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A conference on the impact on the ecology of offshore wind power stations was left wondering why so much effort is expected of the wind industry in the way of environmental assessment -- and so little of other offshore industries -- when the evidence so far indicates that marine life is little affected by wind turbines

Marine life gets along well with offshore wind power. Not only do wind turbines installed at sea pose no danger to birds, fish and aquatic mammals, these creatures thrive in their presence. For the 200 delegates at September's Offshore Wind Farms and the Environment (OWFE) conference in Denmark this was the news they were hoping to hear -- and in good part their hopes were met. The bad news, however, is that it is much too early to draw such generalised conclusions about the effect of wind power stations on the marine ecology.

The conference marked a midterm assessment of the extensive, government-led, environmental monitoring programs at Denmark's two large offshore wind demonstration projects: the 160 MW Horns Reef plant off the west coast of Jutland in the North Sea and the 165 MW Nysted facility in the Baltic Sea just south of Lolland-Falster. Environmental studies must be carried out at the two wind plant from 1999-2006 under the terms for construction laid down by the Danish authorities. Horns Reef has been online since autumn 2002 and Nysted was finished last year, with the result that there has been little time as yet to gather post-construction data.

The conference, held at Billund, was organised by the monitoring program steering group, which consists of the Danish Forest and Nature Agency and the government energy agency, along with utilities Elsam and Energi E2, the respective owners of Horns Reef and Nysted. Many of the participants were offshore project developers or service suppliers to the wind industry. Others included power company representatives, researchers and environmentalists, mainly from Denmark, Germany and the United Kingdom. Sweden, the Netherlands, France, and the United States were represented, too.

Dynamic

The atmosphere at OWFE was dynamic -- question and answer sessions were lively -- and the mix of people was different than the usual abundance of testosterone found at most wind industry gatherings; women were well in evidence. While economics and technical capability are major factors in going offshore, the worries of governments -- and those of the public -- about the potential environmental impact on marine life have introduced a whole new dimension to the offshore business scene.

"People are screaming for results," said Ib Krag Petersen of the Danish National Environmental Research Institute (NERI). Petersen is part of the biologist team studying birds at Horns Reef. While NERI's mid-term reports on the topic have been positive so far, Petersen says it is simply too early to draw conclusions. "We just need to get time enough to get solid cumulative data. We're in a situation where there is still a large amount of human activity in the area -- it's like a continued construction period," he added, referring to the major Vestas retrofit program that brought ships and cranes back out to the Horns Reef site this summer to remove, repair, and re-install all the turbines (“uåX˜äŠÊ˜·³Ç, September 2004).

More research

Birds and their interrelation with offshore wind turbines is one of the most worrisome issues for the industry. In the UK, the Royal Society for the Protection of Birds (RSPB) has widely publicised its concerns about the effect that 90 planned turbines might have on the large numbers of common scoter at Shell Flats in the Irish Sea, with delays to the progress of the project as a result. The site's three developers, Shell Renewables, Elsam and ScottishPower, are going to great lengths to deal with the concerns of RSPB and others (“uåX˜äŠÊ˜·³Ç, October 2004).

According to research, however, more solid data is needed before the industry can put its worries to rest or deal with any problems. From Denmark's NERI, Mark Desholm told delegates that a minimum of three years of post-construction monitoring is needed before conclusions can be drawn from comparisons of initial baseline studies at Horns Reef and Nysted.

"One of the warning signs from a conservationist's perspective is that many offshore wind farms are constructed in shallow water," said Robert Furness, a seabird ecology professor from the University of Glasgow and chairman of the Danish government's international advisory panel for offshore wind development. This water depth also happens to be an ideal environment for many species of birds, he adds, such as scoters and eider ducks. So loss of habitat and collision risk are two main issues. "There is a potential major impact, but this is still unclear."

What Furness and other marine biologists noted, however, is that the biggest unknown environmental issue for offshore wind plant is their cumulative effect. "One wind farm may not impact a bird population, but a lot of wind farms might," he said. "From my perspective, we still don't know any of the answers."

