Why Can’t We Get All Our Electricity from Wind?

by Marlo Lewis on October 4, 2012

in Features

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Wind energy advocates often point out that a State, the U.S., or the entire world has enough wind energy to supply all of its electricity needs many times over. Writing in Scientific American, for example, Mark Jacobson and Mark Delucchi note that the world in 2030 is projected to consume 16.9 trillion watts (terawatts, or TW) of power, with about 2.8 TW consumed in the U.S. Total wind flows worldwide generate about 1,700 TW, and accessible wind resources total an estimated 40-85 TW. 

Based on such math, the American Wind Energy Association (AWEA) argues, for instance, that Arizona has enough wind to meet 40% of its electricity needs, Michigan wind resources could meet 160% of the State’s electricity needs, and wind in Oklahoma could provide nearly 31 times the State’s electricity needs. Yet despite ratepayer subsidies, special tax breaks, and renewable energy mandates and goals in 37 States, wind supplied 2.2% of total U.S. electric generation in 2010. Why don’t we get lots more of our electricity from this ’free,’ ‘non-polluting’ ‘renewable’ source?

The chief impediments are wind energy’s inherent drawbacks. First, wind energy is intermittent — at any given time the wind may blow too hard or too soft or not blow at all. Second, wind is non-dispatchable. When Shakespeare’s Owen Glendower boasted, “I can call spirits from the vasty deep,” Henry Hotspur replied: “Why, so can I, or so can any man; but will they come when you do call for them?” Like Glendower’s spirits, the winds answer to no man. The wind is not ours to ’dispatch’ as electricity demand rises or falls. 

There are three main ways of compensating for wind’s intermittency and non-dispatchability — pumped storage (pump water uphill when there’s too much wind relative to demand; let it run downhill and drive turbines when there’s too little wind), natural gas backup generation, and wind dumping (idle the turbines when demand is low). Incorporating those techniques to keep supply in balance with demand adds to the cost of wind electricity, which is typically more costly than coal- and gas-generated electricity even without storage and backup.

What’s more, according to a new Reason Foundation/Independence Institute report, the storage, backup, and idling costs become prohibitive as wind’s share of total generation increases beyond 10-20%. 

The report, The Limits of Wind Power by William Korchinski, contains several sobering graphics. Figure 6 from the study shows how variable (intermittent) the wind can be, reducing output as much as 16 MW per minute.

The report quotes E.ON, the German power producer that experienced this sudden decline in wind energy during Christmas in 2004:

Whilst wind power feed-in at 9.15 am on Christmas Eve reached its maximum for the year at 6,024MW, it fell to below 2,000MW within only 10 hours, a difference of over 4,000MW. This corresponds to the capacity of 8 x 500MW coal fired power station blocks. On Boxing Day, wind power feed-in in the E.ON grid fell to below 40MW. Handling such significant differences in feed-in levels poses a major challenge to grid operators.

Let’s suppose that some States actually take AWEA’s message to heart and build enough wind capacity to meet 100% of their power needs. To what extent would actual wind generation match electric demand throughout the year? Figure 11 of the study illustrates the results for the PMJ Interconnection region comprising all or parts of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia. 

As the figure shows, on hundreds of days the PJM region’s turbines would produce either significantly more or significantly less power than customers consume.

As noted above, there are three main ways of dealing with wind’s intermittency and non-dispatchability. One technique is pumped storage: “pumping water uphill when there is excess wind energy, and then running the water downhill through a turbine when wind energy is limited.” The PJM pumped storage capacity for 2010 was about 5,000 MW, compared to the area’s average hourly electric demand of 77,800 MW. In other words, PJM currently has about two hours worth of stored power. That’s okay because the overwhelming lion’s share of the region’s electricity does not come from wind.

But suppose PJM got all of its electricity from wind — what would it take to have enough pumped storage in case the wind doesn’t blow? Korchinski calculates that PJM would need to be able to pump uphill “a body of water that is about 2,000 square miles by 100 feet deep” — the dimensions of Lake of the Woods in Canada.

