The 30 dirtiest power stations in Europe were responsible for 10 percent of all European Union emissions of the greenhouse gas carbon dioxide in 2006, finds a new analysis issued Thursday by the global conservation group WWF.

The title of dirtiest power stations goes to Greece's Agios Dimitrios and Kardia, owned by DEH, the Public Power Corporation of Greece. They are immediately followed by Niederaussem in Germany, owned by RWE.

"The facts are clear: the power sector needs to phase out dirty coal as soon as possible," said Stephan Singer, head of WWF's European Climate and Energy Unit. "This must be done through an improved EU Emissions Trading System, helping the EU achieve its target of up to 30 percent reduction in emissions by 2020," he said.