Porpoises and bombs left by Adolf Hitler's forces six decades ago are adding millions of dollars to costs for wind-turbine developers in waters off Germany, delaying the nation's shift from nuclear energy.

EON AG and RWE AG, the country’s two biggest utilities, are using technologies that reduce noise from driving turbines into the seabed after nature groups complained that the work damages the sonar-like hearing of porpoises. Unexploded mines from World War II also are holding up work.

“A porpoise is doomed to die if its hearing is shattered,” Kim Detloff, a marine expert at German nature conservation group NABU, said in a phone interview. “The regulator must sanction developers if they repeatedly violate the noise limit.”

The concerns show that wind developers are beginning to face the same scrutiny as oil companies for projects in sensitive places, a trend likely to add costs and slim profit margins that already are razor-thin. That adds another hurdle to Chancellor Angela Merkel’s effort to build up offshore wind as an alternative to atomic power, a program that may cost 39 billion euros ($48 billion) by 2020.

“Developing offshore wind in Germany is already more expensive than in other countries as projects are situated further from the coast in deeper waters,” said Fraser Johnston, an analyst at Bloomberg New Energy Finance. “Any additional costs such as delays to grid connections and environmental considerations will put more pressure on already low returns.”

Whale Concerns

Three years ago, Exxon Mobil Corp., BP Plc and OAO Rosneft curbed seismic surveys that map underground rock structures near the Sakhalin Island north of Japan after the wildlife group WWF International said loud noises were disturbing endangered western gray whales.

Marine Current Turbines Ltd., a tidal power company that’s now mostly owned by Siemens AG, faced objections to installing a device similar to an underwater windmill in Northern Ireland because of potential damage to sealife. The company paid for all-day monitoring of seals, porpoises, birds and sharks at the site for three years before the turbine began running in 2008.

In Germany, the government envisions installing 25,000 megawatts of wind turbines offshore by 2030, which may cover an area of the sea eight times the size of New York city.

“Quite a large proportion of our sea area will probably be used for offshore wind farms,” said Hans-Ulrich Rosner, head of the Wadden Sea Office for WWF in Germany. “This will have a serious impact on nature, which needs to be mitigated.”

Underwater Sound

By next month, German utility EWE AG plans to complete work using a sound-reduction system developed by the Dutch engineering company IHC Merwede BV. It’s being installed for the first time commercially on offshore wind turbine foundations at the 108-megawatt Riffgat facility in the North Sea, said Christian Bartsch, a spokesman for EWE.

EWE is placing a double-walled, water-filled steel casing about 11 meters in diameter around the foundation. The system produces a screen of air bubbles to absorb sound. Work started in June. EWE is reducing the intensity and duration of hammering piles into the seabed by using vibrations to seat them in the first 30 meters (98 feet) then driving them in the final 40 meters using traditional methods.

“While developers are generally eager to install foundations as quickly as possible, they’ve come under pressure from regulators and nature groups to protect the porpoise,” Otto von Estorff of the Hamburg University of Technology said by phone on Aug. 14. “No developer wants to be seen harming the environment.”

Government Support

Von Estorff, who heads the university’s modeling and computation institute, is part of a group of scientists that will start measuring noise at the Bard Offshore 1 construction in mid-September in the North Sea. The German Environment Ministry is paying for the project.

Developers are spending about 0.5 percent of a wind farm investment on noise reduction, according to industry specialist Hydrotechnik Luebeck GmbH. It’s one of the factors making German wind farms more costly than ones in the U.K.

German projects are developed at costs of between about 4.2 million euros to 4.4 million euros a megawatt ($5.2 million to $5.4 million a megawatt). That compares with about 3.7 million to 4 million euros for most projects in the U.K., according to New Energy Finance.

Testing Results

“We will soon, possibly in the next two months, receive noise test results that should be of interest to the entire industry,” Bartsch said. “Without these measures work would be faster. A crane-ship costs a lot of money each day. We all agree that we need to do this to protect the animals.”

About 231,000 porpoises, which are smaller and stouter than dolphins, live in the North Sea and Baltic Sea, said Sven Koschinski, a German marine biologist and consultant. The population in the Baltic Sea dropped 60 percent to 11,000 between 1994 and 2005, he said.

Porpoises use clicking sounds to navigate, locate prey and find mating partners. While sea mammals are coping with increased ambient noise from shipping, driving foundations into the ground can produce sudden sounds as loud as 245 decibels that can lead to physical injuries, Koschinski said.

“In the central Baltic Sea, there is a separate stock of only 400 remaining porpoises, and that’s an estimate from 1994 that could be smaller today,” Koschinski said. “Every dead animal there is threatening the survival of the population.”

Reducing Costs

More than two decades after the first wind farm at sea was installed in Denmark in 1991, developers are trying to reduce costs linked to building offshore farms, which in most cases require financing of at least 1 billion euros. Germany plans to install 25,000 megawatts of the turbines by 2030, a program that may cost 39.2 billion euros ($48 billion) by the end of this decade, according to Bloomberg New Energy Finance calculations.

Pile-driving into the seabed isn’t the only threat to animals and developers.

TenneT TSO GmbH, the company linking the Riffgat project to the grid, detected several World War II mines as it prepared to lay cables. The bombs must be recovered or detonated, adding to the costs of the project, said Cornelia Junge, a spokeswoman for the grid operator.

EWE commissioned a screening of its turbine field because weapons were known to have been dumped nearby. All the utility found was waste from ships and households, Bartsch said.

“A screening costs money, but much less than if you’d have to recover or defuse explosives,” he said.

Tons of Bombs

About 1.6 million metric tons of weapons, including naval mines, TNT bombs and artillery shells filled with chemical agents, are estimated to be lying in the German North and Baltic Sea, according to a government-sponsored report released in December. Detonating a 300-kilogram mine can tear the lungs of porpoises 4 kilometers away, Koschinski said.

Germany’s Federal Maritime and Hydrographic Agency, or BSH, has set a noise limit of 160 decibels for 750 meters around offshore wind construction work. Developers regularly overshoot the limit, which is not applied to detonating old bombs, the BSH’s Christian Dahlke said.

“Developers are making major efforts, which cost a lot of money,” Dahlke said by phone from Hamburg. “The problem is that the available technologies are only in the development stages.” He estimates that noise reduction costs developers “at least 5 million euros per project.”

Noise Reduction

Utilities including EON, RWE and Dong Energy A/S spent 3.9 million euros to reduce noise at a project completed in the Baltic Sea last month. While the tests “brought the noise level much closer” to the 160 decibel cap, more research and development is needed “to meet the limit reliably in the future,” RWE said in a statement.

RWE is installing a large hose perforated to produce a curtain of air bubbles around each of the 48 turbine foundations at the Nordsee Ost project. It hopes that will absorb the noise of more than 12,000 blows that will drive the structures 35 meters into the seabed.

Noise mitigation systems cost at least 80,000 euros to 100,000 euros per foundation, said Fabian Wilke, the RWE’s noise reduction expert. The utility is also vibrating the foundations as much as 15 meters into the ground to reduce the number of hammer blows by about 1,000. While the method adds to costs, “we want to do this as we aim to get the best possible results for the environment,” Wilke said.

Strabag SE, central Europe’s biggest builder, in March said it plans to spend more than 100 million euros on a factory in Germany to make concrete foundations that are placed on, rather than driven into the seabed.

“Our regulations are creating a new industry,” Dahlke said. “If environmental rules to protect animal life are tightened in other countries as well, our companies may even export these technologies.”

Lead image: Dolphins verses Oil Rigs via Shutterstock