Here is some Biodiesel we make it from used French fry oil we get from restaurants in town. Trucks and tractors all get a 50% mix of the home made brew during the spring, summer ,and fall seasons. 
 It costs about 27 cents per liter to make and I can make about 400 liters in 1 days work.
The amber color liquid is biodiesel and the darker stuff at the bottom is glycerin ( FAT ).