Balancing energy

Balancing energy is the electricity the Transmission System Operator buys or sells in real time to keep system frequency at 50 Hz. The EU EBGL (Commission Regulation (EU) 2017/2195, Article 2(11)) treats it as a single concept; Estonian regulation splits it into two distinct terms whose distinction matters for settlement.

Bilansienergia (imbalance energy)

Bilansienergia is the energy settled financially between the TSO and a BRP under a balance agreement. At the end of every imbalance settlement period, the TSO measures the BRP's actual flows, compares them against schedule, and bills the BRP at the imbalance price for any deviation. This is the cashflow that reconciles forecasts with physical reality.

Reguleerimisenergia (activated balancing energy)

Reguleerimisenergia is the physical energy activated from a BSP's balancing-reserve bid. When the TSO needs to ramp generation up or down to clear an imbalance, it dispatches aFRR or mFRR bids in merit order; the energy that flows is reguleerimisenergia. The BSP earns the activation price; the imbalance price billed to BRPs is derived directly from these activations.

Why the distinction matters

Operationally the two flow through the same kilowatt-hour at delivery time, but they hit different ledgers: reguleerimisenergia is BSP revenue (paid by TSO for activation); bilansienergia is BRP cost (paid to TSO for being out of position). The same MWh that earns one party reguleerimisenergia simultaneously prices another party's bilansienergia. EU EBGL papers over the distinction; Estonian operators do not.