  While the importance of peer influences has been demonstrated in several
studies, little is known about the underlying mechanisms of active peer effects
in residential photovoltaic (PV) diffusion. Empirical evidence indicates that
the impacts of inter-subjective exchanges are dependent on the subjective
mutual evaluation of the interlocutors. This paper aims to quantify, how
subjective evaluations of peers affect peer effects across different stages of
PV adoption decision-making. The findings of a survey among potential and
current adopters in Germany(N=1,165)confirm two hypotheses. First, peer effects
play a role in residential PV adoption: the number of peer adopters in the
decision-maker's social circle has a positive effect on the decision-maker's
belief that their social network supports PV adoption; their ascription of
credibility on PV-related topics to their peers; and their interest in actively
seeking information from their peers in all decision-making stages. Second,
there is a correlation between the perceived positive attributes of a given
peer and the reported influence of said peer within the decision-making
process, suggesting that decision-makers' subjective evaluations of peers play
an important role in active peer effects. Decision-makers are significantly
more likely to engage in and be influenced by interactions with peers who they
perceive as competent, trustworthy, and likeable. In contrast, attributes such
as physical closeness and availability have a less significant effect. From a
policymaking perspective, this study suggests that the density and quality of
peer connections empower potential adopters. Accordingly, peer consultation and
community-led outreach initiatives should be promoted to accelerate residential
PV adoption.