Bird and seal habits

Initial research results have been mostly positive. While most passing bird flocks fly around the two Danish wind farms, some fly directly through it and even take a break and use the platforms on the turbines as overnight resting stops. No observations have been made of actual bird-turbine collisions -- in fact, flocks that entered both wind farms tended to fly between rows, equidistant from adjacent turbines. NERI's observations at both wind farms, however, show that fewer scoter, long-tailed duck and eider have come into the areas to feed than before the wind farms were built.

Another topic of particular interest to many delegates was the effect on seal behaviour of the Nysted facility. The Nysted turbines lie only four kilometres from the Rødsand seal sanctuary. With aerial surveys, satellite tracking and nifty remote-video monitoring of the grey and harbour seals, NERI had good news -- so far. "There has definitely not been a decrease in seals," said NERI's Susi Edrén. In addition to an increase in population, two grey seal pups were born at the sanctuary -- the first recorded births of this species in Denmark in several decades. "The most interesting aspect is that this happened during the construction of the wind farm," said Edrén. "They travel from far away and despite the fact that they have alternative breeding sites they chose Rødsand during construction."

Increased seal presence is possibly due to the wind farm's new role as an artificial reef -- a point of considerable debate at OWFE. While Simon Lenhardt of Danish BioConsult A/S said the find of several new invertebrate species at Nysted is "surprising," the jury is still out on whether this can be considered good or bad. Anne-Grete Ragborg of the Danish Forest and Nature Agency pointed out that the EU Habitat Directive protects the sandbanks at Nysted and Horns Reef; introduction of new species, which forces a new element of survival for existing creatures, does not jibe well with the directive's purposes.

Reinventing the wheel

Furness was not the only person who noted a severe case of "reinventing the wheel" among governments and research programs. "One of the mistakes of the wind industry is a lack of international co-operation over monitoring programs," Furness said. "There's a tendency for each country to carry out its own studies. I recently heard that the UK is starting studies of scoters rather than coming to Denmark and listening to these presentations. And I've heard the same with Germany. It's the same species of duck in each country," he admonished in undisguised exasperation. "They fly the same height in Denmark as they do in Germany and the UK."

Despite his frustration, recognition among delegates of the work being undertaken in Denmark was clear. There were many kind words for the Danes and their environmental monitoring programs, which are overseen by the steering group, six non-governmental organisations, and an international advisory panel of experts on marine ecology. Indeed, researchers in Denmark are doing groundbreaking work in environmental monitoring of offshore wind installations. From real-time video feeds, to acoustic porpoise detectors, to methods that even include the use of old satellite spy photos -- the Danes are leading the pack in innovation.

Relative risk

Marine life monitoring, however, was revealed at the conference as yet another area where the wind industry is putting a lot more effort and investment into protecting the environment than competing industries have ever done. Why must the wind industry shoulder such expense when the oil and gas, or sand and gravel extraction industries, to name just some, seemingly do not? And when will enough be enough?

"I think we're getting to the point where governments need to have relative scale of risk assessment," said Bonnie Ram of Energetics Inc, a consultant to the US Department of Energy. "It should all come down to relative impacts to the marine environment. There's a lot of action in the North Sea here. What about the oil and gas companies in the North Sea? What's the relative risk of operating offshore wind turbines compared to other energy facilities offshore?" she asks, with particular reference to liquefied natural gas (LNG) terminals. "How do we balance the uncertainties with the pressure to diversify energy sources?" Ram added that in the Gulf of Mexico, LNGs are sending their drills thousands of feet downward. "That's scary to me. And here they're worried about what happens to worms in the sandy seabed? I believe we need to level the playing field."

Another perspective on the theme of relative risk came from Magnus Wahlberg, a marine biologist at the Danish University of Århus. He researches the effects of manmade noise on marine life. Studying the noise from offshore wind turbines versus that from ships, he said, is like studying the difference of noise at an airport versus that from a person mowing the lawn on an archipelago. "We did a study in Sweden on offshore wind turbine noise," he said. "We had to stop our measurements every time a boat passed."

Driving the piles for offshore turbine foundations -- as was done at Horns Reef and for only one pile at Nysted -- is indeed very loud, but it is over a short period in the construction phase, he added. "I think this windmill thing is not really important. But there are still so many unknowns."

The final environmental impact assessment report on offshore wind power stations in Denmark will be available when the program ends in 2006.