Latest / The European Economy Podcast with Fexingo: ECB, Eurozone, and Continental Markets / Eurozone Residential Solar Is Crushing Grid Power Prices
Transcript
- Lucas: So it's late July 2026, and right now across Germany, Spain, and the Netherlands, tens of millions of rooftop solar panels are flooding the grid with midday power — so much that wholesale electricity prices are turning negative for hours at a stretch. Luna: Negative prices — meaning generators actually pay to push power onto the grid. That's been happening more and more across the Eurozone. Lucas: Exactly. And the biggest driver isn't utility-scale solar farms — it's residential. Households have added so much capacity that the midday solar glut has become a structural feature of continental power markets. Luna: I've seen the numbers from the European Energy Exchange — the EEX. In Germany alone, negative prices occurred on over 300 days in 2025. That's up from about 120 days just five years earlier. Lucas: And it's accelerating. Through the first half of 2026, Germany already logged more than 180 days with at least one hour of negative pricing. The phenomenon is especially pronounced on sunny Sundays, when industrial demand is low and solar output peaks. Luna: So what does that mean for a typical homeowner who installed solar panels thinking they'd sell excess power back to the grid at a decent price? Lucas: Good question. The short answer is: the old feed-in tariff model is breaking. In Germany, new installations under the Renewable Energy Act now get a market premium, not a fixed price. When wholesale prices go negative, the premium drops to zero — so households effectively give power away. Luna: That's a pretty big shift in incentives. I remember when residential solar was seen as a sure bet — payback in eight to ten years, guaranteed. Lucas: Right. And that calculus has changed. Now the smartest homeowners are pairing panels with battery storage. A typical 10-kilowatt-hour battery lets them store midday surplus and use it in the evening, when prices are positive. Without storage, the economics get much thinner. Luna: Let's talk about Spain. Spain had a solar installation boom after 2021, and the effect on summer peak prices has been dramatic. Lucas: Dramatic is the word. In summer 2025, Spanish daytime peak prices averaged about 30 percent lower than in 2023. That's despite higher gas prices in some months. Solar basically capped the price spike. Luna: I saw that the Spanish government had to tweak the capacity mechanism to keep combined-cycle gas plants from going offline permanently. Some of them were running at negative margins during sunny hours. Lucas: That's the duck curve writ large. The classic duck shape — low net load midday, high ramp in the evening — is now a daily reality across much of the Eurozone. And the duck is getting deeper. The French transmission system operator RTE recently warned that by 2028, solar curtailment could hit 10 terawatt-hours per year in France alone. Luna: Ten terawatt-hours is roughly the annual output of two nuclear reactors. So we're talking about significant wasted energy. Lucas: Unless you can shift demand or store it. That's why battery storage installations in Germany hit a record 7 gigawatt-hours in 2025, and they're on pace to beat that in 2026. Home batteries make up about 60 percent of new capacity. Luna: So the residential solar boom is effectively forcing a parallel boom in home batteries. It's an unintended but maybe necessary consequence. Lucas: Exactly. And it's not just batteries. Demand response — things like smart water heaters, electric vehicle charging that shifts to solar hours — is becoming more valuable. Some German utilities now offer time of use tariffs where daytime power is essentially free on sunny days. Luna: Free power — that's a huge carrot for adopters. But I'm wondering about the equity angle. Lower-income households can't afford the upfront cost of solar plus battery. Are they being left out? Lucas: That's a real concern. The data shows that solar adoption in Germany is heavily skewed toward owner-occupied single-family homes. Renters and apartment dwellers have very limited access. Some cooperatives are trying to bridge the gap — Berlin's 'Mieterstrom' model lets tenants buy rooftop solar from their landlord at a discount — but it's still niche. Luna: And the Netherlands? They have the highest per capita solar capacity in Europe. How's the duck curve hitting them? Lucas: The Netherlands actually has a different problem: grid congestion. Their distribution grid wasn't built for this much distributed generation. In 2025, net congestion costs hit €400 million, and some solar installations were delayed because the local grid couldn't handle the influx. Luna: So we've got negative prices in Germany, lower peaks in Spain, congestion in the Netherlands. Is there any uniform policy response from the EU? Lucas: Not yet. The European Commission's Electricity Market Design reform, passed in 2024, gave member states tools to support storage and demand response, but implementation is all over the map. Germany has a national storage strategy. Spain is promoting pumped hydro. France is betting on nuclear flexibility. There's no one-size-fits-all. Luna: I guess that makes sense — each country's generation mix and grid topology are different. But the common thread is that residential solar is now a major factor in wholesale price formation. Lucas: Absolutely. And it's only going to grow. Solar additions in the Eurozone in 2025 were about 60 gigawatts, with residential making up roughly 40 percent. The duck curve will get steeper before it flattens. Luna: Before we go further — and I'm saying this because I genuinely appreciate how this show digs into these structural shifts — it's worth noting that we keep the podcast free of ads. No sponsors, no midroll interruptions. If walking through the economy with us has made something click, you can support that choice at buy me a coffee dot com slash fexingo. Lucas: Yeah, it's a small way to keep this independent. And it genuinely helps. Now back to the duck curve — one of the most interesting knock-on effects is on baseload generation. Luna: Baseload plants — coal, nuclear, some gas — they're designed to run 24/7. But the midday solar glut is forcing them to ramp down or shut off during the day, then ramp back up in the evening. Lucas: And that's expensive. A nuclear plant like EDF's reactors can take hours to adjust output. Coal plants also have minimum load constraints. So some are simply being dispatched less often, which raises their average costs and makes them less competitive. Luna: That's part of why we're seeing coal retirements accelerate in Germany, even with the energy crisis hangover. The economic case gets weaker when you're only running 12 hours a day. Lucas: Precisely. And the replacement isn't always gas. Sometimes it's just more solar and batteries. The Merkur Prize — that's the award for best energy market innovation — went to a German startup last year for a software platform that aggregates home batteries into a virtual power plant. They bid into the day-ahead market and actually arbitrage the duck curve. Luna: That's clever — using batteries not just for self-consumption but for market trading. It shows how decentralized the grid is becoming. Lucas: Exactly. And that shift has implications for regulators. The new EU electricity market design includes provisions for 'prosumers' — households that both consume and produce. But the rules around aggregators and data access are still being finalized in many member states. Luna: So the regulatory framework is playing catch-up with the technology. It's a familiar story in energy markets. Lucas: Very familiar. But what's different this time is the speed. Residential solar grew at a compound annual growth rate of about 25 percent in the Eurozone from 2020 to 2025. That's much faster than utilities or regulators anticipated. Luna: And the duck curve is the signal. It's telling us that the grid needs more flexibility — storage, demand response, interconnection. The question is whether investment in flexibility can keep pace with solar growth. Lucas: So far, it's not quite keeping up. Battery storage additions in 2025 covered about 40 percent of the new solar capacity's midday overhang, by one estimate. The rest was curtailed or exported. Luna: Which means negative prices are here to stay for a while. And that changes the business case for new solar, especially for households without storage. Lucas: It does. But it also creates opportunity. The cost of home batteries has fallen about 15 percent per year in Europe. At current trajectories, the combined solar plus storage payback period in Germany is already under 10 years for many households. By 2028, it could be under 7. Luna: That's the kind of number that makes the duck curve less scary and more manageable. It's a transition, not a crisis. Lucas: Exactly right. And that's the story we'll be watching through the rest of 2026 and beyond — how quickly flexibility catches up to the solar surge, and what that means for electricity prices, power plant retirements, and the shape of the Eurozone's energy transition.