LONDON - The volume of electricity derivatives traded on the German EEX energy exchange fell 11 per cent last year as traders grew reluctant to take long-term positions amid uncertainty in the markets, the bourse said on Thursday.

A total of 1,075 terawatt-hours (TWh) of power derivatives were traded on the exchange in 2011, compared with 1,208 TWh the previous year.

"The volume traded on the power derivatives market in 2011 reduced ... by 11 per cent since the participants' willingness to establish long-term positions declined in the uncertain energy trading environment," the exchange said in a statement.

Dutch rival APX-Endex also said on Thursday its Dutch power derivatives volumes were declining, with a 58 per cent year-on-year drop to 28.4 TWh in cleared and traded deals, but it disagreed on the explanation.

"The convergence in western European power prices is driving down volumes, not a reluctance to take long-term positions," said Bert den Ouden, chief executive of Amsterdam-headquartered APX-Endex.

The German, French, Dutch and Belgian power markets have been coupled since late 2010, a mechanism whereby power flows from a cheaper to a more expensive market to create a harmonised regional price. Market prices in the central-western European region converged 66 per cent of the time in 2011, APX-Endex said.

Short-term power trading on the EPEX Spot exchange, which the EEX created together with French rival Powernext in 2009, rose 13 per cent last year and trading in the Dutch day-ahead auction run by APX-Endex also rose.

The Leipzig-based EEX bourse said it expected the concentration on short-term trading to continue as the share of renewable energy sources grows. All wind power generated in Germany is traded, and grid operators have to prioritise the use of green energy over electricity produced from traditional plants.

Chief executive Peter Reitz said earlier this week he counted on natural gas as a future growth market for the German EEX exchange.

Exchange-based gas trading in Germany, Europe's second-biggest gas market after Britain, was introduced five years ago and is still small relative to its usage of over 900 TWh.