The vital aspects of UK energy security you probably didn’t know about
When we think about energy security, we tend to focus on Great Britain being able to generate its own power (rather than import it) and to produce enough to ‘keep the lights on’. These are certainly important aspects, but this article’s going to look at some of the other – lesser known – facets of energy security.
The role of NESO
Firstly though, it’s relevant to consider this topic in the context of the government’s Clean Power 2030 Action Plan. This aims to reduce the intensity of electricity generation and cut carbon dioxide emissions, while ensuring that 95% of generation in a typical year comes from clean sources by 2030.
So, the National Energy System Operator (NESO) has a lot of responsibilities. It must balance electricity supply and demand, while also procuring certain services from generators to help keep the system safe, operational and efficient.
This means NESO will, increasingly, be relying on low carbon generation assets that can – relatively quickly – turn their activities up, down, on or off. And these assets can’t be dependent upon the weather conditions or time of day (as power sources like solar and wind are).
Put another way, NESO needs generators that deliver ‘dispatchable’ power flexibly while also being capable of providing services to the grid.
So it’s these services we’ll look at next.
A photograph of Drax Power Station in North Yorkshire, UK
Drax Power Station
As the UK’s largest single-site generator of renewable electricity, Drax Power Station (DPS) near Selby in North Yorkshire is vital to UK energy security and grid stability. Another Drax generation asset – the pumped hydro storage facility at Cruachan Power Station (CPS) in Scotland – plays its part, too.
In 2024, DPS generated 14.6TWh of renewable electricity – enough to power five million households, the total number of homes in Scotland and Wales combined. In addition, DPS provides a range of vital services relating to technical characteristics of the grid. These range from managing voltage support and taking care of stability constraints in parts of the network, to supporting grid inertia. The services also include delivering Black Start capabilities, which reboot the system in the unlikely event of a nationwide blackout.
Because the transition to more renewable power involves a changing asset base, system inertia is falling. This means NESO is becoming increasingly mindful of the need to ensure sufficient inertia is available on the system. Because it’s a dispatchable and flexible generation asset, DPS can oblige. Other sources of renewable generation are unable to provide all these services (traditional wind generators can’t provide inertia, for example ). So in the absence of DPS, NESO would have to procure these services from another low carbon source – or procure gas, a higher-carbon fossil fuel, instead.
In February, Drax and the UK Government agreed Heads of Terms for a Contract for Difference (CfD) mechanism applicable to all four generation units at DPS. Running from 2027 to 2031, the agreement sets a cap on supported generation levels and floor on the minimum level of generation from the plant each year. This means the plant won’t run 24/7 but will operate when the system needs its power to balance supply and demand, or to provide valuable system services.
Cruachan Power Station
A photograph of Cruachan Power Station’s turbine hall in Scotland
Deep inside Ben Cruachan (also called ‘The Hollow Mountain’) in Scotland, Cruachan Power Station (CPS) has a capacity of 440 MW – enough to power around one million homes. The pumped storage hydro station uses one of the oldest forms of large-scale energy storage, involving two reservoirs relatively close to each other but at different altitudes.
The easiest way to think of the plant is to use the analogy of a giant battery. When there’s too much intermittent renewable generation like wind and solar on the system compared to the level of demand, CPS charges up. This means it pumps water from the lower reservoir to the upper one. When that weather-dependent generation reduces, or demand for power increases, CPS can discharge that stored energy by releasing water from the upper reservoir to the lower. The water flows through the turbines inside the mountain, generating the power that the grid requires.
Because CPS can switch from ‘off’ to ‘on’ within 30 seconds, it’s a very flexible resource that can help balance supply and demand. In addition, one of its four generation units only operates as a provider of inertia to the system – a role that will continue until 2026 at least.
Cruachan’s ability to absorb excess generation also reduces the need to curtail wind and solar generation. Curtailment is the deliberate reduction of electricity supply or consumption to balance supply and demand or manage grid stability. These curtailments cost NESO money, which is ultimately passed on to consumers through higher third party costs within their energy bills.
Drax aims to develop CPS further, too. The Cruachan Expansion Project plans to build a new underground pumped hydro storage power station alongside the existing one, more than doubling electricity generating capacity to one gigawatt (GW).
This expansion, subject to a favorable investment environment, will therefore provide even more power, and additional services, to the system.
Beyond dispatchable renewable power generation
Drax Group’s primary generation assets – Drax Power Station and Cruachan Power Station – are both essential to UK energy security. Their role goes beyond supplying dispatchable renewable power when it’s needed (to balance the grid and keep the lights on) to providing vital services such as inertia and Black Start.
Without these assets, the UK wouldn’t be able to keep pushing to have more intermittent renewables like solar and wind on the system. But the country would be paying for a higher volume of imported power that’s derived from higher-carbon sources such as gas.
To discover more about these key generation assets, see the corporate web pages about Drax Power Station and Cruachan Power Station.
Disclaimer
We’ve used all reasonable efforts to ensure that the content in this article is accurate, current, and complete at the date of publication. However, we make no express or implied representations or warranties regarding its accuracy, currency or completeness. We cannot accept any responsibility (to the extent permitted by law) for any loss arising directly or indirectly from the use of any content in this article, or any action taken in relying upon it.
