The continuing debate over wind power and net emissions

Michael Giberson

We’ve discussed the complicated relationship between wind power and the net reductions in greenhouse gas and other emissions here previously. Industry viewpoints come to expected conclusions – it is no surprise that the Colorado oil and gas industry promotes the view that wind is less special than claimed, nor that the American Wind Energy Association argues wind it better than the oil and gas industry says.

Among the things that makes the issue complicated is that the answer will depend on a lot of factors – the power system that the wind is connected to, what other generators are doing, how the power system chooses to manage wind power’s variability, just how variable the wind power is, and when it is generated. Answers can vary depending on how you frame the question and what data you turn to for analysis.

Into the mess wades F.P. Shioshansi, and he does a pretty good job of sorting through conflicting claims in a post at the EU Energy Policy Blog. For more, Shioshansi recommends Ross Baldick’s article in the recent USAEE Dialogue, “Wind and Energy Markets: A Case Study of Texas.”

Reduced air emissions due to wind power: Not as much as you might think

Michael Giberson

A pair of posts at Master Resource (part I, part II) explore the degree to which variable wind power leads to lower efficiency and increased air emissions when natural gas generators are used to provide energy balancing and back-up reserves (and except when and where sufficient hydropower is available, natural gas generation usually is the low cost provider of these services).  Depending on assumptions, Kent Hawkins finds that adding wind power could result in no reduction of fossil fuel use and perhaps even an increase in related emissions.

The results are more dramatic than found by Warren Katzenstein and Jay Apt and published in Environmental Science & Technology, but the difference is primarily in the degree of the effect and not the nature of the issue.  (Katzenstein and Apt found under certain circumstances that wind and solar power added to a natural gas-based power system acheived about 80 percent of expected CO2 reductions but no more than half of the expected NOx reductions.)

NOTE: Environmental Science & Technology has published a comment on the Katzenstein and Apt article by Andrew Mills and co-authors and then a reply by Katzenstein and Apt.  The Mills et al. comment asserts that the methodology used overstates the need for backup power supplies and so at best indicates a possible upper bound on indirect emissions.  The comment suggests that geographic diversity of widespread wind power facilities helps to smooth out some of the variability from individual sites, so studies based on a few units exaggerate the actual effects in larger power systems.  In addition, unit commitment and dispatch practices by power system operators can accommodate some variability without contributing to added emissions.

In the reply, Katzenstein and Apt say the central issues are, “how are the fill-in generators to be dispatched?” and “what are the emissions from those generators in that dispatch method?”  They note that Mills et al. adopt a different approach than the original article, but with either approach their are incremental emissions associated with the dispatch of the required fill-in generators.

UPDATE: The November/December issue of IEEE’s Power and Energy Magazine is devoted to wind power issues. Included is “Wind Power Myths Debunked,” which claims among other things, “the notion that wind’s variations would actually increase system fuel consumption does not withstand scrutiny.” Unfortunately, subscription required so the link only goes to an abstract. The article also reports another analysis saying that adding up to 20 percent wind may extract an efficiency penalty of no more than 7 percent (i.e., emission reductions may be 7 percent lower than expected).

One thing clear from these discussions is that answers to questions about the effect of wind power on emissions will depend very much on what else is going on on the power system to which the wind power is added.

UPDATE 2009/12/04: Kent Hawkins responds to some of these issues in another post up today at Master Resource.

Flywheel technology now ready for takeoff? NYISO tariff changes accomodate energy storage technology

Michael Giberson

The Federal Energy Regulatory Commission has approved NYISO tariff changes intended to accommodate participation of flywheel and similar energy storage devices in markets to supply frequency regulation services.  Flywheel developer Beacon Power applauded the change.

The FERC order, linked above, describes a number of changes to the NYISO tariff and operating procedures needed for flywheel technology to work economically in the ISO’s markets. Interestingly, some of the changes reflect ways in which flywheel-based services are superior to traditional generator-based provision of frequency regulation service (much faster response, much more finely controlable), some of the changes reflect limitations in flywheel capabilities relative to other suppliers (resources under consideration could sustain service for only 15 minutes), and some of the changes just reflect ways in which flywheels are different (operators want to bid in the regulation market without also bidding in the energy supply market).

In the NYISO, much of the frequency regulation services needed have been provided by hydro units, but some of it is provided by thermal generating units. The rapid small ups-and-downs in generator output necessary to supply frequency regulation from thermal units typically cause the units to use more fuel and emit more pollutants than otherwise. The addition of flywheel technologies to the mix should lead to a small environmental benefit, too, in addition to reducing the overall costs of frequency regulation.

