Berkeley Lab study explores how low-income solar adopters can catch the solar bug

Low-income households are more likely to adopt rooftop solar if they live near other low-income rooftop solar adopters

Over a decade of research has shown that rooftop solar is contagious (in a good way). Households that install solar can influence their neighbors to install solar too. The “solar bug” can spread in many ways: households can see panels on their neighbors’ rooftops, or households can speak with neighbors who have adopted, or previous adopters can refer their installers to their neighbors, among many other mechanisms. In social science, this process of social contagion is known as peer influence. Until recently, peer influence has mostly driven adoption among relatively affluent households. As rooftop solar expands, could low-income households also catch the solar bug?

In a new paper published in the journal, Energy Economics, Berkeley Lab researchers explore how rooftop solar peer influence varies across income levels. The researchers reach two key conclusions.

First, peer influence tends to have a weaker impact on adoption levels among low-income households than among high-income households. This result mostly reflects other barriers to low-income adoption. For instance, due to household budget constraints, low-income households face steeper challenges in bearing the up-front costs to buy and own solar panels. Peer influence may prompt low-income households to consider solar adoption, but influence does not address these other adoption barriers.

Second, the analysis suggests that low-income households are more likely to adopt solar if they live near other low-income adopters than if they live near high-income adopters. Put another way, low-income households respond more strongly to the influence of other low-income households. This result is consistent with previous research showing that peer influence is stronger between individuals with shared identities. 

Like other peer influence research, the Berkeley Lab study only estimates the quantitative impact of peer influence but does not identify how or why that influence occurs. Future research could explore specific mechanisms for low-income solar adoption influence, such as visual cues, interactions with previous adopters, installer-related mechanisms, or other factors.

The Berkeley Lab study, The role of peer influence in rooftop solar adoption inequity in the United States, is published in the journal Energy Economics, and is available here. The authors will host a webinar on December 13th at 10:00AM PT/ 1:00PM ET. Register here: https://lbnl.zoom.us/webinar/register/WN_aikGjCi3QlORE1jkkqDVlg

For questions on the report, feel free to contact Eric O’Shaughnessy at Lawrence Berkeley National Laboratory (720-381-4889, [email protected]).

Funding support was provided by the U.S. Department of Energy Solar Energy Technologies Office.