For the first time since the switch to 15-minute trading intervals, negative electricity prices appeared on the Czech day-ahead market

From 1 October 2025, the trading period on the day-ahead market was shortened from 1 hour to 15 minutes. Given the growth and integration of intermittent electricity sources such as photovoltaic power plants (PV) and wind power plants, the longer interval was no longer sufficiently representative, and the move to a shorter period will ensure more efficient balancing between supply and demand. Prices can therefore vary widely even within a single hour – the difference can be, and has already been, more than 250 EUR/MWh. The very first weekend also brought negative prices.

Negative electricity prices were recorded on the OTE day-ahead market for the first time since the switch to 15-minute trading intervals. They occurred as early as Saturday at the very end of the day and remained close to 0 EUR/MWh until 9 am on Sunday. The reason can be sought beyond the Czech border, in strong wind power generation combined with traditionally lower weekend demand.

The price swing within the trading day is also worth noting. On Sunday, prices did not exceed 45 EUR/MWh until 5 pm. However, in the evening, during the demand peak, prices significantly exceeded 200 EUR/MWh, peaking at 269 EUR/MWh. The price difference within a single hour (between 20:00-21:00) was more than 260 EUR/MWh. This places considerable demands on traders' forecasting, while those with significant flexibility and good forecasts can benefit from it. We covered this topic in an interview with a flexibility aggregator - here or here.

But back to wind power generation. Negative electricity prices were recorded on the day-ahead markets in Germany, the Netherlands, Belgium and Denmark. The reason was a storm that caused strong generation from wind power plants in those countries, as foreign news portal Montel reports.

During Saturday, wind power output in Germany reached as much as 49 GW. On Sunday, it was expected to average 39 GW.

The average baseload price in Czechia was around 31 EUR/MWh on Saturday, 32 EUR/MWh on Sunday and already 94 EUR/MWh for Monday.