Wind turbines - what about the birds and the bats?
The Great Lakes have always played a big role in regional and national energy policy. Their waters have cooled steam condensers for dozens of conventional and nuclear power plants for decades and Lake Ontario's flow has generated many megawatts of power for fifty years at huge hydro dams at the Niagara River and Messina plants. And now in an increasingly crowded part of the country subject to sprawl and summer resort homes, the Great Lakes have something increasingly rare- space without human habitation. People don't like to live near power plants. Wind turbines are small power plants. So unless you are getting paid for the space in your corn field, most people would rather not have one very close to their house. So the spaces of the lakes are of prime interest, and not just because of the NIMBY issue either.
Offshore wind is a reliable source of clean, renewable energy. Unlike on-land winds that can be intermittent, gusty, and inefficient, offshore wind is often more consistent and significantly more powerful. Wind speeds and steady open water winds make for better more profitable power production as does the slightly denser cooler air over the lakes. Cooler air at lower altitudes transmits more energy to the turbines than warmer higher altitude air at a given wind speed.
So proposals for offshore wind farms and shoreline farms are on the rise throughout the Great Lakes. Last spring NYS announced a public private initiative for wind power on Lake Ontario and Erie and at least four wind farms with up to 300 turbines total are being proposed to go in on Prince Edward County's favored cruising grounds for “Titania” and “Sara B”. Unfortunately, it seems that some of these shoreline locations would almost certainly have considerable migrating bird and bat impacts.
Wind farm impacts on birds and bats tend to be location rather than size specific, and the Prince Edward County shore is an area heavily used by birds. One proposed wind farm in particular is not far from the Point Traverse birding area that is ranked as of global importance thanks to fall migration patterns. At that time of year many birds move along the north shore of the lake and when they come to the end of Traverse Point they “stack up” and concentrate on peninsula before they jump off across the water. That shoreline geography concentrates them in the fall just as the south shore is a corridor for spring migrants. In other areas where wind turbines have been built in migration corridors there have been heavy impacts on birds and bats. The construction of the turbines also has potential to impact wetlands and habitat.
Trillium's project slated for the shoals southwest of Main Duck is likely to be the first big offshore wind farm on the lake. The topography, proximity to Lennox generating station grid tie in at the Upper Gap and offshore winds make it a good site for development. According to Watertown Times 142 turbines producing up to 710 MW are planned off Main Duck. That story says they'll be in from six to 130 feet of water and it also says few birds were found during a Trillium funded study.
The article also talks about doing the work off barges and jack up rigs rather than using island. Let's hope. Also it says the wind farm is still a few years away. The 80 meter tower was installed in December 2008 and will gather data for two years, according to one website, so that suggests we might have one more summer without turbines on the horizon here.
In my view wind power is vastly preferable to blowing up mountains, poisoning lakes and other areas with mercury, generating acid rain, and the multitude of other impacts of coal burning. It's also in my view preferable to generating zillions of curies of deadly radioactivity now stashed on the shores of a drinking water supply used by 40 million people, a “resource” that unbalanced people with an agenda could try to use to make their point with a dirty bomb or a direct attack somewhere. And besides being a security issue nuclear plants themselves occasionally have little accidents and even big ones ( I suppose everyone in North America has pretty well forgotten Chernobyl and the subsequent rendering of tens of thousands of acres of land unfit for food production or human habitation for many years to come.) But every form of electrical generation be it from dams, winds, or burning fossil fuel, bio fuel or by fission has impacts. Wind turbines do present problems to birds and bats. In fact one website says that North Carolina is proposing a ban on wind turbines built on high ridges in part because of migration pathways that follow these ridges. A brief survey of the literature shows that offshore and on shore wind farms present different problems for wildlife and that we know almost nothing about bat migration patterns. Some studies hint that bats fly low and use visual sight cues while migrating. This would suggest they might opt to stay along shorelines. But another website states that red, hoary, and silver bats migrate over water. Presumably radar studies were used to find the movements cited between Maine and Nova Scotia over water. And bats have been known to land on and roost on ships at sea ( as I saw birds blown offshore on a November night do on a 1974 Gulf of Maine Cruise aboard Albatross IV).
