Originally Posted by 84Scrambler
The problem you are going to run into eventually is that waste oil of any kind has value to large recyclers. Traditionally, they have been paid to take the waste oil. However, as demand goes up and people realize that they have a valuable commodity, the price for it will go up. Most restaurants have a signed contract for waste oil disposal and do not have the authority to give you waste oil. Eventually veggie oil could be recycled by companies for sale to the general public. You really, really need to understand where the market is going before you spend a lot of time and money on a WVO system. I don't see sources drying up over night, but over the next 5 years, it could become pretty hard to find. Just think of the risks vs. your initial investement. It could work out to be some pretty expensive veggie oil if you can't find a supply for the long term.
You are right that it could, however all the above is speculatory and with prices on the commodity markets (petro) dropping one could also speculate the opposite.
I suspect it wouldn't take long to pay for your investment with WVO so even if things changed, you would have the ability to do what the market dictated.