German Chancellor Angela Merkel said on Thursday she favored the decoupling of gas prices from oil prices, which would promote competition and transparency.

Merkel, who is touring energy sites this week and next to examine current issues, also said she hoped Franco-German energy exchange EEX in Leipzig would become the European Union's main platform for trading power and gas.

"Energy history is being written here, inasmuch as the markets are being made more transparent," she said, supporting the EEX's aim to develop a gas price index independent of oil prices. "This is a further step for more competition."

Continental European gas prices are traditionally tied to those of oil under delivery contracts with countries such as Russia and Norway. But a more active short-term trading market has sprung up of late, helped by a global gas glut and weak demand. Merkel's center-right cabinet plans to make a decision at the end of September on a long-term energy strategy for Germany, mainland Europe's biggest gas market and an important landing and transit destination.

EEX earlier on Thursday said it expected year-on-year volume in its key power futures contract to grow 7.3% to 1,100 terawatt hours this year as it strives to become a European marketplace for a range of fuels.

"It is desirable for Leipzig to play a very dominant role," Merkel said of EEX, which now has 256 trading participants from 22 countries, up from 230 a year ago.