There is general agreement that bird and bat mortality is strongly location specific so siting studies for wind farms are crucial to bird and bat welfare. And research on land based mortalities is not necessarily applicable to offshore wind farms. The only other generalization I could find is that we just don't know much about bat migration anywhere on land or over water. We do know though that bats don't like to fly on windy nights and that they often fly low near the forest canopy so they would be in range of turbine blades. We also know that waterfowl tend to avoid wind farms pretty readily. But while they may not be at great risk from direct collision and death, their avoidance can deny them access to important habitat as the wind turbines act as a “barrier”. Also offshore turbine foundation structures sometimes can attract fish which in turn attracts fish eaters, birds that are then subject to collision and mortality.
One survey of literature states offshore islands of the Maine seacoast are important staging areas for migrants and should be avoided. And in some areas large numbers of migratory tree bats are turning up dead under turbines with the hoary bat being a frequent fatality. The bats don't actually collide with the turbine blades. It seems that the low pressure vortices around turbine blades blow their lungs out and kill them. While bat migration patterns are not well known one study of Indiana bats in NY and PA hints that they may follow ridge tops and that they use cleared forest paths such as utility power and gas line right of way areas.
A literature survey for Maine Seacoast wind farm impacts posted on line as a power point states that birds fly lower over water than land and that they also fly lower with headwinds, darker nights and with precipitation. It also states that careful radar surveys to locate localized reasonably consistent migration pathways can considerably reduce bird and bat deaths as often just a few turbines on a wind farm account for most of the mortalities. Animals can also be saved by shutting the turbines down during time of poor visibility, mist drizzle etc when radar surveys detect migrants. Also minimal lighting of the towers and using white rather than red is suggested to help birds avoid the towers. An interesting technology being sold by DeTect a Florida based corporation might also help reduce mortalities. The company offers a variety of bird and bat radar systems that their website says are in use in a number of North American and European locations. Their Merlin Avian Radar was originally developed for Air Force and NASA to reduce bird aircraft collisions. With appropriate software the radar can detect oncoming migrants and automatically shut one or more wind turbines down. The website http://www.detect-inc.com/wind.html states that over 50 systems are in use. It includes a photo of a remotely controlled solar powered system in use at a Netherlands offshore wind farm. They company even offers a radar system that can offer species identification and distribution information using wing beat frequencies for birds, bats, and insects! So there might be ways to at least reduce if not eliminate mortalities at wind farms. The problem is cost. Science Friday on NPR ran a story that cited a trial at a 15 turbine farm. The operators turned all their turbines off during low wind nights while the bats were migrating and experienced a cost of around 3 to 4000 dollars per month. It worked out to about 200 to 266 $ per turbine. Considering the amount of power produced during low wind nights, the limited migration period, and the number of customers, this seems like a pretty reasonable per household cost.
Back in the 1980's rising concern over the impact of nuclear generating station water use on Lake Ontario prompted the regulators to require a large expensive cooling tower be built for Nine Mile 2. The increased entrainment of plankton that was subsequently cooked in the condensers and the cumulative impact of the thermal pollution from a third plant on Mexico Bay where already two big nukes were dumping heated water justified a few pennies per household on the electric bill. Could we likewise require rigorous siting studies and perhaps early warning system radars on large wind farms in critical migration corridors? At the very least we should be requiring the wind farm operators to do good radar surveys of the area for bird and bat traffic before they build. According to one Canadian observer this is not presently being done.
How much is a loon's wild call out on the lake worth? What is the value of a bat's life? And how much more incremental stress can we keep adding to the difficulties already experienced by migrants in an increasingly crowded human dominated landscape? I know the mosquitoes won't miss the bats and night hawks after they're all gone!