Inertia, frequency, voltage, thermal, constraints…these are just a few of the factors that go into the highly complex process of balancing the grid. 

But don’t worry if you’re not up to speed on the detail – balancing the grid is a highly complex activity – and we aim to provide the basics in this section of Electricity Explained. 

The role of the ESO is to ensure electricity supply meets demand second by second, which is what we mean by ‘balancing’ the grid.  

And when you think about how demand rises and falls throughout the day, how it is affected by weather and seasons and then about supply too, how that’s unpredictable and can change at a moment’s notice, it’s clear we need a lot of tools at our disposal.  

Electricity is transported to all corners of Great Britain. And properties like voltage and frequency must be carefully regulated across the whole network to ensure power generated at scale in industrial power stations can be safely used by domestic appliances plugged into wall sockets. 

We see to it this happens smoothly and efficiently, working with industry partners to provide ‘ancillary services’ that keep our electricity supply reliable, affordable and safe.  

What is Frequency?

At the ESO, we monitor frequency second by second to make sure that your appliances and equipment continue to work as they should. But what actually is frequency and why is it so important?

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What is Voltage?

At the ESO, we move high-voltage electricity around the country’s electricity system. But what is voltage and how does it help us keep the lights on?

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What are system notices?

Everything you need to know about the different types of system notices and why we issue them.

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What are margins?

Our role as Britain’s electricity system operator is to manage the flow of electricity around the grid so it’s available when people need it – and that means keeping the supply secure.

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What is inertia?

A simple definition of inertia is that it’s an object’s tendency to continue in its existing state of rest or motion.

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What are constraints payments?

It’s our job to keep the cost of running the system as low as possible, so we can keep energy bills down. One of the ways we do this is with constraint payments.

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What is restoration?

Restoration refers to the process of restarting the grid following a power cut and it is a requirement for us, as the system operator, to have a process in place in the event of a partial or total shut down.

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How does storage help us balance the grid?

Energy storage allows us to move energy through time, capturing it when we have too much and saving it for when we don’t have enough.