Green means go: The effect of a visualization tool towards increased use of renewable energy in households

There is a need to further develop digital and hardware tools to support consumers in the adaptation of their energy use to, for example, integrate renewable sources into it and/or reduce expenses. This paper presents an evaluation study of a tool, including its hardware and software versions, that supports consumers in their electricity consumption optimization, most notably concerning renewable energies for specific devices. We conducted a six-week study in Oldenburg, Germany involving 43 participants divided into three groups: one hardware and one digital variant each of an energy visualization tool, as well as a control group. We furthermore collected quantitative data on energy usage patterns and qualitative insights through semi-structured interviews. Here the participants received information about the percentage of renewable energy currently in the grid, and were asked to document their washing machine and dishwasher use. This paper provides insights into the perception of the proposed visualization tools achieved through semi-structured interviews, comparing the digital and hardware versions, while outlining the challenges of and possibilities for changing energy use behavior, especially regarding the time of day of an appliance's use. Even though the measurable influences of the tool were limited due to thresholds being reached too easily as a result of e.g. high wind levels generating higher-than-anticipated amounts of renewable energy, in terms of the amount of renewable energy use, slight improvements in the two test groups were observed compared to the control group. Regarding consumer behavior, changes in the appliances' use time show slightly higher improvement compared to the control group.