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New Study Provides Insight on the Cost of Transmission to Access Increasing Quantities of Wind Power

Feb 9, 2009 - terrawatt.com

Berkeley, California - The rapid increase in the deployment of wind energy in recent years has been paralleled by increasing consideration of wind in transmission planning studies. A new report released today by Lawrence Berkeley National Laboratory assesses the cost of new transmission for wind through a review of 40 detailed transmission studies that involve wind energy.

“The range in transmission costs for wind implied by these 40 studies was surprisingly large,” says report author Andrew Mills, of Berkeley Lab. “A significant portion of our effort in this report was trying to understand the drivers and implications of these cost differences.”

The mid-range transmission cost per kW of wind was found to be $300/kW, about 15-20% of the cost of a new wind plant. “One of the important motivations of this study was to compare the cost of transmission across a wide variety of studies to the results from higher-level assessments of the need for and cost of transmission for wind,” notes co-author Ryan Wiser. “We found that the transmission costs estimated in a recent U.S. Department of Energy study on 20% wind electricity in the U.S. broadly agreed with our sample of detailed transmission studies.”

Though the cost of transmission for wind is not insignificant, the reports finds little evidence that transmission costs necessarily increase at greater levels of wind penetration. For example, numerous studies of large amounts of new wind generation, including a detailed study of 20% wind energy penetration in the Eastern Interconnection, have transmission costs per kW of wind that are among the lower end of the sample. Additionally, the authors argue that their methodology likely results in an overstatement of the transmission costs uniquely associated with wind deployment.

“It’s clear that there are institutional issues related to transmission that will be obstacles to accelerated wind power deployment, but there is no clear indication of whether the cost of developing transmission for wind will be a major barrier to further wind deployment,” says co-author Kevin Porter of Exeter Associates, Inc. “The cost data presented in this report allow a deeper appreciation of the nature and magnitude of the transmission cost barrier for wind energy.”

The report, “The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies,” can be downloaded from http://eetd.lbl.gov/ea/ems/re-pubs.html.

A PowerPoint presentation summarizing key findings from the study can be found at: http://eetd.lbl.gov/ea/ems/emp-ppt.html.

For more information on the report, contact Andrew Mills (ADMills@lbl.gov, 510-486-4059).