Early adopters and their motives: Differences between earlier and later adopters of residential solar photovoltaics

To facilitate and forecast the diffusion of sustainable innovations, such as solar photovoltaics (PV), it is important to understand what motivates people to adopt them. Early adopters are known to be partly driven by other motives than late adopters, and adoption motives may thus change over time as new user segments gain interest in the technology. This paper investigates differences in adoption motives between the earliest and somewhat later adopters of residential PV systems. First, a systematic literature review is conducted, in which the findings of previous studies are mapped against the market maturity of their empirical contexts. The review reveals that the earliest PV adopters are driven mainly by environmental concern and technophilia, while later adopters are driven predominantly by economic gains. Second, an empirical investigation of Swedish adopters over a nine-year period is conducted, using Green Party voting as a proxy for environmental concern. It is found that the relationship between Green Party voting and PV adoption weakens over time, again suggesting that the earliest adopters are more driven by non-financial motives such as environmental concern than later adopters. The results can inform diffusion forecasting as well as marketing and information campaigning intended to induce PV adoptions.