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"Propane can be used as a supplemental source of producing renewable energy lowering greenhouse emissions. If this process becomes more popular the supply of propane will decrease making a higher demand for it, increasing the price for its use.

The biodigesters converts up to eight tons of food and yard waste per day to both bio-gas and hydrogen, producing enough energy to power approximately 80 homes while reducing solid waste in landfills and greenhouse gas emissions."

Source:http://www.propanecouncil.org/uploadedFiles/12027_Propane_biodigesters_web.pdf