The viability of green hydrogen as a primary fuel for heavy industry and aviation

The viability of green hydrogen (produced via water electrolysis using renewable electricity) as a primary fuel for heavy industry and aviation has transitioned from a phase of unchecked hype to a period of pragmatic, high-stakes execution.

arXiv

While green hydrogen is chemically and physically capable of substituting fossil fuels in hard-to-abate sectors, its widespread adoption faces severe hurdles regarding economics, infrastructure, and energy efficiency.

Project Drawdown®

1. Heavy Industry: The Most Credible Path

Heavy industries—such as steelmaking, chemical processing (ammonia/fertilizers), and long-duration high-heat manufacturing—represent the most realistic domain for green hydrogen because direct electrification is largely impractical.

• Steel Production (Direct Reduced Iron – DRI): Traditional steel manufacturing relies on coking coal to strip oxygen from iron ore, producing massive carbon emissions. Green hydrogen can replace coking coal as a reducing agent, producing water vapor instead of $\text{CO}_2$CO2​ (Hydrogen-DRI). Several pilot and commercial-scale projects are underway, particularly in Europe.
• Chemicals and Refining: Ammonia production (for fertilizers) already consumes millions of tons of “grey” hydrogen derived from natural gas. Transitioning this to green hydrogen is a straightforward chemical substitution, though limited by cost.
• The Bottleneck: Economics and offtake agreements. Green hydrogen remains significantly more expensive than fossil-derived hydrogen. Heavy industry operates on razor-thin margins, meaning widespread deployment requires rigid carbon pricing, government subsidies, and guaranteed long-term buyers (offtake agreements) to secure Final Investment Decisions (FID). Green Hydrogen Organisation

2. Aviation: A Steep Climb with Diverging Pathways

Aviation is one of the toughest sectors to decarbonize. Batteries are far too heavy for commercial long-haul flight due to low energy density, leaving chemical and synthetic fuels as the primary options. Hydrogen enters the aviation space via two distinct routes:

• Direct Combustion or Fuel Cells (Liquid Hydrogen):
  • The Technology: Storing liquid hydrogen ($\text{LH}_2$LH2​) onboard requires cryogenic temperatures ($-253^\circ\text{C}$−253∘C) and lightweight, bulky, form-fitting fuel tanks, fundamentally changing aircraft fuselage design (e.g., Airbus’s ZEROe concepts).
  • The Reality: While technically feasible for regional or single-aisle mid-range flights, direct hydrogen aviation requires a complete redesign of airport refueling infrastructure, safety protocols, and aircraft architecture. Widespread commercial deployment is unlikely at scale until the 2040s. Project Drawdown®
• Power-to-Liquids / Sustainable Aviation Fuels (e-SAF):
  • The Technology: Instead of putting raw hydrogen into a plane, green hydrogen is combined with captured carbon dioxide to synthesize “drop-in” hydrocarbon fuels (e-fuels).
  • The Reality: This is widely viewed as the more pragmatic near-to-mid-term aviation solution because e-SAF can be dropped directly into existing jet engines and distributed via legacy airport pipeline infrastructure without modifying the fleet. However, the energy penalty of synthesizing e-fuels is massive, making them exceptionally costly.

Key Systemic Challenges Impacting Both Sectors

1. The “Efficiency Penalty” (Loss of Energy): Converting renewable electricity into hydrogen via electrolysis, compressing or liquefying it, transporting it, and then converting it back into power (via fuel cells or combustion) results in significant round-trip energy losses. Roughly 50% to 70% of the original renewable energy is lost in the chain. Consequently, electricity is always preferentially routed to direct uses (like EVs or grid power) first.
2. Infrastructure Deficit: Moving hydrogen is notoriously difficult. It requires specialized pipelines (as it causes embrittlement in standard steel pipes), cryogenic tankers, or conversion into ammonia/Liquid Organic Hydrogen Carriers (LOHCs). Building this network demands trillions of dollars in capital expenditure.
3. The Capital and Execution Squeeze: High interest rates and shifting capital markets have forced a flight to quality. Investors now prioritize “bankable” projects backed by cheap local renewable power and regulatory mandates over speculative, standalone infrastructure plays. New Energy Innovation

Summary Verdict

• Heavy Industry will successfully adopt green hydrogen where government policies mandate emissions reductions and cheap local renewable resources exist (e.g., green steel in Scandinavia or Australia).
• Aviation will rely primarily on e-SAF (synthetic kerosene) synthesized from green hydrogen for decades to come, while direct liquid-hydrogen aircraft face a much longer, risk-heavy runway restricted initially to smaller regional applications.