Large-scale US wind energy would cause a warming that would take about a century to compensate – ScienceDaily

"The wind beats coal according to all environmental measures, but that does not mean that its impacts are negligible," said David Keith, an experienced author, professor of engineering and public policy at the University. Harvard. "We need to move quickly away from fossil fuels to stop carbon emissions, and in doing so we must choose between different low-carbon technologies, all of which have social and environmental impacts."

"Wind turbines generate electricity but also change the atmospheric flow," says lead author Lee Miller. "These effects redistribute warmth and humidity into the atmosphere, which has an impact on the climate, and we have tried to model these effects on a continental scale."

To compare the impacts of wind energy and solar energy, Keith and Miller began by establishing a baseline for the US climate from 2012 to 2014 with the help of a standard weather forecast model. Then they added that, on the atmosphere, covering one-third of the US mainland with enough wind turbines to meet the current US electricity demand. This is a relevant scenario if wind energy plays a major role in the decarbonization of the energy system during the second half of the century. This scenario would warm the surface temperature of the continental United States by 0.24 degrees Celsius.

Their analysis is focused on comparing impacts and climate benefits. They found that it would take about a century to offset this effect by reducing wind-related greenhouse gas concentrations. This time scale was pretty much independent of the specific choice of total wind energy production in their scenarios.

"The direct impacts of wind energy on the climate are instantaneous, while the benefits accrue slowly," Keith said. "If you are considering the next 10 years, wind energy has, in some ways, more impact on the climate than coal or gas.If you are planning the next thousand years, the energy Wind turbine is much cleaner than coal or gas. "

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 approximate coherence between observations and the model.

They also compared the impacts of wind energy with previous projections of the influence of solar energy on the climate. They found that for the same rate of energy production, the impact of solar energy would be about 10 times less than that of wind energy. But both sources of energy have their advantages and disadvantages.

"In terms of temperature difference per unit of energy production, solar energy has about 10 times less impact than wind energy," Miller says. "But there are other considerations, for example, solar parks are dense, while the land between wind turbines can be co-used for agriculture." The density of wind turbines and the time at which they operate can also affect climate impacts.

The Keith and Miller simulations do not take into account any impact on weather on a global scale. Therefore, it is difficult to say how such a deployment of wind energy can affect the climate in other countries.

"The work should not be seen as a fundamental criticism of wind energy, and some of the impacts of climate on climate can be beneficial, so they should be seen as a first step in assessing these impacts more seriously," he said. Keith said. "We hope that our study, combined with recent direct observations, marks a turning point in taking into account the wind energy impacts of climate change in the strategic decisions regarding the decarbonisation of the energy system."

Keith and Miller also published an article titled "Capacity Factors and Power Densities of Solar and Wind Based Wind Energy," published in Environmental Research Letters on Oct. 4, which validates production rates per unit area simulated here with the help of observations.

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