European Union leaders are resuming talks to try to reach a deal on a binding target for the use of renewable energy, such as wind and solar power, BBC reports.
German Chancellor Angela Merkel said a "breakthrough" text had been drafted which she would urge leaders to accept.
There has been strong opposition from some countries to the proposal to boost renewable fuel use to 20% by 2020.
On Thursday, EU leaders agreed to cut carbon dioxide emissions by 20% from 1990 levels by the year 2020.
Speaking before talks resumed, Mrs Merkel said a new draft text proposing a binding target on renewable energy was being circulated among EU member states.
If agreed, it would "inject a new quality into the energy and climate policy of the European Union", she said.
"We will still have to have discussions, and take other members' opinions into account, but we'll do everything we can to ensure that this text will be accepted."
'Differentiated' targets
Mrs Merkel, whose country holds the rotating EU presidency, described the agreement on emissions as "a massive step forward".
Friday's talks are expected to focus on each country's specific obligations to meet a binding target on renewables.
The draft statement reportedly suggests that "differentiated national overall targets" should be set "with due regard to a fair and adequate allocation taking account of different national starting points".
Poorer Eastern European countries, which are more dependent on heavy industry and carbon-heavy coal, have argued they will struggle to make the investment in wind farms and solar power necessary to meet binding targets.
The concerns of countries, like France, which want nuclear energy to be taken into account must also be addressed.
Mrs Merkel has said nuclear energy is not renewable energy but has conceded that it may be considered as part of the overall carbon reduction plan.
'Ambitious package'
EU Commission President Jose Manuel Barroso said on Friday he was hopeful a historic agreement would be reached.
"These decisions are very important for the future of our planet, for the future generations, for the global community," he said.
"I hope a very ambitious package will come out of this summit - indeed, the most ambitious package ever agreed by any institution or any group of countries in the world on energy, security and climate protection."
The BBC's Oana Lungescu in Brussels says Europe has decided to go green - but the difficult details have still to be worked out.
The major sticking point remains whether the target for renewable fuel use for 13 years' time should be binding or voluntary, she says.
Some of the poorer EU countries - like Hungary, the Czech Republic and Slovakia - argue they have better uses for their money, our correspondent adds.
It is thought the EU could offer to extend its 20% target for emissions cuts to 30% if other heavy polluters like the US, China and India come on board.
(BBC News, 09/03/2007)