Power-to-X: Engineering methods
Ammonia, methanol, methane or jet: which route wins
What this tab covers The engineering methods that can do this conversion, compared on efficiency, scale, economics, limitations and reliability.The routes share the electrolyser. They differ in what the hydrogen is joined to, how hard the synthesis is, and how much hydrogen ends up as water.
Comparison
| Method | Efficiency | Scale | Economics | Limitations | Reliability |
|---|---|---|---|---|---|
| Power-to-liquid via Fischer-Tropsch (e-kerosene, e-diesel)112 | 57% H2-to-syncrude; 40-60% electricity-to-fuel | Tens to hundreds of MW; 1 GWe would match a 1 Mt CO2 source | USD 80/GJ today, 50/GJ by 2030 | About 25% by-product gasoline; minimum load about 30%, so hydrogen storage is needed | Proven on coal and gas syngas; little experience with variable power |
| Methanol-to-jet1516 | Not published for e-methanol plants | First commercial plant: 100,000 t a year of jet fuel planned in Inner Mongolia (Honeywell UOP eFining) | Builds on cheaper e-methanol; no public cost | Fuel pathway still being certified (ExxonMobil process) | Early stage |
| Green ammonia (Haber-Bosch)15 | 88% H2-to-ammonia | Up to multi-GW (NEOM) | USD 550/t by 2030 (IEA) | Loop prefers steady operation; ammonia is toxic | Haber-Bosch is a century-old, mature technology |
| E-methanol1 | 80% H2-to-methanol | Up to 150 MWe (Ningxia) | USD 700/t by 2030 | Needs a CO2 source of 1.38 t per t (calculated) | Mature catalysts from fossil methanol |
| E-methane (Sabatier)13 | Ceiling about 83% (calculated) | Pilots (6 MWe) | Competes with cheap fossil gas | Methane leaks undo the benefit; grid must be below 95-140 g/kWh | Pilot |
| Direct air capture, solid sorbent47 | About 4-6 GJ heat per t CO2 plus electricity | Modular units | USD 125-335/t for a large plant built today (IEA) | Energy use and cost | Early commercial |
| Direct air capture, liquid solvent47 | About 6-10 GJ heat per t CO2 | Large central plants (up to 1 Mt a year planned) | Same IEA range as solid sorbents | Needs high-temperature heat, today from gas whose CO2 is also captured | Early |
Ammonia is the most efficient and cheapest carrier because it needs no carbon, making it the first market for shipping fuel and fertiliser, though its toxicity and nitrous oxide emissions need care. Methanol comes next: an easy liquid and a route to jet fuel. Fischer-Tropsch gives drop-in jet and diesel but loses most energy. E-methane makes sense only where gas grids exist and leaks are controlled. The CO2 source matters a lot: biogenic CO2 at USD 20-30/t keeps costs down, while air capture is fully circular but can add more than the fuel's electricity bill.
How each method works
Power-to-liquid via Fischer-Tropsch (e-kerosene, e-diesel)CO2 is reduced to CO, then Fischer-Tropsch synthesis grows hydrocarbon chains that a small refinery cracks into jet fuel, diesel and naphtha.
Methanol-to-jetMethanol is turned into light olefins, which are joined into longer chains and hydrotreated to kerosene.
Green ammonia (Haber-Bosch)Nitrogen from an air separation unit and electrolytic hydrogen react over an iron catalyst in a high-pressure loop.
E-methanolCO2 and hydrogen react over a copper catalyst; the crude is distilled.
E-methane (Sabatier)CO2 and hydrogen form methane and water over nickel, and the methane can go into existing gas grids.
Direct air capture, solid sorbentFans push air over amine sorbents, which are then heated to 80-120 C (sometimes under vacuum) to release CO2.
Direct air capture, liquid solventAir contacts potassium hydroxide solution; the carbonate formed is calcined at about 900 C to release CO2.
Sources
- The Role of E-fuels in Decarbonising Transport (revised January 2024) International Energy Agency, 2024
- Global Hydrogen Review 2024: GHG emissions of hydrogen and its derivatives International Energy Agency, 2024
- Direct air capture of CO2: from insights into the current and emerging approaches to future opportunities (Zeeshan, Kidder, Pentzer, Getman, Gurkan), Frontiers in Sustainability 4 Frontiers, 2023
- thyssenkrupp nucera General Investor Presentation, May 2026 thyssenkrupp nucera, 2026
- Direct Air Capture 2022: Executive summary International Energy Agency, 2022
- Willis Sustainable Fuels selects FT CANS (Johnson Matthey and bp Fischer-Tropsch technology) Johnson Matthey, 2025
- Honeywell technology selected by Jiutai for world-leading methanol-to-jet fuel plant Honeywell, 2024
- ExxonMobil methanol to jet technology to provide new route for sustainable aviation fuel production Renewable Carbon News (ExxonMobil press release), 2022