Rooftop solar may see lower development in border regions, study says

The proximity to language borders implies lower rates of adoption of rooftop PV solutions among homeowners and businesses. This is the main conclusion of the study “Social interactions and the adoption of solar PV: evidence from cultural borders,” published by the Grantham Research Institute on Climate Change and the Environment and the Centre for Climate Change Economics.

In the study, three economists claim that the cultural and language barriers inherent to most border regions are responsible for a reduced role of social spillovers and raising awareness processes that usually characterize the development of several rooftop PV projects within a certain urban or rural area, or geographic region.

The research team, which has investigated the effects of spillovers in the border regions between the French-speaking and the German-speaking parts of Switzerland, stressed that word-of-mouth can be an important social spillover to convince homeowners and businesses to install a rooftop array, despite the risk represented by the initial investment. Imitation is considered another plausible channel for social spillovers, as it may push people to adopt climate-friendly behavior, if they see others going green in their neighborhood.

According to the team, however, the research has so far focused on analyzing the positive effects of social spillover, while neglecting to study the potential barriers.

“The number of ‘missing’ PV adoptions resulting from the language border is non-negligible, as the border leads to 20% less PV adoptions,” the researchers wrote in their paper. The effect of the border, however, tends to vanish once extending the analysis to a radius of 15 km or more, they added.

They further found that the border effect is mitigated by the fraction of people who are fluent in the language of the other side. “When this fraction is sufficiently high, the border has no effect on solar adoption,” they said, adding, “In presence of a cultural barrier, the pool of individuals from which to learn, at a given distance, may be smaller, limiting the power of social spillovers to address information asymmetry and reduce uncertainty on investments in solar energy.”