Philip Lowe, the head of the Commission's directorate-general for energy, criticised EU governments for obstructing binding rules to promote energy efficiency, as part of efforts to meet the bloc's aspirational goal of a 20% cut in energy use by 2020.
In June, EU Energy Commissioner Günther Oettinger proposed rules obliging energy firms to cut energy sales by 1.5% each year, and requiring 3% of public buildings annually to be given an energy-efficient makeover (see details).
Lowe said the Commission made its proposal after EU governments refused to consider making the bloc's 20% energy efficiency target legally binding.
"But the conclusion of the last meeting [with governments] was 'well, we don't really like binding measures either'," he said, following an informal meeting of EU energy ministers in Poland last week.
"So they don't like binding targets or binding measures, and yet they regard energy efficiency as the most important priority of the European Union. Sorry, but we must stop this," Lowe told an EU energy policy seminar held by the Brussels-based think-tank Bruegel.
The EU's efficiency goal is designed to cut Europe's carbon emissions while also keeping a lid on an energy import bill that currently amounts to about €270 billion a year for oil and €40 billion for gas.
But the EU is falling far short of its goal, and is set to only achieve about 9% efficiency gains by 2020.
Oettinger has said he will give EU countries two years to get energy efficiency savings back on track before proposing legally binding targets.
EurActiv with Reuters