For two decades, the capacity factor of wind power measuring the mean energy delivered by wind turbines has been assumed at 35% of the name plate capacity. Yet, the mean realized value for Europe over the last five years is closer to 21% thus making levelized cost 66% higher than previously thought. We document this discrepancy and offer rationalizations, emphasizing the long term variations of wind speeds. We conclude with the consequences of the capacity factor miscalculation and some policy recommendations. Click on the link below to download the full document.

The support of renewable energy sources (RES) is one of the key issues in European energy policy. In order to cope with this challenge, European Transmission System Operators launched a European wide grid study on the integration of wind power, focusing on measures needed to be taken by legislators, regulators, grid operators and grid users, aiming at establishing a harmonised set of rules for the integration of wind power. This set of rules is vital for the secure and reliable operation of the electricity networks in presence of variable generation. The scope of work covers all the technical, operational and market aspects related to the integration of large scale wind power all over Europe. Attention will be later focused on system interaction of various wind turbines types, the effects of their variable power output on the system and their ability to provide system service to enable the stable operation of an electricity grid. The final objective is to obtain the necessary information for the technical and operational measures for risk mitigation and the secure operation of the European electricity grid identified by the steady-state and dynamic investigations on electricity grid models which are established within the study. For this, market and regulatory aspects will be taken into consideration.

Extracts from the attached promotional piece. The full report may be purchased from ABS.

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 BirdLife Position Statement focuses on the EU and its relevant legislative instruments, but it could be applied in all countries that are signatories to the Bern Convention too, as the underlying principles are just as relevant. Therefore, BirdLife Partners in the respective countries will be invited to adopt this position.

This letter (in French) written by former French President Valery Giscard contends that industrial wind energy in France is (1) due only to powerful lobbies, (2)creates no employment in France and (3) produces a small amount of electricity that is not competitive today and will not be competitive in the future. (An English translation is in-progress)

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.