By Denis Koshelev 

 

Our world faces two colossal challenges: mountains of ever-growing waste and an urgent need for clean energy. What if the solution to one significantly helps the other? Emerging technologies are now turning problematic waste streams – from household trash to industrial residues – into clean hydrogen, a fuel poised to power a decarbonized future.

 

Generating hydrogen from waste offers a dual advantage: it produces clean energy and provides a sustainable solution for waste management. Converting waste to hydrogen reduces landfill emissions and leverages abundant, carbon-rich materials. 

 

Recent advances span thermochemical routes (gasification, pyrolysis, hydrothermal processing), biological routes (dark fermentation, photofermentation, bioelectrochemical cells), and solar/electrochemical methods (photocatalytic reforming, photoelectrochemical reactors). These approaches vary widely in their development stage, ranging from laboratory proof-of-concept to pilot and near-commercial demonstrations, and in terms of efficiency and scalability. [1]

 

The Case for Waste-Derived Hydrogen

 

Green hydrogen is anticipated to play a critical role in achieving net-zero emissions, particularly in sectors where electrification is challenging, such as aviation and shipping. However, current industrial methods for hydrogen production rely heavily on fossil fuels, resulting in substantial carbon dioxide emissions. This reliance underscores the urgent need for sustainable and low-carbon alternatives to meet the increasing global demand for hydrogen. Waste materials are emerging as a promising feedstock for hydrogen production, offering a pathway toward a circular economy and reducing our dependence on finite fossil resources.

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Learn more about Green Hydrogen in our article Global Push for Hydrogen as a Climate Solution: Examining Green and Blue Hydrogen.

The contrast between hydrogen’s clean combustion, producing only water, and the significant carbon emissions from its conventional production highlights the importance of developing environmentally benign production routes. The increasing volumes of waste generated globally present a significant environmental and economic burden. Converting these waste streams into hydrogen not only addresses the disposal challenges but also transforms them into a valuable energy carrier, signifying a fundamental shift in how we perceive and manage waste. [2] [3]

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Thermochemical Conversion (Gasification and Pyrolysis)

 

Gasification

Thermochemical processes use heat (often with oxygen or steam) to break down waste into a hydrogen-rich syngas (a mix of hydrogen and carbon monoxide). Gasification involves heating waste in a low-oxygen environment to produce syngas, from which hydrogen can be extracted.

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Conventional gasification (fluidized or fixed bed) of mixed waste or biomass is relatively mature. For example, a Chinese demonstration plant in Beijing’s Fangshan District has gasified MSW (Municipal Solid Waste) at 2 t/day and produced syngas that was ~65% H₂ by volume, yielding >99% pure hydrogen after cleanup. The residual ash is converted to a vitrified slag, and a CO₂ byproduct can be sequestered. [4]

Hydrogen Naturally, based in Calgary, is advancing front-end engineering for a green hydrogen plant that will convert 600,000 tonnes of western Canadian forest residues into hydrogen and sequestered CO₂. The Alberta government invested $3 million in 2025 to support feasibility studies and regulatory work for the project. [5] [6] The company’s process pelletizes forestry waste, gasifies it to produce hydrogen, and captures the resulting CO₂ for underground storage, resulting in carbon-negative hydrogen. [7] [6]

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Advanced gasifiers push temperatures higher or use novel reactors. Plasma gasification uses >2000–3000 °C plasmas to decompose waste. [9]  For example, India’s NTPC is building a plasma‐assisted oxy-gasification demo that will gasify ~25 t/day of MSW and agri-waste to produce ~1 ton/day of hydrogen. The syngas (>99% H₂ purity after membrane separation or Pressure Swing Adsorption (PSA)) is exceptionally clean. Sweden’s Plagazi has won a €29.5 M EU grant to scale its high-temperature plasma gasifier for waste-to-hydrogen production. These plants remain at pilot/demonstration scale due to high energy input, but promise very high conversion of all waste constituents. [8]

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“Moving injector” gasifiers represent another innovation. In Australia, Wildfire Energy (Brisbane) launched a pilot “Moving Injection Horizontal Gasifier” (MIHG) that converts organic municipal/biomass waste into syngas. The syngas is cleaned, and hydrogen is separated (the rest is burned for power/heat). [10]

 

Hydrothermal processing is highly relevant and increasingly important for hydrogen production from waste. It’s a suite of high-temperature, high-pressure water-based processes — including hydrothermal gasification and hydrothermal liquefaction — that are especially effective for wet waste streams. [29] [30] Hydrothermal gasification operates at 210–350 bar and 360–700 °C, converting nearly all carbon in the feedstock into a gas rich in hydrogen and methane. This process is particularly suited for organic wastes that are wet or water-miscible, such as sewage sludge, food waste, agricultural residues, digestate from anaerobic digestion, and even some industrial and municipal wet wastes. It can also handle certain plastics and mixed wastes when they are water-compatible. 

