wind speeds

Wind turbines and bats

October 31, 2023 By EarthWise Leave a Comment

Collisions with wind turbines are one of the leading causes of bat mortality in North America and Europe. Most bat fatalities are caused by bats colliding with the rotating blades of wind turbines. Fatalities are highest during autumn migration and on nights with low wind speeds.

According to a recent study, land-based wind turbines kill as many as 880,000 bats a year and are wiping out so many threatened bats that some species may become endangered unless preventative action is taken.

The big challenge is that bat conservation experts and scientists don’t know how to stop or reduce turbine collisions. They don’t really know why bats are interacting with turbines to the extent that they are. Do turbines attract bats? Do turbines’ bright lights or just their silhouettes stimulate an attraction response?

The U.S. Department of Energy has awarded $8 million to five research centers to develop strategies for deterring bats from wind turbines.

One of these is Bat Conservation International, which is an organization whose mission is to accelerate research to address knowledge gaps in bat ecology and behavior and develop technologies and industry methods to reduce fatality of bats at wind farms. Among the approaches to be tested is limiting the use of nighttime lighting on wind farms to make migrating bats less likely to fly through blades.

Another team at Boise State University is designing ultrasonic noisemakers to scare off bats.

In announcing the new program, the Department of Energy states that wind energy must be appropriately and responsibly sited, which includes the protection of wildlife and their habitats.

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Experts Seek to Spare Bats From Wind Turbine Collisions

Photo, posted January 10, 2013, courtesy of Tom Shockey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reef Insurance | Earth Wise

January 4, 2023 By EarthWise Leave a Comment

Coral reefs around the world face multiple dangers from warming waters, acidification, human activity, and more. Powerful storms often cause tremendous damage to reefs. When possible, snorkelers and divers are deployed to try to repair damage to reefs. But philanthropy and government grants are basically the only resources available to fund such actions.

Three years ago, tourist businesses and the government in the Mexican state of Quintana Roo purchased an insurance policy to offset costs of protecting the local parts of the Mesoamerican Reef. The environmental group the MAR Fund later took out an insurance policy on the rest of the reef in Mexico, Belize, Guatemala, and Honduras.

With this precedent, the Nature Conservancy recently purchased an insurance policy on behalf of the state of Hawaii to help offset repair work on its coral reefs. It is the first U.S. coral insurance contract.

Coral reefs are more than just hosts for marine life. They provide barriers against ocean storm surges, which is a major financial incentive for protecting them and hence an incentive to invest in insurance.

The new Hawaiian insurance policy has a premium of $110,000 a year and will provide $2 million in protection. Payouts occur when wind speeds go above 50 knots. No further proof of damage is required.

The Nature Conservancy has created teams called ‘Reef Brigades’ composed of snorkelers and divers who recover reef fragments, store them in ocean or shore-based nurseries, and then re-attach them when conditions are safe. It can be very expensive to do this sort of work, particularly when new corals grown in a nursery are required.

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Analysis: First U.S. coral insurance marks the rise of the reef brigades

Photo, posted September 14, 2011, courtesy of Greg McFall/NOAA Office of National Marine Sanctuaries via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global Stilling | Earth Wise

October 20, 2022 By EarthWise Leave a Comment

During the summer of 2021, much of Europe experienced a “wind drought” – wind speeds in many places were about 15% below average. In the UK in particular, winds were unusually calm and wind energy production was dramatically reduced.

Globally, wind speeds have been dropping by about 2.3% per decade since the 1970s. In 2019, however, global average windspeeds actually increased by about 6%. The question is whether a trend of slowing winds – so-called global stilling – is associated with climate change or is just natural variability in action.

Wind results from uneven temperatures in air masses. Much of the world’s wind comes from the difference between the cold air at the poles and the warm air at the tropics. Because the Arctic is warming much faster than the tropics, it is possible that winds will continue to decline around the world.

Another factor people cite is the increase in surface roughness. The number and size of urban buildings continues to increase, which acts as a drag on winds.

Some models predict that wind speeds will decrease over much of the western U.S. and East Coast, but the central U.S. will see an increase. Experts do not all agree about what is happening with global winds. Many believe that the observed changes to date have been within the range of variability. Furthermore, some places have been windier than usual.

All of this really matters for many reasons. Europe is increasingly dependent upon wind power as an alternative to fossil fuels. A 10% drop in wind speed results in a 30% drop in energy generation. Whatever their cause may be, wind droughts cannot be ignored.

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Global ‘Stilling’: Is Climate Change Slowing Down the Wind?

Photo, posted June 28, 2008, courtesy of Patrick Finnegan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wind Farms Slowing Each Other Down | Earth Wise

July 13, 2021 By EarthWise Leave a Comment

Offshore wind is booming in Europe. The expansion of wind energy in the German Bight and Baltic Sea has been especially dramatic. At this point, there are about 8 gigawatts of wind turbines in German waters, the equivalent of about 8 nuclear power plants. But space in this region is limited so that wind farms are sometimes built very close to one another.

A team of researchers from the Helmholtz Center Hereon, a major German research institute, has found that wind speeds downstream from large windfarms are significantly slowed down. In a study published in the journal Nature Scientific Reports, they found that this braking effect can result in astonishingly large-scale lowering of wind speeds.

On average, the regions of lowered wind can extend 20-30 miles and, under certain weather conditions, can even extend up to 60 miles. As a result, the output of a neighboring wind farm located within this distance can be reduced by 20 to 25 percent.

These wake effects are weather dependent. During stable weather conditions, which are typically the case in the spring in German waters, the effects can be especially large. During stormy times, such as in November and December, the atmosphere is so mixed that the wind farm wake effects are relatively small.

Based on their modeling, it is clear that if wind farms are planned to be located close together, these wake effects need to be taken into account. The researchers next want to investigate the effects that reduced wind speeds have on life in the sea. Ocean winds affect salt and oxygen content, temperatures, and nutrients in the water. It is important to find out how reduced winds might affect marine ecosystems.

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Are wind farms slowing each other down?

Photo, posted November 23, 2011, courtesy of David J Laporte via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wind Farms And Ordinary Farms

January 18, 2017 By EarthWise

Farmers in many places have found additional sources of income by allowing wind turbines to be built on their land. One example is the Amazon Wind Farm, which is a massive project of over 100 turbines near Elizabeth City, North Carolina. The 494-foot tall turbine towers scattered over 34 square miles are rising up above farms that grow corn, wheat and soybeans. It is the first utility-scale wind farm in the Southeast.