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  • Perspective
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Realistic roles for hydrogen in the future energy transition

Nature Reviews Clean Technology volume 1, pages 351–371 (2025)Cite this article

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A Publisher Correction to this article was published on 07 November 2025

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Abstract

Hydrogen has been promoted as a revolutionary fuel for 50 years, yet usage is confined to oil refining and fertilizer production. For hydrogen to advance global decarbonization, many barriers must be overcome. In this Perspective, we examine the challenges hydrogen faces from production to usage, assessing its environmental and economic credentials, controversies and uncertainties. We provide the evidence base for companies and governments to assess clean hydrogen’s current and potential future competitiveness. Fuel cell cars and space heating are among the least promising applications owing to rapid advances in direct electric alternatives. Hydrogen holds potential in industry, long-duration energy storage and long-haul transport, but its competitiveness depends on large-scale deployment yielding substantial cost reductions. Current production cost estimates range by a factor of five and suggest that targets for 2030 will be difficult to achieve, especially once costs for transport and storage are included. The climate impacts of hydrogen production are also uncertain, with production from electrolysis or methane gas with carbon capture potentially increasing system-wide or upstream emissions, alongside water scarcity and persistent organic pollution. Future research must resolve these uncertainties, with strategic focus on deploying hydrogen in priority areas where it is most competitive.

Key points

  • Hydrogen’s versatility means that it can power many applications; however, clean hydrogen should be strategically deployed in areas where it seems likely to have greatest potential for cost and sustainability benefits compared with alternatives such as direct electrification with clean power sources.

  • Supply, demand and supporting infrastructure must all develop simultaneously to overcome systemic barriers; yet hydrogen’s physical properties — its low energy density, flammability and propensity to leak and embrittle metals — impose challenges in terms of cost, safety and acceptance at all stages.

  • For decades, forecasts of a clean hydrogen economy have relied on rapid scale-up driving down costs. However, production costs are dominated by engineering and energy inputs and supplemented by transport, storage and usage costs; none of which seems likely to exhibit the rapid reductions seen with solar photovoltaics and batteries.

  • To contribute to decarbonization objectives, clean hydrogen must have low emissions across its entire supply chain. System-level assessments identify issues with upstream and consequential greenhouse gas emissions from clean hydrogen production, alongside broader environmental impacts. Several preconditions must be met to deliver sustainable and clean hydrogen across its full life cycle.

  • In the short term, renewable electricity could achieve greater emissions abatement if used directly to displace fossil fuels in power generation, heating or transport, instead of being used for green hydrogen production. In the longer term, hydrogen could instead facilitate renewables uptake by integrating excess generation into power systems.

  • Low-carbon hydrogen will be essential to decarbonize its existing applications such as petrochemicals and fertilizers (~2% of global CO2 emissions), or in applications in which decarbonization alternatives are prohibitively expensive, such as steelmaking, heavy transport and long-duration energy storage. Hydrogen strategies should prioritize and support these areas to achieve the greatest impact.

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Fig. 1: Hydrogen in global energy supply and demand.
Fig. 2: Applications for hydrogen, qualitatively ranked in terms of competitiveness against alternatives.
Fig. 3: Projections of global hydrogen production across 100 years.
Fig. 4: Greenhouse gas emissions and efficiency of producing and transporting hydrogen.
Fig. 5: Factors affecting the cost of producing and distributing clean hydrogen.
Fig. 6: Current government policies towards hydrogen and key events over six decades.

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Acknowledgements

The authors thank M. Ewen of Liebreich Associates for support with data gathering and C. Bauer, N. Brandon, M. Chatenet, R. Green, M. Jansen, W. McDowall, H. Schäfer and N. Voulvoulis for constructive feedback. D.M.K. acknowledges support from the Karsten Family Foundation, the Lau Family Foundation and US Department of Energy for their funding through the Water Power Technologies Office (award number DE-EE0009443). R.M. acknowledges support from SHELTERED, funded by the Swiss Federal Office of Energy (SFOE), and the Swiss Center of Excellence on Net zero Emissions (SCENE), co-funded by the ETH Board.

