It is basically possible to upgrade Biogas to something very close to natural gas, and then use it to replace said gas. Biogas to grid is a mature technology now, with about 100 active plants in Germany alone. It is also often discussed to use the upgraded biogas as a vehicle fuel, replacing compressed natural gas (CNG).
If the fueling station is taking the gas from the grid, it does not make a difference if it is natural gas or biomethane. I'm looking for installations where the gas is produced, stored, upgraded and filled into vehicles on site. As we are talking about gas pressures upwards of 200 bar, energy efficient handling of the gas is not trivial. Any pointer to reference material that goes into the gas management would be greatly appreciated.
Edit to add (after Energy Numbers Answer):
Gas upgrading to grid-qualioty is to me an understood problem. The headaches arise with the vehicle fuel application. While a gas to grid installation can basically feed gs into the grid as it is produced, an installation for vehicle fuel would face a very uneven demand (the production is always very steady).
Depending on gas upgrading technology, the gas is delvered at practically air pressure to 5-15 bar. Vehicle fuel needs 200-250 bar. Compressed Natural Gas fueling stations do an interesting juggling act with 3 banks of gas tanks (hih-, mid-, ow pressure) to minimise the energy expenditure in gas compression - and they have the gas grid that delivers on demand.
With a constant supply (that can't be switched off), you'd need to store that gas between the tanking either at low pressure (and we may be talking 1000 m³/h), or compress it and store it at high pressure - and then minimize the loss of energy when the compressed gas is expanded into a vehicle tank. Also, high pressure storage costs serious money.
So what is a cost- and energy-effcient way to match supply and demand here?