Abu Dhabi's state-owned green energy firm Masdar said its plans to invest $15 billion in renewable energy ventures had not been derailed by global economic conditions.

'All of our investments and projects have been carefully developed, carefully managed and carefully financed so we are really not exposed in order for the economic downturn in general to affect us that much,' said Masdar chief executive Sultan al-Jaber said in an interview with Reuters.

'I can comfortably tell you that none of our announcements are being sidelined or put on hold.'

Last year, Masdar unveiled ambitious plans to invest $15 billion in renewable energy projects such as the world's flagship carbon-free city in Abu Dhabi.

Masdar hopes the initiative will earn Abu Dhabi a reputation as the world's main development hub for renewable energy, not wholly reliant on oil profits for its wealth.

Jaber said this project was advancing but there was a possible one-year delay to the city's opening, pushing back the launch to 2019 or 2020.

'There could be a potential one-year delay, not because of financial constraints but because of the technology advancements we are trying to utilise,' he said, adding that geothermal power sourced from underground heat will form an important part of the green city's electricity mix.

He said Masdar is also studying other geothermal projects and will announce further green energy initiatives in January.

On Monday, the firm signed a contract worth nearly 2 billion euros with Germany's E.ON and Denmark's DONG Energy to develop the world's largest offshore wind project in the Thames Estuary, near London.

A firm commitment from the more than 190 countries at the Copenhagen climate change summit on emissions targets could lure more investors to companies like Masdar.

The company is still looking for partners for future projects and has not yet found full financing for the $15 billion already pledged.

While Jaber expects the Copenhagen climate change summit to benefit the green energy industry, he was not hopeful of a binding agreement.

'I'm not in any way expecting that we will have a deal sealed in Copenhagen,' he said, adding that the ability of the summit to attract high-profile decision makers was an achievement in itself.

'But I'm very confident that by the time we have finished we will have a much clearer, more robust, transparent understanding of what is required for us to get to that point where a deal can be put in practice,' he said.

'I believe this is going to be a major stepping stone to a much larger discussion,' he added.-Reuters