Wind turbines could cause temperatures to rise and fall

After I wrote my first paper on energy issues in 1997, a man from Scotland wrote saying that I might be too enthusiastic about wind. My attempt is to make what I say reflect the best understandings of the science and policy communities, but it is true that I was enthusiastic about wind. Over the years, some concerns have emerged, and I have put my enthusiasm on hold to see how analysis goes.

David Keith first raised the concern about climate change caused by wind power some years ago, but made no prediction about the direction that change might be, for good or ill. See Keith’s short overview on Wind Power and Climate Change, or download the longer National Academy of Science study. Now there is a more recent analysis: MIT analysis suggests wind turbines could cause temperatures to rise and fall:

In a paper published online Feb. 22 in Atmospheric Chemistry and Physics, [Chen] Wang [of the Department of Earth, Atmospheric and Planetary Sciences] and [Ron] Prinn ]TEPCO Professor of Atmospheric Science] suggest that using wind turbines to meet 10 percent of global energy demand in 2100 could cause temperatures to rise by one degree Celsius in the regions on land where the wind farms are installed, including a smaller increase in areas beyond those regions. Their analysis indicates the opposite result for wind turbines installed in water: a drop in temperatures by one degree Celsius over those regions.

Prinn cautioned against interpreting the study as an argument against wind power, urging that it be used to guide future research that explores the downsides of large-scale wind power before significant resources are invested to build vast wind farms. “We’re not pessimistic about wind,” he said. “We haven’t absolutely proven this effect, and we’d rather see that people do further research.”

warmer Earth?
warmer Earth? (pdf)

From Potential climatic impacts and reliability of very large-scale wind farms (pdf), The results do need to be checked, especially over the ocean:

Significant warming and cooling remote from the installations, and alterations of the global distributions of rainfall and clouds also occur.

Our ocean results indicating cooling over the installation regions and warming and cooling elsewhere are interesting, but suspect due to the unrealistic increases in surface drag needed to extract the target wind power.

10% of the world’s energy supply is a lot of energy, but the effects may not be so dire if wind is used less:

Installation of wind turbines over land areas that have alternative spatial extents, topographies and hydrological properties would produce different, but presumably still significant, climate effects. Due to the computed nonlinearity between the changes in surface roughness and the climate response, defining the optimal deployment of wind turbines is challenging. Climatic effects increase with power generated and decrease with conversion efficiency, putting aside the potential environmental effects for instance on birds and weather radar as well as on ambient noise levels. Also, for the widely spaced wind turbines simulated in our runs, the environmental effects appear small when they are generating less than 1 TW globally even with current technologies.

Note: at this point, if the problems from wind turn out to be of less importance, or of little importance at small to medium scales, wind with natural gas backup with carbon capture and storage will be an important part of the energy solution for 2030. I am still enthusiastic, I think.

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