Methodology to Develop an Investment Plan for Heating and Cooling Under Climate Uncertainty

Today, over 5 billion people face at least 100 more annual cooling degree days than they did 40 years ago. In parts of Europe, the increase exceeds 55%, largely because these regions were previously less exposed. Despite this rapid change, most European households and many tertiary sector buildings are still unprepared for rising cooling demand. A key reason is deep uncertainty: projections for the next 30 to 50 years vary widely across shared socioeconomic pathways. As a result, decision makers face unclear signals, delaying the adoption of effective adaptation measures. To address this limitation, we developed a method for long-term investment planning under climate uncertainty. We start by generating a thermal demand model using climate projections from the Copernicus Institute and integrating it into an energy system optimization model. Using multi-stage optimization, we identify early investment decisions that can adapt over time through recourse actions. Our case study focuses on a university campus (Vrije Universiteit Brussel) in Brussels, Belgium, which currently lacks adequate cooling infrastructure. The results provide a stepwise investment strategy that stays cost-effective across a wide range of climate futures.