The mega solar Twitter discourse in Japan: Engaged opponents and silent proponents

Social media is used by many for information gathering and sharing nowadays. Public opinion and risk perception are increasingly being shaped online. These online discourses provide valuable insight into the concerns and expectations of its users. This study analyzed more than 50,000 tweets to identify the attitude, locality, and concerns about large-scale solar photovoltaic, so-called mega solar, projects in Japan. The results show that the Twitter discourse is dominated by mega solar opponents who are especially concerned about the negative environmental impact of the projects, as well as the trustworthiness of politicians, developers, and experts. The concerns are not limited to specific local projects but mega solar is often generally dismissed as a suitable energy source in Japan. Twitter allows opinion leaders to reach a large audience with unvetted and biased negative information about mega solar. The lack of opinions that challenge these pre-existing group beliefs indicates the existence of an echo chamber. The currently silent supporters are advised to embrace social media to balance the one-sided discourse and build trust through transparency and engagement with concerned stakeholders. •The online discourse on mega solar projects is dominated by its opponents.•Concerns about mega solar are not limited to specific local projects.•Main concerns are about deforestation, safety issues, and lack of trust in experts.•Many users are confronted with one-sided, negative information in an echo chamber.•The proponents' silence is a missed chance for balancing the biased discourse.