It is true, as the American Wind Energy Association (AWEA) notes (see part 1 of this article), that any wind production must displace some existing generation, but only in terms of electricity, not any of the underlying energy forms transposed into electricity. It is rather due to the stricture that supply match perfectly with demand at all times (and this is another oversimplification of a complicated situation). Just as the grid must reduce supply in precise increments to keep pace with specific reductions in demand—or increase supply in just the right increments to keep pace with increasing demand, the grid must respond to increased wind penetration, which, to a grid operator, looks much like a reduction in demand.
Because wind plants are continuously generating between zero and 100% of their rated capacity, always in flux, providing who knows what for any future time, conventional generation must infill any reduction in wind energy at the precise increment of that reduction and, conversely, it must be withdrawn in increments that match any wind increases. If wind generation were merely intermittent and unpredictable while producing at a steady rate, it might achieve some of its claims about backing down coal. However, its relentless variability imposes daunting challenges for wind integration. Clever engineering schemes can mask the problem, but not without imposing increased costs and thermal activity.
Any fossil fuel saved when it is sporadically displaced by wind is often consumed in even greater volume as it is called upon to compensate for wind’s relentless skittering—the phenomenon described by Bentek. Wind existentially reduces the efficiency of these compensatory plants, raising the heat rate penalties of older, less-efficient coal plants such that they may be forced to emit 40% more CO2 than when operating efficiently. Even efficient penalties of 2% can increase emissions up to 16%. [Note 1] Depending upon the fossil-fired plant involved and the circumstances, a reduction in output in response to the addition of wind "can cause a very small reduction in the efficiency of that fossil-fueled power plant," as AWEA claims. But over time, these inefficiencies accumulate. But where is the evidence for any of this activity in the real world, aside from the Bentek study?
Evidently, AWEA understands and agrees with Bentek’s recommendation that its product would do much better paired with "more flexible, less polluting natural gas units." The association knows nuclear plants are not designed for load-balancing purposes and that cycling coal-fired boilers in a wind-following role is just as problematic, as AWEA obliquely conceded. Yet, as Australian engineer Peter Lang has shown, even the best possible thermal entanglement with wind, comprising both open- and combined-cycle natural gas systems, can save only 15% more CO2 than can be achieved by the natural gas systems alone, without any wind. However, the direct and indirect costs of replacing coal with such a tandem would ensure that all grid-connected Americans would see their utility bills skyrocket, given wind’s capital costs, which, on per kWh production basis, are on a par with nuclear’s. [Note 2]
Inefficient use of natural gas systems with wind, such as responsive open-cycle units normally used only at peak demand, would save no carbon dioxide emissions. And as Canadian Kent Hawkins shows, modeling a combination of coal and natural gas for wind-balancing results in more carbon emissions than would be the case without any wind, despite wind’s huge capital costs. Moreover, as Lang has said, "So wind cannot contribute to reducing capital investment in generating plants. Wind is simply an additional capital investment." And one that seems entirely unnecessary if the goal is reduced CO2 emissions.
Any valid attempt to measure the effects of wind integration must account for all the variables at play, including what generation wind displaces, what generation is used to follow and balance its volatility, the cycling rates and heat rates, type of fuels, even voltage regulation systems, among other things. All of these back end factors must be tallied and weighed against any initial carbon savings claimed for wind at the front end. Here’s how energy expert Tom Hewson, summarized the havoc wind’s presence plays on economic dispatch:
Given the inherent complexity, it is problematic to speculate about how wind volatility either lowers price or improves reliability on the spot market, as AWEA stoutly affirms that it does. Regional transmission operators are obliged to obtain the lowest cost set of suppliers to achieve high reliability, often deploying "redispatch" rebundling of the power mix to solve impromptu predicaments. Consequently, spot market prices are contingent upon many conditions within a series of priorities, some of them temporal, some functional, some related to scheduling. For most regions, about 90% of the spot market supply is purchased in a day-ahead auction in which wind rarely participates because it cannot ensure firm delivery 24 hours in advance (and would be liable for financial penalties). Instead, it usually participates in the real-time, at-the-moment market, which historically accounts for only 10% of the overall spot market. In this situation, if wind can deliver, conventional generators may back down and still receive the agreed marginal price set from the day before while saving fuel—a good deal particularly for natural gas generators in many areas of the country. However, in areas like Texas, where there is no day-ahead spot market, wind is responsible for eroding natural gas prices, as the Wall Street Journal reported last March. Suffice it to say, as Lisa Linowes once did, "Since the price paid for 90% of the generation is established twenty-four hours in advance of the power day, any low-cost participation from wind will have only a marginal impact on prices limited to those resources operating within the real-time market." [Note 5]
Government projections, particularly those from the National Renewable Energy Laboratory (NREL), that show wind can provide a substantial percentage of electricity in the United States while substantially reducing CO2 emissions are uncontaminated by reality; they have no more credibility than college football polls. Simulations based upon even hourly dispatch models without considering the gustiness of the wind and the corresponding heat rate penalties yield incomplete, if not duplicitous, information about a complex process—while assumptions about wind’s ability to replace generation one-to-one are cartoonish misrepresentations of reality. The NREL projections do not even try to account for the impact of thermal cycling events in response to wind volatility. Politically correct but untested testimonials from independent grid operators are equally problematic.
