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A BESS site with all its complex internal components needs to “talk” to the outside world to receive commands, report data, and play its role on the energy grid. The central point for this communication is the Gateway — the primary interface that external parties use to send instructions to and gather information from the battery. The Gateway connects the BESS site to external systems through three main communication channels.

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1. The IoT Box: Monitoring & Wholesale Schedules

The IoT (Internet of Things) Box is a dedicated hardware interface that serves two critical functions: Real-time monitoring: The IoT Box streams operational data from the battery to external systems, including:
  • Live power output
  • Temperature of individual battery modules
  • Overall State of Charge (SoC)
  • Warning signals and alerts
Wholesale market dispatch: This is the primary interface used to send wholesale market dispatch schedules to the asset — the detailed instructions specifying when to charge or discharge, and at what power level, to fulfil commitments in the wholesale energy market. Think of the IoT Box as the dashboard and GPS receiver for the BESS. It constantly sends real-time performance data back to external systems and receives precise operating instructions.

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2. The Ancillary Services Pool Box: Direct TSO Dispatch

This is specialised, robust communication infrastructure purpose-built for ancillary services markets, which require extremely fast and reliable connections. The Ancillary Services Pool Box provides a direct communication link that the TSO can use to dispatch the asset. It effectively bypasses the asset owner and operator for critical, moment-to-moment instructions. The TSO sends activation signals directly to the asset via this box, telling it to immediately change its power output to help balance the grid.
The ancillary services markets are built around extremely fast response times. To keep the grid balanced, the TSO needs an instantaneous, dedicated line into the asset, avoiding any potential delays from going through a third party. The Ancillary Services Pool Box provides this essential direct connection.

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3. The EZA Regler: Local Grid Management Interface

The EZA Regler (Energieerzeugungsanlagen-Regler, or Energy Generation System Controller) is a specific system positioned between the IoT Box and the BESS’s EMS. Its primary function is to support Redispatch 2.0 measures. It provides the local Distribution System Operator (DSO) with a direct line into the asset to send curtailment instructions.
Because it sits between the IoT Box and the EMS, the EZA Regler can override any existing schedules — including wholesale market schedules — in the event of a redispatch instruction. This ensures that local grid congestion issues are prioritised and managed effectively, even if it means interrupting a live wholesale trade.
These three communication interfaces, all part of the larger Gateway system, demonstrate the complex web of interactions a BESS has with grid operators and market participants. They ensure that BESS assets are always connected, controllable, and responsive to the precise needs of the energy grid.
Last modified on April 20, 2026