Rising with the sun? Encouraging solar electricity self-consumption among apartment owners in Sweden

Abstract

Studies suggest that householders who turn prosumers become more energy aware, change their pattern of electricity use and may even start to engage in other pro-environmental activities. However, few of these studies were equipped to investigate such causal relationships—mainly because most prosumers are inherently self-selected. However, as real estate companies and building owners have begun installing photovoltaics on their customers’ behalf, a new breed of non-self-selected prosumers is emerging, which presents new opportunities to address questions of causality and thus improve our understanding of the possible implications of a more prosumer-dense future. Using a sample of 54 apartment households with a shared rooftop PV installation, this article presents the first causal analysis on non-self-selected prosumers’ response to information about having become prosumers, what that means for themselves and the collective they are part of, how to self-consume solar electricity and why they should do so. Using a stepped wedge design and stratified randomization procedure we were able to design an experimental study with sufficient power. A panel regression model and various statistical analyses on pre and post treatment survey- and electricity use data were used to evaluate the intervention. In line with studies of self-selected prosumers, the self-reported measures suggest that householders have shifted the use of major appliances to increase their self-consumption. However, based on the electricity use data, we find no evidence of a such a shift and no indications of spillovers to other pro-environmental behaviours—highlighting the need to use multiple measures to assess behavioural change.