Balcony solar, small, plug-in systems you can hang off a balcony or fence, has exploded in Germany, with millions of households now generating their own power. Low cost solar panels and micro-inverters, regulatory changes that allow simple plug-in installation without the need for an electrician, and soaring energy prices after Russia’s invasion of Ukraine have all driven the surge. What began as a DIY workaround is now an off-the-shelf consumer product, reshaping how people think about energy at home. But balcony solar has its detractors, with resistance emerging from large co-operative and municipal landlords who control much of the rental market. Sebastian Müller, the chair of the German association for plug-in solar, Balkon Solar, explains how the movement gained momentum, what’s holding it back, and what it reveals about the roll out of consumer-led energy systems.