Brian Handwerk
for National Geographic News

August 25, 2008

Wind turbines can kill bats without touching them by causing a bends-like condition due to rapidly dropping air pressure, new research suggests.

Scientists aren’t sure why, but bats are attracted to the turbines, which often stand 300 feet (90 meters) high and sport 200-foot (60-meter) blades.

The mammals’ curiosity can result in lethal blows by the rotors, which spin at a rate of about 160 miles (260 kilometres) per hour.

But scientist Erin Baerwald and colleagues report that only about half of the bat corpses they found near Alberta, Canada, turbine bases showed any physical evidence of being hit by a blade.

A surprising 90 percent showed signs of internal haemorrhaging-evidence of a drop in air pressure near the blades that causes fatal damage to the bats’ lungs with a condition called barotrauma.

In humans, the condition is related to the bends and can affect divers and airplane passengers during ascents and descents.

The “Bends”

“As a turbine blade goes around, it creates lift-like an airplane’s wings-and there is a small zone of [dropping] pressure, maybe a meter or so in diameter, on the tips of the blades,” explained Baerwald, a doctoral candidate at the University of Calgary, in Alberta.

“Bats fly through this area, and their lungs expand, and the fine capillaries around the edges of the lungs burst.”

The bats’ lungs subsequently fill with fluid, and the animals essentially drown.

“We compare it to divers-they are pretty much dying of the bends,” Baerwald said.

Bats have no natural defence against the unnaturally dramatic pressure changes.

“Bats can actually detect pressure changes, but we’re talking large-scale, relatively slow changes, like the coming of a storm front,” said Baerwald. “This is something entirely different.”

Most bats that fall victim to turbines are migrating species, such as hoary bats, eastern red bats, and silver-haired bats.

There are not enough data to determine how wind turbine fatalities might be affecting populations of these slow-reproducing mammals.

Birds are also killed by blows from wind turbine rotors but their rigid, tubelike lungs can better withstand air pressure changes.

The study appears this week in the journal Current Biology.

Curiosity Killed the Bat

“They are the first to have done a large scale look at this barotrauma,” Bat Conservation International (BCI) biologist Ed Arnett said of the researchers.

“It’s fascinating information,” said Arnett, who is not involved with the study.

“But ultimately it might not matter so much how [the bats] die but what is attracting them to the turbines in the first place.”

Preventing the bat deaths has challenged experts for years.

“We’ve partnered with industry and federal agencies to raise and spend about two million dollars looking for a solution,” said BCI founder and president Merlin Tuttle.

Laurie Jodziewicz, of the American Wind Energy Association in Washington, D.C., said where the turbines are placed may be the key.

“Bats are not being [killed] at all the wind projects all over the country-it is happening in some places and not others,” she said.

“We’re trying to determine before construction what areas might be risky.”

Turbines create drops in pressure drop during normal operations, so the problem could possibly be addressed by changing when the turbines run, according to BCI’s Tuttle.

“A large portion of the kills occur at the lowest wind speeds,” he said, “and at those low speeds [the turbines] are not generating appreciable electricity anyway.”

Bats also are at particular risk during migration periods in late summer and early fall, when many turbine related fatalities occur.

Arnett, Baerwald, and others are currently conducting tests to see if raising the “cut-in” wind speed at which rotors begin to turn will save bats-particularly during peak migration periods.

“It won’t eliminate the problem, but it’s a good step in the right direction,” Tuttle said.

NOTE: About 90 percent of the bats studied suffered from barotrauma. The name of the ailment was restored to this article for clarification purposes after initial publication.

Can anyone hear a cock crow? 

