The former US vice president is in line to make a large profit from a firm producing smart meters which monitor household electricity use.
He is a partner in a Silicon Valley venture capital firm which invested £45 million in Silver Spring Networks, a small California company which has been developing technology to monitor household power use to make the electricity grid more efficient.
Last week the US Energy Department announced £2 billion in grants and a proportion of that, thought to be more than £305 million, will go to utility operators with which Silver Spring has contracts.
The venture capitalists who invested, including Mr Gore, now look set to receive a handsome return.
Since leaving office Mr Gore has campaigned relentlessly on green issues. His 2006 film "An Inconvenient Truth', which followed his attempts to educate people about the dangers of global warming, won an Oscar for best documentary. It showed Mr Gore giving ...