Peak load time windows (PLTW) refer to the forecast periods during which the grid loads are highest (e.g. because many consumers require electricity at the same time). They play a central part in the calculation of individual grid fees for final consumers under the Electricity Network Charges Ordinance (StromNEV).50Hertz always determines its peak load time windows at the extra high and transformation level by means of a standard calculation method for all system operators that is imposed by the Federal Network Agency (BNetzA).
According to the BNetzA model, only working days (Monday - Friday) are to be considered as ‘peak load times’. Weekends, holidays and bridging days (May 14, 2021) as well as the time between Christmas and New Year are considered as ‘power off’ time. Spring: 1 March - 31 MaySummer: 1 June - 31 AugustAutumn: 1 September - 30 NovemberWinter: 1 December - 28 February (leap year = 29 February) The peak load time windows are adjusted annually.
The main requirement for individual grid usage charges according to § 19 para. 2 sentence 1 of the StromNEV is that the peak load contribution of a final consumer is predictable and deviates significantly from the annual peak load at the relevant grid level. Final consumers whose annual peak load deviates significantly from the 15-minute capacity value measured in the peak load time window therefore fulfil the main prerequisite for individual grid usage charges according to § 19 para. 2 sentence 1 of the Stromnetzentgeltverordnung (StromNEV).Simply put: larger consumers who plan their own peak load times in such a way that they do not coincide with the peak load time window published by the TSO (so-called atypical grid usage), can pay an individual grid usage charge if they meet certain additional criteria (materiality threshold, materiality gap, de minimus limit).