Methane is a simple hydrocarbon and therefore burns much cleaner than diesel, producing very low particulate (PM) and nitrogen oxides (NOx) emissions. Testing carried out by the Low Carbon Vehicle Partnership on behalf of the Department for Transport found that NOx emissions are 99% lower in Euro VI model dedicated gas vehicles than an equivalent Euro V diesel model.
Standard CNG and LNG can reduce carbon emissions by at least 15% compared to diesel, when used in long haul trunking operations. This saving can increase to 90% or more for biomethane, on a well to wheel basis, depending on the feedstock used to generate the biomethane.
Many CNG and LNG refuelling stations can provide biomethane, which is either certified through the Renewable Transport Fuels Obligation (RTFO) scheme, or by using Green Gas Certificates:
- The RTFO supports the government’s policy on reducing greenhouse gas emissions from vehicles by encouraging the production of biofuels that don’t damage the environment. Under the RTFO scheme, suppliers of transport fuel in the UK must be able to show that a percentage of the fuel they supply comes from renewable and sustainable sources.
- The Green Gas Certification Scheme (GGCS) and Biomethane Certification Scheme (BMCS) also enable biomethane (‘green gas’) to be tracked through the supply chain, ensuring certainty for those that buy it. These schemes work on the basis that each unit of green gas injected into the grid displaces a unit of fossil-derived natural gas.
For many operators, obtaining biomethane through the RTFO scheme is preferred. However, to find out more about these schemes and whether they impact on how you report your carbon emissions, please see your fuel supplier.
Natural gas can offer significantly cheaper running costs – up to 40% – compared to diesel, depending on the vehicle duty cycle. This is primarily due to an advantageous fuel duty rate of 24.7 pence per kilogram, fixed until 2032. By comparison, the diesel duty rate is 57.95 pence per litre. Natural gas prices are relatively stable as a result of this fixed rate of duty. Biomethane can cost slightly more than standard CNG but delivers substantially greater CO2 savings.