The global push toward decarbonization has intensified interest in electrofuels, or e-fuels, as a pathway to reduce emissions in hard-to-abate sectors like aviation and maritime transport. E-fuels, such as e-kerosene and e-methanol, are synthesized using hydrogen and a carbon source, offering a drop-in replacement for conventional fossil fuels. The hydrogen demand for e-fuel production is substantial and varies depending on the type of fuel, the carbon source, and the scale of adoption driven by regulatory mandates.

### Hydrogen Demand for E-Fuel Production
E-fuels require hydrogen as a primary feedstock. The stoichiometry of e-fuel synthesis dictates the hydrogen-to-carbon ratio, influencing overall demand. For example, producing e-kerosene (a synthetic alternative to jet fuel) typically requires approximately 0.15 to 0.20 kg of hydrogen per liter of fuel. E-methanol, though excluded from detailed process discussion here due to its coverage under G59, follows a similar demand profile.

Current projections estimate that global e-kerosene production could reach 5 to 10 million metric tons annually by 2030 in alignment with the International Air Transport Association’s (IATA) net-zero goals. Assuming an average hydrogen requirement of 0.18 kg per liter and a density of 0.8 kg/L for kerosene, this translates to an annual hydrogen demand of 1.1 to 2.2 million metric tons for aviation alone. Maritime e-fuel demand, while less mature in policy frameworks, could add another 1 to 3 million metric tons of hydrogen annually by the same timeframe, depending on the adoption of e-methanol or other hydrogen-derived fuels.

### Carbon Sourcing for E-Fuels
The carbon feedstock for e-fuels is a critical variable influencing both the environmental impact and scalability of production. Two primary carbon sources are under consideration: direct air capture (DAC) and point-source carbon capture (e.g., industrial emissions).

DAC extracts CO₂ directly from the atmosphere, offering a carbon-neutral pathway but requiring significant energy input. Current DAC technologies consume approximately 1,500 to 2,500 kWh per ton of CO₂ captured, with costs ranging from $100 to $300 per ton. For e-kerosene production, DAC-sourced carbon could contribute 3 to 4 tons of CO₂ per ton of fuel, adding both cost and energy overhead.

Point-source capture, by contrast, utilizes CO₂ from industrial processes such as cement production or fossil fuel combustion. This method is more energy-efficient, with capture costs as low as $40 to $80 per ton, but raises questions about long-term sustainability as industries themselves decarbonize. The availability of point-source CO₂ is geographically uneven, potentially limiting e-fuel production to industrial clusters unless transport infrastructure is developed.

### Aviation and Maritime Mandates Driving Demand
Regulatory mandates are accelerating e-fuel adoption in aviation and maritime sectors. The European Union’s ReFuelEU Aviation initiative mandates a 2% sustainable aviation fuel (SAF) blend by 2025, rising to 70% by 2050, with e-fuels expected to comprise a growing share. Similarly, the International Maritime Organization (IMO) has set a 5% emissions reduction target by 2030, incentivizing alternative fuels like e-methanol.

These policies are underpinned by lifecycle emissions criteria, favoring e-fuels produced with low-carbon hydrogen (e.g., electrolysis powered by renewables) and DAC or biogenic CO₂. For instance, ReFuelEU’s sustainability thresholds require a 70% emissions reduction compared to fossil kerosene, effectively excluding e-fuels derived from fossil-based hydrogen or carbon sources without adequate mitigation.

### Challenges and Scalability
Despite the clear demand signals, scaling e-fuel production faces hurdles. Hydrogen supply must align with renewable energy capacity to ensure low-carbon credentials. Electrolyzer deployment for green hydrogen production is growing but remains insufficient to meet projected e-fuel demand without parallel expansion in wind and solar infrastructure.

Carbon sourcing presents another bottleneck. DAC technology, while promising, is not yet deployed at the scale needed for widespread e-fuel production. Point-source capture offers a near-term solution but may conflict with broader decarbonization goals as industries reduce emissions.

Cost competitiveness is also a barrier. E-kerosene currently costs two to five times more than conventional jet fuel, with hydrogen production representing 50% to 60% of the total expense. Maritime e-fuels face similar economics, though bulk transport and simpler infrastructure could reduce distribution costs compared to aviation.

### Future Outlook
The intersection of hydrogen demand, carbon sourcing, and regulatory mandates will shape the e-fuel landscape. By 2030, hydrogen demand for e-fuels could exceed 5 million metric tons annually if policy targets are met, with aviation leading initial adoption. Beyond 2030, the maturation of DAC and renewable hydrogen infrastructure could unlock further growth, particularly if carbon pricing mechanisms or subsidies improve cost viability.

The maritime sector’s trajectory depends on fuel standardization and port infrastructure. Ammonia and methanol are currently favored due to handling and storage advantages, but hydrogen-derived variants must compete with biofuels and other alternatives.

In summary, e-fuels represent a critical avenue for decarbonizing transport sectors resistant to electrification. The hydrogen demand tied to their production is significant and will rise with policy-driven adoption. However, scalability hinges on overcoming carbon sourcing challenges, reducing production costs, and aligning hydrogen supply with renewable energy capacity. The next decade will be pivotal in determining whether e-fuels can transition from niche solutions to mainstream energy carriers.