How Much Does Wind Power Reduce CO ₂ Emissions? Evidence from the Irish Single Electricity Market

This paper evaluates the effect of wind generation on CO ₂ emissions using 2008–2012 historical data for the Irish Single Electricity Market. Wind generation displaces CO ₂ emissions, as expected, in line with the average system emissions. Over the whole period, wind generation avoided about 8.8 million tons of CO ₂, equivalent to about 12% of total system emissions. To understand what drives the level of abatement we evaluate the results by technology and determine that wind generation has similar effects on total emissions from CCGT and coal plants, due to the higher carbon content of coal. Each MWh of wind, however, replaces more generation from CCGTs than from coal plants, in proportion to their generation. We also test the hypothesis that as wind displaces baseload plants it pushes them to generate less efficiently, but find no evidence of a strong negative effect of wind on CCGT or coal plant efficiency. Finally wind displaces about 2.5% fewer emissions when the pumped storage plant is on outage, suggesting that wind is more effective when paired with a flexible system.