Revised technical and compliance requirements for electricity storage in the engineering recommendations EREC G98 and G99 came into effect from September 2022, according to the Energy Networks Association's distributed generation connection guide. The guide states that the requirements were changed so that storage is treated in line with other generating units.
"The technical and compliance requirements for storage have recently been revised in EREC G98 and G99 to be in line with other generating units and come into effect from September 2022."
The two documents split connection rules by size. EREC G98 covers smaller generation with nominal currents up to and including 16A per phase, which the guide gives as 3.68 kW on a single-phase supply and 11.04 kW on a three-phase supply. EREC G99 covers all other projects. The guide states that equipment connecting under G98 must be fully type tested, with the whole micro-generator or power generating module tested rather than just part of it1.
The guide sets out the capacity bands that decide which document applies and how complex the connection process becomes.
| Capacity and connection point | Route |
|---|---|
| Up to and including 16A per phase (3.68 kW single-phase, 11.04 kW three-phase), low voltage, type tested | EREC G98 |
| Above 16A per phase but below 1MW, connection point below 110kV | EREC G99 |
| At or above 1MW, or connected at or above 110kV | EREC G99 |
The guide notes that projects can no longer connect under the earlier EREC G83 and EREC G59, which should no longer be used after the 27th April 20191. It also records that the System Wide Resource Register was renamed the Embedded Capacity Register in July 2020 under DCUSA change DCP 350, and that this register lists generation and storage resources greater than 1MW that are connected or accepted to connect to the distribution network1.
The guide covers the process for connecting generation to distribution networks in Great Britain, and states that Northern Ireland has different connection arrangements1.
Why it matters for households
For a household adding a home battery or solar panels, the September 2022 change means storage is assessed on the same footing as other generating equipment rather than under separate arrangements. Most domestic installations sit within the G98 threshold, so the route that applies is usually the simpler one, provided the equipment is fully type tested. The capacity figures matter because they are aggregate: the guide states that the 16A per phase limit refers to the total micro-generator capacity installed in a single premises, so a battery added alongside existing solar counts towards the same ceiling1. Above that ceiling, a project moves to G99, which the guide describes as the route for all other projects and which carries a more involved process. The practical effect for a home is that the paperwork and technical conditions attached to a battery depend on the combined capacity on site and on whether the unit holds type test certification, not on the battery alone. The connection rules for solar and the separate guidance on notifying a network operator about a home battery set out how these thresholds are applied.
What happens next
The guide gives no further dated steps for storage beyond the September 2022 effective date. No later revision date for the storage requirements has been reported.
Sources1 cited
- [](https://www.energynetworks.org/assets/images/Resource%20library/G98%20Single%20Premises.pdf), energynetworks.org