Problems with Europe's nuclear plants have raised worries just as the energy was gaining support.
Summer is exposing the chinks in Europe's nuclear power networks.
The extended heat wave in July aggravated drought conditions across much of Europe, lowering water levels in the lakes and rivers that many nuclear plants depend on to cool their reactors.
As a result, utility companies in France, Spain, and Germany were forced to take some plants offline and reduce operations at others. Across Western Europe, nuclear plants also had to secure exemptions from regulations in order to discharge overheated water into the environment.Even with an exemption to environmental rules this summer, the French electric company, Electricité de France (EDF), normally an energy exporter, had to buy electricity on European spot market, a way to meet electricity demand.
The troubles of the nuclear industry did not end there. Sweden shut four of its 10 nuclear reactors after a short-circuit cut power at one plant on July 26, raising fears of a dangerous design flaw. One week later, Czech utility officials shut down one of the country's six nuclear reactors because of what they described as a serious mechanical problem that led to the leak of radioactive water.
The disruptions highlight some of the vulnerabilities of nuclear power, just at a time when its future was looking brighter in traditionally nuclear-shy parts of Europe. British Prime Minister Tony Blair, for example, has just launched a drive to promote nuclear as the key to making his country self-sufficient in energy.
But antinuclear activists have seized on nuclear plants' summer troubles as evidence of the energy's limitations.
Austrian protesters, including politicians, have demanded that the Czech reactor – which is located just over the border – be closed. In Germany, influential antinuclear groups reacted to Sweden's closures by calling for the closure of the country's 17 reactors, many of the same design.
"Global warming undermines the arguments we've always heard about nuclear power, that it doesn't damage the environment," says Stéphane Lhomme, spokesman for a French group, Sortir du Nucléaire, or Abandon Nuclear. "Nuclear is not saving us from climate change. It's in trouble because of climate change."
His argument may have more resonance in France than elsewhere because, with 58 reactors, France depends on nuclear energy for 80 percent of its electricity and is criticized by some for failing to diversify its energy resources.
Concerns about global warming are central to the debate in European countries over energy. And this summer's heat wave and droughts, like those in 2003, have added a new and possibly confusing element to that debate.
Nuclear power is promoted as a clean alternative to oil and coal-powered generators that produce greenhouse gases like carbon monoxide, blamed by many scientists for warming the earth's surface and melting polar ice caps.
Public opinion seems to be increasingly open to that argument for nuclear power.
A 2005 European Union poll found 62 percent of those surveyed accepted the advantage of lowering greenhouse gas emissions, compared to 41 percent two years ago. And 60 percent acknowledged the benefits of nuclear power as a climate-friendly way to reduce dependence on oil.
There are vast differences from country to country, though, over whether to invest in new nuclear power technology or even replace aging reactors. Finland is building a giant new nuclear reactor, the first in Europe in 15 years.
In France,the government plans to build a new pressurized-water nuclear reactor by 2010. And in England, where opposition to nuclear plants has been intense, climate change worries may trump antinuclear feeling.
"The jury is still out," says Simon Tilford, an analyst with the Centre for European Reform in London, where the summer heat brought scattered blackouts. "But I think the government has had some success at turning public opinion around because they argued the environmental case."
There are vast differences from country to country, though, over whether to invest in new nuclear power technology or even replace aging reactors.
Finland is building a giant new nuclear reactor, the first in Europe in 15 years. In France,the government plans to build a new pressurized-water nuclear reactor by 2010. And in England, where opposition to nuclear plants has been intense, climate change worries may trump antinuclear feeling.
A recently published assessment by the European Environment Agency warned that Europe could expect more of the extreme weather shifts that it has experienced over the last five years without reductions in greenhouse gases.
Europe's four hottest years on record, the agency said, were 1998, 2002, 2003, and 2004. It did not account for this year's weather.
Overall, about one-third of all water used in Europe is used for cooling electrical generators, including those powered by both nuclear and fossil fuels. Environmental officials in several European countries, including France and Germany, have warned that water levels in some reservoirs are at historic lows and have not returned to pre-2003 heat wave levels.
The power plants now used in Europe are big water consumers. Technological advances have made generators more efficient. But European utility companies have been hesitant to invest in new plants because they are not sure how deeply European governments will make them cut greenhouse gas emissions, according to a study just released by Chatham House, a think tank in London.
The more immediate question in most countries is how much to spend on repairing aging electricity-generating plants, most of them located near shrinking water reserves. About two-thirds of the energy produced in a generator is converted into heated thermal waste water, says Michael Sailer, a researcher at the Institute for Applied Ecology.
"The problem affects both nuclear plants and coal-fired plants," says Sailer.
Older-generation nuclear plants require somewhat more water for cooling, however, so nuclear-dependent countries like France are right to start worrying. It's the second hot summer after 2003, he adds. If they have more, they will have a problem.
Anti-nuclear campaigners say that this summer's problems at European reactors are here to stay. Even if you have one new plant that supposedly is better, says Mr. Lhomme, you still have 58 others [in France] that make the same problems.