In energy projects, especially in controversial ones, two trajectories of assessment can be distinguished: a formal trajectory, embedded in the legal system, and an informal trajectory, residing in the public discourse. Often, there is a fundamental mismatch between these two trajectories. The informal trajectory arises because local residents perceive certain shortcomings in values used to assess the project in the formal trajectory. In this paper, we investigate the role values play in the assessments of eight utility-scale solar farms in two municipalities in the Netherlands. Based on policy documents, transcripts of city council meetings and newspaper articles, we identify seven values that play an important role in the assessment of solar farms. In order of their occurrence: Prudent land use, Procedural justice, Minimized observable impact on surroundings, Legality, Sustainability, Financial distributive justice and Innovation. Of these, Legality and Sustainability are most used as arguments in favor of solar farms (mostly in the formal trajectory), whereas Procedural justice, Prudent land use and Minimized impact on surroundings are most used in arguments against solar farms (in both trajectories). Our empirical results indicate that a solar farm is more likely to be controversial when only a minimal formal evaluation framework is in place. Based on our results, we recommend policymakers to develop comprehensive evaluation frameworks for energy projects, as well as to organize a multitude of interaction opportunities between the formal and informal trajectory. In this way, the interaction between the two trajectories can lead to better-quality and better-supported decisions on energy projects.