A free-market energy blog
Random header image... Refresh for more!

Category — Emissions reduction (wind)

Where Wind Studies Go Wrong: Cullen in AEJ (Part II)

“The level of emissions savings provided by wind plants has never been conclusively determined, taking into account all the factors.”

Part I yesterday questioned the analysis and robustness of Joseph Cullen’s study, “Measuring the Environmental Benefits of Wind-Generated Electricity”. [1] Part II completes the commentary on this paper, covering:

  • Questionable data, which seriously inhibits any analysis of wind performance
  • Interstate trade in electricity, an often overlooked, but important, consideration in understanding impacts on emissions
  • A summary of the acknowledged shortcomings of this paper
  • Questionable opinions/claims made

Questionable Data

The level of emissions savings provided by wind plants has never been conclusively determined, taking into account all the factors. Further, there is no published accurate, minute-by-minute, actual fuel consumption or emissions by individual plant, especially for systems with notable levels of wind present. Note the limitations in the Katzenstein and Apt paper looked to by Cullen for corroboration as discussed in Part I.

In general, government reported emissions are estimates based on calculations using assumptions and relatively simple algorithms. In some cases, actual measurements are taken but are no better than those calculated as reported by the International Energy Agency (see page 35).

“Commercial instrumentation is available for monitoring CO2 concentration and flue gas volume flows. Given the limitations of such instrumentation, the accuracy of directly measured CO2 release is probably no better than that derived by indirect calculation.” (emphasis added)

A report by The Sustainable Energy Authority in Ireland, “Renewable Energy in Ireland”, in Appendix 1 also refreshingly recognizes the limitations to existing reporting methods.

“The assumption underpinning this approach is that the renewable plant is displacing the last plants to be dispatched to meet electricity demand, i.e. the marginal oil and gas plants. There are clear limitations in this analysis but it does provide useful indicative results.” (emphasis added for “indicative”, which is taken to mean “suggestive”)

“The limitations and caveats associated with this methodology include that it ignores any plant used to meet the associated reserve requirements of renewables. These open cycle plants will typically have lower efficiency and generate increased CO2 and NOx emissions compared with CCGT and these emissions should be incorporated into the analysis. The purpose of presenting a simplified analysis here is to provide initial insights into the amount of fossil fuels that are displaced by renewables and the amount of emissions thereby avoided.” (emphasis added)

The issue raised in the last quote speaks to the comments made in the Robustness section in Part I. [Read more →]

February 14, 2014   7 Comments

Where Wind Studies Go Wrong: Cullen in AEJ (Part I)

“The nature of the short-term operation of an electricity system is more like that of a machine than a market.”

A paper published by Joseph Cullen in the American Economic Journal: Economic Policy (November 2013), “Measuring the Environmental Benefits of Wind-Generated Electricity” [1] is important in two regards. First, using Texas data, it shows that even with notable emissions savings attributed to wind, the highly subsidized cost of wind is exceeded only by high estimates of the social costs of pollution.

Secondly and perhaps more importantly, his paper provides an opportunity to illustrate where wind-performance analyses fall short. This is the subject of this two-part post today and tomorrow, and is independent of the issue of carbon dioxide social benefits versus social costs.

Professor Cullen first determines how much electricity production of other generator types is offset by the presence of wind plants in the grid using a reduced form econometric model based on “…observed behavior and current market conditions.” The time frames for production are 15 minute intervals and two hour ahead forecasting by market participants. The market-oriented approach is exemplified by the following quote:

“When low marginal cost wind-generated electricity enters the grid, higher marginal cost fossil fuel generators will reduce their output.” (emphasis added) [Read more →]

February 13, 2014   6 Comments

POWER’s Peltier: Show Your CO2 Hand or Fold, Windpower

“Forgotten by many proponents is the justification for the PTC in the first place: to reduce CO2 emissions…. [Yet] … many utilities with large amounts of wind generation steadfastly refuse to release operating data for analysis. I suspect to do so would mean the release of empirical data to build the opposition’s case for insignificant CO2 reduction and poor operating economics. I was unable to find one study of existing wind energy installations that found the CO2 reductions predicted by AWEA.”

Robert Peltier, editor-in-chief of POWER magazine, is an honest broker. He understands the technical side of electrical generation as a professional engineer. He knows power generation in practice from his years of industry experience on the regulated and the nonregulated sides. He has taught the subject as a tenured professor. And with years of experience in the U.S. Navy and in law enforcement, he has just about seen it all. (See full bio below.)

In his current position, Peltier oversees staff and industry writing on the latest power technology relating to plants using oil, gas, coal, nuclear, water, wind, solar, geothermal, and biomass. Battery technology is regularly updated too.

