Climate messaging and free energy: Are demand-side flexibility incentives effective? Lessons from a UK field experiment

Adding to the empirical body of evidence on residential flexibility responsiveness, this paper presents a field experiment utilizing social norms and pecuniary incentives to promote residential load shifting among households in the United Kingdom, occurring from spring 2024 to spring 2025. The experiment is a randomised controlled trial, where recruited customers were randomly assigned to an intervention and control groups. A third group of non-participants consumers, shielded from the observation effect and the selection bias of the recruitment, is also considered. Four treatment effects, each measuring a desirable outcome of interest are introduced. A purposive sample of the intervention and control groups took part in semi-structured interviews one to two months after the launch of the field experiment. This provided qualitative data on consumer motivations, barriers and enablers as part of a mixed methods approach to explain the resultant energy usage behaviour. Using a set of quantitative methods for causal inference, we examine if normative information can be inducive of a reduction in peak consumption. We assess if the effect of the monetary incentives is crowded out by the normative ones when used simultaneously. A thematic analysis of the qualitative interview data indicated lifestyle factors that could influence behaviour such as predictability of routines and level of control over when energy-consuming tasks could be performed. It also highlighted influential features of information provision such as the frequency of the challenges set by the energy provider and how performance data could be presented to be meaningful to them. Finally, a technical-economic study was carried out to simulate the effect of mass adoption of this scheme on the scale of the electrical system.