Uber users in central London can request an all-electric vehicle instead of a regular ICE or hybrid car, the Financial Times has reported. Called Uber Green, the new service is launching starting today in London’s Zone 1 as part of Uber’s push to be fully electric in London by 2025. Trips must originate in Zone 1, but destinations are unrestricted.

“We continue to partner with drivers to help them make the switch to electric and today we are excited to start offering riders the option to select an electric vehicle at no extra cost, allowing everyone using Uber to play their part in cleaning up urban transport,” said Uber’s EU general manager Jamie Heywood in a statement.

To incentivize drivers, Uber is offering a 15 percent reduction to its usual service fees. Starting in January 2019, the company tacked a 15 pence ($.20) fee per mile to help drivers switch to greener cars. So far, that has raised £125 million ($172 million) and Uber has boosted the number of EVs in its London fleet from 100 to 1,600. Still, that’s a small percentage of Uber’s 45,000 strong London fleet, so riders who request an all-electric ride might be in for a longer-than-usual wait. 

Uber also has a mountain to climb to get its London fleet all-electric by in under 4 years. The company has pledged to go fully electric around the world by 2040, and reach that goal in Europe and the US by 2030. Uber has had an adventurous past year in London, as it recently won a legal challenge to keep its license, and earlier this month, was forced to reclassify its drivers as workers in the city.