When Christmas approaches and the first waves of cold begin to seep through the buildings, Spain turns on its lights again. Streets, balconies and living rooms light up as temperatures drop in winter particularly unstable. But, along with this luminous ritual, a new question has arisen in many homes: can Christmas lights, climbing reindeer or LED garlands interfere with the solar panels that already occupy thousands of balconies and rooftops? The doubt is understandable. For years it has been repeated that shadows are the number one enemy of solar energy, leading to the belief that any object—no matter how small—could ruin production. But the reality is much less dramatic. The coexistence between self-consumption and Christmas decoration is today simple, safe and with practically no impact on the generation. “Lights bordering a solar panel are usually not a problem,” Alejandro Diego Rosell explains to Xatakaenergy consultant and professor specialized in photovoltaics. “The panel isn’t that picky… as long as you don’t cover their face.” A thin LED garland, a light cable passing over it or a spot light “generate minimal or directly negligible loss.” The only scenario to avoid is opaque, large or rigid objects that cast harsh shadows for many hours, or those that physically rest on the glass of the panel. Not due to electrical risk, but for safety and durability: wind, weight and scratches can damage the surface. Not even a slight shadow. To understand why these minor shadows are no longer a relevant problem, it is worth looking at how the panels have evolved. Héctor de Lama, technical director of the Spanish Photovoltaic Union (UNEF), He sums it up to Xataka like this: “A large part of the current panels are monocrystalline split-cell panels. This innovation allows that, if a part of the panel is covered, the performance of the entire module is not lost. In previous panels, if an area was covered, you lost almost all production.” In other words, modern modules work in independent halves and support partial shading much better, especially if they are narrow, discontinuous or moving shadows, such as those generated by LED strips or light decorations. Even so, de Lama clarifies that completely covering a panel can significantly affect “depending on how the circuits are connected and whether they contain optimizers.” In fact, Diego agrees with the idea, but takes it to everyday ground with humor: “Santa Claus hanging from the balcony, acrobatic reindeer, Three Wise Men rappelling… All of this falls into the category of emotionally necessary but technically harmless decoration.” And the invoice? A lot of noise, very little expense. Although many households associate Christmas lights with an increase in electricity consumption, the real impact is minimal. According to energy expert Iván Terrón, interviewed by El Españolthe cost is surprisingly low: “Even if they are on 24 hours a day, LED Christmas lights cost very little. All together they cost about the same as running a washing machine.” Starting from an average price of €0.14/kWh, Terrón estimates that keeping them on for a whole month is around 5 euros. The data from Selectra, a media specialized in energy consumption, offer an even more precise breakdown: 100 LED lights consume 5 W. In 33 days, at 6 hours a day, that is equivalent to 0.99 kWh, that is, about 0.10 euros. An equivalent incandescent garland – already rare – can reach 1.23 euros in the same period. Even in indexed or PVPC rates, where it is advisable to avoid the most expensive hours (between 6:00 p.m. and 10:00 p.m.), the impact remains symbolic. For those who want to optimize thoroughly, early morning usually offers the lowest prices; But in practical terms, the cost of Christmas lights is practically irrelevant. Christmas and self-consumption: coexistence without surprises. In a meteorologically hectic winter and with millions of households more attentive than ever to the price of electricity, any doubt about self-consumption generates concern. But in this case, the technical evidence is clear: the usual Christmas lights and decorations do not damage the solar panels, do not compromise the installation and have almost no economic impact. The final recommendation is as simple as it is poetic: let the lights illuminate your home and let the panels continue to see the sky. With common sense and modern technology, the magic of Christmas and the sun can coexist without a shadow of conflict. Image | Unsplash and FreePik Xataka | Vigo represents its consecration, but the journey of Christmas lights begins in another Spanish town: Puente Genil
