Operability strategy report: our insight into a zero carbon electricity system

Each year our operability strategy report examines the work we’re doing – and the challenges we face – in operating Great Britain’s electricity system safely and securely. Following the publication of our latest report, operability strategy manager Will Kirk-Wilson reflects on an unprecedented year, and looks ahead to how we’ll meet our 2025 zero carbon ambition.

2020 was a record-breaking year for Britain’s electricity system.

Not only was it the greenest on record, we also saw new all-time highs for wind and solar power, as well as the longest run since the industrial revolution generating electricity without using coal.

These records don’t happen by chance. Our operability strategy report highlights much of the work we’ve been doing with industry to make sure the electricity system is ready to handle an increasing share of zero carbon energy – and that it’s ready to run carbon-free by 2025.

2020 presented a unique set of challenges for our control room, and I’m proud to say our analysts and engineers proved equal to the task

The report shares insight on the progress we’re making around our key operability challenges – maintaining frequency, managing voltage, making sure the system is stable, resolving thermal constraints and making sure that we can restore the system.

This progress is laying the groundwork for the renewable records we continue to see, and is central to delivering a safe, reliable electricity supply today and into the future.

Read our 2021 Operability Strategy Report

While our report is framed by our 2025 ambition, there’s no escaping the impact that covid-19 lockdowns and the associated drop in national demand had on the system – and the difference our new way of life made to energy in Britain.

These unprecedented events effectively sent our electricity system five years into the future, with conditions we anticipate having to manage half a decade from now – e.g. lower demand with higher volumes of renewables – arriving early.

It presented a very different set of challenges for our control room, and I’m proud to say our analysts and engineers proved equal to the task.

For a deep-dive on how we managed the electricity system in these unique circumstances, check out our operability strategy report’s case study on May 23, the Saturday of the 2020 spring bank holiday weekend (see box).

What happened on May 23? We had a rare insight into what a future zero carbon electricity system could look like. Low national demand met with high renewable generation (almost 100% zero carbon in the market at times) owing to sunny and windy weather. Our control room had to take action to manage system stability, pulling zero carbon generation back to around 80%. Read page 13 of the report for more on why we took action – and why our operability work means we won’t need to in the future.

Today, Britain’s system is not quite ready to run solely with zero carbon.

By 2025, we’ll have transformed the network and put in place the innovative systems, products and services to make sure that it’s ready to run carbon-free whenever the electricity market can provide that mix.

Below are some of the key developments we highlight in our latest operability strategy report, each of which is helping to make sure we can deliver a secure and affordable low carbon electricity supply.

• Dynamic Containment – the first in a suite of new fast-acting frequency products, which is boosting the network’s ability to respond rapidly to disturbances in the flow of energy around the grid.
• Wider access improvements – including the launch of our wider access API, and smaller providers taking advantage of our changes to access the balancing mechanism for the first time.
• Accelerated Loss of Mains Change programme – our work with regional networks has seen over 3,000 smaller generators change their settings to reduce the risk of unnecessary tripping.
• Stability pathfinder – creating a world-first market to provide stability services to the grid without generating unnecessary electricity – a key milestone for zero carbon operation.
• Voltage pathfinder – working with providers in the Mersey region, we’re finding new sources of and ways to absorb reactive power as we move away from using traditional large power sources.
• Constraint management pathfinder – aims to reduce the impact of network constraints, minimise actions to reduce renewable generation and lower costs for the end consumer.
• Distributed ReStart – rethinking the electricity system’s most important back-up plan for a zero carbon future by using distributed generators to restore the grid in the unlikely event of a blackout.

While these projects and developments represent key steps towards being able to operate the system with zero carbon, they’re just a part of the journey.

Across the ESO we continue to work closely with our stakeholders to ensure our approach takes in systems, markets, policy, technology and innovation as we develop and deliver solutions to tackle the challenges ahead.

Read the full report for further insight into our ongoing operability work.