Electrofuels are synthetic kerosene made by combining green hydrogen with captured carbon dioxide. They are chemically identical to Jet A-1. A Boeing 777 could fill up with synthetic kerosene and fly from London to Singapore without a single engine modification. That drop-in compatibility is why airlines, regulators and investors are paying attention. The energy physics is brutal, and the scale question may already have an answer.
The Fischer-Tropsch process, originally developed in Germany in the 1920s, converts a mixture of hydrogen and carbon monoxide into liquid hydrocarbons. In the modern power-to-liquid variant, electrolysis splits water into hydrogen and oxygen using renewable power. That hydrogen is then combined with CO2 captured from the air or an industrial point source. The resulting synthesis gas feeds into a Fischer-Tropsch reactor, which produces a crude oil substitute that can be refined into jet fuel. Each step loses energy. Overall efficiency from renewable power to fuel in the wing typically sits between 40% and 60%.
Aviation accounts for roughly 2.5% of global CO2 emissions. Unlike cars or short-haul trains, long-haul aircraft cannot run on batteries or hydrogen fuel cells. The energy density of a lithium-ion battery is about 0.3 megajoules per kilogram. Jet fuel delivers 43 megajoules per kilogram. A battery large enough to power a Boeing 777 across the Atlantic would weigh more than the aircraft itself, leaving no room for passengers or cargo. Liquid hydrogen has better energy density by weight, but its volume is four times that of kerosene, and storing it requires cryogenic tanks at minus 253 degrees Celsius. Hydrogen fuel cells would demand a complete airframe redesign. For long-haul aviation, the only practical non-fossil option is a liquid hydrocarbon that fits existing tanks, pumps and engines. Synthetic kerosene fits that slot.
Key Facts
- Aviation share of global CO2: Approximately 2.5%
- E-fuel production process: Fischer-Tropsch process (developed 1920s)
- Power-to-liquid efficiency: 40% to 60%
- First commercial synthetic kerosene plant: Synhelion, Jülich, Germany, opened 2024
- Norsk e-Fuel plant location: Mosjøen, Norway
- Boeing 777 fuel capacity: Over 180,000 liters
- EU synthetic fuel mandate: Sub-target under ReFuelEU Aviation from 2030
The Cost Gap Is Not Marginal
Why fossil jet fuel remains cheap
Fossil jet fuel is cheap because the crude oil is already in the ground, the extraction infrastructure is a century old, and the refining process is mature. Synthetic kerosene must pay for electrolyzers, direct air capture machines, Fischer-Tropsch reactors, and the renewable power to run them all. The result is a price multiple that makes the current cost difference look like a chasm, not a gap.
The price multiple today
Conventional Jet A-1 has traded in a range that makes synthetic kerosene roughly three to six times more expensive per liter at current energy prices. That multiple can shrink if renewable power costs fall further or if carbon pricing rises sharply. The efficiency loss means synthetic fuel will always need more energy input per liter than the fossil alternative. A barrel of oil equivalent in e-fuel requires roughly 200 kilowatt-hours of renewable power to produce. A barrel of oil is extracted with a tiny fraction of that energy.
Biofuels: cheaper but feedstock-constrained
Biofuels, such as hydroprocessed esters and fatty acids made from used cooking oil or animal fats, are also more expensive than fossil jet fuel but typically less expensive than synthetic kerosene. Their limitation is feedstock availability. The world does not produce enough waste fats or purpose-grown oil crops to replace a significant share of aviation fuel. Electrofuels do not compete for agricultural land. They compete for renewable power and green hydrogen, both of which are scarce today.
Comparing Aviation Fuel Pathways
| Pathway | Feedstock | Energy Efficiency | Drop-in | Cost vs. Fossil Jet Fuel |
|---|---|---|---|---|
| Fossil Jet A-1 | Crude oil | ~85% (well-to-tank) | Yes | Baseline |
| Biofuel (HEFA) | Waste oils, fats | ~50-70% | Yes (blended up to 50%) | 1.5-3x |
| E-fuel (Power-to-Liquid) | CO2 + green H2 | 40-60% | Yes (100% blend possible) | 3-6x |
| Battery-electric | Grid power | ~70-80% (grid to motor) | No | Not viable for long-haul |
| Liquid hydrogen | Green H2 + liquefaction | ~50-60% | No | 2-4x (plus aircraft redesign) |
The Power Demand Is Staggering
The energy appetite of a single flight
Replacing even a fraction of global jet fuel with synthetic alternatives would require an enormous build-out of renewable generation. A single long-haul flight on a Boeing 777 burns over 180,000 liters of fuel. Producing the electrofuel equivalent would consume roughly 1.8 million kilowatt-hours of renewable power, assuming 50% conversion efficiency. That is more electricity than the average US home uses in a century.