Since constructing artificial lakes of that size is impractical (and would have significant ecological impacts as well), pumped storage is typically combined with natural gas backup generation and wind dumping. Turbines left idle (dumping) do not generate income. Gas backup means running gas turbines inefficiently, in ”spinning reserve” mode, so they are “ready to increase or decrease power on short notice.” The greater the penetration of wind in the electricity fuel mix, the greater the reliance on wind dumping and gas backup.

Korchinski comments:

As wind penetrations increase, the grid requires increasing amounts of spinning reserves to maintain reliability. At high wind penetrations, even large amounts of power storage cannot prevent significant (and expensive) wind dumping. The already high cost of wind power increases with the construction of storage facilities, and the cost to construct extra wind turbines, which will be dormant during periods of wind dumping.

The takeaway message for policymakers and a public bombarded with propaganda about obtaining 40%, 160%, or even 3100% of a State’s electricity from wind?

Very high wind penetrations are not achievable in practice due to the increased need for power storage, the decrease in grid reliability, and the increased operating costs. Given these constraints, this study concludes that a more practical upper limit for wind penetration is 10%.

Alan White October 5, 2012 at 2:19 pm

For wind to be effective the platform, thus there siting needs to change. There is a true wind turbine that just recieved its patent 8,269,368 call windshine. Scalable so true residential along with utility and commercial will be available. With a much greater wind profile very low cut in and no real cut out speed, plus gust uilization will make for more reliable power output and over wider landscape. Even a model fot the antarctic where no windmill would dare to go.
Windshine Electric Generators the new future in wind.

archaeopteryx October 5, 2012 at 3:08 pm

This is excellent and to the point. The problem with too many wind generators is also highlighted in http://www.welt.de/dieweltbewegen/article13798376/Oesterreich-rettet-deutsche-Stromversorgung.html. Germany has 25,000 wind MW and claims having covered 7.6% of electicity demand in 2011. But, most probably, that does not correspond to 7.6% fuel substituiton, as stand-by backup consumes fuel, and revving up or cutting back increases inefficiency. The Dutch reported an annual fuel substitution equal to 4% of installed rated capacity. The Falklanders measured 4 to 8% fuel savings as a result of “12% or 14% of electricity supply from wind”.

James Rust October 5, 2012 at 7:06 pm

The problems of large-scale wind energy reminds me of a long ago remark by the first head of the Nuclear Regulatory Commission–Dixie Lee Ray. Dr. Ray said, “A viral American male has enough semen to impregnate all the women in the world. The problem is with the delivery system.” I think Dr. Ray was referring to prospects of solar energy which was always mentioned by anti-nuclear activists as a replacement for nuclear power.

Power from the sun is vastly greater than wind power and it is too costly for use on a large scale.

James Rust

Kirby Palm October 7, 2012 at 3:43 am

Excellent. The one thing I would have added would have been to point out that you don’t just need a lake for pumped storage, you need TWO lakes at different elevations. This means that you have the added technical challenge that one of these large lakes needs to be on top of a mountain. And when utilized, the levels of both lakes are going to change dramatically in a very short period of time. You’re not looking at construction of a peaceful, serene fishing spot like you are for damming up rivers to power hydroelectric plants.

For typos, you say PJM several times instead of PMJ. I don’t even know which one is correct at this point.

Michael Goggin, AWEA October 11, 2012 at 10:39 am

If you read the Reason Foundation’s report, it actually says that wind energy can provide a large share of our electricity (at least 50%) and that wind’s benefits are roughly as large as expected (9% reductions in pollution when we get 10% of our electricity from wind, 18% reductions at 20% wind, and 54% reductions at 50% wind). That’s even after the report uses a seriously flawed methodology that overstates the challenges of integrating wind onto the grid and understates wind’s benefits. For more, read the explanation here:
http://www.awea.org/blog/index.cfm?customel_dataPageID_1699=18996

Michael Goggin,
American Wind Energy Association

Steve October 14, 2012 at 11:41 am

First off William Korchinski is a former oil industry chemical engineer — a smart guy no doubt — but suspect as an unbiased expert on wind and energy in general. Secondly Reason Foundation that paid for the report has a bias against alternative energy since its funders are mainly in the oil industry ie the Koch brothers and Exxon.

