Energy transition | Balcony power plants on Kotti: cent collectors on the railing

At the railing with a solar module: Senator for Economic Affairs Franziska Giffey, district mayor Clara Herrmann, Plan B 2030 boss Lu Yen Roloff, Gewobag boss Markus Terboven (back) and tenant councilor Abdul Kadir Aktürk Photo: nd/Christian Lelek He, the Kotti, should shine. A one and a half square meter matt black plate is supposed to make this possible, at least when the sun is shining. In addition to the numerous satellite dishes that already exist, so-called balcony power plants will adorn the facade of the “Zentrum Kreuzberg” in the future and supply the tenants’ households with solar power.

60 selected tenants will receive such a plug-in solar device for free, which is what the mini photovoltaic system is actually called. Berlin's outgoing Senator for Economics and Business Franziska Giffey (SPD), district mayor Clara Herrmann (Greens) and Gewobag board member Markus Terboven presented the project on Wednesday. The state-owned housing company Gewobag bought the 295 apartments and 90 commercial units at the “Kentrum Kreuzberg” in 2017 for 56.5 million euros.

On the one hand, the 60 households were selected based on the location of their balconies. South-facing balconies without shading make the best use of sunlight. At the same time, the tenant council of the “Zentrum Kreuzberg” was involved in the selection. “All tenants want to have a balcony power plant, we actually need supplies now,” says tenant councilor Abdul Kadir Aktürk to “nd”. Due to the high demand, the tenant council made sure that social criteria were taken into account when making the selection.

A person in a single household, for example, who is at work during the day when the sun is shining and cannot use the energy, was not taken into account, says Aktürk. There are old people who have problems with their electricity bills and single parents who spend a lot of time at home with their families, who were given preference. “It should be really social,” says Kadir.

The man from the tenants' council looks at the construction of the solar panel. “Stylish and robust without damaging the facade,” says Kadir. There could also be two or three hanging next to each other, "there are ten-meter balconies here," says Lu Yen Roloff, managing director of the Plan B 2030 association. He wants to help push climate neutrality projects.

Roloff speaks of a snowball effect that the 60 systems at Kotti could trigger. “Since I have my own solar power plant on my balcony, ten new power plants have been born in my area,” she reports.

»The balcony power plant brings a significantly better return on investment than the savings account.«

But it is not the only project presented this morning in which Roloff's association is involved. Many tenants in Berlin would like to install their own solar system on their balcony, but failed due to doubts or requirements from landlords, including the country's housing associations. In 2024 and 2025, the state government approved 98 balcony power plants for a total of 360,000 apartments. In order to receive approval from Degewo, a self-paid suitability test by an electrical specialist company was necessary.

Plan B 2030 wants to overcome this gap with the “Berlin solution kit for balcony power plants”. To do this, the association looks at previous approval procedures, models of balconies and solar modules, but also the new legal situation. Best practices should be prepared. “Publicly accessible sample letters, checklists and other templates are intended to make it easier for landlords in particular to agree to the installation and thus promote the use of balcony power plants throughout Berlin,” says a press release on Wednesday.

A single plate is still waiting for reinforcements. Photo: nd/Christian Lelek The project is funded by the Senate Department for Economics and Business. According to Senator Giffey, there are 27,200 solar systems on Berlin balconies. According to Giffey, the importance of the small systems lies primarily in their integrative effect. »Berlin is a city of tenants. Without the concept of balcony power plants, the part of Berliners who do not own their own home cannot take part in the energy transition.

However, the Senate does not see enough potential in private solar systems to contribute to climate neutrality. "That's why the focus is very clear: the money we have will be used for solar systems that actually achieve something," explained the senator at the end of 2025 when the funding program was ended. 19,000 balcony power plants were supported. The money should now be reserved for large-scale modules on the roofs.

By 2035, solar power is expected to cover 25 percent of the energy supply. This corresponds to a total output of 4,400 megawatts. According to Senate information, as of October 6th, the capital had 69,000 photovoltaic systems with a total output of around 583 megawatts, which corresponds to 7.3 percent of the total output. Compared to the previous year, around 16,000 systems with an output of 124 megawatts were added. “We are on schedule,” said Giffey. However, another two percent would have to be added annually.

The devices can now be purchased at hardware stores for between 400 and 500 euros. The value of the annual electricity savings is an attractive 200 to 250 euros. “The balcony power plant brings a significantly better return on investment than the savings account,” says Roloff from the Plan B 2030 association. In mid-2024, the feed-in power limit per module was increased from 600 to 800 watts. A maximum of 2000 watts may be fed into your own circuit per balcony. Otherwise there is a risk of the home circuit being overloaded.

According to Gewobag boss Terboven, the appeal of balcony power plants is likely to increase. “The parts will become cheaper and the electricity will not be cheaper,” he says, referring to the expected further growth in electricity demand in Berlin. “We need defossilization not just because of climate protection, but also because of more security and more planning,” says Terboven. In view of increasing insecurity in the supply of fossil energy from abroad, he is promoting renewables in the sense of “energy autonomy”.

“The sun shines for each of us,” says Terboven, “so each of us should have something from the sun.” But it could still take a while until then. So far there is only one solar panel hanging on the Kotti. The Gewobag board also announces thorough inspections of the individual extensions. “For us, safety still comes first,” says Terboven.

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