The ride-hailing app’s chief executive Dara Khosrowshahi made the announcement while on a visit to London.
He had been due in Saudi Arabia to attend the so-called “Davos of the desert” investment conference but joined other prominent business leaders in pulling out following outrage over the suspected murder of journalist Jamal Khashoggi.
Mr Khosrowshahi, whose firm has been looking to make amends following a bruising licensing battle with transport regulators in London, told reporters he wanted its vehicles in the city to be all-electric from 2025.
He said that to help that ambition become reality, Uber would introduce the top-up fee on fares from 2019 to create a £200m fund for new vehicles that should be seen as an investment in clean air.
Drivers would also, he said, benefit from every extra 15p they brought in as an incentive payment to switch to greener cars.
The briefing was told that a driver using the app for an average of 40 hours per week would be given around £3,000 towards the purchase cost of such a vehicle in two years, or £4,500 in three years.
Its ambitions were announced as it continues a legal fight with drivers over their rights.
The Independent Workers’ Union of Great Britain (IWGB) expressed its concern over the move.
Its private hire drivers branch chairman James Farrar said: “We are very concerned that this latest PR move from Uber will lure drivers deeper into debt, as they struggle to finance expensive vehicles on below minimum wage income.
“The answer to London’s growing congestion and pollution problem is for the government and the mayor to resolutely commit to capping minicab numbers in London.
“Drivers have long ago given up on Uber to do the right thing and that is why so many will be joining our march next week with other precarious workers, as we get ready to face down yet another appeal from Uber on the worker rights case we already won on two occasions.”
A spokesman for London mayor Sadiq Khan said: “Just four months ago, Uber was forced to overhaul the way it operates after years of poor conduct and the mayor welcomes this change in approach.
“However, electric cars are not a complete solution.
“We also need to address the damaging impact that the rising number of private hire vehicles has on congestion and air pollution.”
The comments come after Mr Khosrowshahi said he was in London to bolster the company’s efforts in becoming a better global partner.
Uber, which is planning a flotation next year that is expected to raise tens of billions of dollars, has also been expanding its interests to concentrate its areas of investment.
Amid reports Uber may acquire UK Uber Eats competitor Deliveroo, he remained coy saying only: “Is something going to happen with Deliveroo? Who knows.”
Asked how Uber might handle any Saudi investment as part of its IPO (Initial Public Offering) , he said: “First we want to get the facts and we will make that determination about how we go forward, how we raise money going forward, what our post-IPO board make-up is.”
“All of those are options and again we make conclusions based on all the facts,” he added.
Uber has signalled its intentions on not only green technology but also significant investment in driverless cars.
It announced in August a development partnership with Toyota while Mr Khosrowshahi also confirmed on Tuesday it was open to the idea of minority stakes in its Advanced Technologies Group.
He said: “It’s going to be part of the family and how the capitalisation looks like is something that we are ultimately open to but it is not an area of focus right now.”