs of wind generation on grid operations and the associated costs. Examples of these costs are (a) committing unneeded generation, (b) allocating more load-following capability to account for wind variability, and (c) allocating more regulation capacity. These are referred to as “ancillary service” costs, and are based on the physical system and operating characteristics and procedures. This topic is covered in more detail by Zavadil et al. [4].

The values in Table 2 are based on total availability and reflect the time that the turbines are available to operate. Hence, no allowance is made for the effects of grid outages or ‘weather days’ which could prevent access to turbines for repairs. The planned availability was exceeded for only one month and the availability across the site was below expectation especially during the autumn period. This was due almost entirely to problems with bearings in the gearbox as will be discussed in Operational Issues.

Eric Rosenbloom writes: "Driving the desire for industrial wind power is the conviction that its development is necessary to reduce the effects of fossil and/or nuclear fuel use. Thus the local impacts of large industrial wind turbine installations are justified by a greater good of healthier air and water, reduction of global warming, and moving away from harmful mining and fuel wars. These are all without question important goals.

While the wind power industry tends to downplay its negative effects, many conservation groups call for careful siting and ongoing study to minimize them. There is debate, therefore, about the actual impacts, but there is none about the actual benefits. Even the most cautious of advocates do not doubt, for example, that "every kilowatt-hour generated by wind is a kilowatt-hour not generated by a dirty fuel."

That may be true for a small home with substantial battery storage, but such a formula is, at best, overly simplistic for large turbines meant to supply the grid. The evidence from countries that already have a large proportion of wind power suggests that is has no effect on the use of other sources. This is not surprising when one learns how the grid works: A rise in wind power simply causes a thermal plant to switch from generation to standby, in which mode it continues to burn fuel."

Author Rosenbloom goes on to take a look at the experience with industrial wind of Ireland, Denmark and Germany and concludes that wind energy's benefits are largely illusory and do not warrant the degradation of rural and wild areas.

Built in 2003, North Hoyle is the UK's first major offshore wind plant.....

BBC Research & Consulting's 2005 report for the National Wind Coordinating Committee that studies 9 wind plant sitings in an effort to identify circumstances that distinguish welcomed projects from projects that were not accepted by communities.

This working paper is made available by the Resource and Environmental economics and Policy Analysis (REPA) Research Group at the University of Victoria. REPA working papers have not been peer reviewed and contain preliminary research findings. They shall not be cited without the expressed written consent of the author(s).

Editor's Note: The authors’ conclusion regarding ‘effective capacity’, i.e. the measure of a generator’s contribution to system reliability that is tied to meeting peak loads, is that it “is difficult to generalize, as it is a highly site-specific quantity determined by the correlation between wind resource and load” and that ‘values range from 26 % to 0% of rated capacity.” This conclusion is based, in part, on a 2003 study by the California Energy Commission that estimated that three wind farm aggregates- Altamont, San Gorgonio and Tehachpi, which collectively represent 75% of California’s deployed wind capacity- had relative capacity credits of 26.0%, 23.9% and 22.0% respectively. It is noteworthy that during California’s Summer ’06 energy crunch, as has been widely publicized in the press, wind power produced at 254.6 MW (10.2% of wind’s rated capacity of 2,500MW) at the time of peak demand (on July 24th) and over the preceding seven days (July 17-23) produced at 89.4 to 113.0 MW, averaging only 99.1 MW at the time of peak demand or just 4% of rated capacity.

This 'informal white paper' authored by the renewable energy industry and the Electric Reliability Council of Texas addresses the impact of wind's intermittency on the need for the development of comparable capacities of reliable sources that can be called upon when the wind is not blowing. It contains a particularly interesting chart that characterizes different energy sources as 'base load', 'peak load' and 'intermittent' with their associated benefits and drawbacks. Wind is deemed 'intermittent' with the following benefits (no emissions, no fuel costs, stable cost, low operating cost) and drawbacks (not dispatchable, not responsive, transmission needs, low peak value).

Scope of Project: Offload windmill components from rail cars to trucks, for transporation west along Route 2 approximately 7.5 miles up Florida Mountain, for final installation as part of the Hoosac Wind Project in Florida and Monroe, MA.

Large wind turbines require a large amount of energy to operate. Other electricity plants generally use their own electricity, and the difference between the amount they generate and the amount delivered to the grid is readily determined. Wind plants, however, use electricity from the grid, which does not appear to be accounted for in their output figures.