Sorting out some claims about Danish wind power

Michael Giberson

A shortened version of Michael Trebilcock’s commentary on wind power, mentioned here the other day, was published in the Financial Post under the not so subtle title of, “Wind power is a complete disaster.”

The Financial Post subsequently published a reply by Sigurd Lauge Pedersen, a Senior Adviser to the Danish Energy Agency: “Wind power works.”

Trebilcock is back in the Financial Post with “The myth of the Danish green energy ‘miracle’.”

Pedersen begins, “It is perfectly legitimate to hate wind power. But it is more convincing if you do your homework first.” Trebilcock, in his reply, begins by casting aspersions on the Danish government’s sensitivity to criticism of their wind power experience. Both authors have some helpful points to make, but I object to the unnecessarily strident and snide tone of the exchange. (Hey, that’s what blogs are for! -ed.)

If Pedersen had done his homework, say by reviewing the Arthur Campbell paper cited in Trebilcock’s submission to the Ontario Legislative Committee on the Green Energy Act (mentioned in the original op-ed), Pedersen would have realized that claiming wind power raises CO2 emissions is not absurd. Instead it is merely unlikely.

If Trebilcock were more careful, or maybe if he understood wind power better, he’d have avoided the modest non sequitur of, “Most wind turbines run at about 25% of rated capacity, requiring back-up generation for the balance of the time.” No one, so far as I am aware, expects to get a constant 100 percent of nameplate capacity delivered from their wind power (or any other) generation, so what “balance of the time” is he referring to?

It is well known that “facts” circulating in public discourse sometimes stray from their original meaning, so it is sometimes useful to track down sources.  In the continuation I try to sort out two disputed claims made by Trebilcock in his first Financial Post op-ed.

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Martin Feldstein in WSJ on “Tradeable Gasoline Rights”

Lynne Kiesling

Martin Feldstein has a column in today’s WSJ (subscription required) in which he recommends that the government issue tradeable gasoline rights (TGRs) instead of either raising CAFE standards or imposing a gasoline tax.

In a system of tradeable gasoline rights, the government would give each adult a TGR debit card. The gasoline pumps at service stations … would be modified to read these new TGR debit cards… Buying a gallon of gasoline would require using up one tradeable gasoline right as well as paying money.

The government would decide how many gallons of gasoline should be consumed per year and would give out that total number of TGRs. In 2006, Americans will buy about 110 billion gallons of gasoline. To keep that total unchanged in 2007, the government would distribute 110 billion TGRs. To reduce total gasoline consumption by 5%, it would cut the number of TGRs to 104.5 billion.

The government could distribute TGRs to reflect geographic differences in driving patterns. … Businesses that use trucks would also get TGRs.

Feldstein goes on to argue that because they are tradeable, they will provide dispersed benefits to individuals, rather like cap-and-trade pollution markets. I am not convinced. My initial thought was that, notwithstanding the tradeability, this scheme sounds like WWII ration cards, digitally updated. Should the government be in the business of gasoline rationing? Isn’t this option more transaction-cost-laden and prone to political manipulation at state and federal levels (allocations, who sets the cap, where the cap is set, etc.) than a gasoline tax?

I can see his logic, although he doesn’t say it this way in the piece: isn’t a TGR scheme a way to define property rights and then enable parties to trade? But it is so potentially prone to political manipulation, and over such a large number of possible stakeholder organizations, that I think it would distort decision-making enough to generate bad outcomes and entrench special interests. If it’s meant to be a CAFE substitute, why not have a cap-and-trade system that applies to automobile fleets? Could be much less fiddly, much lower in transaction costs. But as stated in his piece, I think Feldstein’s recommendation is too Rococo in its design.

In any case, such a policy has to start from a primary objective: is the primary objective here to reduce emissions, or simply to reduce the use of gasoline? I contend that those different objectives have different policy implications.

Other commentary from Mark Thoma and Brad DeLong. Mark’s post provides substantial quoting from the article, for those without subscriptions. Mark is skeptical, Brad is optimistic. I’m with Mark and would go even further, as above.

UPDATE: see also Greg Mankiw’s comments, which are along the same lines as mine.

Still more from The Glittering Eye and Arnold Kling. Their comments get at both the transaction cost issue and the primary policy objective issue that I raised above.