https://m.youtube.com/watch?v=WCNsfYK0ReY&feature=youtu.be
" Kuwait and Saudi Arabia, when the oil is taken out of the ground, it won’t replace itself for about one million years.
If we used grass to produce biogas, we could replace our green oil every six weeks during the growing season.
Green Generation’s AD facility takes in pig slurry, waste food and other waste organic products to produce biogas."
http://www.agriland.ie/farming-news/how-can-irish-grassland-farmers-tap-in-on-a-green-oil-boom/