Two papers published by Harvard University researchers on Thursday indicate that a large-scale transition to renewable sources of energy would require five to 20 times more land than prior studies have shown, and that expanding wind farms would actually warm the continental U.S. more than carbon emissions in the short term.
What are the details?
According to the American Wind Energy Association, wind provides 6.3 percent of America’s electricity. But the Harvard researchers found that if wind farms were expanded to replace other forms of energy like coal and gas on a large scale, the surface temperatures over the continental U.S. would increase by 0.24 Celsius.
Further, co-author Lee Miller told The Harvard Gazette, “For wind, we found that the average power density — meaning the rate of energy generation divided by the encompassing area of the wind plant — was up to 100 times lower than estimates by some leading energy experts.
“Most of these [prior] estimates failed to consider the turbine-atmosphere interaction,” Miller explained. “For an isolated wind turbine, interactions are not important at all, but once the wind farms are more than five to 10 kilometers deep, these interactions have a major impact on the power density.”
Professor David Keith, senior author of both papers, told ABC News, “Any big energy system has an environmental impact. There is no free lunch. You do wind on a scale big enough…it’ll change things.”
But Keith added that his studies “should not be seen as a fundamental critique of wind power.”
“Some of wind’s climate impacts will be beneficial — several global studies show that wind power cools polar regions,” he noted. “Rather, the work should be seen as a first step in getting more serious about assessing these impacts for all renewables.”
Keith also advocated for a transition away from fossil fuels, while admitting the effects renewables have on the environment.
“If your perspective is the next 10 years, wind power actually has — in some respects — more climate impact than coal or gas,” he told the Gazette. “If your perspective is the next thousand years, then wind power has enormously less climatic impact than coal or gas.”
In response to Harvard’s findings, Business Insider’s Kevin Loria wrote an analysis saying that the “study on the side effects of wind energy is almost begging to be misused by climate change deniers.”
Within his assessment, Loria calls the estimated rise in temperature caused by an expansion of wind turbines “a significant amount.” But, as he points out, Miller said that doesn’t mean it’s causing climate change.
Miller told Business Insider, “I have no doubt that these results will be misconstrued and misinterpreted.”