Hydrogen will (still) save the future of commercial aviation

Hydrogen will (still) save the future of commercial aviation

By Rishab Balakrishnan | Connect on LinkedIn

September 12th, 2024 | 12 min 14 sec read

1. Where Hydrogen Turbines Were: A Historical Perspective

Aviation is one of the hardest sectors to decarbonize, with current technologies struggling to meet the sector's growing environmental goals. Hydrogen turbines, a new frontier in propulsion technology, promise a way forward by dramatically reducing emissions and offering a sustainable alternative. At their core, hydrogen turbines operate on the principle of hydrogen combustion, where liquid or gaseous hydrogen is burned to produce thrust, similar to traditional jet fuel but with a crucial difference: the primary byproduct of hydrogen combustion is water vapor, eliminating the carbon emissions associated with conventional aviation fuels (Simple Flying, n.d.).

Hydrogen turbines deliver more energy per kilogram of fuel than traditional jet engines, making them ideal for long-haul flights where efficiency is crucial. Conventional jet engines, which rely on kerosene, emit significant amounts of CO2 and other greenhouse gases, contributing substantially to global aviation emissions. Electric turbines, while a promising technology for short-range flights, currently need more energy density and storage capabilities for longer journeys, thus limiting their utility in the near term (Scientific American, n.d.).

The engineering case for hydrogen turbines was initially hindered by several factors, including the high cost of hydrogen production and storage, and the need for substantial modifications to existing aircraft designs to accommodate hydrogen fuel systems. However, the potential benefits of reduced emissions and improved fuel efficiency have driven continued interest and investment in this technology. Notably, hydrogen's higher specific energy means that less fuel is required for the same amount of work, presenting a compelling case for its adoption in aviation (Nature, n.d.). The interest in hydrogen turbines is rooted in their environmental benefits and potential to maintain the operational range and efficiency of current aviation technologies.

Table 1: Comparison of Aviation Propulsion Technologies

Sources: Simple Flying (n.d.), Scientific American (n.d.), Nature (n.d.)

Hydrogen turbines' importance lies in their potential to decarbonize aviation and their ability to align with existing infrastructure more closely than electric aircraft. For stakeholders in the aviation industry, understanding and investing in hydrogen turbine technology is becoming increasingly crucial as the sector grapples with the dual challenges of meeting growing demand and reducing its environmental impact.

2. Where Hydrogen Is Now: Current Innovations and Challenges

Currently, the hydrogen turbine sector is experiencing a wave of innovation driven by technological advancements and policy initiatives. Companies like Rolls-Royce and Mitsubishi Heavy Industries are at the forefront, developing hydrogen turbine engines capable of substantially reducing aviation's carbon footprint (Reuters, 2022; MHI, 2023). The BeautyHYFuel project by Safran is another notable initiative aimed at developing hydrogen-powered turbines, emphasizing optimized turbine design specifically for hydrogen to achieve significant reductions in carbon emissions (Safran Group, 2024).

The closure of Universal Hydrogen, a startup that aimed to revolutionize aviation with hydrogen-powered aircraft, underscores the financial and strategic challenges in the sector. Despite a successful prototype flight in 2023, the company failed to secure the necessary funding to continue its operations (GeekWire, 2024). This situation reflects broader investor skepticism and high capital costs that hinder the growth of hydrogen aviation technologies, demonstrating the uncertainty and risks involved in developing hydrogen as a viable alternative to conventional aviation fuels.

Policy drivers and industry collaboration are essential to the future of hydrogen turbines. Governments and manufacturers must work together to create a cohesive ecosystem, from developing infrastructure and refining safety regulations to ensuring long-term investments in R&D. The U.S. bipartisan legislation to study hydrogen for aviation reflects growing recognition of hydrogen’s potential to enhance energy security and reduce emissions (Ossoff Senate, n.d.). However, hydrogen infrastructure development is progressing slowly, presenting a significant barrier to broader adoption. The cost and complexity of building hydrogen refueling stations and storage facilities are high, and current production methods for hydrogen—mainly through natural gas reforming—still result in considerable CO2 emissions (Hydrogen Insight, n.d.).

