Increasing the reach of low-income energy programmes through behaviourally informed peer referral

Subsidized energy assistance programmes are a popular policy tool for promoting energy justice, but, like other social benefits programmes, are often undersubscribed. To improve uptake, some programmes have turned to social influence strategies, such as asking programme participants to refer their peers. Here, through a field experiment with California’s low-income solar programme (N = 7,676), we show that referral behaviour depends on how existing participants are approached. Adding behavioural science strategies to a referral reward increases peer referral rates, referral quality and ultimately solar adoption. Compared with only reminding existing adopters of a potential US$200 reward for referrals that result in adoption, adding an appeal to reciprocity through a non-contingent US$1 gift—and further combining this gift with a simplified referral process—leads to 2.6–5.2 times as many solar contracts. These results highlight the potential of behaviourally informed peer referral programmes to accelerate equitable access to clean energy.