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Pyrolysis

Pyrolysis stands as a technology for converting biomass into an intermediate liquid. This liquid can subsequently be refined into drop-in hydrocarbon biofuels, oxygenated fuel additives, and substitutes for petrochemicals. At its core, pyrolysis involves heating organic materials like biomass in the absence of oxygen. Biomass pyrolysis is typically carried out at temperatures of 500 °C or higher, providing sufficient energy to break down the robust biopolymers found in biomass. [12] The lack of oxygen prevents combustion, instead leading to the thermal decomposition of the biomass into combustible gases and biochar. 

The bio-oil produced by pyrolysis can serve as a feedstock for steam reforming, a process where it reacts with steam at high temperatures in the presence of catalysts to generate hydrogen-rich gas. This approach leverages the easier transport and handling of the liquid bio-oil compared to raw biomass, enabling hydrogen production at centralized or distributed facilities. [31]

Overall, thermochemical routes generally yield high-purity hydrogen after gas cleanup, but require significant heat input. High-temperature processes (plasma) can reach very high conversion and H₂ purity (>99%), but have a high electricity demand. On the plus side, carbon monoxide in the syngas can be shifted and captured as CO₂, enabling near-net-zero or negative CO₂ emissions when coupled with sequestration. [5] Scaling up these technologies requires robust reactor design. [13]  Several countries have pilot plants proving the concept, but only a few commercial-scale waste-to-hydrogen gasifiers are in or near operation.

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Biological and Bioelectrochemical Processes

Biological routes use microbes to ferment or convert organics to hydrogen, often at much lower temperatures.

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Dark fermentation

Dark fermentation is a biological process where microorganisms convert organic waste into biohydrogen in the absence of light. [15] This anaerobic process utilizes bacteria to break down complex organic matter present in waste streams. A key advantage is its ability to use a wide variety of organic wastes as feedstocks, such as agro-industrial residues, food waste, and wastewater. The primary desired output from this waste conversion is hydrogen gas (H₂). [16]

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Alongside hydrogen, the process also generates CO₂ and valuable organic byproducts like volatile fatty acids (VFAs), including acetic and butyric acids, from the waste. [17] Bacteria from genera such as Clostridium are commonly involved in this fermentation of waste. [18]

 

Utilizing dark fermentation for waste offers the dual benefits of treating organic waste and producing renewable hydrogen without the need for light energy. However, challenges include relatively lower hydrogen yields compared to other methods and the necessity to separate the produced hydrogen from carbon dioxide. [19] Its primary application in this context is the sustainable generation of hydrogen from diverse organic waste streams. 

 

Recent reviews emphasize the synergy of combining dark fermentation with photobiological conversion [14]. For example, a lab study showed that coupling fermenters with cyanobacteria/algae (which consume the fermentation byproducts under light) can significantly boost overall hydrogen yield from the same waste feed. [14]

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Photofermentation and photobiological systems

Photofermentation and photobiological systems are promising methods for generating hydrogen from waste by leveraging the metabolic activity of photosynthetic microorganisms, particularly purple non-sulphur bacteria, under light conditions. [20] In photofermentation, these bacteria convert organic substrates — often derived from industrial, agricultural, or municipal waste — into hydrogen gas, using sunlight as the energy source. [21] This process can utilize a wide range of waste materials, including food processing waste, distillery wastewater, landfill leachate, and sewage sludge, making it attractive for both waste management and renewable energy production. [22]

Photobiological hydrogen production encompasses both photofermentation and biophotolysis. In biophotolysis, microalgae or cyanobacteria use sunlight to split water, generating hydrogen and oxygen. [23] However, this method faces challenges such as low hydrogen yields and oxygen inhibition, which limit its commercial viability. [23] Photofermentation, by contrast, is more suitable for organic-rich waste streams, but its hydrogen production rates and solar-to-hydrogen efficiencies remain relatively low, presenting a barrier to large-scale application. [24]

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Microbial electrolysis cells (MECs) and bioelectrochemical systems represent another emerging class. Here, wastewater or sludge is fed to a bioreactor: microbes oxidize organics at the anode, and a small applied voltage drives H₂ evolution at the cathode. [25] These systems are still in R&D or small pilot stages due to the need for catalysts and membranes.