His most recent Speaking of Power editorial,Under Seize(December 2012), contains numerous insights that friend and foe of modern windpower should heed. The longtime head of the American Wind Energy Association (and critic of Honest Bob), Denise Bode, is riding into the sunset. But she leaves behind a very subpar, dishonest technology that sans government support will be revealed as the Enron of energy sources. (And, thinking ahead, who will pay for wind-turbine removal?)

His seminal editorial follows: [

December 18, 2012   19 Comments

Wind Consequences (Part IV – Subsidies and Emissions)

This post is part of a five-part series on the adverse consequences of imposing industrial-scale wind plants on electricity systems. The series shows that there is no valid reason to pursue the policy of implementing new renewable energy sources in electricity generation, especially wind.

This post provides more information on the subsidies and emissions considerations for the scenarios summarized in Part I. Parts II and III dealt with cost implications. Part V this Thursday will focus on a number of other issues providing a complete picture of wind’s undesirability and unfeasibility in all respects.

Part I also provides links to the rest of the series.


Because subsidy issues are often raised, comparing those for wind and other generation plants, it is appropriate to show their effect on a MWh basis, regardless of the absolute amounts. The subsidy related to producing a useful output is the important consideration, because this is how electricity is generated, used and paid for. Table IV-1 shows this, but at the level that the wind plant owner experiences, not the full costs of wind to society, that is including wind balancing plant and unique-to-wind grid investments. Note the very high wind subsidies, especially relative to this limited view of costs. [Read more →]

September 25, 2012   4 Comments

Wind Integration Realities: The Bentek Study for Texas (Part IV)

[Editor's note: This is the final post in the series reviewing studies for the Netherlands, Colorado and Texas on (elevated) fossil-fuel emissions associated with firming otherwise intermittent wind power. Part I introduced the issues. Part II showed negated emission savings for the Netherlands at current wind penetration (about 3 percent). Part III extended the Netherland's experience to the higher wind penetration in Colorado (6%) which demonstrates higher emissions. Part IV concludes with the Bentek results for Texas,which confirms those for Colorado.]

There are a number of relevant, notable characteristics of the 2008 Texas electricity production profile, 85% of which is managed by ERCOT:

  • The utility portion of the total electricity production is only about 24% of the total, with independent suppliers providing 57% and CHP installations, 19%. This distribution suggests that ERCOT’s ability to balance wind production is more limited than what might first appear.
  • Wind production is 5% of the total (less CHP), but a very large 17% of the utilities portion.
  • A large proportion of gas production is provided by independent suppliers and CHP, 45% and 39% respectively, again likely limiting ERCOT’s ability to balance wind with gas.
  • The ratio of utility gas to wind production is 192%, which suggests that this is tight if dedicated to wind balancing. This, plus high production from wind at night, explains the high degree of cycling of coal plants required.

Because of recycling events, arguably attributable to the presence of wind plants, the results are the same as for PSCO, that is, there is an increase in CO2 emissions with the presence of wind. In ERCOT, the coal plants produced an additional CO2 emissions in 2008 of about 0-566,000 tons over running stably without these events, and in 2009, an additional 772,000-1,102,000 tons. [Read more →]

May 26, 2010   10 Comments

Wind Integration Realities: The Bentek Study for Colorado (Part III)

[Editor's note: This is the third of four posts on (elevated) fossil-fuel emissions associated with firming otherwise intermittent wind power. Part I introduced the issues. Part II showed negated emission savings for the Netherlands at current wind penetration (about 3 percent). Part III (below) and Part IV tommorow examine the higher emissions from wind in Colorado and Texas, respectively, according to a new study by Bentek.]

The Bentek study is a significant contribution to the wind/fossil-fuel emission literature despite some notable limitations. The study analyzes the PSCO system, which dominates Colorado’s needs, and the ERCOT system in Texas, which manages 85% of that state’s electricity.

The analysis includes SO2, NOx and CO2 emissions. Bentek looks at coal cycling events only in both cases, ignoring any gas cycling, while noting PSCO’s acknowledgement that wind impacts gas as well as coal.

There are reasons why coal cycling is focused upon:

  • Although gas turbine plants are better suited for cycling to support wind, for both PSCO and ERCOT gas resources are insufficient to balance all the wind energy produced.
  • There is a small amount of pumped storage available to PSCO, which can run for only four consecutive hours.
  • Wind is strongest at night when base load coal plants predominate, and there is reduced gas generation, which may not be sufficient to safely cycle gas plants.
  • As a result, reported gas cycling events at PSCO are less frequent than that for coal.

Both analyses utilize published production information. As PSCO does not reveal hourly wind production, for emissions analysis purposes, Bentek has to rely on a few coal cycling events in relation to detailed wind production provided in PSCO training manuals. This limitation is offset by the information available on a notable increase in coal cycling, which has occurred during the period of wind introduction, and which is arguably attributable to wind. As ERCOT does release wind production at 15 minute intervals, the same analysis approach is used in the Texas system to validate the Colorado results, which it does.

