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].

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 REPA working papers have not been peer reviewed and contain preliminary research findings.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 thesis studies the impact of large amounts of wind power on the Nordic electricity system. The impact on both the technical operation of the power system and the electricity market are investigated.

Editor's Note:The author's focus on the averaging effect of a multitude of small wind turbines spread over a large geopgraphical area understates the reliability problems associated with wind power, particularly the cascade effect as wind turbines drop off-line.

This position paper examines the profile of wind power, its impact on the network, security of supply and the quality of the energy delivered. It further deals with the reasons to establish certain technical requirements for the connection of wind power generation to the network.
Editor's Note: This is a worthwhile read in its entirety (attached pdf file). Selected extracts appear below.

Published in the Spring 2002 issue of "Fluent News", this article by Thomas Hahn and Jurgen Kroning addresses the turbulence caused by wind turbines.

"Developers and owners of wind turbines have a duty to ensure the safety of the general public and their own staff. However, there are currently no guidelines for dealing with potential dangers arising from ice thrown off wind turbines. This puts developers, owners, planning authorities and insurers in a difficult position. To rectify this situation, the work presented here has commenced in order to produce an authoritative set of guidelines. Initial work has resulted in the development of a risk assessment methodology which has been used to demonstrate that the risk of being struck by ice thrown from a turbine is diminishingly small at distances greater than approximately 250 m from the turbine in a climate where moderate icing occurs."

Siemens' wind turbine products and specifications are available by clicking on the web link.