The electricity industry is being invited to provide feedback on proposals to decommission the Market Domain Data (MDD) service as the transition to Market-wide Half-Hourly Settlement (MHHS) progresses.
MDD has historically played a key role in supporting settlement, registration, and data exchange processes across the market. However, with Industry Standing Data (ISD) now established as the single source of truth under the MHHS framework, MDD is expected to become a static historical dataset as migration activities conclude.
The consultation will be of particular interest to organisations that currently use MDD, including suppliers, metering agents, Licensed Distribution System Operators (LDSOs), Independent Distribution Network Operators (IDNOs), and industry service providers.
Under the proposal, all remaining MDD entities would be frozen at MHHS Milestone 15 in May 2027. While several data entities have already been frozen, Milestone 15 represents the point at which no further updates would be permitted across the MDD dataset. The industry would then rely on ISD as the authoritative source for market information, supporting:
- Settlement and registration processes.
- Validation of information exchanged between market participants.
- Message routing and data exchange through the Data Integration Platform (DIP).
The proposed change forms part of the wider MHHS implementation programme, which will see meter migrations completed by May 2027 (Milestone 15), followed by the transition to the new settlement timetable in July 2027 (Milestone 16).
Organisations that utilise MDD are encouraged to review the proposals and consider any operational, technical, or governance impacts arising from the service’s decommissioning.
The consultation is open until 17:00 on 26 October 2026.