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Wind power. We have enough wind, but will it last? (NREL photo)

On Trying to Catch the Wind Energy?

A lack of wind won’t stall our future renewable energy economy, but Congress might.

Debunking the Myths That Take the Wind out of Wind Energy’s Sails

Wind has its downsides. It’s intermittent; it’s too expensive. Fair points, but there are ways around them. For example the whole intermittency issue could be handled now by using spatially diverse sources; and once affordable energy storage technologies are developed, intermittency will likely become a non-issue.

And the cost issue is in many ways a red herring. Many argue that fossil fuels are cheaper than renewable energy sources because of the market’s failure to account for the so-called external costs of fossil fuels such as pollution. These are costs we all bear but are not reflected in the price we pay for the energy; if those externalities were included in the price of energy generated from fossil fuels, renewable energy would become more competitive perhaps even less costly. Even now, wind-generated electricity is now in a virtually cost-competitive heat with coal-fired power generation.

But Can We Extract Enough

As a world community, at any given moment our maximum power draw is somewhere between 12.5 and 18 terawatts. That’s orders of magnitude smaller than the amount of power dissipated by the wind — about 50,000 terawatts in the lower atmosphere or troposphere.

So we can all agree that there’s a lot of wind to be had, but can we have it? Can we put enough turbines in place to capture enough energy without affecting the climate? In short, if we wanted to build a clean energy economy around wind, could we? Two new studies say, yes, we have enough wind to power the globe … and then some.

Saturation Point Not a Problem

Writing in the Proceedings of the National Academy of Sciences last week, Mark Jacobson of Stanford University and Christina Archer of the University of Delaware explored the limits of wind availability for energy extraction relative to what is known as the saturation point. In principle one would expect that increasing the number of turbines would increase the amount of energy generated from wind. That’s true but only up to a point, the saturation point, beyond which the benefits of adding another turbine decrease while the costs increase. That saturation point occurs when the turbines get so close together that one is always in the draft of another and there’s just not any more wind to be gotten.

Is this a problem? Jacobson and Archer set out to find out — to see how much energy is available prior to reaching the saturation point. The authors used a dynamic global model to estimate “the maximum wind power that can be extracted upon increasing the number of wind turbines over a large geographic region, independent of societal, environmental, climatic, or economic considerations.” Their calculations indicate that this saturation wind power potential exceeds current energy demand several times over — about 80 terawatts, if the turbines are set at 100 meters above the land surface (excluding Antarctica) and coastal ocean, and 380 terawatts at 10 kilometers above in the jet streams.

No Significant Climate Effects

Another concern over using lots of wind for power generation is that it will disrupt the climate by pulling too much wind energy out of the atmosphere. Not a problem, says a paper published in the journal Nature Climate Change by Kate Marvel of Lawrence Livermore Laboratory and colleagues. They conclude that “at the level of present global primary power demand [about 18 terawatts], uniformly distributed wind turbines are unlikely to substantially affect the Earth’s climate.”

So what are the limitations to developing wind power at the global scale? Marvel et al seem to hit the nail on the head when they conclude their paper with: “It seems that the future of wind energy will be determined by economic, political and technical constraints, rather than global geophysical limits.”

Which brings us to the continuing saga of the Production Tax Credit for wind, which begins way back in the 19th century when the federal government first got into the business of giving a helping hand to fledgling energy industries.

The Production Tax Credit

If you read this blog regularly, you might know that subsidies and tax credits have been an integral part of American energy policy since the 19th century. We built railroads to help the timber industry, and we provided healthy subsidies to jump-start the coal, oil and gas industries. And so it was not at all surprising when, following the oil shock of the 1970s, the federal government began to give a leg up to renewable energy. The first of those came in the form of the Public Utilities Regulatory Policies Act of 1978 which required public utilities to purchase lower-cost energy from independent producers including renewables sources.

With the Energy Policy Act of 1992, Congress first established the Renewable Electricity Production Tax Credit for new facilities that would generate electricity using a renewable energy source — an attempt to somewhat level the playing field with established non-renewable energy sources (see earlier discussion about cost competitiveness). Initially given at 1.5 cents (adjusted for inflation) for every kilowatt-hour produced by a new wind plant for its first 10 years of operation, the subsidy for wind currently stands at 2.2 cents per kilowatt-hour. “In effect,” as explained on the Energy Information Administration’s website, “the subsidy reduces the per-kilowatthour cost of new wind plants by 20 to 25 percent.”

The original Production Tax Credit expired in July 1999 but before the year ran out it was extended to 2001. Since then, Congress has reauthorized and expanded it numerous times, most recently in the American Recovery and Reinvestment Act of 2009 (or stimulus package). Failing Congressional action, this tax incentive for wind will expire at the end of this calendar year (other tax supports for other renewables will extend through 2013).

Should the federal tax credit for wind be extended? The arguments on the pro’s [pdf]  and con’s abound. But there is a pretty strong consensus about one thing: if the tax credit for wind is not extended, the U.S. wind industry will tank, much as it did each time in the recent past when the tax credit went on hiatus. (Indeed, Siemens announced this week that it is laying off 615 workers at its U.S. wind facilities, citing uncertainty over the tax credit as a reason.)

Historic impact of PTC expiration on annual wind installation (AWEA)
“Historic impact of the Production Tax Credit expiration on annual wind installation” (Used with permission by the American Wind Energy Association [pdf])

And right now the chances of extending the tax credit for wind are looking rather slim. While President Obama has called for an extension,presidential nominee Romney has come out against it. Several bills that would extend it have been languishing in Congress. While the U.S. Senate Finance Committee approved an extension with bipartisan support, the bill has yet to come to the Senate floor. On the House side, the Energy and Commerce Committee rejected a bid to add an amendment to the so-called “No More Solyndra” bill that would have extended the subsidy.

And so the future of wind energy development in the United States seems very much, if you’ll pardon expression, up in the air. There is talk of both chambers considering an extension of the subsidy after the election. Sort of makes sense: along with the fiscal cliff why not a wind cliff?

* This post has been amended with the news of the Siemens layoffs.