Policy Study

The Limits of Wind Power

Very high wind penetrations are not achievable in practice due to the increased need for power storage, the decrease in grid reliability, and the increased operating costs

Executive Summary

Environmentalists advocate wind power as one of the main alternatives to fossil fuels, claiming that it is both cost effective and low in carbon emissions. This study seeks to evaluate these claims.

Existing estimates of the life-cycle emissions from wind turbines range from 5 to 100 grams of CO2 equivalent per kilowatt hour of electricity produced. This very wide range is explained by differences in what was included in each analysis, and the proportion of electricity generated by wind. The low CO2 emissions estimates are only possible at low levels of installed wind capacity, and even then they typically ignore the large proportion of associated emissions that come from the need for backup power sources (“spinning reserves”).

Wind blows at speeds that vary considerably, leading to wide variations in power output at different times and in different locations. To address this variability, power supply companies must install backup capacity, which kicks in when demand exceeds supply from the wind turbines; failure to do so will adversely affect grid reliability. The need for this backup capacity significantly increases the cost of producing power from wind. Since backup power in most cases comes from fossil fuel generators, this effectively limits the carbon-reducing potential of new wind capacity.

The extent to which CO2 emissions can be reduced by using wind power ultimately depends on the specific characteristics of an existing power grid and the amount of additional wind-induced variability risk the grid operator will tolerate. A conservative grid operator can achieve CO2 emissions reduction via increased wind power of approximately 18g of CO2 equivalent/kWh, or about 3.6% of total emissions from electricity generation.

The analysis reported in this study indicates that 20% would be the extreme upper limit for wind penetration. At this level the CO2 emissions reduction is 90g of CO2 equivalent/kWh, or about 18% of total emissions from electricity generation. Using wind to reduce CO2 to this level costs $150 per metric ton (i.e. 1,000 kg, or 2,200 lbs) of CO2 reduced.

Very high wind penetrations are not achievable in practice due to the increased need for power storage, the decrease in grid reliability, and the increased operating costs. Given these constraints, this study concludes that a more practical upper limit for wind penetration is 10%. At 10% wind penetration, the CO2 emissions reduction due to wind is approximately 45g CO2 equivalent/kWh, or about 9% of total.

Attachments

William Korchinski is a chemical engineer who has spent his career working worldwide in the oil refining and chemical industries. His primary focuses include the development and deployment of rigorous process simulation technology, the design and installation of real-time multivariable controls, and economic studies related to the process industries. Mr. Korchinski has applied his extensive background in statistical analysis and mathematical solution techniques in working for a number of corporations and consulting firms. He has worked at over 50 industrial sites throughout the world and has developed a dozen commercial technologies. Currently he runs his own business, Advanced Industrial Modeling, Inc, in Santa Barbara, California.

Julian Morris is vice president of research at Reason Foundation, a non-profit think tank advancing free minds and free markets.

Julian graduated from the University of Edinburgh with a Masters in economics. Graduate studies at University College London, Cambridge University and the University of Westminster resulted in two further masters' degrees and a Graduate Diploma in Law (equivalent to the academic component of a JD).

Julian is the author of dozens of scholarly articles on issues ranging from the morality of free trade to the regulation of the Internet, although his academic research has focused primarily on the relationship between institutions, economic development and environmental protection. He has also edited several books and co-edits, with Indur Goklany, the Electronic Journal of Sustainable Development (www.ejsd.org).

Julian is also a visiting professor in the Department of International Studies at the University of Buckingham (UK). Before joining Reason, he was executive director of International Policy Network (www.policynetwork.net), a London-based think tank which he co-founded. Before that, he ran the environment and technology programme at the Institute of Economic Affairs, also in London.