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Authors and Affiliations

  1. Centre for Environmental Policy, Imperial College London, London, UK

    Nathan Johnson & Iain Staffell

  2. Liebreich Associates, London, UK

    Michael Liebreich

  3. Energy and Resources Group, University of California, Berkeley, CA, USA

    Daniel M. Kammen

  4. Goldman School of Public Policy, University of California, Berkeley, CA, USA

    Daniel M. Kammen

  5. Department of Nuclear Engineering, University of California, Berkeley, CA, USA

    Daniel M. Kammen

  6. Institute for Sustainable Resources, University College London, London, UK

    Paul Ekins

  7. Chair of Energy Systems Analysis, Institute of Energy and Process Engineering, ETH Zurich, Zurich, Switzerland

    Russell McKenna

  8. Laboratory for Energy Systems Analysis, PSI, Villigen, Switzerland

    Russell McKenna

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Contributions

I.S. conceived the article with support from N.J. and M.L. N.J. wrote the article with support from I.S. I.S. and N.J. designed the figures. All authors collated data, discussed article content and reviewed and edited the manuscript.

Corresponding author

Correspondence to Iain Staffell.

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Competing interests

N.J. provides consultancy services through Imperial Consultants, and I.S. is the director of Wooler Energy, which provides techno-economic analysis, data analytics and decision support services for the energy sector. Their clients in the past 12 months include Aurora Energy Research, Baringa, The Brattle Group, Drax Group, Octopus Energy and SSE. M.L. is the director of Liebreich Associates and managing partner of EcoPragma Capital. He holds investments in companies including those in green hydrogen, fuel cells, ammonia, heat pumps and electric vehicles. D.M.K., P.E. and R.M. declare no competing interests.

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Supplementary information

Glossary

Additionality

The principle that renewable electricity used for hydrogen production must come from newly added capacity, so it is not diverted from existing uses of energy.

Blending hydrogen

The process of mixing hydrogen with natural gas in pipelines to reduce CO2 emissions from burning the blended gas.

Boil-off

The evaporation of liquid hydrogen during storage or transport owing to its cryogenic temperature requirements.

Clean hydrogen

Hydrogen produced with substantially lower greenhouse gas emissions than traditional methods.

Consequential emissions

Indirect greenhouse gas emissions arising from hydrogen production, such as increased fossil fuel use for electricity to balance intermittent renewables or diverting clean electricity from other sectors.

Critical minerals

Rare and essential materials such as platinum, iridium and nickel used in hydrogen technologies, with supply constraints and environmental extraction impacts influencing the scalability of the industry.

Deliverability

The principle that renewable electricity is sourced from within the same geographic region as hydrogen production to minimize grid congestion and ensure that it can power the electrolysis.

E-fuels

Synthetic fuels produced by combining hydrogen with captured carbon dioxide, which can directly replace fossil fuels in existing engines and infrastructure.

Embodied emissions

Greenhouse gas emissions from the production of materials and infrastructure, such as electrolysers and pipelines.

Embrittlement

The weakening and cracking of metals caused by hydrogen exposure, posing challenges for pipelines and storage tanks.

Geological storage

The storage of hydrogen in underground formations such as salt caverns or porous rocks, offering large-scale, long-duration energy storage options.

Hydrogen derivatives

Chemicals such as ammonia, methanol or synthetic methane, produced from hydrogen and used as fuels or industrial feedstocks.

Hydrogen direct reduction of iron

A steelmaking process using hydrogen in place of coal to reduce iron ore, producing water instead of CO2, which could substantially lower emissions when combined with electric arc furnaces.

Hydrogen economy

A vision of a global energy system in which hydrogen serves as a major energy carrier, supported by large-scale production, distribution and end-use applications.

Hydrogen hubs

Regional centres that integrate hydrogen production, storage and usage infrastructure, facilitating economies of scale.

Hype cycles

A model describing the adoption of emerging technologies, characterized by inflated expectations during early growth, disillusionment when these are not met and finally realistic adoption and integration into the market.

Leakage

The unintentional release of hydrogen, methane or other gases during production, transport or storage, with implications for climate impacts.

Learning rates

The percentage reduction in capital cost for technologies with each doubling of cumulative production; learning is the accumulation of experience in manufacturing.

Levelized cost of hydrogen

The average cost of producing hydrogen over a project’s lifetime, incorporating all capital, operating and energy costs, which reflects the minimum viable sale price to achieve breakeven.

Perfluoroalkyl substances

(PFASs). A broad class of chemicals used in many consumer and industrial products, which do not naturally degrade and raise health concerns as they bioaccumulate.

Temporal matching

The alignment of renewable electricity supply with hydrogen production over time, to minimize reliance on grid electricity, which could be produced from high-carbon sources.

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Johnson, N., Liebreich, M., Kammen, D.M. et al. Realistic roles for hydrogen in the future energy transition. Nat. Rev. Clean Technol. 1, 351–371 (2025). https://doi.org/10.1038/s44359-025-00050-4

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