Windpower Emissions: Kleekamp Critique (Part I – Introduction)
This post is the first in a three part series that critiques the recently published article “Wind Power Always Replaces Fossil Fuels” by Chuck Kleekamp, which provides material for another in the series of my critiques of wind proponents’ claims. Previously analyzed were papers by Milligan, Komanoff and Gross. My understanding is that this author has previously made notable contributions to environmental matters. Let’s see how he does with respect to wind.
To begin, I cannot help commenting on the inclusion of “Always” in the title. The apparent certainty in this term immediately alerts me to a questionable analysis. Perhaps the author meant to be provocative, and was not serious in the use of this word. If so, this does not give due consideration to the importance of the matter.
This leads to another general comment. In a circulation of a draft of these posts to a panel of reviewers, one commented on the nature of Kleekamp’s article as that of not having sufficient knowledge of the subject, but attempting to appear so. He provides descriptions, but makes errors in the process. Cases in point are his (1) example of the Mirant Canal oil-fired plants and (2) description of electricity system markets and activities of the System Operator of New England (ISO NE).
Mirant Canal Plants
As the illustration for conclusions, the author uses information about the Mirant Canal oil-fueled, supercritical, steam turbine plants. He describes the high efficiency performance of these two plants and the low loss of efficiency at notably low loading, which are characteristic of the supercritical type. Based on two points of steady-state operation, he therefore draws two conclusions:
“Therefore to say when wind power comes on line it will not reduce fossil fuel consumption is simply erroneous.”
“The point of this discussion is that no fossil fueled generating unit consumes more fuel than that which is absolutely necessary to produce the dispatched power allowed under the rules of the ISO. When the wind comes up or air conditions [sic] and lights are turned off, less fuel is consumed on a linear basis.” (Emphasis added)
Although the detailed information provided is interesting and may well influence a general audience, it is not relevant to the discussion. Frequent cycling is required to balance wind’s volatile output. It is also required to balance short term demand fluctuations, and fast acting, but less efficient (in the case of fossil fuel plants), generators are required for the continual up and down ramping required in both cases. According to a National Petroleum Council (NPC) report on Electric Generation Efficiency”, supercritical plants are not capable of cycling without reducing their longevity and efficiency. Power-Gen Worldwide makes the same point.
So, the inherent assumption, and not considered in his description of normal demand fluctuations (Kleekamp’s example of when lights or air conditioners are turned off and on), is that there is no increased fossil fuel consumption impact as a result of the frequent cycling of the balancing units, aside from their less efficient operation at lower load levels. These units just “magically” change to operating at the new level in response to continuous short term demand fluctuations. Unfortunately for his argument, there is an impact, and this is part of the necessary “cost” of keeping the electricity system in balance. Add wind, especially large quantities, and this effect is magnified significantly. See the following section for more on this.
Kleekamp thus makes two mistakes. The first is extending his conclusions, derived from the specific oil-fueled plants he focuses on, to all fossil fueled plants, and the second is to ignore the impact of the frequent cycling required, which many fossil fueled plants, especially the Mirant Canal plants, are not suitable for.
Finally, why choose oil-fueled electricity plants to make his point? As reported by the EIA, oil-fueled plants account for only 1% of all U.S. electricity generation, admittedly higher (about 5%) in New England, but still not worthy of general conclusions on the subject.
Perhaps the explanation is Kleekamp’s reliance on this to support his questionable argument that electricity generated from oil is the first displaced by wind, and the even more questionable conclusion of meaningful, increased energy independence.
Electricity Market Considerations
The author’s description of the electricity market appears to focus on the day-ahead market, versus the spot market, which is the one that wind largely participates in. Although there are variations, in general the day-ahead market typically provides about 90% of the electricity generation requirements (not one-quarter as Kleekamp suggests) and the spot market is used for final balancing requirements. Wind plant owners typically do not participate in the day-ahead market because this market has an implicit guarantee of availability, which wind cannot provide. In some cases though, wind does participate but is uniquely “excused” for non-delivery in the event of the unavailability of its fuel, wind.
