National Grid ESO’s new Dynamic Containment (DC) service “performed as expected” as Flexitricity and Arenko became the first successful bidders.
Launched on Thursday (1 October), the service saw six tenders received for the following 24 hours, with battery energy storage units from Flexitricity and Arenko accepted for that period.
A spokesperson for National Grid ESO also informed Current± that for the tender spanning 11pm Friday 2 October to 11pm Saturday 3 October, four units – this time from Habitat Energy and Zenobe – were accepted, totalling 165MW.
During the initial 24 hours of the service, National Grid ESO called upon the DC service to bring frequency back into a normal operating range following an interconnector fault that took 1GW off the system.
In a LinkedIn post, Arenko chief technology officer Roger Hollies outlined how at 09:30 on 2 October, a French interconnector fault resulted in frequency dipping to 49.597Hz.
Whilst this is within National Grid ESO's 49.5-50.5Hz limit, frequency did fall out of its normal operating target of remaining within 0.2Hz of 50Hz, with Arenko then called upon as part of the DC service to discharge its battery.
Hollies explained how the asset was discharging over 28MW ten seconds after the interconnector fault, with frequency beginning to recover another five seconds later. Within two minutes frequency was back to normal.
He went on to detail how during these sorts of events the frequency often swings positive after the fault "as the system overreacts slightly", however on this occasion "the response was near perfect with no over response", with Hollies praising National Grid ESO's "impressive control".
A similar event occurred in June 2019, with the French interconnector tripping and taking around 1GW off the system. During this event, batteries were also called upon to bring frequency back to normal.
The DC service is to see 500MW of low frequency response initially bought from providers, although this will then grow to 1GW next year and include high frequency response.
The ESO is to run tenders for DC seven days a week, procuring from 11pm to 11pm, with the intention of bringing frequency response closer to real time.