Tertiary control power (TRL), also known as minute reserve, is an essential component of the electricity market and is used to balance out longer-term grid fluctuations. It is activated when electricity generation and consumption diverge over an extended period (usually more than 15 minutes).
Activation occurs only after 15 minutes
Tertiary control (TRL) is used when the power grid becomes unbalanced over an extended period of time. The deviation of the grid frequency from 50 hertz serves as an indicator of whether there is too much or too little electricity in the grid. In contrast to faster types of control energy such as primary control power (PRL) or secondary control power (SRL) , TRL does not need to be fully available until after 15 minutes. This makes it possible to incorporate a wide variety of facilities, including biogas plants, hydroelectric power plants, and combined heat and power (CHP) plants.
From gas-fired power plants to virtual power plants
Tertiary control power is increasingly being provided by flexible power generators. In addition to conventional power plants, such as gas-fired power plants and pumped-storage power plants, smaller decentralized facilities and energy storage systems can provide TRL. Electricity consumers can also provide negative TRL by adjusting their consumption patterns. Participation requires prequalification of the facility. Smaller facilities often join together in virtual power plants to provide a sufficient amount of control energy as a group.
Weekly Auction Based on the Merit Order List
Trading in tertiary control power takes place through auctions, which are typically held weekly. Suppliers must set both a capacity price and an energy price in advance. The bids are sorted by price in what is known as a merit-order list. The grid operator selects the lowest-cost suppliers one by one until the entire demand is met. Billing is based on the pay-as-bid method.
Compensation consisting of a capacity charge and a generation charge
The compensation for tertiary control power consists of a capacity charge and an energy charge. The capacity price is paid for maintaining the capacity to provide tertiary control energy, regardless of whether the energy is actually drawn upon. The energy price is payable when the plant actually feeds control energy into the grid.
15 minutes instead of seconds: the difference between PRL and SRL
The biggest difference lies in response time and deployment time: Primary control power (PRL) is activated within seconds and serves to immediately compensate for frequency deviations. Secondary control power (SRL) responds within minutes and stabilizes the grid during short-term imbalances. TRL, on the other hand, takes 15 minutes to take effect but remains active for a longer period of time.
Lower requirements, a wider range of providers
Thanks to the longer availability period, a wide variety of energy sources—such as biogas plants, hydroelectric power plants, and combined heat and power (CHP) plants —can participate in the TRL. Despite lower revenues compared to the PRL and SRL, providers benefit from less demanding technical requirements and more flexible integration into the balancing energy market.
Conclusion: indispensable in cases of long-term imbalances
Tertiary control power plays a crucial role in the energy market, particularly in the event of longer-term imbalances between electricity generation and consumption. By combining renewable energy sources, battery storage, and smart control systems, participation in the Tertiary Regulation (TRL) market can be optimized.
Frequently Asked Questions (FAQ)
What is tertiary control power (TRL)?
TRL, also known as the minute reserve, balances out long-term imbalances between electricity generation and consumption and must be available within 15 minutes.
How quickly does TRL need to be available?
TRL must be fully available within 15 minutes at the latest, which is significantly slower than PRL (seconds) and SRL (minutes).
Who can provide tertiary control power?
In addition to traditional gas-fired and pumped-storage power plants, there are also decentralized facilities, battery storage systems, and consumers with flexible load profiles, often grouped together in virtual power plants.
What is the difference between TRL and the reserve of minutes?
TRL and “Minutenreserve” refer to the same product—”Minutenreserve” is the older term, while TRL is the term commonly used today.
