also could be pointed out that a big drum of potassium hydroxide, some smaller, sealed containers of sodium sulphate and a big separatory funnel makes it pretty easy to turn any available fat into diesel fuel, i mean literally anything, butter/cream, dripping, seed oils, coconut oil

probably these days some seed oils are so cheap you can actually save money doing this to keep a backup supply that you can convert into diesel ready to go within a few days