A 10% target demands a grid-scale commitment
If synthetic kerosene were to supply 10% of global aviation fuel demand by 2050, a target many analysts consider optimistic, the power requirement would exceed 1,000 terawatt-hours per year. For comparison, the entire European Union generated about 2,700 terawatt-hours of electricity from all sources in 2023. Powering a 10% electrofuel share would mean dedicating roughly a third of the EU's current total generation to making jet fuel. The International Civil Aviation Organization's CORSIA scheme and national policies push for emissions reductions, but none of them account for the grid capacity needed to deliver those reductions via synthetic fuels.
Competing claims on every kilowatt-hour
The competition for that power is intense. Ground transport is electrifying, industrial processes are switching from fossil fuels to green hydrogen, and data centers are adding load. Every kilowatt-hour used to make synthetic kerosene is a kilowatt-hour not used to decarbonize steel, cement or trucking. The question is whether aviation's willingness to pay premium fuel prices can outbid other sectors for scarce renewable power.
Pilot Plants Are Running, But Scale Is Distant
A proof-of-concept in Jülich
The first commercial plant to produce synthetic kerosene using direct air capture and renewable energy opened in Jülich, Germany, in 2024. It was built by Synhelion, a Swiss spin-off from ETH Zurich. The plant is small, designed to prove the concept rather than supply airlines.
Norway's commercial-scale bet
Norsk e-Fuel is building a commercial-scale facility in Mosjøen, Norway, targeting synthetic fuel for aviation. As of July 2024, the Mosjøen plant had not reached final investment decision, and its capacity would still represent a tiny fraction of global jet fuel consumption.
Offtake uncertainty stalls financing
Airlines have announced interest. Several carriers have signed agreements with producers, but the distinction between a binding offtake contract and a non-binding memorandum of understanding is important. Without long-term purchase commitments at prices that cover the producer's capital costs, the plants cannot secure financing. The current price premium means airlines would be paying several times the market rate for jet fuel, a cost that would either be passed to passengers or absorbed as a loss.
No electrofuel plant in operation or under construction today can produce enough fuel to serve a single major airport's daily demand. The industry is at the stage where a pilot plant is newsworthy. Scaling to commercial relevance will require hundreds of plants, each costing hundreds of millions of dollars, and each dependent on large amounts of dedicated renewable generation that does not yet exist.
Regulation Creates a Market, but Not at Any Price
Europe's mandate locks in a buyer
The European Union's ReFuelEU Aviation regulation, adopted in 2023, mandates that aviation fuel suppliers blend increasing proportions of sustainable aviation fuels into kerosene sold at EU airports. Starting in 2030, a specific sub-target applies to synthetic aviation fuels. The mandate creates a guaranteed buyer for synthetic kerosene inside the EU, which is why producers are building plants in Germany and Norway. Without the mandate, there would be almost no commercial incentive.
US policy: credits with caveats
In the United States, the Inflation Reduction Act includes tax credits for sustainable aviation fuels, but the credits are based on lifecycle greenhouse gas reductions, not on production pathway. Electrofuels with very low carbon intensity would qualify, but the exact level of credit depends on emissions modeling that was still being finalized as of mid-2024. The US policies may shift with the political cycle, adding uncertainty for investors who need decade-long payback periods.
CORSIA's weak price signal
ICAO's CORSIA scheme, which aims to offset aviation emissions through carbon credits and the use of lower-carbon fuels, recognizes synthetic kerosene as eligible. But CORSIA's baseline and offset rules are voluntary for many countries until 2027, and the carbon price under CORSIA is far too low to make electrofuels competitive without additional subsidies or mandates. Regulation can create a market. It cannot create the power or the hydrogen at the required scale.
Frequently Asked Questions
Can e-fuels be used in existing aircraft without modifications?
Yes. Synthetic kerosene produced via the Fischer-Tropsch process is chemically identical to conventional Jet A-1. It is a drop-in replacement that requires no engine or fuel system changes.
How much renewable electricity is needed to make e-fuels for aviation?
Producing enough synthetic fuel for a single long-haul flight on a Boeing 777 requires roughly 1.8 million kilowatt-hours of renewable power. Supplying 10% of global aviation demand would need over 1,000 terawatt-hours per year, comparable to a third of the EU's total electricity generation.
Are e-fuels cheaper than biofuels for aviation?
No. Synthetic kerosene is typically 3 to 6 times the cost of fossil jet fuel, while biofuels from waste oils are generally 1.5 to 3 times the cost. Biofuels are feedstock-limited, however, while electrofuels are limited by renewable power and hydrogen availability.
When will e-fuels be available at scale?
As of July 2024, the first commercial plant had just opened in Germany. Commercial-scale production that could meaningfully impact aviation emissions is unlikely before the late 2030s at the earliest, and may not align with the industry's 2050 net-zero pledge.
Do e-fuels compete with other uses of renewable energy?
Yes. Synthetic fuels require large amounts of renewable power and green hydrogen, both of which are also needed for decarbonizing ground transport, industrial heat and power generation. Aviation will have to outbid other sectors for that energy.
