Black start from the bottom up: rethinking our most important back-up plan

You’ve seen them in the movies and in dramas on telly, but nationwide blackouts are a rare thing – we’ve never had one in Great Britain, and as the nation’s electricity system operator we’re confident of keeping it that way.

But what’s our back-up plan should the worst happen? A power outage across the entire grid would mean rebooting individual power stations from scratch, and that’s a challenge when there’s no electricity in the system. 

Fortunately, it’s our job to be prepared for the most extraordinary of scenarios, and a nationwide power cut – however unlikely – is something we’re ready and regularly reviewing our plans for. 

Those plans form what we call our Black Start strategy, which gives us the ability to fire up Britain’s electricity system after a total blackout. Black start uses smaller generators to kick-start bigger ones – historically gas and coal plants – creating ‘islands’ of power which connect together on the main transmission network to gradually restore the grid. 

But as we move away from using these large thermal power stations and towards being able to operate the electricity system entirely with zero carbon energy, we need a black start alternative that doesn’t rely on fossil fuel.

It’s a world-first initiative that’s making it possible for renewables to deliver a new kind of black start capability.

That’s why we’re working on the Distributed ReStart project with industry partners SP Energy Networks and TNEI. It’s a world-first initiative that’s harnessing the rapid growth of distributed energy resources (DERs) – including renewables – and making it possible for them to deliver a new kind of grid restoration capability. 

The Ofgem-funded project takes a ‘bottom up’ approach to black start. Instead of creating individual islands of thermally-generated power to reconnect Britain’s transmission network after a blackout, the whole process starts with distributed energy – those smaller generators connected in much greater numbers to the regional distribution networks. 

These DERs create clusters of power which scale up through the regional networks, gradually restoring grid power through the high-voltage transmission lines. It’s an exciting prospect and one which is in tune with the country’s net zero targets. In a near-future where Distributed ReStart has replaced our black start strategy, we could see renewable generation alone meet our grid restoration needs – whether it’s from hydro power, biomass or intermittent generators like wind and solar.

Find out more from our June 2020 Distributed ReStart virtual event 

It’s all more easily said than done, of course. Our Distributed ReStart project experts are working hard on tackling the different challenges associated with getting Britain’s grid back on its feet using DER alone. 

From the power engineering aspects of making Black Start from DER possible and the operational and telecommunications challenges of coordinating a swift and effective response during a blackout, to the commercial and regulatory framework to make it happen, there’s a whole range of workstreams that ESO and our partners are finding solutions for – and you can read more about their progress in our latest report.

We’re now in the design stage of the project, and are on target to start live trials within the next 12 months. Trials will take place with various generation technologies and in different locations to simulate a variety of network characteristics. It’ll be a significant moment and a major milestone – we’ll be showcasing for the first time anywhere in the world how a black start process could work using distributed energy.

Read the latest Distributed ReStart progress report (June 2020)

In the meantime, at ESO – and with our industry partners in the project – we’ll be working hard to make sure Britain’s electricity supply remains safe and secure, and that black start is consigned to the scripts of movies and TV shows.