In Grand Junction, Colorado, buses, garbage trucks and street sweepers run on compressed natural gas produced from a wastewater treatment plant.
In Riverview, Michigan, excess gases from a landfill are being converted to CNG to power seven city vehicles.
Plans are in the works to convert police cruisers to CNG, which costs about $1 per gallon.
And in Louisiana, St. Landry Parish installed a system in 2012 that can produce 240 gallons of CNG a day but recently expanded its production capabilities to produce 630 gallons a day. CNG not only fuels its own vehicles, but it is also sold to a large local waste-hauling firm to power its garbage trucks.
What started for Madison-based BioCNG as a small pilot project at the Dane County Landfill is spreading to other parts of the country.
And if gasoline and diesel fuel prices remain unpredictable, company officials believe their systems can help cities, counties and other government agencies, as well as private businesses, reduce fuel costs, lock in fuel budgets for up to two decades and let them market themselves as being friendly to the environment.