Three green inertia services will go live by summer, along with new technology which measures the amount of inertia on the network, according to the system operator.
Julian Leslie, Head of Networks at National Grid ESO, said: “Building a green system with enough inertia is an engineering challenge for system operators worldwide and we’re the first to be solving it. Plus, we’ve solved it in a way that means it’s significantly cheaper for consumers than before we made the investment, with all the benefits of zero carbon.”
The three ‘green turbines’ – new-build synchronous compensators – are at Killingholme, Lincolnshire (due to start up this spring); Grain, Kent (due to start up in early summer); and Lister Drive, Liverpool (due to start up in summer). NGESO spent £328 million on six years of inertia services from them, compared with the £456 million it would otherwise have paid, according to the Guardian.
The new measurement technology is a £7.5 million ultracapacitor, which has been deployed in Teesside and will enter operational service this summer. Built by Reactive Technologies, but owned by the ESO, the tool will directly measure inertia by sending pulses of power through the grid, accurately mapping any deviations in levels of inertia and frequency
The ESO has also invested nearly £1 million in another inertia measuring and forecasting tool developed by GE Digital, which is in the process of being deployed across the whole of the grid for the first time. The software will provide a real-time measure of inertia across all regions of the country and will improve the ESO’s ability to manage system stability across the entire network as more renewable energy sources connect to the grid.
Other grid stability projects already delivered are:
• New-build synchronous compensation at Rassau South Wales, which went live on 22 February.
• Two purpose-built green turbines at Keith Greener Grid Park, in Moray, Scotland, which started supplying inertia to the grid in December 2021.
• A repurposed gas fired power station in Deeside, which has had a stability contract effective since June 2021.
• Cruachan, a pumped hydro station in Scotland, which has had a stability contract effective since July 2020

NGESO said it expects to announce more investment into stability services this spring.

Statkraft adds inertia to Liverpool mix
Meanwhile in Liverpool, renewable energy generating company Statkraft is also investing in technology that will provide stability services.
At the company’s Lister Drive Greener Grid Park , a 67MVA reactive synchronous condenser, coupled with a 40t flywheel, will be used to provide the inertia required to ensure network frequency and voltage are held stable as wind and solar power is generated. The scheme, which is expected to be operational by autumn 2022, will mimic the spinning turbines of a traditional power station. It will use digital condition monitoring services from ABB, which will be used to optimise performance and predict maintenance needs.
Guy Nicholson, head of grid integration UK at Statkraft, added: “Finding ways to stabilise the national grid without the use of fossil fuels is integral to the UK’s ability to achieve its zero carbon ambitions. Utilising ABB’s innovative technology, our Greener Grid Park will help provide a solution to this problem – maximising the amount of renewable energy being generated in Great Britain and distributed throughout Liverpool.”

Further reading
NGESO says system needs more wires, and more options for managing frequency and voltage, during this decade
Inertia measurement solutions under investigation
Reactive Technologies plans international expansion of inertia measurement tech with $15M funding