National Grid ESO advances inertia management on GB grid

National Grid Electricity System Operator (ESO) has deployed GE’s Effective Inertia Metering & Forecasting solution across the GB electricity network and secured ten net zero inertia contracts.

The solution, built on GE’s Wide Area Management (WAMS) applications, is designed to inform on grid inertia day to day as well as on long term investment assessments.

Most inertia comes from big fossil fuel, nuclear and hydro generation. With the shift to renewables, grid inertia is reducing. What’s left is harder to measure because much of it is coming from demand, smaller generators and ‘below the surface’ grid behaviour.

“This pioneering tool will improve the ESO’s ability to manage system stability across the entire network as more renewable energy sources connect to the grid,” said Julian Leslie, Head of Networks at National Grid ESO.

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“It forms a suite of world-leading technology procured by the ESO that will enable us to generate inertia in a greener way and map and monitor it rather than bringing on coal or gas plants when inertia levels are estimated to be low.”

The WAMS software is designed to provide system management through enhanced situational awareness, proactive grid management and maximised transfer capability.

Effective Inertia Metering & Forecasting measures the combined inertia-like effects of rotating machines, passive load responses and active generator controls. The metering function is software-based, with no injection of forced stimulation or additional hardware into the network.

WAMS data and analytics measure effective inertia in each regional area of the power system in real time and can combine them to a system-wide value.

The implementation was staged with incremental software releases, enabling rapid feedback and adaptation and helping to navigate external dependencies, such as links to external energy forecast systems.

Real-time inertia metering has now been live for more than 200 days and inertia forecasting for a number of weeks across the Scotland region of the Great Britain grid.

All that remains is to install additional Phasor Measurement Units (PMUs) in a handful of remaining substations to complete the Great Britain regional inertia picture.

Inertia contracts

With the availability of the new inertia management solution, National Grid ESO has secured ten contracts with four companies for carbon-free inertia to help manage the growing wind capacity in Scotland with the imminent closure of nuclear power stations there and in the north of England.

The contracts, which start in April 2024 with a total value of £323 million ($421 million), are split five each between synchronous condensers and grid forming converters, with the latter believed to be a world first large scale implementation of the technology.

They are intended to solve the issue in two ways, primarily solving insufficient short circuit levels (SCL) in various locations across Scotland but also providing a ‘green’ form of inertia to help keep the electricity system stable, such as after a rare trip at a large power station.

The green solutions are expected to provide the equivalent combined SCL and inertia of almost four coal-fired power stations.