National Grid ESO - gprah of Welsh Power condenser

Latest boost for Stability pathfinder as construction of flywheel begins

Construction of a synchronous condenser and flywheel at Welsh Power’s Rassau site in Ebbw Vale has begun.

This asset will play a key role in our new approach to mananaging the stability of the electricity system – with different parties providing stability without having to provide electricity – allowing more renewable generation to operate and ensuring system stability at lower costs.

Welsh Power was awarded a contract to provide stability services earlier this year and expects the new plant to be operational by autumn 2021.

What’s the new approach?

Historically, grid stability had been maintained by large, predominantly fossil fuel power plants with large, spinning synchronous generator.

These traditional plants are being phased out and renewable generators like wind and solar connect to the grid in a different way, without the same stabilising properties - so we’re exploring new ways to manage stability.

The Rassau synchronous condenser and flywheel technology will provides inertia and short circuit level to further strengthen the grid as well as reactive power for voltage control in the South West region.

It’s the latest development in our Stability pathfinder project, following Drax’s hydroelectric pumped storage plant in Cruachan – a facility built inside a hollowed-out mountain in the Scottish highlands – which started providing these vital stability services in July, without generating unnecessary electricity.

How is this boosting Britain’s zero carbon ambition?

We’re preparing Britain’s electricity system to be able to run on purely zero-carbon electricity by 2025 – ready to accommodate whatever quantity of renewable electricity is being generated at that time.

These stability services are a crucial piece of the puzzle towards 2025, which will in turn play a role in meeting the government’s 2050 net zero ambition.

Our pathfinder is bringing the stabilising ingredients we need to the grid, and will help us to harness all of the available renewable power. That means we’ll be much less likely to need to pay renewable generators to reduce their output to make room for power stations that can bring us stability – a saving that is passed on to electricity consumers.

This new thinking – and our new approach to boosting the resilience of our electricity system – is bringing us a big step towards achieving our zero carbon goals.