More and more eco-conscious German consumers are opting for plug-in solar devices. Some 150,000 are estimated to be in use, such as the popular balcony-mounted photovoltaic (PV) panels and portable PV devices for motorhomes. However, the industry suffers from a lack of transparency around the manufacturers’ energy savings claims and payback periods.

The Berlin University of Applied Sciences (HTW Berlin) has stepped in with the release of the Plug-in Solar Simulator tool for assessing the effectiveness of many different types of plug-in solutions that are now on the market. "Marketers sometimes advertise here with high amounts of electricity or short payback periods," says Joseph Bergner, a research associate from the PV.plug-inTools project, in a press release.

The project team worked with plug-in manufacturer Indielux, the German Section of the International Solar Energy Society and the Verbraucherzentrale North Rhine-Westphalia. Together they aim to bring greater clarity to the debate about how much power these devices actually save, to what extent their performance is affected by locational factors and whether they provide value for money.

"To do this, we used 1.3 million annual simulations to vary various technical parameters such as the installation situation or the module output and intersected them with 41 residential and household load profiles," says Nico Orth, another researcher on the project. "To make the results playful to experience, they were condensed into an online tool, the plug-in solar simulator."

The PV.plug-inTools project is funded by the Institute for Applied Research Berlin.