In france (and certainelly in others states) you can change your diesel engine to roll with the sunflower oil. Inform you!! peace laura
You can also use leftover grease that's been filtered from places like McDonald's or burger King. I used to work in a deli and we sold the filtered grease we fried chicken in to people for their diesel engines!
You have to have a special tank and converter and equipment for it. Can't just pour in vegetable oil unfortunately.