What P442 actually did
BSC Modification P442 carries the unlovely title “Reporting to EMRS of chargeable volumes for SVA Metering Systems that record both exempt and licensed supply”. Strip that back and it solves a specific, expensive problem.
Electricity Market Reform levies, which fund the Contracts for Difference scheme and the Capacity Market, are charged to licensed suppliers based on the volume they supply. Where a meter records both licensed supply and licence exempt supply, the central systems historically could not separate the two. The exempt volume got swept into the licensed supplier’s gross demand, and the levy was charged on power the licensed supplier never sold.
That cost lands somewhere. Usually on the exempt arrangement, which is precisely the arrangement the exemption was meant to make viable.
P442 introduced a new party agent role, the Exempt Supply Notification Agent, to calculate licensed and exempt volumes separately and submit them into central systems. Ofgem approved it in May 2024 and Elexon implemented it in 2025. The practical effect is that exempt volumes can be excluded from the EMR levy calculation, which changes the economics of private wire and community supply arrangements materially.
The bit with a date on it
Before P442 there was a manual workaround, run under the Supplier Volume Allocation Group on behalf of the Panel, which existing arrangements have been allowed to continue using. Elexon has announced that the interim process closes to existing users on 31 October 2026.
If you are relying on it, you need a qualified ESNA in place. Qualification takes time, so start early. Do not leave this to the last week of October.
Who this affects
- Private wire arrangements where a generator supplies a neighbouring site alongside a licensed supplier’s top-up
- Community energy schemes supplying local customers under a class exemption
- Landlord and multi-tenant sites where on-site generation is supplied to occupiers
- Any site where one metering system records both exempt and licensed volumes
What to do
Three questions, in order. Does your arrangement rely on the interim process, and does your licensed supplier know? Is an ESNA appointed and qualified? And has anyone recalculated the arrangement’s economics on the P442 basis, since the levy treatment is the whole point of doing this?
The third question is the one people skip. Several arrangements built before P442 were priced on the assumption that the levy leakage was unavoidable. It is not, and the difference is worth finding.