A study on Fuelling Farm Vehicles with Compressed Biogas was completed by the Canadian Biogas Association with support from Natural Resources Canada. The study aims to educate farmers and technology providers on opportunities to utilize biogas to fuel farm vehicles, evaluate applications and provide a cost-benefit analysis.
This study investigates the technical feasibility and value of using compressed biogas (CBG) as a vehicle fuel to displace diesel in converted farm vehicles. The entire process of fuelling farm vehicles with CBG is considered, including bolt-on biogas conditioning systems for existing biogas facilities to produce vehicle fuel, dual fuel vehicle conversion systems, capital and operating costs and considerations for improving future economics.
Most on farm biogas systems do not have a valuable option to utilize excess biogas that is produced beyond their energy contract requirements. The farmers consulted indicated their biogas systems could achieve additional biogas production of 50-200 m3/hour by increasing feedstock to the system. There may be potential for Canadian biogas operators to produce more renewable energy from biogas systems, if the operators can identify economical pathways for using the biogas. This study considers on-farm vehicle fuelling as an opportunity.
Raw biogas is a mixture of 55%-65% methane (CH4), 35%-45% carbon dioxide (CO2) and small amounts of other gases such as hydrogen sulfide. Minimally processed biogas can be combusted in stationary engines to produce electricity, but for current vehicle fuelling technology further conditioning is required. Moisture and hydrogen sulfide must be removed to prevent engine corrosion and compressor damage. While CO2 does not have any energy value it technically does not need to be completely removed. CO2 should be managed so the biogas has a predictable CH4 to CO2 ratio as current vehicle conversion technology require a stable fuel supply.