Looking for more information about the 9 August power cut?

See our interim technical report and other ESO resources.
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System Operability Framework (SOF)

The System Operability Framework (SOF) takes a holistic view of the changing energy landscape to assess the future operation of Britain's electricity networks. The SOF combines insight from the Future Energy Scenarios with a programme of technical assessments to identify medium-term and long-term requirements for operability.

Evolving year-on-year 

Through extensive industry interaction, the SOF evolves year‑on‑year to meet changing operational and stakeholder needs.

Growth of low carbon and renewable generation, closures of conventional thermal power stations and changing interactions across the whole of the power system are just a few of the areas considered in the context of a rapidly changing power system.

Operability Strategy Report update 2019

The Operability Strategy Report summarises our work towards meeting the future operability challenges, how they are impacted by our ambition for zero carbon operation in 2025, and opportunities for stakeholders to get involved in shaping how we can achieve zero carbon operation.

Download the operability strategy report

Impact of declining short circuit levels

We at National Grid ESO are identifying and quantifying system requirements which are affected by reductions in Short Circuit Level and we share some of our work in this document.

Download the Impact of declining SCLs document

Whole system short circuit level

Short circuit levels on the distribution networks are increasing driven by the growth in distributed generation and demand. This report looks at how these two trends interact and their net effect on the whole system.

Download the whole system SCL document

Regional Trends and Insights

Changes in the generation and demand are effecting how the power system is operated on a regional basis.

Find out about our latest analysis by downloading the report.

Download the regional trends and insights document

Voltage and Frequency Dependency 

Traditionally, voltage and frequency have been treated independently when considering operability. In the future, they will interact more.

Find out about our latest analysis by downloading the report.

Download the voltage and frequency document

Past SOF documents