Assessing ecosystem services under uncertainty to inform robust solar energy siting in Switzerland

Global efforts to mitigate climate change rely on a transition towards renewable energy systems. In Switzerland, the high potential for solar energy production has led to an increasing interest in expanding solar energy infrastructure, such as ground-mounted photovoltaic systems. However, the siting of these systems requires space that comprises ecosystems providing benefits for human well-being, i.e., ecosystem services, such as habitat quality, agricultural production and recreational opportunities. Uncertainty arises because ground-mounted photovoltaic systems can create both trade-offs and synergies with existing ecosystem service supply. In addition, ecosystem service supply is influenced by climate and land-use changes, as well as shifts in people’s worldviews, beliefs, and values, introducing additional layers of uncertainty. Conceptually, uncertainties in ecosystem services assessments arise from scenario development (scenario uncertainty), modeling (model uncertainty), and the translation of results into decision-making (decision uncertainty). Integrating these different sources of uncertainty into ecosystem services assessments is therefore essential to support robust solar energy siting and enhances the potential uptake of results in decision-making.

For this purpose, we present a spatially explicit, expert-based Bayesian network that addresses scenario, model and decision uncertainty to inform robust solar energy siting under consideration of ecosystem services. The model integrates data from scientific literature, expert knowledge, and future change scenarios, including exploratory and normative scenarios, to identify suitable locations for solar energy systems in Switzerland, which are robust to future changes. Expert knowledge is collected through an online questionnaire, engaging representatives from academia, private sector and public institutions, with particular attention to regions characterised by high solar potential. Using this approach, we map the site suitability across Switzerland and evaluate the robustness, highlighting associated opportunities and risks. By revealing where uncertainties prevail, this study supports an energy transition that aligns with the sustainable management of ecosystem services and can inform planning decisions for solar energy siting.