National Grid Electricity System Operator (ESO) has awarded contracts worth £328 million over six years to manage the stability of the electricity grid.

Drax, Rassau Grid Services (Welsh Power), Statkraft, Triton and Uniper will either build new or modify existing assets to provide stability services to National Grid ESO to help manage electricity system properties such as inertia, voltage and short circuit.

The key service to be provided is inertia, which helps to keep the electricity system running at the right frequency.

System inertia is a measure of the energy network’s resilience to some types of disturbances on the power system, such as the sudden disconnection of a large power station due to a fault.

This service is currently a by-product of traditional power generation, like coal or gas – however, the new approach will see the new or modified assets providing a standalone service to the ESO, without the need to produce electricity at the same time.

This will allow more renewable energy generation to operate, helping reduce energy use and carbon emissions and is expected to save consumers up to £128 million over six years.

The contracts are procuring 12.5GVA seconds of inertia – the equivalent of the inertia provided by around five coal-fired power stations.

Julian Leslie, ESO Head of Networks said: “This approach is the first of its kind anywhere in the world and is a huge step forward in our ambition to be able to operate the GB electricity system carbon free by 2025.

“Our system is one of the most advanced in the world, both in terms of reliability and the levels of renewable power, and we’re really excited to be adding to that with this new approach to managing stability. These contracts are finding new ways to help balance the grid which are cheaper and greener, reducing emissions and saving consumers over £100m.”