All large-scale energy systems have environmental impacts, and the ability to compare the impacts of renewable energy sources is an important step in planning a future without coal or gas power. Extracting energy from the wind causes climatic impacts that are small compared to current projections of 21st century warming, but large compared to the effect of reducing US electricity emissions to zero with solar.
In the journal Joule, Harvard researchers report the most accurate modelling yet of how increasing wind power would affect climate. They find that large-scale wind power generation would warm the Continental United States 0.24 degrees Celsius because wind turbines redistribute heat in the atmosphere.
Wind beats coal by any environmental measure, but that doesn’t mean that its impacts are negligible. We must quickly transition away from fossil fuels to stop carbon emissions. In doing so, we must make choices between various low-carbon technologies, all of which have some social and environmental impacts.
—senior author David Keith, an engineering and public policy professor at Harvard. . . .
To compare the impacts of wind and solar, Keith and Miller started by establishing a baseline for the 2012-2014 US climate using a standard weather forecasting model. Then they added in the effect on the atmosphere of covering one third of the Continental US with enough wind turbines to meet present-day US electricity demand. This is a relevant scenario if wind power plays a major role in decarbonizing the energy system in the latter half of this century. This scenario would warm the surface temperature of the Continental US by 0.24 degrees Celsius.
Their analysis focused on the comparison of climate impacts and benefits. They found that it would take about a century to offset that effect with wind-related reductions in greenhouse gas concentrations. This timescale was roughly independent of the specific choice of total wind power generation in their scenarios.
The direct climate impacts of wind power are instant, while the benefits accumulate slowly. If your perspective is the next 10 years, wind power actually has—in some respects—more climate impact than coal or gas. If your perspective is the next thousand years, then wind power is enormously cleaner than coal or gas.
—David Keith. . . .
More than ten previous studies have now observed local warming caused by US wind farms. Keith and Miller compared their simulated warming to observations and found rough consistency between the observations and model. . . .
[list]In terms of temperature difference per unit of energy generation, solar power has about 10 times less impact than wind. But there are other considerations. For example, solar farms are dense, whereas the land between wind turbines can be co-utilized for agriculture.
—Lee Miller. . . . [/list]
Keith and Miller's simulations do not consider any impacts on global-scale meteorology, so it remains somewhat uncertain how such a deployment of wind power may affect the climate in other countries. . . .
This research was funded by the Fund for Innovative Climate and Energy Research. David Keith is a board member and acting chief scientist at Carbon Engineering, a clean energy company that aims to make carbon-neutral transportation fuels from wind and solar power.
The bolded quote is something I've been emphasizing since I was designing and selling off-grid equipment and systems. Every tech or approach has an impact, you make choices based on the advantages and disadvantages of each and your priorities. TAANSTAAFL.