I have a close relative that manufactures plants that produce E85 and bio plants. According to him bio-diesel is very expensive to produce and that is what is preventing more plants from opening up.

Here's the company:
http://www.agraind.com/

He's a project manager and claims ethanol plants are really taking off. Bio diesel is just to darn expensive to produce right now for investers to jump on board. I beleive him - he's been doing this for 15 years.