The primary control reserve (PRL) plays a crucial role in the stability of European power grids by enabling rapid adjustments to frequency deviations, thus keeping the grid frequency constant at 50 Hertz.
Automatic response within 30 seconds
Primary control reserve must be activated within 30 seconds to compensate for sudden frequency deviations. A frequency meter on the system continuously monitors the grid frequency and automatically adjusts the system’s output as soon as these deviations exceed the defined tolerance range. This rapid response is crucial for grid stability. For more details on other types of control reserve, such as secondary control power (SRL) and tertiary control power (TRL), please visit the corresponding entries.
Demand assessment via ENTSO-E: approximately 3,000 MW
The primary control reserve requirement is determined within the ENTSO-E (“European Network of Transmission System Operators for Electricity”). It is assumed that, in the worst case, two large power plant blocks could fail simultaneously, resulting in a total requirement of around 3,000 MW. This amount is recalculated annually and distributed among the grid operators based on the previous year’s feed-in.
Auction procedure for primary reserve
An auction for PRL is held weekly, usually on Tuesdays, at www.regelleistung.net. Providers must conclude a framework agreement with their transmission system operator and prove the prequalification of their systems. The bids are sorted by price, and the contracts are awarded starting with the lowest prices until the required amount of PRL is reached. Further details on auction processes in the area of control reserve can be found in the EPEX Spot Intraday Market.
Weekly Auction on regelleistung.net
Every week, usually on Tuesday, a PRL auction is held on www.regelleistung.net. Suppliers must enter into a framework agreement with their transmission system operator and provide proof of their facilities’ prequalification. Bids are sorted by price, and contracts are awarded starting with the lowest prices until the required amount of PRL is reached.
Compensation based solely on the service price
Payment for primary control energy (PRL) is based exclusively on a power price. Since the amounts of positive and negative power balance out on average, there is no additional energy charge, which reduces administrative costs and simplifies billing.
Advantages and disadvantages of primary control reserve
Advantages: Response time within 30 seconds, significant importance for grid stability, and the ability to be powered by renewable energy sources such as battery storage.
Disadvantages: high demands on the technology used, infrastructure that can be costly in some cases, and the need for the participating facilities to be operational at all times.
A Growing Role for Biogas, Storage, and Power-to-Gas
Although the primary reserve currently has the lowest cost share among the control reserve types, its importance is steadily increasing. The technological progress in biogas plants, battery storage and power-to-gas plants will further strengthen the role of PRL and contribute to improving grid stability.
Conclusion: the fastest form of balancing power
Primary control power is crucial for maintaining a stable grid frequency and, consequently, for overall grid stability. Its rapid response time to frequency deviations makes it an indispensable form of energy. Ongoing technological developments will further increase the importance of primary control power in the energy supply.
Frequently Asked Questions (FAQ)
What is primary control energy (PRL)?
Primary control power is the fastest form of control power: It automatically compensates for frequency deviations in the power grid within 30 seconds and keeps the grid frequency stable at 50 hertz.
How quickly must primary control energy be activated?
PRL must be fully activated within 30 seconds as soon as a frequency deviation exceeds the permissible tolerance range.
Who is eligible to provide primary control energy?
Suppliers must have a framework agreement with their transmission system operator and must provide evidence of their facility’s technical prequalification—such as power plants, battery storage systems, or virtual power plants.
Compensation based solely on the service price
PRL is compensated exclusively through a performance-based price, since positive and negative adjustment volumes balance each other out on average.
