London, Nov 4 Former US Vice President Al Gore has hit back at his critics who have described him as the world's first carbon billionaire following his investments in green energy companies, and dismissed them as global-warming deniers.

Defending his business activities on ABC TV, Gore denied he was on the way to becoming a carbon billionaire.

"I am proud to have put my money where my mouth is for the past 30 years. And though that is not the majority of my business activities, I absolutely believe in investing in accordance with my beliefs and my values," he said.

Gore has become a powerful advocate of government policies to limit carbon dioxide emissions since leaving office in 2001.

As the Copenhagen talks on a new climate-change treaty approach and the US Congress grapples with draft laws to curb emissions, Gore's profile will only swell further, The Independent reports.

Gore's venture capital company has been investing to develop energy-saving technologies, which could make electricity grids more efficient. Last year, they had loaned a California firm, Silver Spring Networks, 75 million dollars to produce hardware and software to improve electricity grid efficiency.

The deal appeared to pay off in a big way last week, when the Energy Department announced 3.4 billion dollars in smart grid grants and of the total, more than 560 million dollars went to utilities with which Silver Spring has contracts, ccording to media reports. (ANI)