Measurement of greenhouse gas emissions is imprecise and statistical. Power plants are apparently not equipped with monitoring sensors for these gases; consequently, emission data are not based on direct observation. Rather, data are derived by plugging in numbers according to a formula, factoring information about fuel type and operating hours, estimating a plant’s thermal efficiency, and then leavening all that with a coefficient that calculates the pounds of CO2 produced by particular fossil fuels. It is unlikely that these averages are computed at time frames less than a day, which greatly disguises the effects of minute-to-minute wind flux. In short, reported numbers are typically formed from indirect model calculations, which themselves are fraught with a series of estimates.
Any statistician familiar with the problem of "averages" knows the difficulty of using them to explain complex phenomena. Wind behavior is different than the rather straight-on performance of conventional generation. As stated earlier, trying to describe wind activity with snapshots at any given time masks its volatility, making it seem steady and sober, deceptively giving the impression that the energy yield from wind is the same as that from conventional sources.
For the purpose of more accurately accounting for the way wind volatility distorts the general formula in use for calculating emissions production, given the present limitations for direct measurement, load dispatch analyses at, say, 15-minute intervals should be the preferred modeling tool, italicized here to emphasize that models are merely a means of examining reality, not reality itself. They would allow a much better look at the way routine wind flux affects the overall thermal activity on the grid.
What the EIA Data Really Show
No one with knowledge about how CO2 emission data are estimated should say that those data represent objective reality, as AWEA does, for the possibility of plus or minus error is nontrivial. With this in mind, let’s look more closely at what the Energy Information Administration (EIA) has actually said about wind and carbon emissions, in context. Here’s what Robert Bryce reported in his Wall Street Journal article (see part 1 for more on this article): "The U.S. Energy Information Administration (EIA) has estimated the potential savings from a nationwide 25% renewable electricity standard. . . . Best-case scenario: about 306 million tons less CO2 by 2030. Given that the agency expects annual U.S. carbon emissions to be about 6.2 billion tons in 2030, that expected reduction will only equal about 4.9% of emissions nationwide." There is a worst-case scenario: all that wind will produce virtually no reductions, a conclusion of the National Academy of Science. [Note 6]
Bryce also reported that NREL believes that if 20% of the electricity in the eastern U.S. came from wind, "the likely reduction in carbon emissions would be less than 200 million tons per year"—not even a drop in the bucket, as we will see.
Here’s what the EIA national generation mix data for 2007 and 2008 reveals:
- U.S. electricity demand in 2008 fell 0.9% from the previous year. Peak summer demand fell 3.8%. Coal generation declined 1.5%; natural gas, 1.5%; nuclear, 0.3%. CO2 emissions fell 2.5%—"largely due to decreased fuels consumption," explained the EIA commentary.
- During this period, wind generation increased 60.7%, from 34.5 million MWh in 2007 to 55.4 million MWh in 2008.
- "The overall improvement in the average natural gas capacity factor since 2003 reflects both the increased reliance on combined-cycle generation to meet energy requirements and further efficiency gains in combined-cycle generation technology, leading to lower CO2 emissions."
