Warming up to geothermal? The effect of participation on acceptance of local geothermal energy projects in the Netherlands

Extended abstract 1-276-26

Public participation is widely promoted as a means to enhance the social acceptance of renewable energy projects, yet its effects are neither uniform nor well understood for controversial technologies such as geothermal energy. This study examines how decision-making procedures and decision outcomes shape local social acceptance of geothermal energy projects, and whether these effects depend on decision importance and trust in the project operator. We focus on acceptance at two levels: acceptance of specific project decisions and acceptance of the geothermal project as a whole.

We conducted a large-scale online between-subject experiment among 1,882 Dutch respondents. Participants evaluated a hypothetical geothermal project in their neighbourhood and were randomly assigned to one of three participation formats (informing, consulting, or co-deciding) and one of three trust conditions (low, unknown, or high trust in the operator). Respondents assessed five project-related decisions, indicating their preferred outcome, the importance of each decision, and their acceptance after learning the outcome. Decision outcomes were randomized, allowing us to causally disentangle procedural effects from outcome favourability. Acceptance was analysed using cumulative link mixed models.

The results show that participation effects are limited and context-dependent. Co-deciding modestly increases project-level acceptance compared to informing, whereas consulting has no significant effect. Participation does not significantly affect acceptance of individual decisions. In contrast, outcome favourability is by far the strongest determinant of acceptance at both levels, with additional cumulative effects of prior favourable outcomes. Decision importance is negatively associated with acceptance, while high trust in the operator directly increases both decision and project acceptance. Neither decision importance nor trust moderates the effect of participation.

These findings indicate that meaningful influence over decisions can enhance overall project acceptance, but fair procedures alone cannot compensate for unfavourable outcomes, especially for concrete decisions. This indicates that participation must do more than check procedural boxes: it must genuinely address community concerns and reflect local preferences. The study contributes experimental evidence to debates on procedural versus outcome-based drivers of social acceptance and highlights the need for participatory approaches that combine genuine decision influence with outcomes that reflect community preferences.

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