This article highlights the Water Pollution Control Plant in
Millbrae, California that generates heat for its facility from
biogas. This biogas is available due to kitchen grease provided
from local restaurants. Interestingly, the project was possible
because of Chevron Corporation's Energy Solutions unit.
This was found at Renewableenergyworld.com, and is titled "Turning
Kitchen Grease into Biogas"
This EPA.gov page also mentions the Millbrae project, and quite a
few others, read on for more examples of bioenergy projects: