Balancing Sustainability and Stability

Spain’s ambitious push for sustainable energy has transformed its power grid, but the April 28, 2025, blackout affecting Spain, Portugal, and southern France exposed critical vulnerabilities. The grid’s low inertia—caused by a heavy reliance on solar and wind power, which lack the stabilizing kinetic energy of traditional generators—played a key role. Unlike coal, gas, or nuclear plants with spinning turbines, renewables like solar panels and wind turbines offer minimal inertia, making the grid prone to rapid frequency swings during disruptions. Spain’s grid, with 50.3% renewable electricity in 2023, saw solar alone generate 59% at the blackout’s onset, exacerbating instability when 15 gigawatts dropped in seconds.

Spain’s National Integrated Energy and Climate Plan (PNIEC) aims for 81% renewable electricity by 2030, quadrupling solar capacity to 76 gigawatts and adding 22 gigawatts of storage. Meanwhile, all coal plants closed by 2025, and nuclear power, supplying 20% of electricity, is set for phase-out by 2035. These moves reduce inertia further, challenging grid reliability.