[F-127]

I guess it mostly depends on the situation. If you have a readily available, low cost waste oil you can get and all you need to do is filter it, I can see you being able to cash flow it somewhat easily. However if you need to purchase a screw press or other large investment, its going to take longer. I worked on this as a research project and we were able to 'use' a screw press at no cost from a local cooperative, and the local county highway department used the fuel at no cost(we needed to find a operator who was willing to participate). In the situation, the tractor mowed road ditches and did not have any problems with lacking horsepower. I would say its not short term payback, but definitely long term. Although I haven't really taken into consideration labor costs, which most people don't care because if they are doing this they probably have a general opinion of "screw foreign oil" and are going to do whatever it takes.