Below zero this month
At least 18 hours
Coverage is incomplete, so the real total can only be higher.
Negative-price history
Agile negative prices — South Wales
A record of the half-hourly periods when Agile Octopus prices were below zero.
Below zero this year
At least 171 hours
Coverage is incomplete, so the real total can only be higher.
Below zero last year
144.5 hours
Most recent plunge
7 hours
6 September 2026, 09:00 to 16:00
The trend, month by month
How much time each month spent below zero.
Oct 2024Feb 2025Jun 2025Oct 2025Feb 2026Jun 2026Sept 2026
Every day, two years
One cell per London calendar day. Darker means longer below zero.
LessMoreNo data
MonTueWedThuFriSatSun
MonTueWedThuFriSatSun
MonTueWedThuFriSatSun
The biggest plunges
Open one to see the shape of the dip, half hour by half hour.
Mean price: -3.244p/kWh
Mean price: -1.197p/kWh
Mean price: -2.206p/kWh
Mean price: -2.002p/kWh
Mean price: -0.672p/kWh
Mean price: -2.621p/kWh
Mean price: -3.559p/kWh
Mean price: -4.512p/kWh
Mean price: -4.291p/kWh
Mean price: -1.498p/kWh
Mean price: -3.316p/kWh
Mean price: -0.861p/kWh