The Hidden Energy in Hydrogen Production's Waste
- 1 day ago
- 3 min read
Bich Ha Nguyen
Dai Nam University, Hanoi 100000, Vietnam
*Contact: hanb@dainam.edu.vn
Hydrogen is often portrayed as one of the key fuels of a low-carbon future. Produced using renewable electricity, it can help decarbonize industries that are difficult to electrify, store energy for long periods, and support the integration of wind and solar power into modern energy systems (Koivunen et al., 2023).
Yet hydrogen production comes with an overlooked irony.
Electrolyzers—the devices that split water into hydrogen and oxygen—are celebrated for producing clean fuel. But they also generate large amounts of heat. Traditionally, this heat has been treated as a by-product, something to be removed so the system can continue operating efficiently. In a world urgently searching for clean energy, letting this energy simply dissipate into the air raises an important question: are we overlooking a valuable resource because we are too focused on the hydrogen itself?
This question is becoming increasingly relevant in countries such as Germany, where hydrogen demand is projected to reach between 95 and 135 terawatt-hours annually by 2030 (Bundesministerium für Wirtschaft und Energie, 2024). Producing such quantities will require extensive electrolysis capacity. Since electrolyzers typically operate at efficiencies of only 60–70%, a substantial fraction of the input energy becomes heat, often at temperatures between 50°C and 80°C (Hu et al., 2020; van der Roest et al., 2023).
Conveniently, this temperature range matches the requirements of many district heating systems that provide warmth to homes and commercial buildings.
A recent study explored what happens when this heat is no longer treated as waste. The researchers examined a renewable energy-powered hydrogen production system and compared different approaches to utilizing electrolyzer heat. When no heat recovery was employed, the system merely balanced earnings and expenditures. Simply recovering and using the waste heat reduced expenditures by more than 22% while maintaining profitability. More remarkably, when heat demand was incorporated directly into the system design from the beginning, profits increased by 86.5%, although expenditures also rose by 79.8 %.
The findings reveal that energy systems may be more interconnected than they first appear. Electricity, hydrogen, and heat are often planned separately, each with its own infrastructure, markets, and optimization goals. Yet the study demonstrates that decisions made in one sector can significantly influence outcomes in another.
This insight carries a broader lesson. Humans often evaluate resources according to their primary intended purpose. A forest becomes timber. A river becomes water supply. A solar panel becomes electricity. In doing so, we can overlook the web of relationships through which value emerges.
The same principle applies to hydrogen systems. If policymakers and engineers focus exclusively on hydrogen production, they may miss opportunities hidden in the surrounding energy flows. The heat released by an electrolyzer is not merely a technical by-product. It is part of a larger energetic ecosystem connecting homes, industries, electricity networks, and renewable resources.
As societies pursue decarbonization, success may depend not only on producing more clean energy but also on learning to recognize the value embedded in the connections between systems (Khuc & Nguyen, 2026). Sometimes, the energy we need is already there—we simply call it waste because we are not yet looking at the whole picture (Vuong, 2025; Tran, 2026).
References
Bundesministerium für Wirtschaft und Energie. (2024). Bundeskabinett beschließt importstrategie für wasserstoff und wasserstoffderivate. https://www.bundeswirtschaftsministerium.de/Redaktion/DE/Pressemitteilungen/2024/07/20240724-importstrategie-wasserstoff.html
Dibos, S., Pesch, T., &, Benigni, A. (2026). Impact of heat demand integration on optimal design and operation of renewable-based electrolyzer system. Energy, 360, 141473. https://doi.org/10.1016/j.energy.2026.141473
Hu, Q., et al. (2020). Optimal control of a hydrogen microgrid based on an experiment validated P2HH model. IET Renewable Power Generation, 14(3), 364-371. https://doi.org/10.1049/iet-rpg.2019.0544
Khuc, V. Q., & Nguyen, M. H. (2026). Cultural Additivity Theory. Available at SSRN 6767760. https://ssrn.com/abstract=6767760
Koivunen, T., Khosravi, A., & Syri, S. (2023). The role of power – to – hydrogen in carbon neutral energy and industrial systems: Case Finland. Energy, 284, 128624. https://doi.org/10.1016/j.energy.2023.128624
Tran, T. M. A. (2026). Conversations with Kingfisher: Wisdom from Vuong’s wild wise weird stories. Planet Forward. https://planetforward.org/story/kingfisher-stories/
van der Roest, E., et al. (2023). Utilisation of waste heat from PEM electrolysers – Unlocking local optimization. International Journal of Hydrogen Energy, 48 (72), 27872-27891. https://doi.org/10.1016/j.ijhydene.2023.03.374
Vuong, Q. H. (2025). Wild Wise Weird. AISDL. https://books.google.com/books?id=C5dDEQAAQBAJ
Comments