Diesel engines are a large answer to getting "us out of that dependence cesspool" of foreign oil. You can run many, many oils and even used hamburger grease (lots of filtering required) in a diesel with only a few hundred dollars of retrofit. If you process the grease (you can buy kits for garage use ~$800) you can make B95 biodiesel and simply pump it in your tank like regular diesel. As someone has already make reference; the best combo would be a diesel-electric hybrid (running on biodiesel). By the way garage, made biodiesel costs the maker about $0.75/gallon assuming he gets the grease free.