In the first update since the latest energy union framework was launched in February 2015, Sefcovic said: "Nine months down the road, we can say with confidence that we are on track to deliver the energy union."
However, the update said EU member states need to do more to incorporate renewables into the energy system. "Further efforts are needed in the vast majority of member states to ensure that renewable energy is better integrated into the market, and to ensure consistency between support schemes and the functioning of the electricity markets in particular."
The EC's energy union aims to develop an integrated energy market from the 28 separate regulatory frameworks of member states.
It includes measures to reduce reliance on imported energy, emissions and costs. The emissions trading system will also be overhauled.
A minimum interconnection target has been set at 10% of installed electricity production capacity per member state, which should be achieved by 2020, with a view to increasing this to 15% by 2030.
The EC is also running a public consultation on the Renewable Energy Directive to install a framework to ensure the bloc meets the 27% renewable energy target by 2030.
Five member states – France, Luxembourg, Malta, the Netherlands and the UK – "need to assess whether their policies and tools are sufficient and effective in meeting their renewable energy objectives", the Commission's update said.
Belgium, Spain, Hungary and Poland are also at risk of missing their renewables targets.
EWEA's CEO Giles Dickson supported the suggestion the EC could step in to ensure member states reach the targets: "Today's energy union address is a statement of intent. For the first time the Commission brings clarity on how it intends to administer the binding renewable energy target by saying it's ready to apply the rules if member states do not step up to the plate on renewables."
The Commission must now define the circumstances under which it would intervene and how such measures would be enshrined in the new Renewable Energy Directive, EWEA added.