- "Sulfur dioxide (SO2) emissions fell 13.4%, from 9.0 million metric tons to 7.8 million metric tons, between 2007 and 2008. This amounts to the largest year-over-year decline since 1995. The large reductions in SO2 in 2008 resulted in part from a decline in fuel consumption but mostly from the installation of emissions reduction equipment in response to the Environmental Protection Agency’s Clean Air Interstate Rule."
- "Estimated carbon dioxide emissions by U.S. electric generators and combined heat and power facilities fell 2.5% from 2007 to 2008 (from 2,540 million metric tons to 2,477 million metric tons), largely due to a fall in fuel consumption at electric power plants" (emphasis added).
The substantial increase in installed wind clearly had little to do with reductions in CO2 and other greenhouse gasses. Rather, according to the EIA, they were almost entirely due to reductions in demand, with corresponding reductions in generation. There were additional reductions of CO2 emissions attributed to increased use of more efficient combined-cycle gas turbine units. Significant CO2 reductions at a national level in 2008 cannot be tied to wind, even indirectly. And, most likely, no CO2 reductions can be ineluctably credited to wind activity.
According to the EIA, the total U.S. electricity-related emissions of greenhouse gases in 2008 were 2,499.8 million metric tons (mmt) of carbon dioxide equivalent (CO2e), or about 35% of total U.S. greenhouse gas emissions. In 2009 it experienced a decline of 205 mmt, the largest in recent times. Moreover, this 4% drop in the carbon intensity of the electric power sector, was
In discussing 2009 CO2 reductions, the EIA does state that wind was responsible for avoiding 39 mmt of CO2. This was 19% of the total claimed CO2 emissions drop for the year—205 mmt—which also factored in reduced demand and improved nuclear (26 mmt) and natural gas (82 mmt) efficiency. However, since the total CO2 emissions tied to electricity production for the year was 2,295 mmt, the 39 mmt from wind contributed only 1.6% of the total—a thimbleful, despite the presence of more than 35,000 MW of installed wind capacity. And even this may have substantially overstated the case for wind, given the margin for error inherent in the EIA’s emission savings projection from wind, which also did not account for wind-induced emissions from inefficient cycling.
Burden of Proof
Any explanation about causation must honestly and transparently account for all variables at play. It should not consist of cherry-picked items favorable to a particular agenda while ignoring other, less-favorable factors.
Dr. Marcello Truzzi, recounted who is obligated to do what in the process of investigating, vetting, and validating explanations:
AWEA’s extraordinary claim is this: That an ancient source of energy—which relentlessly, continuously destabilizes the balance between supply and demand, is highly variable and unresponsive, and provides no capacity value while inimical to demand cycles—can effectively replace the capacity of modern machines and their fuels, in the process preventing significant amounts of greenhouse gas emissions that are the by-product of the burning of those fuels. This claim is particularly egregious given that wind does not even provide modern power performance—only desultory energy. Given that energy is the ability to do work and power is the rate work is done, wind technology delivers fluctuating power at a rate appropriate for 1810, not 2010.
The assertion that wind technology is a necessary, let alone sufficient, cause of reductions in the use of fossil fuels and their various emissions cannot withstand even casual scrutiny, for there are, in virtually every case, other much more plausible causes for any CO2 or fossil fuel reductions—such as a falling away of demand, substitution of other fuels, improvements in conventional machine efficiencies, and even changes in weather conditions.
Even more bizarre than AWEA’s extraordinary claim is its assault on the bedrock scientific principle of refutability, what scientists call "falsifiability." Any claim about truth in the material world must be testable using standards of empirical evidence to determine if it is false. Because an assertion is "falsifiable" does not mean it is false. Rather, it means that if the statement were false, then its falsehood could be demonstrated. By hiding the way wind affects overall grid thermal behavior behind proprietary confidentiality laws, not allowing disinterested, independent observations of the relevant phenomena, wind’s limited liability companies remain mired in what Richard Feynman once called "cargo cult science." AWEA could claim there are 1,352 angels sitting on the head of a pin in Nashville. But if that pin were sealed away in a safe deposit box controlled only by AWEA and the bank, how could anyone test it for truth? What is even more outrageous is the way government has abetted this absurdity, passing laws ensuring "confidentiality," while regulators look the other way and the Department of Energy engages in promotional, very hypothetical, wind "studies" alienated from reality.