Despite these hurdles, investments in hydrogen turbine R&D continue to grow. Companies are betting on the long-term potential of hydrogen to reshape aviation, even as they face significant near-term challenges. The technological barriers include the need for robust storage solutions that can handle hydrogen's flammability and the sub-zero temperatures required for liquid hydrogen storage (Scientific American, n.d.). Furthermore, regulatory frameworks need to evolve to address safety concerns related to hydrogen use in aviation.

Table 2: Current Barriers to Hydrogen Turbine Development

Sources: Hydrogen Insight (n.d.), Scientific American (n.d.), Ossoff Senate (n.d.)

The present state of hydrogen turbine technology suggests a cautious optimism. The advancements in turbine design and hydrogen combustion efficiency are promising, but they must be supported by simultaneous developments in infrastructure and regulatory adaptation to ensure a viable pathway to decarbonized aviation.

3. Where Hydrogen Will Go: The Future of Hydrogen Turbines in Aviation

The future of hydrogen turbines in aviation is set for remarkable advancements, driven by the need for decarbonization and improved efficiency. With its high energy density, hydrogen offers the potential for aircraft to cover longer distances without refueling, making hydrogen-powered planes a viable option for intercontinental travel (Hydrogen Insight, n.d.). As the aviation industry continues to explore sustainable alternatives, hydrogen turbines could become a cornerstone of future fleets.

• Safety and Technological Considerations: As hydrogen becomes more prevalent in aviation, safety regulations will need to evolve. Although hydrogen is highly flammable, advancements in fuel storage technology and stringent safety protocols could significantly mitigate these risks. Aircraft designs, such as the integrated fuselage of the Boeing 797 (or Jet Zero’s Blended wing design-recently backed by Alaska Airlines), are particularly well-suited to hydrogen fuel systems, optimising space and reducing aerodynamic drag (Canary Media, n.d.). These innovations point towards a future where hydrogen not only enhances fuel efficiency but also aligns with new safety standards.
• Progress and Industry Projections: Over the next decade, hydrogen-powered aviation is expected to grow significantly as technological, infrastructural, and regulatory hurdles are progressively overcome. If current investments in hydrogen technology and infrastructure persist, commercial operations of hydrogen-powered planes could begin by the mid-2030s. This timeline aligns with estimates from industry leaders such as Rolls-Royce, which foresee a transformative shift towards sustainable aviation (Hydrogen Insight, n.d.; Rolls-Royce, 2022).
• Infrastructure Challenges: A critical barrier to the widespread adoption of hydrogen-powered aviation is the development of a robust infrastructure. ZeroAvia has highlighted the need for substantial investments in airport hydrogen storage and refueling facilities, and recently raised $150M series C towards this effort. Without this infrastructure, scaling up hydrogen-powered flights remains a challenge. While the technology shows promise for both regional and intercontinental routes, its success depends on coordinated efforts from the aviation industry, governments, and fuel suppliers to establish a reliable hydrogen supply chain at airports (ZeroAvia, n.d.).

Applications for Different Flight Types

The versatility of hydrogen turbines positions them as a favorable option for both cargo and passenger flights, especially for medium to long-haul routes. In contrast, electric aviation, with its current range limitations, is more suitable for short-haul flights under 250 miles, providing a cleaner and quieter option for urban and regional mobility. This dual approach—employing hydrogen for longer journeys and electricity for shorter trips—could maximize the aviation sector’s efforts toward sustainability (MIT Climate Portal, n.d.). By leveraging the strengths of both technologies, the industry can better navigate the path to a greener future.

Table 3: Comparison of Propulsion Technologies for Aviation

Sources: MDPI Energies, Aviation Today, H2FLY, MIT Climate

4. Adoption Curves driving Hydrogen Turbine Technology

Background Data

The analysis incorporates several key quantitative data points from the sources to project the future adoption of hydrogen turbine engine technology in aviation.

