Renewable methane – whether produced from waste, manure or synthetic sources – could displace at most 7% of natural gas in Europe at the current demand rate, according to a new study by the International Council on Clean Transport (ICCT).
By 2050, this could cover at most 12% of gas demand in Europe, or 36 billion cubic metres of gas, far less than the 122 billion m3 projected by an industry-commissioned study, according to the report, published on Tuesday (16 October).
This is because the greenhouse gas savings obtained from replacing fossil fuels with renewable methane can differ widely depending on the feedstock and technology used, said the ICCT, a US-based research group which uncovered the Volkswagen emissions scandal in 2015.
“Generally, renewable methane generated from waste delivers greater GHG reductions,” the report points out. Sludge from wastewater treatment is available in large quantities and can be processed inexpensively close to population centres, allowing ready connection to the urban gas grid, it says.
However, economies of scale there are limited, while renewable gas derived from agricultural crops compete with land used for food production, which hampers their potential as a fuel source, the report said.
Meanwhile, methane and hydrogen converted from renewable electricity is an energy-intensive process in itself that entails inefficiencies from the construction of new wind and solar installations to produce the fuel, the ICCT said.
“Our study finds that sustainable renewable methane can play a small role in decarbonising the EU economy in 2050, though it cannot represent the primary strategy for decarbonising an entire sector,” says Stephanie Searle, the lead author of the study.
Overall, the economic case for renewable gas is not straightforward, the study argues, pointing to scalability issues, limitations and trade-offs in various areas.
For instance, while the greatest potential in the ICCT analysis lies with livestock manure, the report underlines “significant obstacles” to unlocking it – chiefly the fact that production is typically scattered across farms in the countryside, far away from population centres and the gas grid.
“Poor economics limit the production of many types of renewable methane today, and that constraint is likely to persist into the future because it is difficult for renewable methane production to compete with inexpensive fossil gas,” the report says.
The ICCT projections contrast with industry figures, which put the potential for renewable gas at 122 billion cubic meters for 2050, or more than 70% of the expected total gas demand. For transport, industry association NGVA Europe predicted a 10% market share for cars running on gas by 2030 and a 20-30% share for trucks and buses.
All projections converge on one point, though: gas demand will decline after 2030, due to energy efficiency measures and a switch to wind and solar in power generation. That leaves heating as an area where gas can expect to retain a significant share.
For road transport, the picture is less clear. While gas is currently a niche fuel, power-to-liquids and drop-in liquid fuels produced from gasification could be an alternative, especially for long-distance freight where electrification is not yet feasible, according to the ICCT.
The gas industry projections for transport are “probably ambitious but could be feasible, especially for heavy-duty transport,” said Searle. However, moving to renewable methane in road transport would require large-scale investment in the vehicle fleet and fuelling infrastructure, the ICCT points out.
In any case, all renewable methane pathways would require public incentives to expand production. And the uses of gas cannot be added up across sectors, which implies trade-offs between gas used in transport, heating and power generation, the report points out.
This means the decarbonisation potential of renewable gas is limited, the study concludes, and in any case “far lower” than the projected total gas demand in 2050.
“If the entire renewable methane potential were used in transport, it could displace only 7% of total transport energy demand in 2050. If it were instead used in heating, it could displace 10% of energy use in residential heating, or 3% of energy demand in power generation,” the report says.
“Sustainable renewable methane can achieve significant GHG mitigation, but the overall potential for decarbonisation from renewable methane is limited,” the report concludes – “even if cost barriers can be overcome.”
The conclusions of the ICCT study are broadly in line with the European Commission, which sees gas demand declining after 2030, even though it “remains relevant” as part of the energy mix “in all decarbonisation scenarios”.
In a leaked draft of its upcoming low-carbon economy strategy for 2050, expected on 28 November, the EU executive sees renewable gas such as hydrogen mostly used for heavy-duty transport, industry and residential heating.