A sustainability framework for ranking industrial heat decarbonisation technologies using multi-criteria analysis

Industrial decarbonisation is a central challenge in achieving global climate targets, particularly due to the sector's heavy reliance on fossil-based heat generation. As efforts to transition toward electrified and low-carbon heating technologies intensify, it becomes essential to assess their full range of environmental impacts beyond carbon emissions alone. Recent studies have drawn attention to the risk of unintended trade-offs when climate targets are pursued without considering other environmental impacts, such as resource depletion and pollution. To address this challenge, a multi-objective optimisation model was developed that combines techno-economic analysis with absolute environmental sustainability assessments. It aims at guiding the design of industrial heat systems under future electricity grid scenarios.

We present a novel methodology that identifies and ranks combinations of optimal technology for industrial heat production at low temperature (100–150 °C) using a genetic algorithm alongside three distinct sustainability-based ranking approaches. The framework incorporates dynamic electricity mixes projected over three future time periods and clusters representative national scenarios. Results show that while electrification through mechanical heat pumps performs well under conventional life cycle weighting (R1), more stringent sustainability-oriented rankings (R2, R3) tend to favour hybrid solutions that combine electrification with gas or biomass boilers. Notably, no configuration fully meets all sustainability thresholds, with resource use often exceeding sustainable limits ‒ even in the most favourable scenarios.

This method goes beyond current LCA-based approaches by integrating absolute sustainability criteria and underscores the importance of selecting appropriate ranking methodologies in political and industrial decision-making. Ultimately, this work lays the groundwork for more holistic assessments that balance decarbonisation with broader environmental objectives and provides a reproducible approach to evaluating technological transitions within the constraints of planetary boundaries.