"The recommendations do not have the quality of a law and they haven't yet been formally adopted into legislation by the German Länder," says Ralf Schlusemann, noise expert at the International Industry Forum for Renewable Energies in Münster. "Stricter practice on noise measurements could help to prevent disputes about noisy turbines arising," he adds.
Press coverage of the noise issue has not helped. In January the Münster Superior Administrative Court ruled that the distance between a wind turbine and the nearest housing had to be at least 950 metres. "The press reported this as a blanket judgement for all turbines when in fact it applied to a single, individual case," says Schlusemann. Meanwhile, news of the recommendations seems to lie behind a sudden rash of reports in both the German and Danish press of growing opposition to wind energy from the German public.
Existing practice in Germany is for the standard noise measurement data for each certified turbine model on the market to be used in all documents relating to the permitting process for specific projects, whether for single turbines or wind farms. The new recommendations, "Noise protection in the licensing procedure for wind turbines," call for a new system. Sound emission should be measured at wind speeds of up to 10 m/s (and not just 8 m/s) and a "safety margin" of 2 dB(A) should be included, they suggest. Failing that, noise emissions must be measured again once the wind plant is operating.
The report's authors, experts from noise protection authorities and test institutes, suggest running a test phase until April 1999, where measurements continue at 8 m/s, but include a safety margin of an additional 3 dB(A), and further noise measurement is conducted after installation.
Among the groups and authorities who have approved the recommendations are environmental authorities in the Länder of Lower Saxony, Schleswig-Holstein, North Rhine Westfalia, Mecklenburg, Hesse, Saxony Anhalt, Brandenburg and Bavaria, as well as the wind turbine testing organisations Windtest Kaiser-Wilhelm-Koog, Deutsches Windenergie Insitut and WindConsult.