Europe's electricity grid is straining under the weight of its own success. Renewables saved the EU an estimated €51 billion last year by displacing oil and gas imports, but the infrastructure built for an earlier era is struggling to absorb the new supply. A 2026 report by consultancy AFRY, commissioned by the non-profit Beyond Fossil Fuels, found that 375 gigawatts (GW) of clean energy projects and 455 GW of battery storage are stuck in distribution grid queues across the continent. That backlog represents more than €100 billion of investment waiting to connect—delaying access to solar panels and heat pumps for households facing high energy bills.
The curtailment problem
Europe's grid was designed around centralised coal and gas plants, not the dispersed, weather-dependent output of wind and solar farms. When supply outstrips demand, prices can go negative and operators are forced to switch off turbines and panels—a practice known as curtailment. In 2024 alone, the EU curtailed 10 terawatt-hours (TWh) of renewable energy, enough to power three million homes for a year, at a cost of €4.3 billion in wasted electricity.
Battery energy storage systems (BESS) are widely seen as the fix, but investment lags far behind need. That's where retired EV batteries come in. Most EV batteries are retired with 70–80% of their original capacity still intact—not enough for a car, but plenty for stationary storage.
“Old EV batteries really are a gold mine,” says Adrian Hiel, director of the Electrification Alliance. “Even if their performance has degraded to the point that they aren’t great for a car anymore they can easily have a second life, measured in decades, as storage for the grid, for businesses or domestically.”
A coming wave of second-life batteries
Today, Europe relies on batteries from EVs that are over a decade old or from accident-damaged vehicles. In 2016, only 215,000 EVs were sold in Europe, according to the International Energy Agency (IEA), compared with 4.2 million last year—a 1,853% increase. Modern batteries are also far larger, ranging from 50 kWh to 100 kWh, versus the 22–24 kWh packs of a decade ago.
“We are looking at two different trends that could radically change the grid in 10 to 15 years,” Hiel explains. Last year, the EU added 27 GWh of stationary batteries to the grid, but it added roughly four to five times that amount in the form of EV batteries. “When those EVs eventually retire and their batteries become standalone storage, it will transform how the grid is run and operated,” he adds. “With each year as those storage levels increase we should see bigger and bigger price decreases in electricity—it is a very exciting virtuous circle.”
The IEA projects that more than a million EV batteries could reach end-of-life by 2030. Without efficient repurposing, they risk becoming one of the world's fastest-growing waste streams. Recycling is technically difficult and costly, involving discharging, dismantling, and separating components, with safety risks from toxic chemicals like hydrofluoric acid. Repurposing for grid storage is often more practical and economically attractive.
How second-life batteries help
The classic “duck curve” problem—low daytime demand when solar peaks, then a sharp evening ramp-up—is a perfect fit for second-life storage. Excess solar power generated at midday can be stored and discharged in the evening when households return home. In winter, the same batteries can shift wind power from overnight to daytime peaks. This not only reduces curtailment but also eases pressure on grid infrastructure, potentially lowering bills for consumers.
The concept is already being deployed. In California, a 12 megawatt-hour (MWh) facility by B2U uses hundreds of second-life Honda EV batteries charged by 1.5 MW of solar, selling electricity and grid services into the California Independent System Operator market. Similar projects are emerging in remote regions, where second-life batteries offer a more affordable alternative to new storage.
For Europe, the opportunity is clear. As the continent pushes to expand renewables and electrify transport, the batteries that once powered cars can become a cornerstone of a more flexible, resilient grid. The challenge is to build the regulatory and market frameworks that encourage repurposing rather than premature recycling or disposal. With the right policies, Europe could turn a looming waste problem into a strategic asset—and keep more of its clean energy where it belongs: in homes and businesses, not in the bin.
