Biogas has long been promoted as a climate-friendly transport fuel. That made sense in an earlier phase of the energy transition, when battery-electric vehicles were expensive, charging infrastructure was limited, and many heavy vehicles still had no practical zero-emission alternative.
That period is ending.
The strongest use case for biogas is no longer as a substitute for diesel or natural gas in internal combustion engines. The better use is as a fuel for stationary oxyfuel combined heat and power plants, where it can produce dispatchable electricity, useful heat, and highly concentrated CO₂ that can be captured at exceptionally low cost.
In other words: biogas should move out of vehicle tanks and into carbon-removing combined heat and power (CHP) systems.
Battery-electric drive is winning on life-cycle cost
The central reason is economics. Battery-electric drivetrains are now cheaper, simpler, and more efficient than internal combustion engine systems. This applies first to passenger vehicles, then buses, delivery vehicles, municipal fleets, port equipment, ferries, and increasingly short- and medium-distance trucks.
Internal combustion engines are mechanically complex. They require fuel handling, combustion, exhaust systems, lubricants, filters, gearboxes, catalytic cleanup of exhaust gases, and frequent maintenance. Battery-electric drivetrains are simpler. They convert electricity to motion far more efficiently, have far fewer moving parts, and can be powered by increasingly low-cost renewable electricity.
The comparison is not between “green gas” and “dirty diesel.” The relevant comparison is between using scarce biogas in a combustion engine, with all the losses and maintenance costs of that platform, versus using electricity directly in an electric drivetrain.
On that basis, battery-electric drive is structurally advantaged.
Even when biogas is renewable, using it in transport still means putting a valuable molecule through a relatively inefficient engine. The result is motion, but with avoidable energy losses and continued tailpipe emissions. Battery-electric vehicles increasingly deliver the same transport service with lower energy input, lower maintenance cost, and lower total cost of ownership.
This changes the strategic role of biogas.
Biogas is too valuable to waste in engines
Biogas is not unlimited. It depends on organic waste streams: manure, sewage sludge, food waste, agricultural residues, and industrial organic byproducts. These feedstocks are valuable, but finite.
That means the question is not simply whether biogas is good. The question is where each unit of biogas creates the highest climate and economic value.
Using biogas as a transport fuel avoids some fossil fuel emissions. That is useful, but it is a relatively low-value use when battery-electric alternatives are available.
Using biogas in an oxyfuel combined heat and power plant can do more. It can produce electricity when the grid needs it, deliver useful heat to industry or district heating networks, and generate a CO₂-rich exhaust stream that is cheap to capture and store.
That turns biogas from a “lower-carbon fuel” into a platform for carbon removal.
Oxyfuel combustion changes the economics of CO₂ capture
Conventional combustion uses air. Air is mostly nitrogen. When a fuel is burned in air, the flue gas contains a large volume of nitrogen, along with CO₂, water vapor, oxygen, and trace pollutants. Capturing CO₂ from this diluted flue gas is expensive because the CO₂ has to be separated from a large stream of mostly nitrogen.
Oxyfuel combustion is different.
In an oxyfuel system, the fuel is burned with nearly pure oxygen instead of air. Since nitrogen is largely excluded from the combustion process, the main products are water vapor and CO₂. When the water vapor is condensed, what remains is a highly concentrated CO₂ stream.
That is the key advantage.
The CO₂ does not need to be extracted from a huge nitrogen-diluted exhaust stream. It is already concentrated by the combustion process itself. This can make CO₂ capture far simpler, cheaper, and more energy-efficient than conventional post-combustion capture.
For biogas, this is especially powerful because the carbon in the fuel is biogenic. If the CO₂ from biogas combustion is captured and permanently stored, the result can be net removal of CO₂ from the atmosphere. Plants absorbed the carbon. Organic residues became biogas. The biogas was used for energy. The CO₂ was captured and stored underground. This is maximum carbon circularity, sending carbon back to its geological store from where most of it came.
That is a carbon-removal pathway, not merely an emissions-reduction pathway.
Combined heat and power adds another advantage
Biogas should not only be used for electricity. It should be used where both the power and the heat have value.
Combined heat and power systems can deliver electricity to the grid while also supplying heat to district heating, greenhouses, food processing, industrial sites, wastewater treatment plants, or other local heat users. This raises total system efficiency and strengthens the business case.
This matters because the energy system increasingly needs flexible, dispatchable capacity.
Wind and solar are growing rapidly, but they are variable. Batteries are excellent for short-duration storage, but they do not solve every seasonal or industrial heat need. Biogas-fired oxyfuel CHP can operate when electricity prices are high, when heat is needed, or when the grid is under stress.
In this role, biogas complements electrification rather than competing with it.
The transport sector should electrify directly wherever possible. Biogas should be reserved for stationary applications where its combustion can be controlled, its heat can be used, and its CO₂ can be captured.
Transport policy should stop locking biogas into yesterday’s technology
Many countries have supported biogas vehicles through tax exemptions, fuel mandates, certificates, public procurement rules, and infrastructure support. These policies helped build early markets for renewable fuels.
But policy should now adapt.
Continuing to promote biogas as a transport fuel risks locking scarce renewable gas into a declining technology platform. It also risks delaying the transition to battery-electric fleets that are already cheaper and cleaner on a life-cycle basis in many applications.
Public buses are a good example. A city that replaces diesel buses with biogas buses has made an improvement. But a city that moves directly to battery-electric buses usually gets a better long-term platform: lower operating cost, no local tailpipe emissions, quieter vehicles, and compatibility with renewable electricity.
The same logic increasingly applies to taxis, vans, refuse trucks, municipal fleets, port vehicles, ferries, and regional logistics.
Biogas transport should therefore be treated as a transitional use, not a destination.
A better hierarchy for biogas use
The future use of biogas should follow a simple hierarchy.
First, electrify transport directly wherever battery-electric drive is practical.
Second, use biogas in stationary systems where high total efficiency is possible through combined heat and power.
Third, prioritize oxyfuel combustion or other configurations that produce a concentrated CO₂ stream suitable for capture. This is also enabled by using surplus (low-cost!) pure oxygen from the growing water electrolysis industry built to produce green hydrogen.
Fourth, store the captured biogenic CO₂ permanently, creating verified carbon removal.
This hierarchy gives biogas a more valuable role in the energy transition. It avoids wasting renewable molecules in engines and instead uses them in systems designed for efficiency, flexibility, and carbon capture.
From renewable fuel to carbon-removal infrastructure
The debate about biogas has often been framed around fuel substitution: can biogas replace diesel, gasoline, or fossil natural gas?
That is now too narrow.
The more important question is how biogas can create the greatest system value in a mostly electrified economy. The answer is not to keep burning it in vehicles. The answer is to integrate it into stationary energy systems that produce useful heat, dispatchable electricity, and capturable biogenic CO₂.
Battery-electric transport and biogas-based carbon removal are not competitors. They are partners in a more rational energy system.
Electricity should do what electricity does best: move vehicles efficiently.
Biogas should do what biogas can uniquely do: provide storable renewable energy, dispatchable heat and power, and a concentrated biogenic CO₂ stream that can be permanently stored.
That is the strategic shift policymakers, fleet operators, utilities, and biogas producers should now make.
The future of biogas is not in the fuel tank. It is in new oxyfuel combined heat and power with carbon capture.
