When we talk about decarbonisation, we usually think of electrification, solar panels or wind farms. However, there is another key player that is gaining ground, especially in heavy road and maritime transport: biomethane in the form of BioCNG and BioLNG. Understanding what these are and how they help decarbonise is key to anticipating where energy is heading in the coming years.
What decarbonisation is and why transport is so critical
To decarbonise means to drastically reduce greenhouse gas emissions, mainly CO₂, until we get close to climate neutrality. It is not just about emitting less at the exhaust pipe, but about cutting emissions across the entire life cycle of energy, from production through to end use.
Transport plays a leading role in this challenge. In the European Union, emissions from intra‑EU transport account for over 22% of the total; when international aviation and shipping are included, the proportion rises to nearly 27%. Within that total, heavy road transport makes up around 30–35% of the sector’s emissions in countries such as Spain and Portugal. This explains why decarbonising heavy transport is a priority: it is not a niche, but rather one of the major levers for mitigating climate change.
This is the context in which renewable gases emerge, including biomethane used as BioCNG and BioLNG.
What are BioCNG and BioLNG?
Both BioCNG and BioLNG are forms of biomethane, i.e. methane gas produced from renewable sources and obtained from organic waste through anaerobic digestion. The difference lies in their physical state and in their main use.
Biomethane is produced from biogas generated from agricultural and livestock waste, industrial residues, sewage sludge or the organic fraction of municipal waste. Once purified and upgraded, the resulting gas has a composition closely resembling fossil natural gas, although from a renewable source.
When this biomethane is compressed, we refer to it as BioCNG (renewable compressed natural gas). When it is liquefied at very low temperature, it becomes BioLNG (renewable liquefied natural gas).
The main technical advantage is that both can be fully interchanged with conventional CNG and LNG: they can be used in the same engines and make use of existing infrastructure (service stations, gas networks and regasification plants) without requiring major technological changes.
From waste to fuel: circular economy applied to decarbonisation
One of the most interesting aspects of BioCNG and BioLNG is that they reduce emissions not only at the point of use, but also in the way they are produced.
If not properly managed, organic waste releases methane uncontrollably into the atmosphere. Methane is a far more potent greenhouse gas than CO₂ in the short and medium term. Capturing that biogas and converting it into biomethane prevents methane from being released into the atmosphere and turns it into a renewable fuel.
MITECO’s Biogas Roadmap highlights that using biogas for electricity generation and biomethane for transport, when produced from manure, can achieve emission reductions greater than 200% relative to conventional waste management, as it prevents the emissions that would otherwise be generated. This means that in some cases the overall balance can even be “climate negative”, i.e. more emissions are removed than are generated.
Moreover, the digestate produced after anaerobic digestion can serve as fertiliser, replacing mineral fertilisers and closing the soil nutrient cycle, thereby strengthening the circular economy approach.
What role do BioCNG and BioLNG play in cutting emissions?
Emission reductions across the full cycle
When evaluating a fuel from a decarbonisation perspective, the focus shifts from just “tank to wheel” to “well to wheel”, meaning the entire life cycle is considered.
Research on renewable gases for heavy transport indicates that biomethane can cut greenhouse gas emissions by between 65% and over 200% compared to fossil fuels, depending on the type of waste used and the management system avoided. Other analyses indicate that biomethane can reduce greenhouse gas emissions by up to 99% compared to conventional fossil fuels.
In the case of BioLNG used in maritime transport, some studies put the net reduction in CO₂ at up to 92% compared to heavy fuel oil, which is the traditional fuel used by many vessels.
These figures explain why European institutions and industry associations regard biomethane as a key element for decarbonising heavy and maritime transport, particularly in segments that are challenging to electrify in the short term.
Applications in heavy road transport
In heavy transport, BioCNG and BioLNG enable a swift transition by relying on technology already familiar to many fleet operators who currently use CNG or LNG.
BioCNG fits particularly well with urban distribution, waste collection and municipal services, where gas vehicles are already in place. Using biomethane in these segments allows the carbon footprint to be reduced immediately without changing the type of vehicle.
BioLNG, for its part, is more geared towards long-haul heavy transport. Thanks to its high energy density, it is suitable for long-distance routes with refuelling times similar to traditional fuels. Truck manufacturers and logistics operators regard it as a practical route towards CO₂-neutral freight transport, particularly when the proportion of BioLNG in blends with fossil LNG is increased up to 100% renewable content.
On the Iberian Peninsula, the combined use of biomethane, hydrogen and natural gas in heavy transport avoided the emission of around 500,000 tonnes of CO₂ in 2022, showing that the aggregate effect of these solutions is already significant.
Applications in maritime transport
Maritime transport is also a significant source of emissions, and at the same time a sector where direct electrification remains highly complex. Here BioLNG emerges as a particularly interesting alternative.
BioLNG can be used in engines designed for LNG, a technology already gaining ground in new vessels. Shipowners can therefore begin with fossil LNG and, as BioLNG becomes available, steadily increase its proportion to progressively reduce their carbon footprint and move towards near‑zero CO₂ emissions.
Recent studies suggest that pure liquefied biomethane could account for between 3% and 13% of total fuel demand in the global maritime sector between 2030 and 2050, making a significant contribution to the decarbonisation of this activity.
Additional benefits beyond CO₂ reduction
The contribution of BioCNG and BioLNG to decarbonisation is not limited to the CO₂ emissions they prevent.
Firstly, they help to make use of waste that would otherwise pose an environmental problem, reducing diffuse methane emissions and improving organic waste management. Secondly, they help generate economic activity and jobs in rural and industrial areas where that waste is produced, supporting local development.
Thirdly, as they are produced and consumed on a regional scale, they can reduce dependence on fossil fuel imports and improve security of supply. Companies and operators who have committed to BioLNG also highlight that producing it close to the point of consumption lowers transport costs and emissions linked to fuel logistics.
All this fits with the vision of a more circular and resilient economy, where energy is generated from local, renewable resources.
Challenges and future outlook
Despite their potential, the large-scale roll-out of BioCNG and BioLNG still faces challenges. These include the need to continue expanding biomethane production infrastructure, to ensure stable regulatory frameworks and robust guarantee‑of‑origin systems, and to support fleets in the technological and financial transition.
European legislation, through the Renewable Energy Directive (RED II and its update), already sets specific targets for the use of advanced biofuels and renewable fuels of non‑biological origin by 2030, reinforcing biomethane’s role in transport decarbonisation.
At the same time, the combination of factors (climate pressure, rising emission costs, technological maturity and the potential of waste) makes BioCNG and BioLNG particularly valuable tools for taking action now, without waiting for solutions that are still at an early stage.