How should you heat your home in the green energy transition? A scenario-based multi-criteria decision-making approach

The choice of heating system is significant for city planners and building owners alike, and many important areas, such as the well-being of residents, climate change impact and resource efficiency, may influence the choice. Understanding how to balance these areas is crucial for effective decision-making that can contribute to sustainable development and the green energy transition. However, these decisions represent complex problems where disparate knowledge areas must be considered simultaneously. When faced with this type of decisionmaking problem, employing different multi-criteria decision-making methods is common. However, such methods only provide a snapshot of which alternative is preferred and because of this, their results may become obsolete due to changes in the performance of alternatives or the value perceptions of the decision-makers. To overcome this challenge and to improve the longevity and reliability of multi-criteria decision-making results, the authors of this study explored a novel approach to producing semi-dynamic results through scenarios, which were used to consider possible future changes to the alternatives' performance and the decision-makers' value perceptions. The application of scenarios in the multi-criteria decision-making method enabled nuanced information to be produced on how the performance of different heating alternatives may change under different plausible futures. This approach was demonstrated by applying it to the case of residential heating in Denmark, where results showed that while final rankings varied across both scenarios and ranking methods, solar heating was the preferred alternative, while the oil boiler alternative performed the worst. Overall, this study highlights the importance of considering likely future changes to both the performance of alternatives and the value perceptions of decision-makers when making decisions with long lifetimes and suggests an approach for doing this.