Is Wind’s Climate Contribution Overstated?

When it comes to the ability of wind power to reduce carbon dioxide emissions, is there less than meets the eye? That’s the argument that Australian energy engineer and geologist Peter Lang makes in a filing with the Australian government earlier this spring and flagged by Georgia Tech’s Judith Curry on her Climate Etc. blog.

Lang argues, “Wind turbines are significantly less effective at reducing CO2 emission than commonly assumed. This means that the CO2 abatements cost (i.e., the cost per tonne CO2 avoided by wind turbines) is higher than commonly recognized.” His analysis of Australia’s wind program finds that “each unit of electricity generated by wind turbines avoided about 80% of the emission that would have been emitted generating a unit of electricity in the absence of wind.”

Paradoxically, says Lang, the abatement cost “is inversely proportional to the proportion of electricity supplied by wind power. “At 80% effective, the actual abatement cost would be 25% higher than the analysts’ estimates if their estimates did not take effectiveness into account. At 50% effective, the actual abatement cost would be twice the estimates.” That means, Lang says, that the cost of reducing CO2 with wind power “could be 2 to 5 times the carbon tax which was rejected by the voters at the 2013 Federal Election; 6 to 14 times the current EU carbon price; and more than 100 times the price of international carbon futures out to 2020.”

According to Lang, “Empirical analyses of the emissions avoided in electricity grids in the U.S. and Europe indicate that (1) wind turbines are significantly less effective at avoiding emissions than is commonly assumed and (2) effectiveness decreases as the proportion of electricity generated by wind turbines increases.” Lang bemoans the lack “good data from power stations at time intervals of 30 minutes or less,” which means that estimates of avoided emissions from wind “are biased high (i.e. overestimated) and have large uncertainty (i.e. we don’t know what emissions reductions are actually being achieved by wind generation).”

Australia has a “Renewable Energy Target” or RET of a base of 15% of electricity from wind by 2020, and as much as 53%, notes Lang. He offers his assessment of wind abatement costs of these targets, using a levelized cost of electricity model, as $168/tonne of CO2 by 2020. That compares to government estimates of $32-$70/tonne. The official estimates, he says, don’t “take effectiveness into account.” Including his effectiveness analysis, the abatement costs rise to $60-$136/tonne of CO2 using the government’s assumptions. When Australia’s voters rejected the carbon tax in 2013, the tax was set at $24.15/tonne.

Lang has 40 years’ experience with energy projects around the world including hydro, geothermal, nuclear, coal, oil and gas and energy end-use management projects.