Korchinski conclusions are accordingly suspect for a number of reasons. He fails to acknowledge that the fossil fuel industry gets at least $10 billion in annual subsidies http://priceofoil.org/fossil-fuel-subsidies/
He fails to account for the pollution costs of fossil fuel energy including carbon pollution.

Marlo Lewis October 23, 2012 at 3:26 pm

Steve,

Nearly all policy studies are undertaken by researchers with a bias or agenda. After all, few people do policy-relevant research just to satisfy intellectual curiosity. Plus, rigorous quantitative analysis is expensive and somebody has to pay for it. That “somebody” is almost always not an honest broker but a stakeholder — an organization with a material stake in the outcome of the policy battle.

Consider the American Wind Energy Association (AWEA), which also sponsors studies. AWEA members benefit directly from market-rigging interventions like renewable electricity mandates and the wind energy production tax credit (PTC). Those policies transfer wealth from ratepayers and taxpayers to wind energy producers. So what are the odds AWEA would ever pay for a study critical of mandates and the PTC?

Nor should we look to “the government” for an unbiased assessment. The Department of Energy’s National Renewable Energy Laboratory (NREL) produces lots of studies and reports on wind energy. It too is a dog in the fight. The agency’s budget and very existence ultimately depend on persuading policymakers and the public that renewable energy and the policies supporting it are a great bargain. Don’t expect to find a bias-free zone there.

In short, policymaking, like litigation, is an adversarial process. We know in advance that the lawyer is an advocate, not an honest broker, and argues in the interest of his client. That, however, does not excuse the jury from listening to both sides of a controversy and attempting to reach a judgment based on the evidence presented.

Whether the Reason Foundation study makes a contribution to the debate or is deceptive garbage depends entirely on the validity of its assumptions, methods, data, and conclusions. You have not offered any evidence rebutting it. Dismissing the study out of hand because Reason gets funding from Koch is to argue ad hominem. It’s an argument not based on facts or logic but your particular bias!

Some quick additional points. Wind energy is one of the least cost-effective ways to improve air quality. It is much more efficient to attack air pollution directly via emission controls than to impose renewable energy quota. Nor is wind energy a cost-effective carbon mitigation policy. That’s why the Waxman-Markey bill included a national renewable electricity mandate in addition to a cap-and-trade program. Waxman and Markey are big boosters of wind, but they knew that simply putting a price on carbon to penalize fossil-fuel electric generation isn’t enough to make wind energy competitive.

As for $10 billion in oil subsidies, oil is a bit player in U.S. electric supply and has been since the 1970s. So even if oil gets all the subsidies you claim, that’s not a good reason to subsidize wind.

Moreover, most of the tax breaks often condemned as subsidies to “Big Oil” are in fact broadly available to many industries, as William O’Keefe explains (http://energy.nationaljournal.com/2012/10/should-oil-and-naturalgas-tax.php#2253278). For example, the Sec. 199 manufacturing tax credit is available to all domestic U.S. manufacturers. Similarly, the protection against double taxation for U.S. oil companies with operations overseas applies to all U.S. firms. The tax break for “intangible drilling costs” applies to drilling operations a basic principle of the tax code, namely, expenses are deducted from revenues to determine taxable income. The depletion allowance tax may or may not be a good idea, but it applies to all forms of mining, not just oil and gas.

O’Keefe used to be an executive of the American Petroleum Institute, so his bias may offend your bias. To repeat, that does not tell us whether his argument is valid or not, because identifying bias is not refutation.

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