"The Parliament will strongly lobby for a binding target," Jo Leinen told EurActiv. "We can criticise the executive of the EU and at the very end we can even sanction the Commission if there is a strong will."
The German Socialist MEP said that the Parliament would be reporting back to Commission President José Manuel Barroso on energy efficiency as part of inter-institutional protocol.
"Since we have positioned ourselves more than once for a binding 2020 target, I think we will get a large majority this time again," he said.
A 20% improvement in energy savings is the only one of the EU's three 2020 targets that is not compulsory, and the only one not on track to be met. Instead, savings of just 9-11% are forecast.
The other EU goals are for a 20% reduction in greenhouse gas emissions and a 20% increase in the share of renewables in its energy mix, all measured against 1990 levels.
Towards the end of last year, environmentalists had been optimistic that the Commission might push for action on the efficiency targets, after President Barroso called for "concrete steps" to be taken towards the EU's goal.
Countries not on track
But a draft of the Commission's Energy Efficiency Action Plan obtained by EurActiv says that for the next two years, the Commission will only monitor the implementation of national efficiency targets.
"If, nevertheless, the 2013 review shows that the overall EU target is unlikely to be achieved," the document states, "then as a second stage the Commission will consider whether to propose legally binding national targets".
EU diplomats say that 20 states have so far submitted their energy efficiency National Reform Programmes ahead of an April deadline.
However, the average reduction on 2020 figures involved is said to be just -14%.
"It's disappointing that even after the energy summit in February, the Commission is still not learning the lesson," Leinen complained.
The Commission proposals were "too hesitant and half-hearted," he said, "and we are losing too much time".
Targets established in 2013 would probably only apply after 2014 and half of the most decisive decade for halting global warming would already be lost by then, he explained.
The vice-chair of Leinen's committee, Green MEP Carl Shlyter, is fiercely committed to a 30% energy efficiency target for 2020, but also tactically cautious.
"We can propose binding targets in Parliament," he suggested "but then we'll face a problem when the energy directive comes to be directly implemented".
Even so, "we still have a chance to push the Commission further," he added.
Less contentious measures in the efficiency plan include the establishment of national energy saving obligation schemes in all member states, and the development of public procurement criteria that incorporate efficiency standards.
The Commission will propose that public authorities be required to refurbish at least 3% of their buildings a year to bring them up to the standard of the top tenth of national building stock.
From 2019, new buildings in all public bodies subject to EU directives will have to reach a "nearly-zero energy" performance level.