Nuon’s website notes with glee, and we were horrified to hear, that the Brixworth Planning Committee recommended that the Brixworth Parish Council support the Harrington proposal.  Our dismay on hearing the news was the greater when we heard that Nuon had been granted an audience at the Brixworth Planning Committee meeting, when no one from the SNTHWF group was invited.  Furthermore, the planning reasons for opposing a similar development between Brixworth and Hanging Houghton are almost identical on the Harrington site - there are valid objections on matters regarding heritage (in the case of Brixworth the church, and at Harrington the Thor Missile Site); there are valid objections on matters regarding landscape.  We have to wonder, therefore, at the sagacity of Brixworth Planning Committee’s decision and would be interested to know if any of those that gave the reported ‘general assent’ to Nuon’s proposal actually read the Environmental Statement and associated appendices and figures as distinct from just the non-technical summary of the ES and the spin put on it by the Nuon staff whose presentation they heard.

We believe this is yet further reason to ensure that residents who live close to the Harrington site, and others who have an interest in the area, be they walkers, bird watchers, cyclists or horse riders, protect this landscape, the rich heritage, the precious wild life and fight this development by lodging objections with Daventry Planning Department. 

We are pleased to note that the Draughton with Maidwell Parish Council have sent a letter of objection to DDC.  We note that several of the councillors examined the proposal, including the full Environmental Statement, in detail, reporting back to others, and their vote against the proposal was unanimous.

Planning application notices were posted around the site on 9th April.  Members of the public have 21 days from the date of the notices to object.  The current deadline was therefore 30th April 2009, but we understand from the planning office that letters received before the proposal is submitted to the planning committee, and that date is as yet unpublished, will be recorded in the file.  We therefore urge you to make your voice heard - YOU could make a difference!

Financial Post, 08 April, 2009
By Michael J. Trebilcock

There is no evidence that industrial wind power is likely to have a significant impact on carbon emissions. The European experience is instructive. Denmark, the world’s most wind-intensive nation, with more than 6,000 turbines generating 19% of its electricity, has yet to close a single fossil-fuel plant. It requires 50% more coal-generated electricity to cover wind power’s unpredictability, and pollution and carbon dioxide emissions have risen (by 36% in 2006 alone).

Flemming Nissen, the head of development at West Danish generating company ELSAM (one of Denmark’s largest energy utilities) tells us that “wind turbines do not reduce carbon dioxide emissions.” The German experience is no different. Der Spiegel reports that “Germany’s CO2 emissions haven’t been reduced by even a single gram,” and additional coal- and gas-fired plants have been constructed to ensure reliable delivery.

Indeed, recent academic research shows that wind power may actually increase greenhouse gas emissions in some cases, depending on the carbon-intensity of back-up generation required because of its intermittent character. On the negative side of the environmental ledger are adverse impacts of industrial wind turbines on birdlife and other forms of wildlife, farm animals, wetlands and viewsheds.

Industrial wind power is not a viable economic alternative to other energy conservation options. Again, the Danish experience is instructive. Its electricity generation costs are the highest in Europe (15¢/kwh compared to Ontario’s current rate of about 6¢). Niels Gram of the Danish Federation of Industries says, “windmills are a mistake and economically make no sense.” Aase Madsen , the Chair of Energy Policy in the Danish Parliament, calls it “a terribly expensive disaster.”

The U.S. Energy Information Administration reported in 2008, on a dollar per MWh basis, the U.S. government subsidizes wind at $23.34 - compared to reliable energy sources: natural gas at 25¢; coal at 44¢; hydro at 67¢; and nuclear at $1.59, leading to what some U.S. commentators call “a huge corporate welfare feeding frenzy.” The Wall Street Journal advises that “wind generation is the prime example of what can go wrong when the government decides to pick winners.”

The Economist magazine notes in a recent editorial, “Wasting Money on Climate Change,” that each tonne of emissions avoided due to subsidies to renewable energy such as wind power would cost somewhere between $69 and $137, whereas under a cap-and-trade scheme the price would be less than $15.

Either a carbon tax or a cap-and-trade system creates incentives for consumers and producers on a myriad of margins to reduce energy use and emissions that, as these numbers show, completely overwhelm subsidies to renewables in terms of cost effectiveness.

The Ontario Power Authority advises that wind producers will be paid 13.5¢/kwh (more than twice what consumers are currently paying), even without accounting for the additional costs of interconnection, transmission and back-up generation. As the European experience confirms, this will inevitably lead to a dramatic increase in electricity costs with consequent detrimental effects on business and employment. From this perspective, the government’s promise of 55,000 new jobs is a cruel delusion.

