Joined by the European energy commissioner, EU Commission head Jose Manuel Barroso chided European countries for being too nationalistic in the energy sector, and not working hard enough to find a common EU approach to the continent's approaching energy crisis.

"The energy challenges of the 21st century require a common EU response," said Barroso at the press conference introducing the report on Wednesday.

The EU had called for the report after a gas dispute between Russia and Ukraine caused energy shortages in Europe in January. Eastern European countries, but also major EU players like Germany, are heavily reliant on Russian natural gas, with Algeria and Norway also important providers.

Nationalism an energy problem

At the moment, 50 percent of the EU's energy use is dependent on energy imports. By 2030, according to the report, that figure could rise to 70 percent and require more than 1 trillion euros of investment in infrastructure. Though Europe is a champion of alternative energies and low-emissions cars, the report accuses the continent of not working hard enough to integrate its utility markets and increase competition among energy providers fighting for Europe's 450 million consumers.

"We should refuse nationalism of an economic kind, especially in the energy sector in Europe," said Barroso.

The comments came on the heels of German utilities company E.On's failed takeover of Spain's Endesa and the government-engineered merger of Gaz de France and Suez, which scared off Italy's Enel. The EU Commission has asked Spain and France for explanations on the failed takeover bids, but the Greens in the European Parliament criticized the report for not taking a harder line on the energy "oligopoly" in Europe.

"The current surge in mergers risks concentrating EU energy provision in the hands of a small oligopoly of energy behemoths to the detriment of the EU economy and consumers across Europe," said Claude Turmes, vice-president of the Greens/European Free Alliance in the EU Parliament in a statement. "Protectionism is not the answer."

A plea for more efficient energy use

His party also criticized the EU for placing too much emphasis on securing current energy supplies, rather than searching for more efficient uses of energy. They point out that in 2005, 96 percent of energy use in the transportation sector stemmed from oil.

"We cannot reduce our oil dependency without tackling our oil-guzzling transport sector," Turmes said.

The report foresees increased reliance in alternative energies and calls for more innovation, especially in the development of low-carbon fuels. NGOs like Greenpeace urged the EU to hold the 25 member states to pledges that demand 20 percent of energy use from alternative fuels by 2020. Alternatives such as wind and solar power are gaining ground in countries like Germany, but Barroso said that every possibility -- including nuclear energy -- should be considered in the attempt to diversify Europe's supply.

Meeting with Russia on gas reliance

"We do not have the luxury of promoting one energy source to the exclusion of others," he wrote in a statement with European Commissioner of Energy Andris Piebalgs printed in the International Herald Tribune.

Barroso has called for a "debate without taboos" and EU chiefs will get the opportunity to do just that at an upcoming summit on March 23 and 24th.

A week before EU leaders meet, Barroso will travel to Moscow to discuss Europe's energy reliance with Russian President Vladimir Putin.

"Our approach is to engage constructively with our Russian partners, and that is the message I'm going to give," he said.

Around 25 percent of the European Union's gas supply comes from Russia.