System Performance Reports

At NESO, we’re committed to being transparent and sharing information with our partners in the energy industry.

On this page, you will find reports that NESO publishes as required for:

  • GB National electricity transmission system performance as required by Transmission Licence Standard Condition C17: Transmission System Security Standard and Quality of Service. 
  • Reports for industry and the Grid Code Panel to monitor the effectiveness of technical requirements in the Grid Code and Distribution Code – GC105 and GC151
  • UK Statutory Instrument - Electricity Network Codes and Guidelines (Markets and Trading) (Amendment) (EU Exit) Regulations – Article 15 and 16.
  • UK Statutory Instrument - The Electricity and Gas (Internal Markets and Network Codes) (Amendment) (EU Exit) Regulations – Clean Energy Package Article 13.

Transmission performance reports (C17)

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These reports show how well system operation has fared through auditors' assessment of our processes and also by quantifying key reliability measures. The Winter and Summer Outlook reports provide forecasts of the anticipated supply/demand for electricity over the coming period.

You can access the Winter Outlook and Summer Outlook reports in the Research and publications section of our website.


Reports

Proposed Condition C17 Statement changes, Official Consultation 2023-24

This consultation has been produced under Condition C17 of the Transmission Licence to undertake a review of National Energy System Operator’s (NESO) Condition C17 Statement based on proposed changes that NESO are seeking to make to the statement.

The Condition C17 Statement sets out the criteria used to produce the yearly National Electricity Transmission System Performance Report

GC105 & GC151 System Incidents Reports

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Our monthly System Incidents Report is now available to download and indicates system incidents and losses of load or generation on transmission and/or distribution networks.

This report is important to industry and the Grid Code Panel to monitor the effectiveness of technical requirements in the Grid Code and Distribution Code.

The report facilitates insight-led discussions at our regular Grid Code panel meetings.

Find out more about the GC0105 modification and the considerations behind it.

Annual report on operational security indicators (Article 15 - ICS)

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Under the UK Statutory Instrument - Electricity Network Codes and Guidelines (Markets and Trading) (Amendment) (EU Exit) Regulations, NESO has the obligation to publish the following annual report.

By 30 September, the national electricity transmission system operator shall publish an annual report on the incident classification scale (ICS).

Previous years annual report can be found on entso-e website here.

Annual report on load-frequency control (Article 16 - aLFC)

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Under the UK Statutory Instrument - Electricity Network Codes and Guidelines (Markets and Trading) (Amendment) (EU Exit) Regulations, NESO has the obligation to publish the following annual report.

By 30 September, the national electricity transmission system operator shall publish an annual report on load-frequency control.

Previous years report can be found on entso-e website here.

Annual report on Clean Energy Package ( Article 13 – Redispatching)

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Under the UK Statutory Instrument - The Electricity and Gas (Internal Markets and Network Codes) (Amendment) (EU Exit) Regulations, NESO has the obligation to publish the following annual report.

By 30 September, the national electricity transmission system operator shall publish an annual report on redispatching.

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Need the data from this report?

As the authority on electricity data, we are committed to communicating our work and making our data accessible – whether that’s the Historic Frequency Data report or FFR market data. Head over to the NESO Data Portal to browse all the data we publish.