Smart Secure Electricity Systems (SSES) tariff interoperability: code modifications for Phase 1a
The Secretary of State has made changes to the Retail Energy Code using his power under section 245(1)(e) of the Energy Act 2023.
Applies to England, Scotland and Wales
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The Smart Secure Electricity Systems (SSES) Programme is designed to create the technical and regulatory frameworks to unlock the untapped flexibility from small scale devices, such as domestic electric vehicle charge points and heat pumps. The Tariff Interoperability Arrangements is an important government-led initiative which will make it easier for electricity customers to participate in consumer-led flexibility by automating how Energy Smart Appliances (ESAs) respond to price signals. This will enable consumers to save money on their electricity bills.
Section 245(1)(a) of the Energy Act 2023 gives the Secretary of State power to make modifications to licences, and section 245(1)(e) provides power to modify the industry codes maintained in accordance with the conditions of these licences for the purposes of facilitating, promoting, ensuring the security of, or otherwise regulating load control. In accordance with section 246(1) of the Energy Act 2023, the Secretary of State consulted on the initial Tariff Interoperability proposals in the 2024 Delivering a Smart Secure Electricity System consultation, and the 2025 Tariff Interoperability consultation in collaboration with the Retail Energy Code Company (RECCo).
The initial phase of Tariff Interoperability was delivered by introducing an obligation on electricity suppliers to make pricing data available in a standardised format through changes to the Electricity Supply Standard Licence Conditions through a new Standard Licence Condition 11C and modifying the Retail Energy Code (REC) to include a new REC Schedule 35: Tariff Interoperability Arrangements and changes to REC Schedule 1: Interpretations and Definitions. These changes were made by the Secretary of State on 18 May 2026.
In addition, the government response to the 2025 Tariff Interoperability consultation, published in May 2026, baselined the Tariff Interoperability (TI) Phase 1a technical specification. This baseline gave the relevant stakeholders a clear basis to build and test their TI Phase 1a solutions, while allowing for testing and further engagement before formal incorporation into the REC.
The Secretary of State has most recently consulted in August 2026, again in collaboration with RECCo, on proposals to formally incorporate the TI Phase 1a technical specification into the REC to confirm the final technical requirements for implementation before the planned TI Phase 1a go-live on 18 February 2027. The government response to the 2026 Phase 1a TI consultation has now been published on the RECCo website.
Taking responses into account, the Secretary of State has made a modification to the REC as set out in this Decision Notice. The modification sets out the requirements for how electricity suppliers must share tariff data. The modifications, as set out in the Decision Notice, will take effect from 6 November 2026.