Wind power has the potential to reduce emissions associated with conventional electricity generation. Using detailed, systemic hourly data of wind generation and emissions from plants in ERCOT (Texas), we empirically estimate the SO2, NOx and CO2 emissions offset by wind generation. Our estimation strategy implicitly captures both the marginal unit of generation displaced by wind on the electrical grid, and the marginal emissions reduction from that displaced unit. Our results also reveal substantial variation in emissions reductions, which appear to be strongly driven by differences in the generation mix. The environmental benefits from emissions reductions in ERCOT fail to cover government subsidies for wind generation.

Using detailed 5-minute electricity generation data, we examine the impact of wind intermittency on carbon dioxide (CO2) emissions savings from wind energy in the Southwest Power Pool from 2012-2014. Parametric and semi-parametric analysis confirms concerns that intra-hour wind intermittency reduces CO2 emissions savings from wind—in the top decile of wind intermittency, emission savings are reduced by nearly 10 percent. However, the average wind intermittency effect on emission savings is modest, on the order of 6.5 percent when accounting for dynamic effects. Evidence suggests the intermittency effect is likely to remain modest in the near-term.