A Swedish government representative travels to Berlin on Friday to sort out state-owned power supplier Vattenfall's €1.4 billion lawsuit against Germany.

Swedish state-owned Vattenfall, Germany’s fourth- largest power supplier, is on collision course with Germany after a dispute regarding investments in the country.

In April the power supplier brought Germany before the international arbitration body ICSID, International Centre for Settlement of Investment Disputes, an institution of the World Bank group based in Washington, D.C.

The facedown involves an environmental restrictions on the coal-fired power plant Moorburg in Hamburg that Vattenfall begun project in 2004, with the support of the German Christian Democrats.

However, after the 2008 election the Christian Democrats fell out with the Green party and the Moorburg project was hit by restrictions and laid in fallow. The company claims that they have lost some 15 billion kronor (€1.4 billion) due to the inconsistency, according to several media sources.

On Friday Swedish government representative Ola Alterås, undersecretary to Sweden’s Minister for Enterprise and Energy Maud Olofsson, travels to Berlin to meet his German counterpart, daily Dagens Nyheter wrote. He will also meet with Vattenfall in Berlin.

The decision to sue Germany is said to have been made by Vattenfall’s managers without the knowledge of the owner, the Swedish state.

Meanwhile, several non-governmental organizations calls for transparency in the arbitration proceedings. Greenpeace Germany and the World Economy, Ecology and Development organization are pressing the German government to take its decision not to comment or disclose information regarding the Vattenfall arbitration proceedings back.

“This dispute poses a real danger to critical environmental measures and for that reason alone needs to be conducted in an open and transparent manner,” said Juergen Knirsch of Greenpeace Germany, in an interview with Investment treaty news.

Adding to the conflict, hiccups at Swedish Vattenfall's ageing Kruemmel nuclear reactor near Hamburghas enlivened Germany's election campaign, potentially giving the centre-left the chance to chip away at Chancellor Angela Merkel's commanding lead in the polls, AFP writes.

The Kruemmel reactor near Hamburg, one of Germany's oldest, underwent what its Swedish operator Vattenfall called an "emergency shutdown" after a short circuit in one of its transformers.