Pathways for optimal hydrogen integration in hard-to-abate sectors: An application in the glass industry

Aligned with European Union climate objectives and recent United Nations climate conferences in 2023 and 2024, this study evaluates hydrogen as a decarbonisation option for the hard-to-abate glass industry. A multi-energy hub simulation model couples energy conversion technologies—including combined heat and power units based on internal combustion engines and gas turbines, burners, boilers, heat pumps, and recuperative boilers—with segment-specific electricity and heat demands at high, medium, and low temperature. The approach is applied to several glass product lines, with flat glass and glass wool analysed in detail as representative cases with contrasting heat–power ratios.Simulations of hydrogen and methane blending in furnaces, boilers, and combined heat and power units show that carbon dioxide emissions can be reduced by up to 50%–55% when switching from natural gas to fully hydrogen-fuelled furnaces; combined heat and power units based on internal combustion engines can deliver a further 8%–10% reduction, while gas-turbine-based units are constrained by a 50% hydrogen blending limit. Under current hydrogen prices, carbon dioxide savings lead to substantial operating cost penalties: operating expenditure can rise by more than 250% for small plants (approximately 200 tonnes per day) and around 140% for large plants (approximately 1000 tonnes per day). A scale analysis of on-site photovoltaic-powered electrolysis indicates that the levelised hydrogen cost decreases from about 13–14 euros per kilogramme at 200 tonnes per day to 8–9 euros per kilogramme at 1000 tonnes per day. Heat pumps and waste-heat recovery provide incremental benefits but do not alter these trends. Overall, hydrogen emerges as a technically robust yet economically challenging lever whose deployment will rely on economies of scale and supportive policy frameworks.