24/09/2026
Insights Blog

The CRU published its decision approving Grid Code modification MPID 345 and endorsing, with amendments, EirGrid’s associated Compliance and Derogation Framework.

This follows the consultation we considered in our briefing: New requirements for transmission-connected demand facilities.

The Grid Code modification introduces fault ride through (“FRT”), RoCoF and active power recovery requirements for current and future transmission-connected demand facilities. Broadly, the modification requires these customers to remain connected during transient faults on the system. A similar modification has been approved in Northern Ireland, and ESB Networks intends to propose a modification for distribution-connected demand facilities.

For customers unable to comply with the modification, there is a Compliance and Derogation Framework (the “Framework”). The CRU expects demand facilities to report their non-compliance and submit a request for a derogation to EirGrid before the Modification Effective Date (five weeks from the date of the decision on 22 September 2026).

Demand facilities will be required to either demonstrate compliance with the modification or seek a derogation. Unless a facility obtains a derogation, failure to comply with the modification from the Modification Effective Date will be a Grid Code breach (and therefore a Connection Agreement breach).

The Framework

The three derogation routes have been retained in the final decision: the group process for data centres, the group process for non-data centres, and the standard non-group process. Obtaining a derogation essentially gives a demand customer a pathway over a longer period to comply with the amended Grid Code.

Both data centre and non-data centre group processes are available only to demand facilities connected or connecting before the end of 2026. EirGrid indicates there are advantages of the group processes in terms of immediate assessment and recommendation to CRU. EirGrid states there is a risk that non-group applications may not be assessed by EirGrid and the CRU before the Grid Code Modification effective date.

Data centres receiving a derogation also receive a Demand Utilisation Threshold (“DUT”). A DUT effectively limits Maximum Import Capacity (“MIC”) by applying a fixed monthly average MW limit on the data centre’s non-compliant demand under the Connection Agreement, with limited scope to exceed it by 10% during short-term peaks, so long as the monthly average is not exceeded overall. Data centres with a portion of compliant demand may utilise that portion of their demand with no derogation-imposed limitations, but the portion of their demand that is not compliant will require the owner to seek a derogation and will be subject to a DUT. Any peak that exceeds the DUT by more than 10% without EirGrid’s prior written approval is a breach of the derogation conditions and the Grid Code. Separately, exceeding the DUT on a monthly average basis is a breach, regardless of whether any individual peaks were approved.

Changes to the Framework since the consultation include:

  • For data centre facilities, the timeline for submission of compliance plans is extended from three to six months from the Modification Effective Date, with status reports required every three months. The timeline remains 12 months for non-data centre facilities.
  • For group non-data centre applications, the derogation length is extended to five years. For the data centre group process, it remains at 24 months.
  • Data for calculating and monitoring DUTs will be metering data, not the proposed SCADA-based methodology or the “higher of” hybrid option. Facilities should expect previously communicated indicative DUTs to change once EirGrid finalises the metering-based methodology.
  • The 10% allowance above the DUT may be revised by EirGrid if monitoring shows it creates system security risks.
  • The proposed portfolio approach (management of DUTs across multiple connections) will not be implemented.

Customers are encouraged to engage with EirGrid on the compliance and derogation process, to monitor the finalised DUT methodology, and to ensure operational impacts from compliance are reflected in service level agreements.

While facilities must self-assess their compliance with the Grid Code amendments and submit an assessment, a facility is not considered compliant unless it has received written confirmation from EirGrid.

Existing operational measures

Operational measures currently used by EirGrid to manage FRT risk remain in place, impacting other system users including generators and storage operators, as well as interconnectors. The CRU indicates that the level of compliance with the Grid Code modification required to start reducing current operational measures is unclear. It directs EirGrid to develop a roadmap to reduce and remove operational constraints in place to manage FRT, provide improved costs to the CRU regarding impact across the system, and progress new and updated modelling to take into account several further areas, including future data centre development. EirGrid is directed to provide quarterly progress reports, beginning by the end of 2026.