The inventory recently passed the million mark - and the boom continues.

The number of balcony power plants in Germany increased by more than 220,000 in the first half of the year. As of June 30, 1,009,390 of these systems were registered with the Federal Network Agency on Tuesday. The actual number is likely somewhat higher, as there is a one-month deadline for late registrations and, despite the mandatory registration requirement, not all systems are registered.

Growth in the first half of the year is thus roughly at the same level as the previous year. Carsten Körnig of the German Solar Industry Association also sees no significant slowdown so far: "Plug-in solar devices remain extremely popular. We expect demand to remain high," he says. The main drivers are the legal simplifications passed under the last federal government, as well as the recent drop in prices for the systems.

Another factor contributing to the boom could be the fact that more and more well-known retailers have recently started stocking these devices in their product ranges. "This should reinforce the perception that balcony power plants have become mainstream," says Körnig.

Unsurprisingly, the most balcony power plants are located in the most populous federal states of North Rhine-Westphalia and Bavaria, with over 200,000 and over 150,000, respectively. However, when comparing the number of power plants with the number of households recorded by the Federal Statistical Office, for better comparability, Lower Saxony and Rhineland-Palatinate lead the way. There, there are just under 34 and just under 31 plants per 1,000 households, respectively. Brandenburg, with just over 28, and Schleswig-Holstein, with more than 27, are also well above the national average of just under 25.

The lowest densities, however, are found in the city states, with Hamburg bringing up the rear at just under 8 per 1,000 households. The structure of the building stock is likely the decisive negative factor here. Among the non-urban states, however, North Rhine-Westphalia and Bavaria fare poorly, with just over 23 and just under 24 systems per 1,000 households, respectively.