Octopus Energy, which has been taking on customers from collapsed rival suppliers, has secured up to $600m (£438m) from an investment fund set up by the former US vice-president Al Gore. Generation Investment Management (GIM), a $36bn fund manager that finances businesses focused on sustainability and tackling climate change, will take a stake of up to 13% in a deal that values Octopus at $4.6bn. The price tag means Octopus, a renewable energy specialist launched in 2016, could be worth more on paper than Centrica, the parent company of British Gas, by the time the investment is complete. Gore, the environmentalist and former presidential candidate who co-founded Generation in 2004, broke news of the investment via a Zoom call to Octopus staff earlier this afternoon. Octopus said it would use the cash to build on its rapid growth, founded on the success of its green energy platform Kraken, software that helps manage power usage more efficiently. The platform is used to manage 17m energy accounts globally, including Octopus customers, as well as those of rival suppliers such as npower, E.ON and Good Energy. Kraken served 2.5m Octopus customers as of last week but over the weekend, Octopus agreed to take on 600,000 customers from its collapsed rival Avro Energy, increasing its customer base to 3.1m. Avro was one of seven small suppliers to have exited the energy market since the start of August, amid a crisis caused by rising gas prices that has resulted in the energy regulator, Ofgem, moving 1.9m customers from failed firms to rivals since the start of the year. Octopus said the new funds from GIM, in two tranches of $300m, would help scale up the business, with the aim of supporting 100 million energy customers by 2027. Octopus Energy’s founder and chief executive, Greg Jackson, said the company’s staff had been inspired by the film An Inconvenient Sequel, a follow-up to Gore’s landmark documentary about climate change, An Inconvenient Truth. Jackson and Gore are understood to have held personal discussions about the sale of a stake to San Francisco-based GIM, which Gore co-founded in 2004 with the former Goldman Sachs asset management head David Blood. The deal involves an initial $300m investment, with a further $300m to follow by June 2022 if Octopus meets certain undisclosed conditions. The valuation of up to $4.6bn, implied if GIM goes ahead with the second tranche of funding, would result in the company more than doubling in size since it hit a $2bn price tag in December 2020, thanks to investment from Tokyo Energy and the Australian firm Origin Energy. Octopus said on Monday that Origin had also agreed to invest a further $55m alongside Generation’s new funds. Octopus is one of several firms that have become “suppliers of last resort” for customers of rivals that have collapsed in recent weeks. Shell Energy announced on Monday that it would take on 255,000 customers from Green, which exited the market on the same day as Avro. Suppliers have been rocked by surging wholesale prices for gas and electricity, which reached record highs in recent weeks as multiple factors combined to send the market soaring. A global surge in demand for gas after a cold winter that left gas storage facilities depleted has been exacerbated by a rebound in post-lockdown energy demand across Asia. Half of the UK’s electricity is generated in gas-fired power plants, while a series of nuclear reactor shortages, as well as the recent shutdown of an important power cable that brings in electricity from France, have made matters worse. The UK has also had one of its least windy summers since 1961, meaning wind power has been low. Experts fear the situation will become worse as temperatures become colder.