Wind farm's radar system stops birds getting the chop

www.guardian.co.uk
Mon, 4 May 09

Texas claims world first in using Nasa technology to spare migrating species

It could be considered an air traffic control system for birds who have flown perilously off course. A windfarm in southern Texas, situated on a flight path used by millions of birds each autumn and spring, is pioneering the use of radar technology to avoid deadly collisions between a 2,500lb rotating blade and bird.

US windfarms kill about 7,000 birds a year, according to a recent study. Other studies of individual windfarms suggest a higher toll on bats and birds, which crash into towers, blades, power lines and other installations. Estimates from a single windfarm in Altamont, California showed as many as 1,300 birds of prey killed each year - or about three a day.

Such direct threats to wildlife, and concern for habitats, have increasingly pitted conservationists against the renewable energy industry. A handful of wind energy projects in the US have been shelved because of wildlife concerns. But it is claimed that radar technology now in use at the Penascal windfarm in Texas has found a balance between competing environmental concerns - taking action against global warming and protecting wildlife - by protecting migrating birds at times of peak danger.

The 202 MW farm, operated by the Spanish firm Iberdrola Renewables, is the first in the world to use radar systems to enable it to shut down automatically if bad weather hits in peak migration times. The installation, which opened late last month, uses radar systems originally developed for Nasa and the US air force to detect approaching birds from as far as four miles away, analyse weather conditions, and then determine whether they are in danger of flying into the rotating blades.

If they are, the turbines are programmed to shut down, restarting once the birds are safely on their way, said Gary Andrews, the chairman of DeTect Inc, the Florida company which developed the technology. The system spots the birds and assesses their altitude, numbers and the visibility. "With all these pieces coming together properly ... the turbines will shut down," said Andrews.

The Penascal windfarm is located on the Central Flyway, a main route for migratory birds in the Americas. Millions of birds funnel through the narrow air corridor during the semi-annual migration. A study in the autumn of 2007 found 4,000 birds an hour passing overhead. More than 30 species of warbler alone fly the route, with water fowl, raptors and hawks.

In ordinary circumstances, the birds would be thousands of feet above the windfarm, passing the turbines without incident. But that can change dramatically in a sudden storm. "The birds may be very vulnerable," said Christopher Shackleford, an ornithologist with the Texas Parks and Wildlife Department. Andrews says his radar systems can avoid such consequences - and the windfarm would be forced to close only between 40 to 60 hours during peak migration times.

But conservationists say that windfarms should still be sited away from migration routes, and that the technology does nothing to solve the problem of installations that disturb bird and animal habitats and nesting grounds. "The bottom line with wind energy is that it has great potential but it must be done correctly," said Doug Inkley. a senior scientist at the National Wildlife Federation.