The transition to renewable energy is vital when it comes to confronting the climate crisis, and Germany is seeing this progress domestically.
Small solar devices that can be plugged into a household socket are becoming increasingly popular in the country, with more than 1 million installed in the past three years.
The modules are typically about 2 square meters (21.5 sq ft) in size, with four of them included in the minisystem, and are easily installed in areas such as balconies, where they operate safely like other home appliances – only in the opposite direction. Electricity flows from the solar module through an inverter back to the power grid via a household socket.
Increasingly, these systems also include battery storage, meaning excess power can be saved for later use.
Electricity from your own balcony
The rapidly falling costs of solar power and battery storage have been a major climate success story of recent years, allowing renewables to overtake coal for the first time in global electricity generation in 2025.
The price decline in Germany has reached domestic levels. The price of solar panel systems for balconies has halved in the last two years, with small models available from around €200 ($233) and larger models with storage costing less than €1,000 ($1166). In Germany, they generate electricity at less than half the price of electricity from the grid.
According to the Berlin University of Applied Sciences (HTW), the purchase usually pays off within four to seven years. After that, the electricity households generate for themselves is free.
Volker Quashing, professor of renewable energy systems at HTW, said solar modules can operate for more than 30 years, and batteries “can be expected to have a service life of 10-15 years”. With four modules and storage, about half of the electricity needs of a two-person household in Central Europe can be covered.
Germany is the leader in this group
“The majority of plug-in solar equipment is still sold in Germany, far ahead of the rest of the world,” says David Breuer, managing director of Yuma, a German-based company that sells plug-in solar equipment.
Although sunny areas elsewhere have the potential to generate far more electricity, in Germany falling prices, better technology and political support have helped boost solar balconies.
From 2023, private solar installations are exempt from VAT in the country, and, from autumn 2024, tenants and apartment owners are allowed to install their own solar modules on their balconies.
In most EU countries devices with a module output of up to 2,000 watts are permitted, and devices feeding up to 800 watts of power directly into the residential grid are permitted. This limit protects the power lines in the home from overload, making it safe to use.
Interest is now spreading to other countries, including several countries in the European Union as well as Brazil, the United States, and Japan.
“We just had a delegation from Tokyo visit. They want to introduce plug-in solar devices and were gathering information about technical safety,” Thomas Seltmann, an expert on plug-in solar devices at the German Solar Industry Association, told DW.
reduce energy costs
Germany is aiming to be climate-neutral by 2045. Claudia Kaempfert, head of the department of energy, transport, environment at the German Institute for Economic Research, told DW that plug-in solar devices could cover up to 2% of electricity demand by then. So far, most of the solar energy in the country comes from rooftop installations, followed by large solar parks.
For many customers, the plug-in system for the balcony is only the beginning. “They are a gateway to other measures like the purchase of larger photovoltaic systems or electric cars or heat pumps,” says Christoph Kost, head of energy system analysis at the German research organization Fraunhofer Institute for Solar Energy Systems ISE.
“Plug-in solar devices enable people to be part of the energy transition themselves, reducing their electricity costs and making themselves less dependent on energy price fluctuations,” Kaempfert said.
Consult before buying
It is important to be well-informed before buying, said Tobias Otto of the German Solar Energy Association, which provides independent advice.
It should start by first considering how many modules will fit on the balcony, terrace or terrace and at what angle they can be installed, as well as how the sun will fall on that location.
For those with three to four modules, a battery storage unit with intelligent control often makes sense. This means that the electricity demand can be measured at the meter or socket and then ensured that the battery supplies the exact amount required. “Without such measuring instruments, storage systems usually cannot be controlled effectively,” Otto told DW.
Some battery-powered plug-in devices also have an emergency supply to help in the event of a power failure. Many can also be installed outside, although they themselves consume power when kept in very cold or hot temperatures.
Experts also recommend sticking to trusted suppliers. “There are a lot of questionable things on offer,” Seltman said. “That’s why we recommend purchasing from specialist retailers.”
This article was originally written in German.