European regulators have launched an enquiry over the power cut that briefly left 10 million people in the dark last week-end. But the outing also raised questions about the grid's ability to cope with the addition of renewable energy sources.

Despite the ongoing liberalisation process, EU electricity markets remain largely national, due in part to lack of interconnection between countries. At their March 2006 summit, EU leaders agreed to increase the level of interconnection in order to make the internal market for electricity a reality.

The aim is to reach "at least 10% of member states' installed production capacity". Financing, they said, should be borne "mainly by the enterprises involved".

A series of seven smaller-sized regional markets for electricity are in the process of being established as a first step towards a truly integrated EU market. Each one is led by a national energy regulator.

The outage that left 10 million Europeans without power on 6 November is still being investigated, but some think that the grid's inability to deal with ever-increasing amounts of wind power might be an explanation. "We don't know whether wind is responsible or not," said Daniel Dobbeni, the President of the European Transmission System Operator (ETSO) at a press conference on large-scale integration of wind energy on 7 November. European Energy Regulators agreed on 7 November to launch "an urgent inquiry" at a European level as to what caused the blackout.

Sir John Mogg, the president of the Council of European Energy Regulators (CEER) said the blackout "demonstrates the need, now more than ever, for an integrated European electricity grid subject to proper regulatory oversight". However, such proposals have so far met with resistance from the member states. At a summit in March this year, they rejected a Commission proposal to introduce a single European energy regulator as "premature".

ETSO President Daniel Dobbeni underlined that a country's choice of energy mix - the share of coal, renewables, nuclear, or other sources it chooses to produce its energy - is an essential element to account for when installing new grid capacity. "Network operators need to know about future decisions concerning the energy mix so that we can design the network accordingly," Dobbeni said.

But according to Claude Turmes MEP (Greens, Luxembourg), the grid is simply ill-adapted to cope with renewable energies. He said future infrastructure investments should "take account of the grid's ability to cope with decentralised power generation" such as that coming from large offshore wind farms or small-scale solar panels installed on private homes.

Grids are currently designed to distribute electricity from centre to periphery. But wind farms or small domestic renewables installations typically follow the opposite route, creating problems when connecting to the network. According to the Commission, "existing electricity grids are not keeping pace with changes within the energy industry," preventing the EU from producing more of its energy from renewable sources. At EU level, research was launched to resolve the issue.

"The situation that Europe faces today is that the fundamental architecture [of electricity networks] is based on the needs of large, mostly carbon-based power generation, which are often distant from the consumers they feed," the Commission said when launching SmarGrids, a European Technology Platform in April this year (EurActiv 7/04/06). "Ultimately the system could be developed so that even individual homes that have their own electricity-generating sources, such as a wind turbine or solar panels, could sell unused power back to the grid," it said. Airtricity, an international renewable energy company operating in the US and Great Britain, says the answer would lie in "a European supergrid" to accommodate large amounts of wind electricity produced from wind farms planned in the North Sea and the Baltic.

"By connecting and integrating geographically disperse wind farms across Europe… electricity is produced wherever the wind is blowing … ensuring a reliable and predictable source of energy," says Airticity. In the UK, the Department of Trade and Industry and the national energy regulator, OFGEM, recently launched a call for evidence to identify barriers to decentralised electricity generation.