At National Grid ESO we balance supply and demand for electricity second by second. It’s a complex task and isn’t as simple as connecting a generator with a kettle or iPhone charger in your home.
The transmission network (what most people think of when they think of the National Grid) is like the motorways and dual carriageways of the electricity system - with miles of cables running overhead through pylons and underground too. The local distribution system is like the smaller roads that deliver the electricity to millions of homes and businesses.
We’re used to working with large generators connected to the transmission networks, but across the country there are also sources of electricity generation that are connected to regional distribution networks too. Many of these are what we think of as ‘large’, but many more of them are relatively small – for example, private solar panels on domestic roofs, wind turbines on private land, or small-scale power stations connected to a single, private distribution network. And when there is excess electricity generated from these sources, it can be sold back to electricity suppliers. We describe this as distributed generation.
Reducing the risk of tripping and disconnection
We’re proud that the GB system is one of the most reliable in the world. On the national network, operated by National Grid ESO, there have only been two widespread power cuts since 2008. At a local level the number of power cuts has shrunk significantly since 1990, with a 60% cut in the length of outages too - mainly due thanks to the work done by the electricity distribution companies, who connect domestic customers to the national power network
But we can’t be complacent and last year, after many months of preparation, in partnership with the electricity distribution companies and the Energy Networks Association, we began helping owners of electricity generation to make changes to their equipment as part of the Loss of Mains Change programme.
The programme requires generators, such as solar and wind farms and anaerobic digestion plants, to change their settings to reduce the risk of inadvertent tripping and disconnection, following a recent update to the Distribution Code. We can only do this by working with the electricity distribution companies - Electricity North West, Northern Powergrid, Scottish and Southern Electricity Networks, Scottish Power Energy Networks, UK Power Networks and Western Power Distribution – and enabling them to work with their customers. The DNOs are all working hard on this along with the ‘iDNOs’ (Independent Distribution Network Operators who develop, operate and maintain local electricity distribution networks, mainly extensions to the DNO networks serving new housing and commercial developments), where GTC has taken the lead.
Keeping up the momentum
As its level increases across Great Britain it’s important we understand how distributed generation responds to fluctuations in supply, helping us to better manage the grid. The first window of the project has completed and we’re pleased how the programme is going so far. 2000 generators have already signed up, a combined total of 4352MW, and received a total of £6 million in support. More funding is available and we’re keen to hear from generators, or organisations which either has members who own electricity generation assets or works closely with them. We know that the change we’re asking for is easier for some than others and we’re keen to learn from experience, whether good or bad.
For more information please see the first window report, or to see the full criteria for eligible generators visit the ENA website.