Energy Reserves Property of EU?

The aftermath of Katrina threw up an interesting little spat over German Oil Reserves. Angel Merkel suggested that were she Chancellor, she would release some of the country’s reserves to settle the market. Schroeder decline to make such a move unless it was internationally coordinated. So far just election politics, but next the EU waded in to the debate:

"a member state can not release its reserves not arbitrarily nor totally nor partly" Spokesman of energy commissioner Andris Piebalgs

Why?

"The height of the reserves is regulated through the EU. Changes must be approved by the commission"

Had the Constitution passed, this would have been the case, as it is, there is no legal basis for this comment. Which raises the question, are these people just making power grabs to see if anyone will notice, or was the idea to meddle in German Domestic politics? Its not a pretty state of affairs whichever one is right.