1. The first source estimates a global demand for hydrogen in aviation potentially reaching 17 million tons (Mt) by 2050 under optimal pricing conditions (ScienceDirect, 2024). This figure was crucial as it highlights the significant potential scale of hydrogen adoption, emphasizing the necessity for extensive infrastructure development and cost-effective hydrogen production.
2. The second source focuses on regional data, projecting a demand of up to 120,000 tons per year by 2050 in South West England and South Wales under accelerated adoption scenarios (Hydrogen in Aviation Report, 2024). This regional perspective is vital because it illustrates the varying adoption rates across different geographies, influenced by local policies, technological readiness, and infrastructure capabilities.
3. Research from Carnegie Mellon suggests that hydrogen demand for aviation could potentially reach between 42 million tons (Mt) and 79 Mt by 2050, depending on different adoption scenarios. These figures are significantly higher than the 17 Mt previously estimated, indicating a broader range of adoption potential. This data is essential because it provides a more expansive view of the possible global hydrogen market, taking into account different rates of technological adoption and replacement of conventional aircraft with hydrogen-fueled alternatives (Carnegie Mellon, n.d.).

Methodology

To estimate the adoption scenarios—pessimistic, realistic, and optimistic—various factors influencing hydrogen demand were considered.

• Pessimistic Scenario (75% SAF, 10% Conventional Fuels, 5% Hydrogen, 10% Electric): In this scenario, hydrogen technology adoption remains low due to continued reliance on SAF and conventional fuels, coupled with slow infrastructure development and high costs. This scenario is revised to assume a maximum hydrogen demand of about 5 Mt by 2050, reflecting minimal market penetration.
• Realistic Scenario (70% SAF, 5% Conventional Fuels, 15% Hydrogen, 10% Electric): This scenario now assumes moderate hydrogen adoption with a demand of around 15 Mt by 2050. It considers gradual improvements in hydrogen technology, infrastructure investments, and regulatory support, alongside moderate competition with SAF and conventional fuels. This aligns with the EU’s fit for 55 Package, which mandates that from 2025, at least 2% of aviation fuel must be green, increasing to 70% by 2050.
• Optimistic Scenario (55% SAF, 5% Conventional Fuels, 30% Hydrogen, 10% Electric): Under this scenario, rapid adoption of hydrogen technology could push demand up to 79 Mt by 2050. This aggressive adoption rate assumes significant advancements in hydrogen production and storage technologies, substantial cost reductions, and strong regulator.

Table 4: Hydrogen Demand in Aviation from 2025-2050

Year	Pessimistic Demand (Mt)	Realistic Demand (Mt)	Optimistic Demand (Mt)
2025	0.5	1.5	3
2030	1.0	3.0	6
2035	2.0	6.0	15
2040	3.0	10.0	25
2045	4.0	15.0	50
2050	5.0	15.0	4

Note: The data represents projected hydrogen demand in aviation in million tonnes (Mt) under different adoption scenarios. Sources: ScienceDirect (2024), Hydrogen in Aviation Report (2024).

5. Using Adoption Curves to Forecast Hydrogen Turbine Sales

The methodology for estimating hydrogen turbine sales is rooted in analyzing hydrogen consumption projections and translating them into the number of turbines needed to meet aviation demand. This process utilizes hydrogen adoption curves in various scenarios (pessimistic, realistic, and optimistic) as a basis for understanding future market growth and technology penetration rates. The rationale for this approach lies in the interdependencies between fuel demand, fleet growth, and engine replacements in aviation over time.

