McDonald’s will convert its British delivery fleet to run on biodiesel made largely from its own recycled cooking oil, Reuters reports.

The company says it should eventually be able to replace the six million liters of diesel its fleet used last year with cooking oil from its 1,200 restaurants in Britain.

The biodiesel will initially be made up of 85 percent used cooking oil collected from around 900 McDonald’s restaurants and 15 percent from pure rapeseed oil.