 

Photocatalytic Hydrogen Production from Waste

Photocatalytic hydrogen production involves using a photocatalyst and a light source to split water molecules into H₂ and O₂. In photocatalytic hydrogen production from waste, the waste itself is the electron source for hydrogen evolution, and its degradation is directly coupled to H₂ production. [32] This method has shown significant improvements and promising yields in hydrogen production. It can be used to treat environmental waste and produce hydrogen simultaneously. [26] The environmental impacts of photocatalytic waste treatment and synchronous hydrogen production primarily affect freshwater, marine, and terrestrial ecological toxicity, as well as non-carcinogenic toxicity to humans.

These ecological impacts result from the catalyst’s adsorption and metal leaching during photo-degradation and hydrogen production.[26] These effects can be mitigated through reasonable modifications and morphological refinements to the catalyst, enhancing the efficiency of environmental waste processing and hydrogen production. Photocatalytic valorization transforms waste into energy or chemicals using only sunlight. 

Photocatalytic reforming, where organic compounds in waste (e.g., pollutants in wastewater) are converted into H₂ and other less harmful substances using a photocatalyst and light, is a reasonable alternative to methods like anaerobic fermentation, especially for highly toxic waters. A drawback of using complex aqueous streams for photocatalytic hydrogen production is the potential presence of substances that may inhibit the reaction by blocking active sites or consuming photo-generated electrons.

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The Promise and Potential of Waste-Derived Hydrogen in a Sustainable Energy Future

Emerging methods for generating hydrogen from waste, including thermochemical, biological, and photocatalytic approaches, represent significant advancements in clean energy production and sustainable waste management. These technologies offer the potential to convert various waste streams into a valuable clean fuel, contributing to a circular economy and reducing reliance on fossil fuels. While challenges related to efficiency, scalability, and cost-effectiveness remain, ongoing research and development are continuously improving the performance and viability of these methods.

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It’s not just theory: the increasing number of pilot and commercial waste-to-hydrogen plants worldwide demonstrates the growing recognition of waste as a valuable resource in the transition towards a sustainable hydrogen economy. Two pilot plants are being developed in Oman by Manah Hydrogen, each with a capacity of 1 tonne of waste per day, producing 110–140 kg of hydrogen daily. [33] In the United Kingdom, a demonstration plant using the RODECS pyrolysis and gasification system produces up to 1.5 tonnes of hydrogen per day from waste. [34][35] At the Sunamachi Water Reclamation Center in Japan, a small-scale plant processes one tonne of sewage sludge daily, yielding 40–50 kg of hydrogen. [36] The Suez Canal Economic Zone (SCZONE) in Egypt is partnering with Germany’s H2 Industries to develop a $4 billion waste-to-hydrogen plant in East Port Said. The plant is projected to convert 4 million tonnes of waste into 300,000 tonnes of clean hydrogen each year. [37] More projects are on the way.

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Continued innovation, coupled with supportive policies and strategic investments, will be crucial in fully realizing the promise of waste-derived hydrogen and its role in a cleaner energy future.

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References

1. https://www.ox.ac.uk/news/features/green-fuels-breakthrough-bio-engineering-bacteria-become-hydrogen-nanoreactors

2. https://www.plasticsengineering.org/2023/09/novel-process-affordably-turns-waste-plastic-into-green-hydrogen-001925/

3. https://pubs.rsc.org/en/content/articlehtml/2025/ya/d4ya00292j Plastic waste gasification for low-carbon hydrogen production: a comprehensive review Muhammad Aamir Bashir, Tuo Ji, Jennifer Weidman, Yee Soong, McMahan Gray, Fan Shi and Ping Wang 

4. https://task33.ieabioenergy.com/wp-content/uploads/sites/33/2023/12/IEA-Bioenergy-Task-33_Newsletter-II-FINAL.pdf

5. https://calgary.tech/2025/04/28/alberta-local-hydrogen-fuel-production-project/

6. https://www.eralberta.ca/media-releases/turning-forestry-waste-into-industrial-fuel/

7. https://www.canadianbiomassmagazine.ca/fibre-fuel-canadian-company-looks-to-create-hydrogen-from-marginalized-wood/

8. https://fuelcellsworks.com/2024/11/04/green-investment/plagazi-secures-29-5-million-eu-grant-to-advance-waste-to-hydrogen-technology

9. https://www.sciencedirect.com/topics/engineering/plasma-gasifiers

10.  https://hydrogensociety.org.au/wp-content/uploads/2023/10/HSA-Newsletter-Issue-No-20-September-2023.pdf

11.  https://interestingengineering.com/energy/hydrogen-made-from-plastic-waste

12.  https://www.ars.usda.gov/northeast-area/wyndmoor-pa/eastern-regional-research-center/docs/biomass-pyrolysis-research-1/what-is-pyrolysis/