• Hydrogen Demand and Aviation Adoption: As hydrogen consumption grows between 2025 and 2050, it drives the need for hydrogen-powered engines in the aviation sector. The adoption curves reflect varying rates of technology acceptance and infrastructure development, which are essential for scaling hydrogen use. By forecasting the hydrogen demand using adoption scenarios (low, medium, and high), we back out the number of hydrogen-powered turbines that will be required to meet this consumption demand.
• Hydrogen Efficiency of Turbines: We assume that each hydrogen turbine consumes a known amount of hydrogen per year. This allows us to translate hydrogen demand (in million tons) into the number of engines required to sustain aviation activity. As hydrogen turbine technology improves, the demand for these engines will accelerate, particularly under optimistic adoption scenarios where hydrogen is adopted at a much faster rate than conventional fuels.
• Replacement Cycle and Fleet Growth: Hydrogen turbine sales not only depend on the initial adoption but also on the replacement cycle and fleet expansion. Over time, existing hydrogen turbines will need to be replaced, and the total aircraft fleet size will grow, creating ongoing demand for new turbines. By factoring in the turbine lifecycle and growth in hydrogen-powered aircraft, we estimate recurring sales, which increase over time as hydrogen becomes a mainstream aviation fuel.

Table 5: Key Constants and Assumptions Used

Adoption Curves as a Strategic Predictor

The adoption curves (pessimistic, realistic, and optimistic) are ideal for estimating turbine sales because they encompass a range of technological and regulatory conditions that could impact hydrogen adoption. For example:

• Pessimistic scenario: Represents low adoption due to slow technological development or lack of supportive infrastructure.
• Realistic scenario: Reflects moderate adoption driven by regulatory pressure and advancements in hydrogen turbine technology.
• Optimistic scenario: Assumes rapid adoption spurred by breakthroughs in hydrogen production and storage technologies, as well as favorable policy interventions.

Table 6: Projected Hydrogen Turbine Sales (2025-2050)

Total Financial Impact

With hydrogen turbine sales forecasted based on different adoption curves, we can translate these projections into financial outcomes. The following table illustrates the total revenue expected from turbine sales based on an average price of $15 million per turbine. The revenue increases substantially under the optimistic scenario due to the rapid adoption and scale of hydrogen technology.

Table 7: Expected Total Revenue of Turbine Sales (2025-2050)

Year	Pessimistic Revenue (Billion USD)	Realistic Revenue (Billion USD)	Optimistic Revenue (Billion USD)
2025	10.11	20.22	39.97
2030	26.34	51.48	98.71
2035	57.78	123.87	212.24
2040	99.84	189.75	363.27
2045	128.27	246.71	455.62
2050	149.51	297.36	498.76

Note: The adoption of hydrogen turbine technology is set to follow a phased trajectory, beginning with modest sales between 2025 and 2030, reflecting the early-stage development of infrastructure and technology. In this period, turbine sales are projected at around 1,000–4,000 units in the optimistic scenario. However, by 2030–2040, the market is expected to accelerate significantly, with over 12,000 turbines sold by 2035 in the realistic scenario, driven by rapid adoption rates and increased investment in hydrogen infrastructure. As the market matures by 2045–2050, growth will stabilize, with turbine sales nearing 30,000 units by 2050 and revenues approaching $300 billion.

6. Conclusion

The pathway to adopting hydrogen turbine technology in aviation is fraught with both significant challenges and unprecedented opportunities. While established manufacturers like Rolls-Royce and Mitsubishi Heavy Industries have the resources and expertise to drive this transition, there is also immense potential for smaller, agile companies to innovate and disrupt the status quo. The case of Boom Supersonic demonstrates that nimble startups, equipped with innovative technologies and approaches to hydrogen production, storage, and safety, can play a pivotal role in accelerating the adoption curve.

However, achieving widespread adoption of hydrogen turbines will require more than just technological breakthroughs. It will necessitate a concerted effort across the aviation industry, from developing robust infrastructure and reducing hydrogen production costs to establishing comprehensive regulatory frameworks that address safety concerns. The industry's future hinges on its ability to navigate these challenges and make strategic investments in hydrogen technology.

As the demand for sustainable aviation solutions grows, the potential market for hydrogen turbines could expand significantly, provided the industry can overcome the existing barriers. Investors, innovators, and policymakers must act decisively to support the development of a hydrogen-based aviation ecosystem. As hydrogen technology progresses, the industry must align its investments, policy frameworks, and collaborative efforts to drive meaningful change. Those who lead this transition will not only push the aviation sector towards sustainability but also gain a competitive edge in a rapidly evolving market.

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