A sprawling Spanish supermarket complex wanted to shrink its carbon footprint and its electricity bill. I answered with a massive 228.6 kW rooftop installation spanning three buildings. The numbers speak volumes: over 381,000 kWh generated annually, covering nearly 70% of their energy appetite. Production costs tumble to an almost unfair €0.0499/kWh, while the 14.81% IRR and sub-7-year payback make this a retail energy revolution.