With more than 100,000 massive wind turbines around the world—35,000-plus in North America—not one coal plant has closed due to the installation of any wind projects. Nor is there empirical evidence that there is less coal burned per unit of electricity produced as a specific consequence of wind.
Ontario has long promised to retire (but has never been able to do so) all its coal plants. Officials tout that they will be replaced by wind. To hedge its renewable energy bet, the Ontario government is building natural-gas facilities as insurance against new wind projects. In other words, the province expects to replace coal with natural gas, not wind. The latter could not exist without either hydro, which currently provides the province with about 25% of total generation (wind is about 1%) or flexible natural gas generators. Projections by the Ontario Power Authority depend upon planned conservation savings and natural gas, not wind, as a means of displacing coal.
Similarly, boasts by the former governor of Kansas that her state would not approve a new coal plant because of its increasingly expansive wind projects conveniently forgot to mention how the state had planned to increase its importation of natural gas—at higher cost. Many new coal plants are in the offing, both in the United States and throughout the world—even in Kansas, since the new governor, "recognizing the need for baseload power," struck a deal allowing one new coal plant in the western part of the state.
Depending upon government sanctioned secrecy of its performance data and therefore confident that there would be no fact checking in the real world, AWEA has exploited the arcane, very complex nature of greenhouse gas emissions—arcane because so few have knowledge about it and complex because of its incredible scale and the difficulties involved with actual measurement. It then produced highly selective evidence based upon a series of hypothetical projections, mathematical models with incomplete information, and well-crafted but ultimately vacuous statements such as "one of the universally recognized and uncontestable benefits of wind energy. . . ." Everyone should dust off and reread Darrell Huff’s classic, How to Lie with Statistics.
Let’s Get Real
Wind technology is not "universally recognized" for its ability to reduce CO2 emissions, for many have contested that presumption. And, in the wake of Bryce’s article, many more will soon join the fray. According to their calculations, whatever wind produces will replace some existing conventional generation for a brief and highly fluctuating time; but in terms of overall fuel use, wind production rarely "saves" anything and, in most cases, as shown in the Bentek study, requires that more fuel be consumed in highly inefficient ways over time. The Bentek study is supported by the work of engineers like Kent Hawkins in Canada), Peter Lang in Australia (here and here), Bryan Leyland in New Zealand, Jim Oswald in Britain, C. le Pair and Kees de Groot in The Netherlands, and several studies in Germany, Spain, and Denmark, some of which are summarized in Bryce’s latest book.
Responding to both the letter and spirit of Truzzi’s charge, critics of wind technology not only have cast doubt upon AWEA’s claims, showing that the organization has not met the requisite burden of proof, but they also offer a means of testing their thesis that wind does not offset much CO2. Lang, Le Pair/De Groot, Oswald, and Hawkins have independently developed differing methodologies for assessing wind’s potential to engage greenhouse gas emissions, and they are in remarkable agreement about their conclusion: that the higher wind penetration on virtually any grid system, the greater potential for more CO2 emissions than would be the case without any wind at all.
These methodologies now must be tested against reality, made so difficult because of proprietary confidentiality laws that shield wind performance activity from critical scrutiny. Thus far, only Bentek has been graced with this opportunity.
Consider just a few of the questions that must be answered and the issues that must be properly accounted for, at minimum:
- The amount of conventional generation necessary when wind is producing nothing?
- The amount of conventional generation necessary to infill the gap between when a 100-MW wind project is producing, say, 50 MW in one minute and, minutes later, only 40 MW?
- The amount and pace of conventional generation that must be withdrawn when that wind project increases its yield quickly, moving, say, from producing 10 MW in one minute and, 15 minutes later, 80 MW? This may not be consequential for any grid in terms of security, particularly large grids like the PJM with over 140,000 MW of peak demand generation. But even this relatively trifling flux has cost and emissions consequences, which should be properly assessed.
