Biomethane milk trucks become reality

The first trucks in the United States to be fueled by cow power were unveiled at the World Ag Expo in Tulare, Calif. a few weeks ago. Two trucks that normally run on diesel fuel now run on biomethane gas from manure at Hilarides Dairy in Lindsay, Calif.

Manure from the dairy flushes to a covered lagoon digester where bacteria convert volatile solids into biogas, which is captured by the lagoon covers. Biogas is piped from the digester to a pre-assembled biogas upgrading system, where carbon dioxide, hydrogen sulfide and other impurities are removed, yielding clean-burning biomethane.

The converted milk trucks each haul two tankers of milk a day to Hilmar Cheese Company in Hilmar, Calif., a 270-mile roundtrip. Mileage on the trucks is comparable to diesel – about six miles per gallon, says Rob Hilarides, owner of Hilarides Dairy. The dispensing pump is similar to those at compressed natural gas stations.  

In addition to the two milk-trucks, Hilarides has six pick-up trucks that run on biomethane. He hopes to convert more vehicles to run on biomethane in the future, as the biogas upgrading system is not running at full capacity.  

Hilarides offers this advice to dairymen considering biomethane, “Do your homework. The basic process of harvesting gas is very simple, but all the details can mess up a project. From the mechanization and design to the regulations, you need to be willing to jump through hoops.” Hilarides did not disclose the cost associated with this process.  

This conversion is a win-win for the dairy industry and environment. It reduces global warming emissions (methane from manure), air pollution (from diesel emissions) and dependence on fossil fuels, without a food-fuel trade-off in land use. Across the nation, the benefit to the climate could be as great as taking 16 million cars off the road.  

To see the trucks in action, go to: