Europe must spend much more on new infrastructure to get renewables into the grids, but the system has to be commercially viable, the participants agreed.
The debate, hosted by Fondation EurActiv in the European Parliament, was held in the light of the EU's 2020 energy strategy, which was endorsed by EU leaders at the first ever energy summit on 4 February.
"More than 70% of all investments in supply in the next ten years must be in renewables in order to reach the binding targets," stressed MEP Claude Turmes, vice-chair of the Greens group in the European Parliament.
The EU has committed itself to a 20% increase in the share of renewable sources in its energy mix by 2020, compared to 1990 levels.
Reducing the dependency on fossil fuel imports is a "crucial element" of the plan, which will require a "revolution" among regulators and companies at EU, national and local level, said Philip Lowe, director-general for energy at the European Commission.
Lowe stressed that firms must be given incentives to develop green energy and create a market-based system that does not rely on subsidies. He said there have been cases of over-installation of renewables in places like Spain.
Turmes claimed that large energy companies are trying to slow down the success of renewables, as they are decentralised and bring more competition. "We need to establish a counter power to these ten or twelve energy oligarchies," he said.
To achieve the 2020 aim, the EU adopted a Renewables Directive which set targets for each member state. Yet recent figures show that only seven countries expect to meet or exceed their interim goals for 2010.
Last month, EU Energy Commissioner Günther Oettinger called for a doubling of capital investments in renewable sources, from €35 billion to €70 billion, but set no time frame.
Lowe regretted that some member states have changed their national support schemes for renewables since 2009, as new governments have come in and modified the plans. But downgrading now will end up costing them more in future, he added.
Turmes said that transforming the ideas in the national schemes into concrete plans and laws will be the ''litmus test'' of the Renewables Directive.