The AGRIGNV technology is allowing a bio CNG (compressed natural gas) production by picking up a small biogas flow produced by the AD plant for the CHP (heat and power generation). This technology compiles a purification part with activated carbon, membrane (for CO2 removal), compressor and pump nozzle. Also, it allows users to add storage for quick refueling.
The feasibility has tested three pilot projects in Auvergne-Rhône-Alpes region and shown that the biggest size of this technology is the more profitable (4Nm3h bio-methane production): the global investment is around 120 000 € allowing 400 000 km/y for a car or the yearly fuel for one milk truck. However the fuel price still not competitive with diesel without subsidies, especially because it is difficult to use all the gas production only in farms. Farmers have to find local consumers but the market is really important: each AD plant with CHP units and small water treatment plants producing biogas can use this technology. Additionally, farmers are really interested to produce their own fuel.
More information (in french) here