Wind Power CO2-Cutting Benefit Challenged

We’ve long known wind power’s flaws – produces inconsistently, can’t be economically stored, kills birds – but along with those came an obvious, sparkling virtue: It runs clean, helping drive down carbon dioxide (CO2) emissions in a big way. But a Colorado-based energy research firm is challenging that last assumption, asserting that analysis of real-world data shows in most areas of the country the CO2 savings from wind “are either so small as to be insignificant or too expensive to be practical.”

Bentek Energy calls this “the wind power paradox,” and says the issue is what happens when wind power comes onto the grid. “When power plants on a regional power grid are ‘cycled’ to accept wind energy, the plants run less efficiently, leading to significant emissions and higher plant maintenance costs,” the firm said.

wind power, CO2 emissions

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Bentek bases this conclusion on what it calls the first study “to systematically assess the emission reduction performance of wind generation based on hourly generation and emissions data.” The firm said it worked with Daniel Kaffine of the Colorado School of Mines to collect and analyze hourly data – instead of making projections based on average data – on U.S. wind generation and emissions from plants in four regional power areas.

Esoteric though it may sound, this point of hour-by-hour vs. average is crucial to the criticism of wind power, because it focuses the analysis on marginal emissions as generation shifts between wind and conventional sources. In a draft paper on his website entitled “Emissions savings from wind power generation: Evidence from Texas, California and the Upper Midwest,” Kaffine and his co-authors explain that wind power coming onto the grid tends to overwhelming replace relatively clean natural gas, not dirty coal. That alone trims wind’s CO2-saving contribution, Kaffine writes. And so does the ramping up and down of coal-fired generation. After drawing an analogy with an automobile driving steadily at 55 mph vs. one stop and starting, Kaffine writes: “When coal plants are cycled down to accommodate wind, those plants will be operating at an inefficient level of output, raising emissions rates.”

In his academic study, Kaffine concludes “this paper provides a transparent framework for updating and refining emission savings estimates as data.” Bentek, however, goes much further, stating that while some regions of the country – the Midwest, especially – show more CO2 savings from using wind power, “In none of these areas … are the savings sufficient to justify the federal tax credit that underpins the technology.”

Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.


  • Reply July 28, 2011

    Michael Goggin

    It is unfortunate to see the fossil fuel nindustry continue its misinformation campaign to muddy the waters about none of the indisputable benefits of wind energy u2013 its success in nreducing the use of fossil fuels and the harmful emissions associated nwith their use. It should be noted that the report presented in this article was written by Bentek, a nnatural gas consulting firm whose President and CEO happens to be the nChairman and Director of the Natural Gas Committee of the fossil fuel nlobby group the Independent Petroleum Association of Mountain States, asn well as a member of the Colorado Oil and Gas Association.nUnsurprisingly, the Bentek report is directly contradicted by a largen body of government data and numerous studies by independent grid noperators conclusively showing that the emissions savings of adding windn energy to the grid are substantially larger than had been expected. nBenteku2019s report is filled with a number of salient errors, most notably nthat the authors used a method that takes very small snapshots of the npower grid in both time and geographic space, and thus overlooks a largen share of the emissions savings produced by wind energy. As an example, nBenteku2019s methodology gives wind energy deployed in California or in the nPacific Northwest no credit for the emissions reductions achieved by nreducing coal electricity imported from other states, which is a main nreason why the report so grossly understated the actual emissions nbenefit of wind in those regions. As another example, their methodology ngives wind energy credit for only one hour of emissions savings when it nforces a coal power plant to turn off for a much longer period of time, nand it gives no credit to wind energy when it allows the grid operator nto store additional water behind a hydroelectric dam that is used to ndisplace fossil generation later on, both of which are common events. nThe flaws in Benteku2019s work are too numerous to discuss here, although nthe following fact sheet lists many of them as well as providing the ndetailed results of government data and grid operator studies that nconclusively show that wind energy significantly reduces fossil fuel usen and emissions:nn Goggin,nnAmerican Wind Energy Associationn

  • Reply July 31, 2011


    Companies like Bentek need to grow up and start diversifying. Specialising in a sector that has an obvious limited life span, is rather short sighted. Instead of producing commercially biased reports that contradict known research doesn’t help at all. Engineers are educated to solve problems and one of the issues that need to be solved is matching generation to demand. The reason why current systems cope with demand, is because they were engineered that way! So what Bentek is effectively saying is that past engineers were brilliant and today’s engineers are morons. This attitude is typical of a company stuck in an industry that is being bypassed. Does Bentek (or America) really believe they can stop the tide of change around the world? I don’t think so.

  • Reply August 1, 2011

    Glenn Tamblyn

    The key problem with looking at the potential of wind power (in fact all intermittent renewables) on the basis of their current impact on the grid and GHG emissions, and that any such analysis constitutes a meaningful critique of the future potential of renewables is that it is ignoring the essential Chicken & Egg issue of large scale conversion to renewables.nnAt their current scale of penetration into the energy industry renewables do need backup generation from other sources and yes, this may impact on the net efficiencies of those sources. However, this isn’t the name of the game. The key consideration is whether renewables can deliver the most if not all electricity generation when they have achieved complete market penetration.nnThe answer to this is yes! A range of studies have shown clearly that a geographically dispersed mix of Solar with thermal storage, Wind, other renewables as available, hydro and biomass can supply 100% of electricity demand without needing FF backup. However, at the much lower levels of penetration currently that back up required.nnThe point is that this need for FF backup CURRENTLY is not a criticism of the long term technical potential of renewables. It is rather a measure of the TRANSITION costs of moving to renewables. And our key goal of in economy wide switch to renewables is that the need for this transition is driven by our need to eleminate carbon emissions and limit CO2 levels in the atmosphere. nnConsidered in this context the key question is what pathway gets to the lowest final CO2 level in the atmosphere at the CONCLUSION of this transition, not what the relative merits are at individual points along the Journey.nnAnd the unavoidable conclusion is that we need to transition to renewables as rapidly as possible. To many years have been wasted already, making the speed of transition required every more rapid and difficult.nnComparisons between different subsidies and the relative competitiveness of FF vs Renewables is really a second order consideration. The impacts to our societies of failing to address global warming dwarf any economic impact of the transition. And the simple fact is that most Fossil Fuel industries are really, ‘Dead Men Walking’. We cannot afford to prolong their life one day longer than is absolutely avoidable.

  • Reply August 1, 2011


    It seems like the issue revealed here is the tie-in with the coal grid. There must be lots of locations that could use it on a bypass. Wasn’t the windmill a common sight on farms and ranches all over the country not so long ago? What do those farms and ranches have in common with contemporary locations? Being off-the-grid.nnI’ve also read that new, slow turbines kill very few birds — something like five birds a year. That seems like a sad, but acceptable level considering how many birds are killed by other forms of energy sourcing.

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