SolarPower Europe has released its first report on plug-in solar photovoltaics, concluding that in some European markets, it could cover up to 25% of a household's annual electricity needs.

The EU and national governments are increasingly recognizing the potential of plug-in solar energy, and new policies are emerging to adapt to market realities. Belgium is expected to legalize plug-in solar energy in April 2025, while Germany has taken significant steps to simplify the grid registration process for this type of energy.

Germany leads the sector with over 780,000 plug-in photovoltaic systems registered by the end of 2024. It is estimated that up to 4 million systems could be operating in Germany, many of which are still unregistered. Alongside the growth of plug-in solar energy, small-scale battery storage solutions (1-5 kWh) for plug-in systems are also on the rise in Europe, with the number of small batteries (with a capacity under 2 kWh) multiplying by 24 between 2023 and 2024 in Germany.

The EU and national governments are increasingly recognizing the potential of plug-in solar energy, and new policies are emerging to adapt to market realities. Belgium is expected to legalize plug-in solar energy in April 2025, while

Germany has taken significant steps to simplify the grid registration process for this type of energy. The report highlights that this renewable energy source has also rapidly gained popularity in the Netherlands and France. In 2025, it will be legalized in Belgium.

The solution typically consists of one or two PV modules, which are plugged into a household power outlet with a grounded connection. A common type of plug-in solar PV is "balcony solar."

The increasing popularity of this solution, according to the report's data, comes with some challenges. While demand is significant and the market is growing rapidly, low-cost products are gaining ground, and product standards and regulations are developing slowly. The lack of registration for these systems poses a transparency and visibility problem for grid operators across the EU.

Moreover, plug-in systems have limited interaction with the grid, as most of the electricity generated is self-consumed, even in countries like Spain, which have very favorable irradiation levels.

The current research identifies an urgent need to develop strict standards by which responsible manufacturers can certify their products. Current technology, such as power control systems (PCS), can use software to limit all relevant parameters to levels deemed safe by regulators and standardization bodies. The first such standard is expected to be developed by the German VDE in 2025.

Pros:

-Democratizing the energy transition: Plug-in solar systems can help reach more citizens, including tenants and low-income households.

-Easy access to solar energy: The system is designed to be installed by the owner, saving costs and time.

-Affordable access to solar energy: Its low cost compared to standard systems and reasonable payback period allow a broader segment of society to invest in renewable energy generation.
Increasing acceptance of solar energy: Due to its accessibility and visibility, plug-in systems can contribute to greater acceptance of renewable energy in society.

-Blueprint for further growth: The lessons learned from the pioneering German market can facilitate rapid expansion into other EU countries.

Cons:

-Limited self-consumption potential: The small system size and often suboptimal orientation and angle of installations can limit the potential to cover a large part of household electricity demand.
Potential competition with larger residential systems: Many plug-in systems are installed in garages, where larger traditional rooftop systems could be installed.

-Grid friendliness and registration: Plug-in systems generally have limited interaction with the grid. However, given the recent market uptake and the large number of unregistered systems, it is essential to facilitate system registration, especially when combined with storage solutions, to ensure grid compatibility and visibility for national regulatory authorities and system operators. To facilitate this, the EU/2024/1711 Directive of the new Electricity Market Design already includes recommendations to streamline the installation of “mini plug-in solar systems.”

-Quality and safety: Generally, there is no high DC voltage in plug-in systems, making them safe to use. However, standards and certifications are needed to increase product quality and safety, thereby boosting consumer confidence.

Michael Schmela, Market Intelligence Director at SolarPower Europe, stated, “This pioneering report provides a comprehensive analysis of the growth, opportunities, challenges, and regulatory landscape of the rapidly expanding plug-in solar photovoltaic segment in Europe.”

Leah Le Pénuizic, project director of the report, emphasized the importance of the rise of plug-in solar energy, saying, “Europe needs clear product standards and consistent installation guidelines to ensure safety, grid compatibility, and consumer trust.”