Electricity prices in Spain are not uniformly cheap, but the country frequently experiences periods of low wholesale spot prices during times of high renewable generation, driven by its massive investments in solar photovoltaic and wind energy infrastructure. When weather conditions favor high renewable output, clean generation floods the grid at near-zero marginal costs. However, retail bills can still fluctuate significantly due to regulated capacity tolls, taxes, and the marginal pricing design where natural gas backup plants set the final rate during peak demand windows.