I few years back, I read an interesting article in Discover magazine. Though the oil being produced is "light oil", we probably still have the problem of emissions. Don't know if this truly falls under "green" but at least this process can help with the solid waste that is currently being produced around the world.
Agriculture represents over 50% of the estimated 12 billion tons of solid waste produced each year in the U.S. The food processing industry in the U.S. alone generates billions of pounds of organically rich wastes each year. These wastes are associated with the processing of both animal and plant products. If all agricultural waste were made available for use in the TCP, an extraordinarily large amount of oil could be generated that almost meets the 4 billion barrels of oil that are imported to the U.S. each year.
This plant can help.