UK writes tariff data rules for smart appliances into the Retail Energy Code
Victoria Shinder1 min readThe UK Secretary of State for Energy Security and Net Zero has modified the Retail Energy Code to bring in Phase 1a of Tariff Interoperability, using the power in section 245(1)(e) of the Energy Act 2023, the department said in a notice on 30 October. The modification sets out how electricity suppliers must share tariff data, and it takes effect on 6 November 2026. Phase 1a is planned to go live on 18 February 2027.
Tariff Interoperability is part of the Smart Secure Electricity Systems programme, which aims to unlock flexibility from small devices such as home EV chargers and heat pumps. The idea is to automate how energy smart appliances respond to price signals, so that customers can save money without having to manage the response by hand.
The first step was taken on 18 May 2026, when a new standard licence condition, 11C, obliged suppliers to make pricing data available in a standardised format, and a new REC Schedule 35 set out the Tariff Interoperability Arrangements. The government's response to a 2025 consultation then baselined the Phase 1a technical specification so that companies could build and test against it. After a further consultation in August 2026, run with the Retail Energy Code Company, the specification is now formally part of the code.
What it means
A heat pump or charger can only follow prices it can read. Until now, each supplier's tariff came in its own format, so automation meant a separate integration per supplier. A single, mandated data format turns that into one integration for every appliance maker. The dates matter for both sides: suppliers have the final requirements now, and devices will have real data to respond to from February.