the wisdom of "green" biological diesel derived from waste cooking oil. When people talk about it on TV, they never talk about the energy needed for the conversion, the energy and work needed in collecting, transporting, distributing to the end users. When you add all these costs, is it still make sense to make and use "biological diesel"?

Of course, in the 1960's Taipaidongs, there were already a sort of burner that could burn used oil as long as you can separate it from water and dirt, which should not be too difficult to do. And doing so does not add costs of processing, transporting or the extra work in managing everything.