Ed. note: This story is an extended version of an article that appeared in the Wall Street Journal on August 24.

Over the last few years, the wind industry has achieved remarkable growth largely due to the industry’s claim that using more wind energy will result in major reductions in carbon dioxide emissions. There’s just one problem with that claim: it’s not true. Recent studies show that wind-generated electricity may not result in any reduction in carbon emissions, or those reductions will be so small as to be almost meaningless.

This issue is especially important now that states, even in the absence of federal legislation, are mandating that utilities produce arbitrary amounts of their electricity from renewable sources. By 2020, for example, California will require utilities to obtain 33% of their electricity from renewables. About 30 states including Connecticut, Minnesota, and Hawaii, are requiring major increases in the production of renewable electricity over the coming years. Wind, not solar or geothermal sources, must provide most of this electricity, because it is the only renewable source that can rapidly scale up to meet the requirements of the mandate. But those mandates will mean billions more in taxpayer subsidies for the wind industry and result in higher electricity costs for consumers.

There are two reasons wind can’t make major cuts in carbon emissions. The wind blows only intermittently and variably; and wind-generated electricity largely displaces power produced by natural gas-fired generators rather than that coming from plants that burn more carbon-intensive coal.

Because the wind is not dependable, electric utilities must either keep their conventional power plants running all the time (much like “spinning reserve” in industry parlance) to make sure the lights don’t go dark, or they must continually ramp up and down the output from conventional coal- or gas-fired generators (“cycling”).

Coal-fired and gas-fired generators are designed to run continuously. If they don’t, fuel consumption, and emissions of key air pollutants, generally increases. A car analogy helps explain the reason: An automobile that operates at a constant speed -- say, 55 miles per hour -- will have better fuel efficiency, and emit less pollution per mile traveled, than one that is stuck in stop-and-go traffic. But the wind, by its very nature, is stop-and-go. The result: minimal or no reductions in carbon emissions by shifting conventional generation to wind.

In 2008, a British energy consultant, James Oswald, along with two co-authors, published a study in the journal Energy Policy, which said that any reductions in Britain’s carbon dioxide emissions due to added wind generation capacity “will be less than expected.” The study went on to say that neither the extra costs of cycling the power plants “nor the increased carbon production are being taken into account in the government figures for wind power.”

An April study by Bentek Energy, a Colorado-based energy analytics firm, looked at power plant records in Colorado and Texas. (It was commissioned by the Independent Petroleum Association of the Mountain States.) Bentek concluded that despite huge investments, wind-generated electricity “has had minimal, if any, impact on carbon dioxide” emissions. Thanks to the cycling of Colorado’s coal-fired plants in 2009, for example, at least 94,000 more pounds of carbon dioxide were generated because of the repeated cycling. In Texas, Bentek estimated that the cycling of power plants due to increased use of wind energy resulted in a slight savings of carbon dioxide (about 600 tons) in 2008 and a slight increase (of about 1,000 tons) in 2009.

This month, the US Association for Energy Economics published a paper by Ross Baldick, a professor of electrical and computer engineering at the University of Texas at Austin, which concluded that new wind generation capacity “may not be decreasing greenhouse emissions. However, even assuming that wind displaces fossil emissions, it is not ‘worthwhile’ for reducing greenhouse emissions” even if regulators put a price on carbon dioxide of up to $35 per ton.

The problems posed by the intermittency and variability of wind energy could quickly be cured if only we had an ultra-cheap method of storing large quantities of energy. If only. The problem of large-scale energy storage has bedeviled inventors for centuries. Alessandro Volta and Thomas Edison both produced working batteries. Edison spent years working on battery technology, sinking about $30 million of his own money (in current dollars) into his quest for a durable, high-capacity battery. He had some success. But modern batteries have the same suite of problems that Edison faced: they are too big, too expensive, too finicky, and lack durability.

Other solutions for energy storage like compressed air energy storage and pumped water storage are viable, but like batteries, those technologies are expensive. And even if the cost of energy storage falls dramatically -- thereby making wind energy truly viable -- who will pay for it? Further, even if we have a dramatic breakthrough in energy storage, the deployment of that new technology will likely take decades.

Despite the lack of storage, the US and other countries continue to deploy huge amounts of new wind generation capacity and that expense is being undertaken with the assumption that wind energy will lower carbon dioxide emissions. But federal authorities have done some estimates on how more wind energy will affect emissions. And those estimates are revealing.

Last year, the Energy Information Administration estimated the potential savings from a proposed nationwide 25% renewable electricity standard, a goal that was included in the Waxman-Market energy bill which narrowly passed the US House last year. In its best-case scenario, the annual carbon dioxide savings from that mandate would be about 306 million tons by 2030. Given that the EIA expects annual US carbon dioxide emissions to be about 6.2 billion tons in 2030, that expected reduction will only equal about 4.9% of US emissions. That’s not much when you consider that the Obama administration wants to cut US carbon dioxide emissions by 80% by 2050.

Earlier this year, another arm of the Department of Energy, the National Renewable Energy Laboratory, released a report whose conclusions were remarkably similar to those of the EIA. This report focused on integrating wind energy into the electric grid in the eastern US, which has about two-thirds of all US electric load. If wind energy were to meet 20% of electric needs in the eastern US by 2024, according to the report, the likely reduction in carbon emissions would be less than 200 million tons per year. (All the scenarios in the NREL analysis cost a minimum of $140 billion to implement and the issue of cycling conventional power plants is only mentioned in passing.)

Coal emits about twice as much carbon dioxide during combustion as natural gas. But wind generation mostly displaces natural gas because natural gas-fired generators are often the most costly form of conventional electricity production. That said, if regulators are truly concerned about carbon emissions (and cutting air pollution) they should be encouraging gas-fired generation at the expense of coal. And they should be doing so because drillers are unlocking galaxies of natural gas from shale beds, so much so that US natural gas resources are now likely large enough to meet all of America’s natural gas needs for a century.

Meanwhile, the wind industry is pocketing subsidies that dwarf those garnered by the oil and gas sector. The federal government provides a production tax credit of $0.022 for each kilowatt-hour of electricity produced by wind. That amounts to $6.44 per million BTU of energy produced. Meanwhile, a 2008 EIA report said subsidies to the oil and gas sector totaled $1.9 billion per year, or about $0.03 per million BTU of energy produced. Thus, on a raw, per-unit-of-energy-produced basis, subsidies to the wind sector are more than 200 times as great as those given to the oil and gas sector.

Kevin Forbes, the director of the Center for the Study of Energy and Environmental Stewardship at Catholic University, told me that “Wind energy gives people a nice warm fuzzy feeling that we’re taking action on climate change.” But when it comes to carbon dioxide emissions, “the reality is that it’s not doing much of anything.”