In most cases around the country, the answers will involve coal plants—as they do in Texas and Colorado, Minnesota and, especially, Iowa—working highly inefficiently. The heat rate penalties involved logically lead to more fuel use—which exhausts more CO2 emissions. However, even in those areas where natural gas generators can serve as the principle means of balancing wind flux, inefficient cycling would remain an issue, subverting CO2 emissions offsets, as Lang and Hawkins predict.
Logic also dictates, in answer to these questions, that any grid must be able to support the entire range of wind flux—from zero to the highest installed wind capacity. Therefore, a grid must have a 1:1 compensatory generation for wind available at all times. Moreover, with more wind penetration, additional conventional generation must be brought on board to keep the grid’s reserve margins intact. AWEA’s footnoted statement that there is existing reserve capacity available to cope with the loss of a large generating set that can be used to "back up" wind is seriously misleading. Such reserves provide for grid security; using them to mollycoddle wind flux should be a breach of priority and protocol. In the real world, wind can only be a small bit player in a much larger machine complex, a complex made more inefficient because of wind caprice.
Allowing researchers access to wind performance data (such as wind speeds) at appropriate time intervals will advance the cause of knowledge. But it will also have practical policy uses, for it would permit the public subsidies now provisioning wind projects to be indexed to functional measurements showing how much CO2 and fossil fuel wind actually reduces, so that the public—and policy makers—would know the value obtained for those tax dollars. It would also inform the various renewable portfolio standard laws, which now only require "deployment" of technologies like wind. The way such laws are currently written, there is nothing whatsoever requiring wind to "do" anything, nothing mandating that wind output show that it, and nothing else, is responsible for reducing CO2 emissions and fossil fuel consumption. (This is equally true for renewable energy credits and stock portfolio reports.) Because there is no physical accountability, renewable portfolio standard laws today could mandate deployment of pixie dust, subsidize it, and obtain the same "benefit" currently derived from wind.
Looking at the evidence provided on behalf of wind technology, which is at best equivocal, and critical analyses like Bentek’s that expose the technology’s limitations, perhaps it’s fair to conclude by extending AWEA’s distasteful analogy. Those who claim that wind technology can abate meaningful levels of CO2 emissions would admire the three-pack-a-day guy who decides to improve his health by smoking four packs of filtered cigarettes instead.
Portions of this article have appeared on MasterResource and the Institute for Energy Research.
—Jon Boone retired after a 30-year career at the University of Maryland, College Park as an academic administrator, but he is a lifelong environmentalist and co-founder of the North American Bluebird Society. Today, Boone’s interests are painting and seeking "informed, effective public policy and an environmentalism that eschews wishful thinking because it is aware of the unintended adverse consequences flowing from uninformed decisions."
1. When coal-fired turbines are frequently and rapidly ramped up and down to compensate for wind variation, "the unit emission of CO2 per kWh increases . . . to cope with load. This can easily be 2% or more . . . depending on the degree of ramp-down. On a coal-fired boiler, a 2% reduction in efficiency increases the unit emissions from 950 grams per kWh to nearly 1,100 grams per kWh, a change of 150 grams per kWh . . . —a 16% increase in emissions." David White, "Reduction in Carbon Dioxide Emissions: Estimating the Potential Contribution from Wind Power," Renewable Energy Foundation, December 2004, p. 16.
4. Tom Tanton, personal email dated Aug. 21, 2010, and personal email dated Aug. 27, 2010.
5. See Russell Gold, "Natural Gas Tilts at Windmills in Power Feud," The Wall Street Journal, Mar. 2, 2010. See also John Chandley, "How RTOs Establish Spot Market Prices (and How This Helps to Keep the Lights On)," PJM Interconnection, Sept. 27, 2007. See also Ross Baldick, "Single Clearing Price in Electricity Markets," University of Texas at Austin, Feb. 18, 2009. Quote taken from Lisa Linowes’ essay, "WindAction," Mar. 2010. Special thanks to Tom Stacy for providing the Chandley article.
6. The NAS worst-case scenario—1.2% reductions. "Wind power will offset emissions of carbon dioxide by 1.2-4.5% from the levels of emissions that would otherwise occur from electricity generation."
7. Marcello Truzzi, "On Pseudo-Skepticism," Zetetic Scholar, 12/13, pp. 3-4, 1987.