Ofgem sends back BSC modification P441 and REC change R0268 for further work, pushing complex site classes decision to 5 October 2026

Ofgem has issued send-back decision letters for BSC modification P441 - "Creation of Complex Site Classes" - and its Retail Energy Code counterpart R0268, returning both proposals to industry for additional work^[1]. The regulator's timetable now lists 5 October 2026 as the target decision date for both modifications, a delay of several months from the June 2026 implementation window that had been anticipated when P441 was formally submitted to the Authority on 19 March 2026^[1].

What P441 proposes

P441 seeks to formalise the concept of Complex Sites - metering arrangements too intricate to be captured in standard BSC data flows - by codifying them into six defined classes^[1]. The BSC Panel unanimously recommended approval at its meeting on 12 March 2026, and 22 responses to the report-phase consultation were received, with the majority in support.

The six classes break down as follows:

• Classes 1-4: codify criteria for existing standard complex site arrangements already in use across the industry
• Class 5: permits netting of imports and exports at separate boundary points for local energy schemes operating under a supply licence exemption
• Class 6: captures non-standard arrangements not covered by Classes 1-5, subject to BSC Panel approval on a case-by-case basis

Class 5 carries the most commercial weight. Because netting reduces net import volumes, participants would be exempt from Balancing Services Use of System (BSUoS) charges on the netted portion - a material cost saving that Ofgem has flagged as requiring careful analysis before it can be locked into the code.

Why Ofgem sent it back

The send-back is consistent with a pattern of extended scrutiny on P441. Ofgem first signalled the need for further analysis at the eighth workgroup meeting in September 2023, prompting a six-month assessment extension that October. Subsequent extensions followed in April 2024 and again in 2025, with the BSC Panel granting a 21-month extension at its July 2025 meeting to allow CEPA to complete a two-phase cost-benefit analysis.

The outstanding concern centres on whether the BSUoS exemption available to Class 5 participants is justified by wider network benefits - or whether it simply shifts costs onto non-participating consumers. Elexon has indicated that a post-implementation review mechanism would assess this after go-live, but Ofgem has not yet accepted that as sufficient assurance.

R0268 is a consequential cross-code change in the Retail Energy Code that mirrors P441's metering and data-flow requirements. Because it cannot proceed independently of the BSC modification, it is sent back on the same timeline.

What to watch

The 5 October 2026 decision date gives Elexon and the REC Company roughly eight weeks to address Ofgem's outstanding concerns and resubmit. The key question is whether the CEPA modelling - described as concluding "over summer" in the July 2026 BSC Change Report - will be complete and accepted by the Authority in time. Community energy schemes and local supply operators that have been waiting on P441 to formalise their metering arrangements face continued uncertainty in the interim. A further send-back or extension beyond October would push implementation into 2027.