Kleekamp provides a very simplistic (and incorrect) explanation of the operation of the New England electricity market as managed by the ISO NE. He states the following:
“The ISO dispatches generators in the region from an hourly bid stack that starts from the lowest-priced bids (this includes generators that bid $0, such as [wind], hydro, and nuclear units) and progress to higher-priced bids (i.e., from coal, natural gas, and oil fueled generating units) until there is sufficient generation to meet consumers’ demand for each hour of the next day.” (Emphasis added)
Although, based on a general statement in an ISO NE document, Kleekamp has inappropriately altered it by adding wind, admittedly contained in square brackets indicating an edit. Note this ISO NE statement refers to the day ahead electricity market operation and dispatchability. His edit alters the high-level generality of the statement that addresses the general operation of the electricity system, naturally starting with baseload generation sources and progressing further from there.
A source of Kleekam’s error is in attributing dispatchability to wind. True, by mandate wind is used whenever it is available, with an exception that will be described later, but this does not mean that it is dispatched as such. In this context dispatchable means sources of electricity that can be called on at the request of power grid operators (ISOs), that is, it can be turned on or off upon demand. The author persists in his interpretation in the subsequent discussion with a commenter.
Kleekamp then incorrectly claims, based on fuel costs and price alone, that wind replaces oil, natural gas and coal in that order, drawing on the above (edited) quote. Closer investigation reveals different information. The ISO NE responded to a question from a reviewer about what can expected to be backed down in a wind event, and the response was (quote from the reviewer, not from the ISO NE):
At least 500 variables are run in the dispatch model every 5-10 minutes, and there is no way they [ISO NE] could tell us what the system will do. They said, we [ISO NE] can only look at what resources are easiest to back down, and given we have a good supply of pumped storage in the region, and a good supply of gas, as well as a good supply of biomass (which can be backed down some) there is a reasonable chance wind will back down other renewables, or our cleanest source of generation. (Emphasis added)
On the subject of exceptions to taking wind as available, there are times when wind production is not used, known as wind “curtailment”. This usually occurs when wind penetration exceeds a few percent. It is a widespread practice in Germany and is notable in Texas and the UK. Do not be distracted by questionable comments by wind proponents in the referenced articles.
Also not mentioned by the author, is the price paid to wind plant operators for delivery of electricity. Regardless of the price in the auction process, wind is paid at its agreed premium price in any long term Power Purchase Agreement (PPA) it may have. Who pays for the difference? The electricity customers and tax payers in the jurisdiction where the wind plants are situated pay for this.
Kleekamp’s claim that Cape Wind Project PPA will save $4.6 billion based on a study by Charles River Associates has been refuted here.
Also, the argument that long term, fixed price PPAs protect against future price volatility does not withstand scrutiny, especially considering the very high prices in wind plant PPAs (about 20 cents/kWh with escalators for Cape Wind, or many times the going rate in a 20 year contract with escalators). Would you take a 20 year term mortgage on your house at 20% (plus escalators) to protect against future interest rate volatility? Some of his references to prices date from just after the 2005 very high gas price spike.
Whoever the wind production is ultimately sold to will pay the auction price and receive the associated cost benefit. This is what is happening in Denmark for most of the wind produced there. In this connection, it is also notable that in Germany there are cases where some fortunate customers are actually paid to take wind generation, often at night. Readers should be careful not to take this as evidence that wind contributes to lower electricity rates. Although such lower prices may be enjoyed by a few fortunate local customers occasionally, or more frequently by those in other jurisdictions, the “piper must be paid” by all who have the wind plants in their country, state or province.
Is Wind Production the Same as Normal Demand Variation?
The answer is no. This is another area where error is demonstrated by Kleekamp.
There are two distinct changes in normal user demand. The first is the regular daily increase to one (sometimes two) peaks and subsequent reduction as night approaches. This is relatively predictable and is responded to with intermediate generation sources that typically cycle once per day in response. The peaks experienced each day are met by responsive peaking generation units. The author seems to say that these are rarely used “…except for unusually cold winter days or extremely hot summer days…”, which is not correct, and the possible source of this error is explained below. Secondly, there are the short term variations in demand that are balanced by responsive online “spinning” reserves, which provide for this and other contingencies. Again these short term variations are fairly predictable, especially with respect to size.
In addition to spinning reserves, there are other reserves, on a different availability basis, designed to meet (1) extreme weather conditions (the possible source of the error above), (2) replacing spinning reserves committed to meet an unscheduled outage of a single major plant as well as (3) scheduled maintenance.