13.  https://www.gamechangers.technology/challenge/Technologies_to_scale_thermochemical_methods_of_hydrogen_production

14.  https://www.eurekalert.org/news-releases/1069181

15.  https://www.energy.gov/eere/fuelcells/hydrogen-production-microbial-biomass-conversion

16.   https://www.mdpi.com/1996-1073/17/24/6350 (Insights into Biohydrogen Production Through Dark Fermentation of Food Waste: Substrate Properties, Inocula, and Pretreatment Strategies by Djangbadjoa Gbiete 1, Satyanarayana Narra 1,*,Damgou Mani Kongnine 2, Mona-Maria Narra and Michael Nelles 1

17.  https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.614612/full (Volatile Fatty Acids (VFAs) Generated by Anaerobic Digestion Serve as Feedstock for Freshwater and Marine Oleaginous Microorganisms to Produce Biodiesel and Added-Value Compounds Alok Patel1Amir Mahboubi2Ilona Sárvári Horváth2Mohammad J. Taherzadeh2Ulrika Rova1Paul Christakopoulos1Leonidas Matsakas1*

18.  https://academic.oup.com/femsre/article/41/2/158/2979383?login=false (Microbial ecology of fermentative hydrogen producing bioprocesses: useful insights for driving the ecosystem function (Lea Cabrol ,  Antonella Marone ,  Estela Tapia-Venegas ,  Jean-Philippe Steyer ,  Gonzalo Ruiz-Filippi ,  Eric Trably]

19. Hydrogen Production During the Dark Fermentation of Glycerol, Guochen Zhang

20.  https://www.rees-journal.org/articles/rees/full_html/2021/01/rees210064/rees210064.html

21.  https://www.sciencedirect.com/science/article/abs/pii/S0960852411004743

22.  Bio-Hydrogen Production Using Landfill Leachate Considering Different Photo-Fermentation Processes. Hind Barghash1*Kenneth E. Okedu2,3*Aisha Al Balushi

23.  https://www.energy.gov/eere/fuelcells/hydrogen-production-photobiological

24.  Biological fermentation pilot-scale systems and evaluation for commercial viability towards sustainable biohydrogen production Quanguo Zhang 1,2, Youzhou Jiao 1, Chao He 1, Roger Ruan 3, Jianjun Hu 1, Jingzheng Ren 4, Sara Toniolo 5, Danping Jiang 1,2, Chaoyang Lu 1, Yameng Li 1,2,✉, Yi Man 4, Huan Zhang 1,6,✉, Zhiping Zhang 1,6,✉, Chenxi Xia 2, Yi Wang 6, Yanyan Jing 1,6, Xueting Zhang 2, Ruojue Lin 4, Gang Li 6, Jianzhi Yue 1, Nadeem Tahir 6 (https://pmc.ncbi.nlm.nih.gov/articles/PMC11133433/)

25.  Microbial electrolysis cells: Fuelling the future with biohydrogen – A review. Divyanshu Sikarwar, Indrasis Das, Anusha Ganta (https://www.sciencedirect.com/science/article/pii/S2949839225000197)

26. Environmental Impact of Waste Treatment and Synchronous Hydrogen Production: Based on Life Cycle Assessment Method. Yiting Luo, Rongkui Su

27. Assessment of Photocatalytic Hydrogen Production from Biomass or Wastewaters Depending on the Metal Co-Catalyst and Its Deposition Method on TiO2/ Mikel Imizcoz, Alberto V. Puga

28. https://pubs.rsc.org/en/content/articlehtml/2025/cs/d4cs00604f

29. https://www.natrangroupe.com/sites/default/files/hy/hydrothermal-gasification-white-paper.pdf

30. https://www.energy.gov/eere/bioenergy/articles/hydrothermal-processing-wet-wastes

31. https://www.energy.gov/eere/fuelcells/hydrogen-production-biomass-derived-liquid-reforming

32. https://www.sciencedirect.com/science/article/abs/pii/S0021979724012852

33. https://energy-utilities.com/oman-based-startup-launches-waste-to-hydrogen-news125112.html

34. https://www.beeahgroup.com/beeah-chinook-hydrogen-air-water-gas-solutions-inaugurate-the-super-green-hydrogen-waste-demonstration-plant-at-cop28/

35. https://chinook-hydrogen-rc2.squarespace.com/cop28-announcement

36. https://www.prnewswire.com/news-releases/ways2h-shareholder-japan-blue-energy-launches-tokyo-renewable-hydrogen-production-facility-301258110.html

37. https://www.thenationalnews.com/business/2022/06/01/egypts-sczone-signs-agreement-with-h2-industries-for-4bn-waste-to-hydrogen-plant/