Gas should be treated as other fossil fuels, biomethane a "pipedream" solution - T&E
Powering Europe’s transport with fossil gas – widely known as ‘natural’ gas – would emit as much greenhouse gases (GHG) as using petrol, diesel or conventional marine fuels, according to a study by the European Federation for Transport and Environment AISB (T&E). Fossil gas could increase GHG emissions by up to 9 percent or decrease them by a maximum of 12 percent across all transport modes, the study suggests, taking into account the effects of leakage of methane – itself a potent GHG.
According to the study “CNG and LNG for vehicles and ships – the facts“, fossil gas cars emit as much air pollution as petrol ones and their limited advantage over new diesel cars that comply with the latest emissions standards could be eliminated by the planned introduction of new Euro VII/7 standards.
Yet, by taxing gas for transport at a rate much lower than petrol and diesel, European lawmakers are incentivising the use of this fossil fuel.
T&E says that the report is based on the most up to date literature, test results and data building on a previous report by AEA-Ricardo but analyses in more detail issues such as the role of biomethane (renewable natural gas – RNG) and power-to-methane or the impact of tax policy.
Marginal air quality benefit
In cars, burning compressed natural gas (CNG) has a similar climate impact to diesel, while in trucks it emits GHGs in the same range as best-in-class diesel lorries.
The study finds that gas cars – including those running on biomethane, emit out as much air pollution as petrol ones and marginally less than new diesel cars that comply with new real-world limits.
In trucks, liquefied natural gas (LNG) can increase or decrease NOx, depending on the engine type, and can have higher particulate number emissions than diesel.
Using LNG in ships has a clear benefit compared to heavy fuel oil (HFO) although NOx after-treatment systems and further desulphurisation of existing marine fuels can achieve similar results.
However, according to the study, there is little or no GHG improvement over using marine gas oil (MGO), but these figures are highly dependent on engine methane slip and upstream leakages.
When an engine burns LNG, unburned methane escapes through the exhaust and leakages may occur during storage. Methane is also released ‘upstream’ during the production and transportation of fossil gas.
T&E said the car, truck and shipping industries should use the shift to low-carbon technology to also move to low air pollution technology.
Fossil gas for transport is currently taxed in the EU, on average, at rates 76 percent lower than diesel. Countries that have high sales of CNG and LNG vehicles tax fossil gas at even lower rates.
For example, in Italy, which consumes 60 percent of the methane used in European transport and accounts for 68 percent of CNG car sales, fossil gas at the pump is about half the price of diesel. This is due to a CNG tax rate of 0.5 percent of the diesel tax rate.
Similarly, for trucks, the business case for LNG depends entirely on gas’ low tax treatment.
Gas cars, trucks and ships have no real benefits for the climate and they’re a distraction from our real objective, zero-emission transport. Governments should resist the gas lobby’s offensive and stop wasting precious public money on gas infrastructure and tax breaks for fossil gas, said Jori Sihvonen, Clean Fuels Officer at T&E.
Biomethane not the solution
According to the study, biomethane (upgraded biogas) from waste does not offer a comprehensive solution as it could only supply, at maximum, 9.5 percent of transport’s needs. This would also mean no biomethane would be left to decarbonise the other sectors already using gas – residential, heating and power – where the infrastructure already exists.
Renewable gas based on electricity (power-to-gas) is very energy intensive and costly to produce, the study finds.
The idea that we can decarbonise transport with renewable gas is a pipedream. What little biomethane and electro-methane we’ll have will be needed to decarbonise the heating and power sectors, which currently rely on fossil gas. Pushing biomethane in transport actually makes the climate battle harder by depriving industry and domestic heating of this limited renewable resource, concluded Jori Sihvonen.