Criticisms that the PSCO analysis is based on two days experience only, are well answered in the Bentek report. The reality is that PSCO does not make the necessary information available, and Bentek has done well with what they had to work with. Also, the validation of results based on the ERCOT experience is important. Finally, Bentek appropriately acknowledges limitations by calling for more comprehensive studies based on detailed information.

Having established that RPS appear to add to the emissions problem, Bentek concludes that, given RPS, it will be necessary to incorporate adequate flexible fuel capacity facilities (gas plants) to ensure reduction in emissions, which is true enough. What is missed in this logic is that incorporating such new facilities without RPS will achieve even lower emissions. More on this is provided below. There are not only more emissions with RPS than without them, but also there is duplicate capacity installed (wind) at significantly higher costs, which adds notably to the costs of electricity. [Read more →]

May 25, 2010   5 Comments

Wind Integration Realities: The Netherlands Study (Part II)

[Editor's note: This is the second part in a four-part series on two new studies examining the negation of windpower emissions savings from fossil-fuel firming. The Netherlands study below, which is found to be consistent to Mr. Hawkins's calculator approach, indicates a total negation of emissions savings from fossil-fuel fill-in.]

Windpower has traditionally been considered a substitute for carbon-based energy and thus a strategy for reducing related emissions, including that of carbon dioxide (CO2). However, reality is more complicated. Either natural gas-fired or coal-fired power must rescue wind from its intermittency problem, a role that creates incremental fuel usage and emissions compared to a situation where the conventional capacity could operate on a steadier basis.

Previous studies have highlighted this unsettling tradeoff for proponents of windpower. And a new study by C. le Pair and K. de Groot based on actual experience in the Netherlands finds:

The use of wind energy for electricity generation in combination with the requirement for fossil fuel powered stations to compensate for wind fluctuations can easily lead to loss of the expected saving in fuel use and CO2 emission. In addition, the conventional stations will be subject to accelerated wear and tear.

It is recommended to get an accurate and quantitative insight into these extra effects before society sets out to apply wind energy on a large scale. All producers must be required to publish data on the efficiency effects and fuel use when wind energy is added on.

This post reviews their study and compares its results with that produced by my fossil fuel and CO2 emissionscalculator, both of which show how quickly any claimed saving from wind can become negative given the reality of fossil-fuel backup to firm-up intermittent power. [Read more →]

May 24, 2010   3 Comments

Wind Integration Realities: Case Studies of the Netherlands and of Colorado, Texas (Part I: Introduction)

There is no convincing proof that utility-scale wind plants reduce fossil fuel consumption or CO2 emissions. Although there are are a number of reports claiming gains can be made that will combat climate change, free us from fossil fuel “addiction,” provide energy independence and needed 21st century industrial development, such reports are not substantiated by definitive and comprehensive analyses.

To determine the actual effects will require long-term time series, at intervals significantly less than one hour, of wind production and fuel consumption due to fast ramping of fossil fuel plants to compensate for wind’s volatility in an electricity system where wind represents approximately at least 1-2% of production.

As opposed to wind proponents’ claims, studies based on actual experience with wind integration are emerging  that demonstrate the fossil fuel and CO2 emissions gains are not valid. The two reviewed here are examples but are limited by the lack of availability of complete information on operational performance, especially of wind plants. Fortunately, enough information can be gleaned that provides a strong indication of what those who have studied this objectively have long suspected.

Why is more complete information about wind performance and integration not available? Is it because wind proponents, including some policy makers and wind industries, do not want the realities disclosed, or, in the case of many environmentalist organizations, because they would interrupt established agendas? Or is it that these groups believe it unnecessary because they do not understand the realities of utility-scale wind power? [Read more →]

May 22, 2010   14 Comments

The U.K. Fact-Checks Wind on Carbon Emissions

There are a lot of good reasons to be suspicious of regulators who claim to be guardians of the truth, but every now and then they get something right. The United Kingdom’s Advertising Standards Authority (ASA, http://www.asa.org.uk) is that country’s equivalent of the Federal Trade Commission, with jurisdiction over false advertising. Last month, the ASA reached a settlement with the British Wind Energy Association acting as agent for the country’s wind generators. Two months earlier, a local anti-wind group filed a complaint at the ASA against Npower, a subsidiary of Germany’s RWE. Npower’s advertising claimed that every kilowatt-hour of wind power displaced 860 grams of CO2 emissions from fossil-fuel power plants. The ASA determined that the amount was badly overstated. [Read more →]

January 14, 2009   1 Comment