How to engage consumers in energy transition at the ground level and help them to reduce their electricity consumption? This is the pithy question that inspired the renewable energy supplier Naturstrom to join forces with the Berlin company power42 to develop a smart phone app primarily aimed at people involved in the German concept of “Mieterstrom” (tenant electricity). It means that the owner of a building can directly sell the electricity produced on her rooftop to those who rent the apartments. The process of providing the electricity to the households can also include an electricity provider, and this is why the supplier Naturstrom developed the app for its clients.

The resulting “tenant electricity app” visualises the generation, supply and use of electricity by individual household and across the whole building. The user-friendly interface displays individual consumption, total building consumption and CO2 savings compared to the average German electricity mix. For example, tenants can compare usage across different time periods and be alerted with real-time energy saving tips linked to local weather forecasts.

"With the app, we are giving property owners a means of increasing tenants' loyalty to their property and generating enthusiasm for the local energy transition," explains Sarah Debor, the project lead at Naturstrom, in an article in Solarserver. "In addition, the app is designed to very specifically increase the added value of tenant electricity supply by motivating tenants to use the clean electricity generated in the building as efficiently as possible."

The app – which is free to all users – is particularly handy for landlords, who have a vital role to play in decarbonising the housing sector, and who will be expected to conform to higher standards such as Efficiency House 40 Plus in the future.

The first four residential projects to use it are in Wuppertal, Heppenheim, Eckernförde and Guxhagen, but others will follow suit. The tool was developed by power42, the energy data specialist behind the powerfox platform. "Decentralised supply concepts and smart sector coupling thrive on the digital collection and processing of energy data," comments power42’s Managing Director, Marcus Becker.