Aligning prosumers' electricity consumption to the availability of self-generated electricity decreases CO₂ emissions and costs. Nudges are proposed as one behavioral intervention to orchestrate such changes. At the same time, fragmented findings in the literature make it challenging to identify suitable behavioral interventions for specific households and contexts - specifically for optimizing self-consumption. We test three sequentially applied interventions (feedback, benchmark, and default) delivered by digital tools in a field experiment with 111 German households with rooftop-photovoltaics. The experiment design with a control-group, baseline measurements, and high-frequency smart-meter-data allows us to examine the causal effects of each intervention for increasing self-consumption. While feedback and benchmark deliver small self-consumption increases (3–4 percent), the smart changing default leads to a 16 percent increase for active participants. In general, households with controllable electric vehicles show stronger effects than those without. For upscaling behavioral interventions for other prosumers, we recommend interventions that require little interaction and energy literacy because even the self-selected, motivated sample rarely interacted with the digital tools.

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Smart metering and home energy management systems (HEMS) support households with roof-top photovoltaic (PV) to optimize self-consumption. These HEMS can convey subtle guidance for consumption shifts that address intuitive consumption routines. However, the efficacy of the guidance depends on the regulation of self-consumption. This presentation provides experimental evidence on the interplay between both for the case of Croatia, where households that produce more electricity than they consume over the year are automatically re-classified as renewable traders and have additional administrative duties, as well as less favorable tax treatment. This creates perverse incentives to reduce PV generation or increase energy consumption. We document strong behavioral reactions within a real-life field experiment, which was conducted as part of the larger Horizon 2020 project NUDGE. The project collected both survey and smart meter data, which allows for a comprehensive picture of the behavioral reaction. According to the survey wave before the end of the year, almost half of the participants considered curtailing their PV output. According to the smart meter data, a sizable share did indeed take action by shutting down production or by powering additional devices to reduce the surplus near the end of the calendar year. In the final survey wave, prosumers provide ex-post insights on the specific measures taken to reduce surplus. Finally, we discuss insights from the experiment regarding the transparency and control offered by the HEMS, as well as how this can influence household behavior regarding the regulatory framework.@en