A recent detailed analysis (focusing mainly on Spain) finds that for every job created by state-funded support of renewables, particularly wind energy, 2.2 jobs are lost. Each wind industry job created cost almost $2-million in subsidies. Why will the Ontario experience be different?

In debates over climate change, and in particular subsidies to renewable energy, there are two kinds of green. First there are some environmental greens who view the problem as so urgent that all measures that may have some impact on greenhouse gas emissions, whatever their cost or their impact on the economy and employment, should be undertaken immediately.

Then there are the fiscal greens, who, being cool to carbon taxes and cap-and-trade systems that make polluters pay, favour massive public subsidies to themselves for renewable energy projects, whatever their relative impact on greenhouse gas emissions. These two groups are motivated by different kinds of green. The only point of convergence between them is their support for massive subsidies to renewable energy (such as wind turbines).

This unholy alliance of these two kinds of greens (doomsdayers and rent seekers) makes for very effective, if opportunistic, politics (as reflected in the Ontario government’s Green Energy Act), just as it makes for lousy public policy: Politicians attempt to pick winners at our expense in a fast-moving technological landscape, instead of creating a socially efficient set of incentives to which we can all respond.

Financial Post
Michael J. Trebilcock is Professor of Law and Economics, University of Toronto.

Total electricity generation must be equal to total demand second-by-second around the clock and total UK demand varies around the clock, second by second, from middle-of-night base load to peak demand rise when people reach the end of Coronation St and switch electric kettles on almost simultaneously around the nation.
This rapid rise is matched by fossil generating plant, hydro and pumped storage. This is mainly automatic by closed loop monitoring grid frequency (50Hz) which has to be maintained within +/- a small fraction of 1%.Nuclear is not used for frequency control for economic reasons (it shortens the economic life of the fuel, but it can be, and is, used as force majeure). When frequency falls below 50.00Hz, valves open automatically on all fossil plant to increase steam flow to turbine generators, and vice versa. Hydro is also used, but we don’t have much.
Wind generators can only generate what the variable wind provides (within rather tight limits as well. Off design point operation (at lower wind speeds) loses output very fast because wind energy flux varies as (wind speed) cubed. When the wind speed falls or rises, most of the compensation from other generators is fossil-sourced in UK and this standby generation has to be available at all times for grid management. It is set statistically as a strategic fraction of total generation to cover plant failures, and now also, to cover unpredictable wind output. The fossil stations on standby must be ticking over at low load with boilers and turbines primed at high temperature for fast pick-up. At this condition they are operating at very low thermal efficiency with higher atmospheric emissions. As wind generating capacity increases, more fossil stations must operate in this standby mode because the potential fall or rise in wind output to grid increases. Hence, more emissions attributable to wind, which the operators of wind do not pick up the tab for!
Not only that, but we are running out of conventional capacity we can use. The European emissions directive has given fossil plant operators a fixed budget of CO2 (plus other gases), after which they must back fit emission control plant. The operators of such plant then decide that the cost of backfitting is not worth it and shut down their plant for economic reasons. They are using their budget of emissions faster because they are compensating for more and more wind output. This is forcing many of them to review the economics of backfit earlier than they expected. The operators of Cockenzie have already said they will close down as soon as they have used up their emissions ration. This behaviour is accelerating the onset of grid frequency control difficulties. Germany has big problems already.
Grid control experts prescribe a fractional limit of wind as a % of total capacity for sensible grid management, maybe around 40% but expert opinion varies. In the days before electricity privatisation, the CEGB had a statutory duty to maintain grid stability. No single company now has that duty. The new mantra is that market forces will provide (just like it works with banks and pensions).

November 09You can download Newsletters here.  Newsletter 3 describes planning policies and reasons for objecting to the planning application, together with the planning application process.

Newsletter 1:  october-08

Newsletter 2:  december-08

Newsletter 3:  April-09

Newsletter 4:  August 09

Newsletter 5:  November 09