After a protracted period of negotiation, Dusseldorf-based energy heavyweight E.ON has finally clinched an agreement to take a 25% minus one share stake in the giant Yuzhno-Russkoye gas field in Siberia.

The field, which has reserves of over 700 billion cubic meters, is set to provide a key source of gas to flow through the North European Gas Pipeline, a Gazprom-led project currently under construction. The NEGP, in which E.ON also has a stake, controversially pipes gas from the Russian steppe to Germany via the Baltic Sea, avoiding the traditional overland routes through Ukraine and Poland.

In return for the stake in the field, Gazprom is receiving minority interests of 50% minus one share in the Hungarian gas companies E.ON Foldgaz Storage and E.ON Foldgaz Trade, a stake of 25% plus one share in the regional power and gas supplier E.ON Hungaria and a compensation still to be quantified, the firms said in a statement.

In addition, E.ON and Gazprom have agreed to work together on specific gas-fired power station projects in Europe.