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.

Solar eclipse 2026

As solar generation capacity increases, so does the potential impact of a solar eclipse. We look at how the next significant eclipse in the UK might affect system operation.

Find out about what we're planning, including how the eclipse could affect power systems, by downloading the solar eclipse document.

Download the solar eclipse document

Low frequency demand disconnection (LFDD)

LFDD is a resilience scheme to support the system frequency during rare events. We investigate how the scheme's capability is reduced by the growth in distributed generation.

Find out about the LFDD scheme and our recommendations by downloading the LFDD document.

Download the LFDD document

Black start from distributed sources

Black Start is the ability of the power system to restart itself after a full or partial black out. Over future years large power stations which traditionally provide Black Start are predicted to have a declining role. 

Find out how we have worked with distribution companies to explore getting Black Start from the distribution network.

Download the SOF Report Black Start document

Performance of phased-locked loop based converter

Phased-locked Loops (PLL) are used by non-synchronous generators such as wind farms and HVDC to see the electricity networks status, like how motorist use SatNav to see route information. However, these technologies rely on a strong system to operate. 

Find out how we analyse the impact of reducing system strength on the effectiveness of PLL technologies.

Download the Phased-locked Loop document

Past SOF documents