How many hours per month the day-ahead clearing price falls below zero, for every European bidding zone. Only strictly-negative hours count — at-zero hours are excluded — and 15-minute markets are aggregated to hourly first. Monthly counts and share of hours, 2015 to present. Source: ENTSO-E. Free, no API key.
Pair each market with its day-ahead prices and solar & wind capture rates, or chart any zone and window in the interactive explorer.