Tariff Interoperability Phase 1a – Supplier Performance Assurance Requirements
Summary
Obligations are being introduced into the REC to require Suppliers to make Tariff Pricing Data available to Tariff Interoperability Users (TI Users) using a new Tariff Interoperability Application Programming Interface (TI API). This proposal will provide Code Manager with data to assure supplier performance against obligations in a new REC Schedule: Tariff Interoperability Arrangements.
Latest update and next planned activity
Date of latest update
Latest Update
13/08/2026 - Consultation opened for responses until 23:59 on 07/09/2026
Impacts Overview
Impacted REC Parties and Market Participants
Energy Supplier
Other
Priority and rationale
High
Priority last updated on 17 Sep 2026
Solution development
No documents available.
There is currently no Change Plan.
Original submission
Change details
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20 Apr 2026
Change details
Tariff Interoperability Phase 1a – Supplier Performance Assurance Requirements
Obligations are being introduced into the REC to require Suppliers to make Tariff Pricing Data available to Tariff Interoperability Users (TI Users) using a new Tariff Interoperability Application Programming Interface (TI API).
This proposal will provide Code Manager with data to assure supplier performance against obligations in a new REC Schedule: Tariff Interoperability Arrangements.
Tariff Interoperability obligations will apply to Electricity Suppliers that are captured within the scope of a new Electricity Supply Licence Standard Licence Condition, and to Suppliers that are not required to comply, but have opted into the arrangements.
Tariff Interoperability Phase 1a, which provides publicly available Tariff Pricing Data to TI Users, is due to go live in early 2027 and it is important that monitoring is in place from this point onwards.
To improve overall efficiency in supplier reporting, and where requested to do so by DESNZ and/or Ofgem, the reporting will reflect the information required to be provided by suppliers in the new Tariff Interoperability Electricity Supply Licence Standard Licence Condition.
This proposal will provide Code Manager with data to assure supplier performance against obligations in a new REC Schedule: Tariff Interoperability Arrangements.
Tariff Interoperability obligations will apply to Electricity Suppliers that are captured within the scope of a new Electricity Supply Licence Standard Licence Condition, and to Suppliers that are not required to comply, but have opted into the arrangements.
Tariff Interoperability Phase 1a, which provides publicly available Tariff Pricing Data to TI Users, is due to go live in early 2027 and it is important that monitoring is in place from this point onwards.
To improve overall efficiency in supplier reporting, and where requested to do so by DESNZ and/or Ofgem, the reporting will reflect the information required to be provided by suppliers in the new Tariff Interoperability Electricity Supply Licence Standard Licence Condition.
If Suppliers do not meet their Tariff Interoperability obligations, this could lead to consumers’ energy supply not being optimised, meaning that consumers may incur higher charges. If price signals are not responded to through optimisation, this may also have other impacts such as reduced Net Zero benefits and reduced response to capacity constraints.
In addition, if poor Supplier performance reduces trust in the Tariff Interoperability Arrangements, this may dissuade consumers from engaging in optimisation and overall response to energy price signals.
In addition, if poor Supplier performance reduces trust in the Tariff Interoperability Arrangements, this may dissuade consumers from engaging in optimisation and overall response to energy price signals.
Addition of proportionate and targeted reporting obligations on Suppliers.
It is proposed that these reporting obligations will be added to the Performance Assurance Reporting Catalogue (PARC) and will be provided by Suppliers on a monthly basis from go-live of Phase 1a of the new TI Arrangements.
This monthly reporting will provide additional information to the TI Monitoring Tool. This is being developed by RECCo and will send TI API messages to a Supplier to understand API availability and response times.
It is proposed that these reporting obligations will be added to the Performance Assurance Reporting Catalogue (PARC) and will be provided by Suppliers on a monthly basis from go-live of Phase 1a of the new TI Arrangements.
This monthly reporting will provide additional information to the TI Monitoring Tool. This is being developed by RECCo and will send TI API messages to a Supplier to understand API availability and response times.
In November 2025, DESNZ and RECCo consulted on the required changes to the Electricity Supply Standard Licence Conditions and the REC that would be required to implement the new TI Arrangements - Tariff Interoperability Consultation. These changes will be introduced by DESNZ using Section 245 powers under the Energy Act 2023. A Government response, setting out the licence and REC for implementation is expected to be published in May 2026.
The November 2025 consultation set out the expectation that RECCo would raise a change to the REC to propose the required Supplier reporting requirements for performance assurance.
The November 2025 consultation set out the expectation that RECCo would raise a change to the REC to propose the required Supplier reporting requirements for performance assurance.
Impacts
No details provided
Ability to pay, Achieving Net Zero, Billing accuracy, Security of supply, Trust and confidence
it is anticipated that the TI Arrangements will support consumers in optimising their energy consumption and responding to price signals that reflect Net Zero impacts.
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Performance Assurance Report Catalogue
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Energy Suppliers
TI Users (these are the individuals or organisations that will request and obtain Tariff Pricing Data from Suppliers).
No details provided
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Priority & timing
No
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No details provided
Ability to pay, Achieving Net Zero, Billing accuracy, Security of supply, Trust and confidence