EU member states have been granted an opt-out from efficiency plans that would force energy companies to make savings among final customers of 1.5% a year.
"Our proposal aims at making the way we use energy in our daily life more efficient," EU Energy Commissioner Günther Oettinger said in a statement.
It would also "lead to a reduced energy bill," he said.
Climate Commissioner Connie Hedegaard went further, hailing an "important day for European climate policy" after years of failure to meet EU efficiency targets.
"If member states follow the Commission's proposal, that will now change," she added.
A wave of criticism
But environmentalists were dismayed at proposals allowing EU states to "opt to take other measures to achieve energy savings among final customers" than compelling efficiency savings.
"There will be no changes to company business models now," the World Wildlife Fund's Arianna Vitali told EURACTIV, "and no clear way of proving that actions taken by member states are additional to what they would have done anyway".
"It is a big disappointment," she continued.
The opt-out is believed to have been agreed under pressure from Germany and Sweden.
According to figures compiled by Friends of the Earth, even a fully implemented 1.5% energy savings obligation would only recoup energy worth at most 12 Million tonnes of oil equivalent (Mtoe) in its first year.
The EU is committed to reaching annual savings of 368 Mtoe by 2020.
In 2009, EU member states committed to meet three targets for 2020: a 20% cut in emissions reductions, a 20% rise in the share of renewables in the energy mix, and a 20% cut in energy consumption, all on 1990 levels.
But the efficiency pledge was voluntary, and it is the only one that Europe is on track to miss.
"I don't think it is a coincidence that we are on track when it comes to the binding  renewables target but not on the non-binding energy efficiency target," Commissioner Hedegaard told a UN conference last week.
Energy savings are profitable in the long term but also require capital outlays that can put firms at a short-term competitive disadvantage. As a result, enterprises and environmentalists have both looked to Brussels to level the playing field.
However, Randall Bowie, an energy consultant for Rockwool who has designed past EU efficiency directives, said that this one had "missed an opportunity" by trying to cover all objections anticipated at the Council of Ministers.
"When you start from a weak level, you risk going to a weaker level in the Council discussions," he told EURACTIV. "Normally you start from a strong and ambitious proposal and argue to keep it. You don't give in before the discussions even start."
Public procurement opt-outs
He complained that the EU had also rowed back on proposals to force member states to refurbish 3% of all public buildings – 12% of Europe's building stock – for heat loss.
Opt-outs from the proposal will be given to social housing, and buildings under 250 square metres, such as post offices.
Renovations will also only be carried out to 'minimum energy performance requirements' rather than the 'best practice' standards previously mooted.
"They left out the quality of the measures needed," Bowie said, "and there is a real risk that member states may meet their obligations with short-term cherry-picking measures, instead of longer-term deep renovations, where the real savings potential lies."
Vitali agreed that this was the directive's "black spot".
Cost effectiveness and economic criteria were also added to the public procurement provisions.
But the European Commission's energy and climate departments (DGs) buried the hatchet in a long-running dispute over which should implement energy efficiency measures against big industry.
In a compromise deal, industrial installations already covered by the Emissions Trading Scheme (ETS) will now also be covered by the new directive.
The European Commission will monitor the situation to ensure that carbon prices do not collapse as a result.
If necessary, Brussels would consider "recalibrating the ETS by setting aside a corresponding number of allowances from the part to be auctioned during the period 2013-2020, should a corresponding political decision be taken".
EURACTIV understands that such a move could come in the form of a regulation or co-decision.
One official at DG Climate hailed the deal as a success. "Europe is moving forward on carbon emissions," he told EURACTIV. "We've found a good compromise and matters have been solved."
But Brook Riley of Friends of the Earth only welcomed the news as the death of a red herring. "There never was any threat to CO2 prices from this energy efficiency directive," he told EURACTIV.
"It was always far too weak to be a threat to the ETS, unfortunately."