Build the molecule that an engine takes apart
Combustion combines a hydrocarbon with oxygen and releases heat, CO₂, and water. Power-to-liquids pays energy to reverse that direction: split water, recover carbon, create carbon monoxide, form longer chains, and refine them into a specification.
The product's advantage is compatibility. Dense liquid fuel can use aircraft, engines, tanks, pipelines, and logistics built around hydrocarbons. Its disadvantage is the same fact viewed thermodynamically: electricity is converted into a molecule and later converted again into motion, losing useful energy at both stages.
Compatibility is what the losses buy
Those percentages are demand obligations, not evidence that production has reached scale. EASA's 2026 market report said no large synthetic-fuel facility had yet reached final investment decision in its assessed EU pipeline.
The atoms set a lower bound
An idealized hydrocarbon repeat unit, CH₂, has one carbon atom and two hydrogen atoms. Molar mass makes the minimum feed transparent before conversion losses enter.
Not all captured carbon reaches saleable jet fuel. Fischer–Tropsch synthesis produces a distribution of chain lengths. Gas and light fractions may be recycled or used for heat; heavy waxes are hydrocracked; oxygenates and water are separated. A plant should report carbon efficiency to each product, not only conversion inside one reactor.
Every individually reasonable step takes a cut
Electrolysis, compression, reverse water-gas shift, synthesis, separation, and upgrading multiply rather than add their efficiencies.
A 70%-efficient electrolyser followed by an 80%-efficient synthesis and upgrading chain retains only 56% before balance-of-plant loads. Real system comparison must include capture energy, compression, recycle, heat integration, auxiliaries, and the fuel fraction that meets the target specification.
| Layer | Main measure | Failure mode |
|---|---|---|
| Electricity | Hourly $/MWh and carbon intensity | Cheap hours leave capital idle |
| Hydrogen | kWh/kg, stack life, utilization | Replacement and compression erase gains |
| Carbon | Origin, purity, $/t, capture energy | Cheap fossil CO₂ does not close the loop |
| Synthesis | Carbon efficiency and target yield | Off-products dilute saleable output |
| Upgrading | Certified litres per feed tonne | Fuel misses freezing, density, or blending rules |
Cheap electricity is not the same as cheap fuel
Change power price and plant utilization together. The model exposes electricity, carbon feedstock, and capital recovery for a nominal 100,000-litre-per-day plant; it is not a delivered-fuel quote.
Exposed production burden
- Electricity
- $0.77/L
- CO₂ feedstock
- $0.32/L
- Capital + fixed
- $2.13/L
- Electricity input
- 21.9 kWh/L
- Implied power-to-liquid
- 43%
A litre of jet-range hydrocarbon contains roughly 9.5 kWh of lower-heating-value energy. The model's implied efficiency divides that by electrolyser plus selected process electricity; it therefore excludes upstream generation and downstream engine losses.
Calculation and boundaries
Electricity cost = (hydrogen input × electrolyser kWh/kg + other process kWh) × $/kWh. Carbon cost = kg CO₂/L × $/kg. Capital + fixed cost = installed capital × annual charge rate ÷ (100,000 L/day × 365 × utilization).
Excluded: water, catalysts, replacement stacks, oxygen or heat credits, carbon-capture energy if not included in CO₂ price, product yield outside the selected inputs, storage, blending, transport, taxes, margin, and financing beyond the annual charge. Installed capital is deliberately user-set; no single public number describes projects with different boundaries.
The cheapest electron can make expensive fuel
A synthesis plant sized for occasional surplus power earns revenue occasionally but carries capital continuously.
Hydrogen storage can decouple a flexible electrolyser from a steadier synthesis loop, but it adds compression, tanks or caverns, inventory, and another utilization problem. Firm clean electricity costs more per MWh but can lower capital cost per litre. The optimum depends on the joint hourly system, not an annual average power price.
Electrolysers can flex
Stacks can follow power more readily than a hot, pressurized chemical loop, though cycling can affect efficiency and life.
Synthesis prefers continuity
Catalysts, recycle ratios, separation columns, and heat integration work best near a designed operating state.
Storage buys coupling
Hydrogen or intermediate storage protects synthesis utilization while exposing capital, safety, and geography.
Contracts shape operation
Hourly clean-power rules, grid access, and product offtake determine whether an optimized plant is legally low-carbon and financially useful.
The cheapest source may defeat the purpose
Concentrated industrial CO₂ is easier to purify than atmospheric CO₂, but carbon origin changes the lifecycle story.
Biogenic CO₂ and direct air capture can create a circular atmospheric carbon flow when powered cleanly. Fossil point-source CO₂ can reduce emissions relative to extracting fresh oil but still introduces geological carbon after combustion. A credible fuel certificate traces carbon origin, hydrogen electricity, process energy, transport, and co-product allocation.
Aviation pays for density and compatibility
Cars can use batteries directly. Long-haul aircraft carry their energy source, making mass, volume, freezing behavior, and global refuelling compatibility unusually valuable.
This makes aviation the strongest case for synthetic hydrocarbons—and a stringent test. Fuel must meet ASTM pathways and blend rules, contain appropriate aromatics or be paired with them, work at low temperature, and arrive at airports through certified custody. Policy can create initial demand; only operating plants reveal the eventual premium.
An optimistic view, with conditions
Use synthetic fuel where the molecule earns its losses
The stack can improve through cheaper power, durable electrolysers, heat integration, higher selectivity, modular construction, and shared carbon infrastructure. It should compete first where direct electrification cannot deliver the same service.
Prove full balances
Publish hourly electricity, net carbon intensity, utilization, carbon efficiency, target yield, and delivered litres.
Concentrate demand
Aviation mandates and durable offtake can support initial plants without pretending they match fossil price.
Standardize trains
Repeatable electrolysis, synthesis, upgrading, and certification packages must turn projects into products.
Sources, method, and boundaries
Stoichiometric figures are derived from molar mass; the calculator exposes assumptions rather than predicting market price. Policy shares are legal requirements. Announced capacity and targets are not operating production.
