The output restriction schedule for non-controllable RES power sources (photovoltaic and wind plants) is developed by the transmission system operator control centre in cooperation with the control centres of distribution system operators. The schedule sets out the procedure for and the extent of the restriction of the amount of power supplied from non-controllable power sources to relevant distribution systems for individual restriction stages applied to prevent or manage a state of emergency in compliance with Regulation of the Ministry of Industry and Trade No. 80/2010.
The ČEPS Control Centre determines and subsequently publishes on day D-1 an indicative limit value for the output from photovoltaic and wind plants; this data can be found on the publicly accessible section of the Damas Energy portal at dae.ceps.cz. If the safety limit value has been exceeded, the imposition of output restriction measures is probable, which can then be signalled on D-1.
Following an assessment of a situation wherein a significant power surplus occurs, a decision on the imposition of an output restriction schedule for non-controllable RES power sources is made by the ČEPS Control Centre after all the measures available concerning ancillary services, controllable generation, the balancing market and power export abroad have failed to cope with the situation.
The output restriction schedule is applied for RES power plants with a licensed reserved capacity above 100kW which can be remotely controlled from distribution or transmission system control centres. An output restriction must be implemented within 15 minutes of the issuance of a restriction stage. Each restriction stage represents an installed capacity of approximately 150MW; the number of restriction stages corresponds to the total installed capacity that is subject to the restriction schedule.
The extent of the restriction of the output from non-controllable RES power plants in a situation wherein Czech power system balance and operational security are under threat depends on the relevant stage of the output restriction schedule as determined by ČEPS Operational Instruction PI 820-3 in compliance with Regulation of the Ministry of Industry and Trade No. 80/2010.