Methanol vs Ammonia vs SAF — Techno-Economic Comparison for eFuels

How to Use This Guide

Use this comparison when evaluating green hydrogen derivative pathways for a specific project or market. It covers production routes, economics, infrastructure, and safety for the three leading e-fuel candidates. The “right” answer depends on end-use, geography, CO₂ availability, and offtake — this guide helps frame that decision.

Overview

Green hydrogen is energy-dense per unit mass but terrible to store and transport. Converting it to a hydrogen carrier — methanol, ammonia, or synthetic aviation fuel (SAF) — solves the logistics problem at the cost of conversion efficiency and capital. Each pathway has a different sweet spot.

Production Pathways

Green Methanol (e-Methanol) Route: Green H₂ + captured CO₂ → methanol (via catalytic synthesis, Cu/ZnO/Al₂O₃ catalyst, 450–530 °F, 725–1450 psia). Mature technology — identical to fossil methanol synthesis except the feedstock is green H₂ and biogenic/DAC CO₂.

Green Ammonia Route: Green H₂ + N₂ (from ASU) → ammonia (Haber-Bosch, 750–930 °F, 2200–4400 psia). Also mature — the only new element is replacing grey H₂ from SMR with electrolytic H₂. Air separation units (ASUs) are commodity equipment.

Synthetic Aviation Fuel (SAF via Fischer-Tropsch) Route: Green H₂ + captured CO₂ → syngas (reverse water-gas shift) → FT liquids → hydrocracking/distillation → SAF (kerosene cut). Multi-step, less mature at scale. The FT reactor is the bottleneck for selectivity and conversion.

Energy Density Comparison

Key takeaway: SAF has 2× the volumetric energy density of methanol and 2.5× ammonia. Ammonia carries the most hydrogen per unit mass but requires refrigeration or pressure.

Process Efficiency

Overall electricity-to-product efficiency (including electrolysis at 70% HHV):

• Methanol: 46–52% (electrolyzer + synthesis). Limited by H₂ production efficiency and synthesis heat rejection.
• Ammonia: 44–50%. Haber-Bosch is exothermic but operates at very high pressures, requiring significant compression energy. ASU adds ~0.35 kWh/kg NH₃.
• SAF: 32–42%. RWGS + FT + upgrading is multi-step with heat losses at each stage. This is the fundamental disadvantage of the FT pathway.

Capital Cost Benchmarks

Approximate installed CAPEX for a greenfield plant (2024 dollars, excluding electrolyzer):

Electrolyzer cost adds $600–1,200/kW on top, which dominates total CAPEX for all three pathways. Stack replacement every 60,000–80,000 hours adds OPEX.

Levelized Cost of Product (LCOP)

Electricity cost dominates (60–80% of LCOP). Approximate ranges:

The green premium: At $30/MWh (good solar/wind), methanol is 2–3× fossil, ammonia is ~2× fossil, and SAF is 2–3× Jet-A. At $60/MWh, the premiums roughly double.

Infrastructure & Logistics

Methanol — Liquid at ambient conditions. Compatible with existing chemical tanker fleet, bunkering infrastructure, and methanol terminals (>100 globally). Can be blended with gasoline. Very easy to handle relative to the other two. Largest current market: chemical feedstock (~85 Mt/yr).

Ammonia — Requires refrigeration to -28 °F at atmospheric pressure, or pressurization to ~150 psig at ambient. Existing global ammonia trade is ~20 Mt/yr with established port terminals and shipping. Expanding infrastructure for fuel use is the main challenge. Cannot be easily blended into existing fuel systems.

SAF — Drop-in fuel: uses existing jet fuel infrastructure with zero modifications. This is its single biggest advantage. No new storage, pipelines, or aircraft modifications needed. ASTM D7566 certified FT-SPK blend up to 50%.

Safety Considerations

Methanol — Toxic by ingestion and inhalation (TLV-TWA 200 ppm). Burns with near-invisible flame. Lower flammability limit 6% in air. Spills are water-soluble and biodegrade relatively quickly. Main risk: accidental ingestion and invisible fire.

Ammonia — Highly toxic (IDLH 300 ppm, TLV-TWA 25 ppm). Corrosive to eyes and respiratory tract. Lighter than air (disperses upward — somewhat favorable). SCC risk with carbon steel above 100 °F — must use PWHT’d carbon steel or stainless. Existing industry has decades of safe handling experience, but scaling to fuel use in new sectors (e.g., shipping) introduces unfamiliar operators.

SAF — Essentially identical hazard profile to conventional Jet-A. Well-understood, extensive existing safety infrastructure. By far the lowest incremental safety risk.

Market Readiness & Offtake

Methanol: Shipping (Maersk has ordered 19 methanol-fueled vessels as of 2024), chemical feedstock replacement, potential power generation. IMO regulations driving adoption. Current green methanol capacity: <1 Mt/yr but growing rapidly.

Ammonia: Co-firing in coal power plants (Japan, Korea targeting 20% blend by 2030), shipping fuel (pilot projects), fertilizer decarbonization. Largest near-term demand: fertilizer sector greening (~180 Mt/yr conventional market). JERA and IHI leading ammonia co-firing demonstrations.

SAF: Aviation mandates driving demand — EU ReFuelEU requires 2% SAF by 2025, 6% by 2030, 70% by 2050. ICAO CORSIA creates global demand. Airlines actively signing SAF offtake agreements. Current production: <0.5 Mt/yr vs. ~300 Mt/yr total jet fuel demand.

CO₂ Requirement

Methanol: ~1.37 tonnes CO₂ per tonne methanol. Requires biogenic CO₂ or DAC — point-source fossil CO₂ undermines the green credential under most frameworks.

Ammonia: Zero CO₂ required. This is a major advantage in regions without CO₂ sources.

SAF: ~3.1 tonnes CO₂ per tonne SAF (FT route). Higher CO₂ intensity than methanol per unit product. DAC at $300–600/tonne CO₂ adds $1.00–2.00/gal to SAF cost.

Decision Framework

Choose methanol when: You have access to cheap biogenic CO₂ (ethanol plants, biogas upgrading, pulp mills), the end-use is shipping or chemical feedstock, and you want proven, ambient-temperature handling.

Choose ammonia when: CO₂ is not available or expensive, the market is fertilizer replacement or power generation co-firing, and the end-user has ammonia handling experience.

Choose SAF when: The customer is an airline or military aviation, drop-in compatibility is mandatory, and you can absorb the higher production cost and CO₂ requirement. Regulatory mandates create guaranteed demand.

For an eFuels project developer: Methanol and ammonia are the lowest-risk entry points (proven technology, lower CAPEX, larger existing markets). SAF commands the highest price premium but requires more capital, more CO₂, and lower overall efficiency.

Sources

• IRENA, “Innovation Outlook: Renewable Methanol,” 2021
• IEA, “Global Hydrogen Review,” 2023
• IRENA, “Renewable Ammonia,” 2022
• Dry, M.E., “The Fischer-Tropsch Process: 1950–2000,” Catalysis Today 71, 2002
• ICAO, “CORSIA Sustainability Criteria for SAF,” 2022
• DNV, “Maritime Forecast to 2050,” 2023
• BloombergNEF, “Hydrogen Economy Outlook,” 2024
• European Commission, “ReFuelEU Aviation Regulation,” 2023