Replacement Reserve

Replacement Reserve (RR) is one of the reserves used by the transmission system operator (in Poland – PSE, Polskie Sieci Elektroenergetyczne) to ensure the stability and balancing of the power system.

What is Replacement Reserve (RR)?

RR is a power resource that can be activated within a specific time frame to:

• Compensate for power shortages in the system, e.g., after the failure of generating units or during an unexpected increase in demand.
• Replace other short-term reserves (e.g., mFRR – manual Frequency Restoration Reserve) that have already been used.

Characteristics of RR

RR is activated over a longer time period than fast reserves (e.g., mFRR). Typically, it takes between 30 minutes and a few hours. It is primarily used in planned or predictable situations, rather than emergencies, to maintain the balance between generation and consumption over a longer time horizon.

Role in System Balancing

Replacement Reserve plays a key role in long-term balancing of the power system, helping to avoid situations where the system would be at risk of power shortages and supply interruptions.