Proc. Natl Acad. Sci. USA http://doi.org/m29 (2013)

Credit: © THINKSTOCK/HIGHSTOCK

Wind and solar power can reduce emissions of CO2 and air pollutants by replacing energy from fossil fuels, and bring climate, health and environmental benefits. The windiest or sunniest sites yield the best energy performance, but not necessarily the highest emissions reduction, as this depends on the conventional generators displaced.

Kyle Siler-Evans of the Carnegie Mellon University, USA, and colleagues analysed wind turbines at more than 33,000 locations and solar panels at more than 900 sites across the USA and found a significant regional variation in emissions reduction. The monetary value of the combined health, environmental and climate benefits falls between US$10 MWh−1 and US$100 MWh−1 depending on the location, and the sites with the highest energy output do not provide the greatest social benefits in many cases. The researchers find that the cost of the Production Tax Credit — a federal subsidy for wind energy— is more than outwieghed by the social benefits from wind farms, but the same investment could achieve greater benefits if differentiated by region.