Because the vagaries of wind production must be responded to with other generation means, it is often considered to be negative demand, versus production. When the random wind production is netted against normal demand, two things occur. The first is that the sum of two such events produces a resulting random event with larger ranges of fluctuations. Further, the wind variations alone have amplitudes that are not predictable and can be larger than the normal demand short term fluctuations. Do not be mislead by the use of statistical analyses over long periods of time, which are a form of averaging that smoothes out this effect.
The net of this is that wind introduces a larger, less predictable net demand that must be continuously met with other generation sources by the system operator, as already indicated. At low wind penetrations, say in the range of 1-2% (in energy terms, that is watt-hours), this might be “manageable” in some cases without undue perturbation or changes. As wind penetration increases this cannot be easily masked and becomes a significant problem, as experienced elsewhere, especially in Denmark and Germany. These two countries, in combination, appear to be able to handle wind penetration of about 7%, albeit with some difficulty, and only due to access to the regulation capabilities of the other Nordic countries, the large hydro power in Norway and Sweden. This actual experience likely represents the upper limit for wind. It is also quite unique because of the availability of very large hydro resources.
The impact of this consideration, and other “schemes” being discussed to mitigate the inclusion of intermittent renewables in electrical systems, are covered in an assessment by the North American Electric Reliability Corporation (NERC). An overview is available here.
Nowhere has actual experience shown that there will be no major impact from wind until it reaches about 20% (in energy not capacity terms). Denmark does produce wind electricity in this range, but must export the majority of it, which is otherwise not manageable. Readers are particularly directed to Part III of this series for more information.
EnerNex Simulation Study
This is one of the studies cited by Kleekamp and is discussed very briefly here, based on an admittedly quick review. It is very comprehensive (Volume 1, 91 pages and Volume 2, 135 pages), involving simulation and considerable statistical averaging over long time periods, of a type which usually misses important points. It was published in 2006 and appears to be based on a previous, also very extensive, EnerNex study (145 pages), published in 2004. Although involving long time series of data for short time intervals, the approach is useful primarily for long-term capacity planning, not short term impacts. Admittedly impressive in scope, this study must be viewed in the light of some of the following statements taken from the Executive Summary (shown in italics), which reveal important considerations as described for each.
- (EnerNex) Wind generation cannot be controlled or precisely predicted. While these attributes are not unique to wind generation, variability of the fuel supply and its associated uncertainty over short time frames are more pronounced than with conventional generation technologies. (emphasis added). This is a considerable understatement. A more realistic statement would be that wind production cannot be predicted for sub-hourly intervals a day, an hour or multiple hours in advance. To suggest that precision is the issue, or that such unpredictability is not unique to wind (true only in a very narrow sense, but not generally attributable to the more common category of non-intermittent sources), is really a stretch. To say that the uncertainty of wind production is merely “more pronounced” than conventional generation technologies is also a considerable stretch of reality. This also applies to any imagined improvement in the accuracy of wind forecasting.
- (EnerNex) If the daily pattern of wind generation matched the daily load cycles, wind generation would likely have no integration cost. It is very difficult to imagine wind matching the daily load cycles. Does this mean the diurnal changes only (this is one of wind’s considerable shortcomings) or are the sub-hourly changes in load included in this statement? To suggest that this is a base case where volatile wind would have no integration cost is another considerable stretch of reality. The same extensive cycling of wind balancing generation plants would still be required.
- (EnerNex) As more wind energy is added, the production cost and load payments decline. This is due to the displacement of conventional generation and the resulting reduction in variable (fuel) costs. The underlying assumption is that reduced electricity production under conditions of frequent and rapid ramping of output shows a direct relationship between electricity production and fuel consumption, which is arguably not the case.
The considerations referred to above indicate that there are likely some important threads running through the study that significantly affect the theoretical results. Sufficiently motivated readers can investigate and decide for themselves.
On a final point, in the use of the term “capacity value”, EnerNex means capacity credit as defined here.
So far Kleekamp has failed to be convincing about the value of wind plants. Part II will address further issues, with a focus on capacity considerations. Part III completes the series covering the costs of nuclear versus wind plants, which disproves his apparent warning about nuclear costs exceeding that of wind.