The 4-minute blackout that crippled Britain
The disaster could not have come at a worse time. Exactly 5 minutes before the rush hour, darkness descended upon the U.K at 16:55 on Friday, Aug 9.
When a lightning strike took out a gas-fired power plant in Bedfordshire and one of the power stations at the Hornsea offshore wind farm in the U.K., chaos ensued. The electrical frequency of the U.K.’s National Grid has dropped to 48.9 Hz, which is much lower than the accepted rate of 50 Hz. The trains were grounded on the tracks, or worse, stuck in tunnels that were then pitch black without the lights. BBC reported that the train passengers near Kentish Town station had to get off the train in the middle of the track and walk along the railway line to the station. The train passengers traveling on Thameslink had to wait for six hours to be evacuated to another train due to railway safety requirements and fleet.
To make the matters worse, BBC reported that a backup generator also failed to step up at Ipswich Hospital, plunging the premise into complete darkness. The siren went off, the elevators stopped abruptly, forcing the staff to evacuate patients manually.
Batteries, the unsung heroes
As horrendous as the blackout was, the situation could have gotten much worse, had battery companies not stepped up to mitigate the disaster. Our media partner, pv magazine, has reported that RES’ 80 MW storage portfolio in the U.K. has come to the rescue of the National Grid. Upside Energy’s 6 MW batteries have also kicked into the motion during the disaster.
When the two power plants both went down one after another in a matter of minutes, the grid was short of 1.5 GW. According to RES, the grid frequency fell as fast as 0.144 Hz/s. However, its battery portfolio was flexible enough to switch from charging to discharging mode in 25 seconds, picking up the slack and pumping the much needed power back to the grid. Therefore RES declared that the swift reaction of the battery storage may have prevented a blackout that could have impacted the entire U.K.
RES is not the only company taking credit for the heroic efforts. Upside Energy is the firm that supplied 6 MW to the National Grid from its five gigantic Li-ion batteries on a solar power plant near Luton Airport. 6 MW does not sound like a huge chunk of electrical capacity. However, it is a game-changer to the supply of national electricity. “A home on average is consuming about two kilowatts – six megawatts gets you 3,000 homes maybe.” explained Tim Green, the co-director at Imperial College London’s Energy Futures Laboratory.
Another company, Statera, has also made its controversial assertion to pv magazine that their flexible gas peaker plants could be very helpful for countering the frequency drop of a renewable energy grid.
Flexibility assets gaining momentum
Having grid-connected batteries at the disposal of National Grid has proven to be a great improvement. Current± reported that, compared with the previous blackout in 2008, the incident in last month took precisely 3 minutes and 47 seconds to restore the grid frequency to its operating standard. The incredibly rapid speed is four times faster than the 11 minutes it took 11 years ago.
There is certainly room for improvement. Despite the heroic efforts to mitigate the blackouts, nearly a million customers are still affected. The transport customers got hit the hardest.
Erik Nygard, the chief executive of Limejump, an energy software company based in the U.K., has demanded the stock of firm frequency response (FFR) batteries to expand substantially on account of its ability to mitigate a failing electric grid such as the episode on 9 August.
Jonathan Ainley, head of public affairs and UK program manager at KiWi Power has also weighed in on the matter. According to Ainley, it would be advisable for National Grid to have more quantities of distributed generation in the Balancing Mechanism (BM).
There are still many uncertainties regarding what changes the U.K. government would make in the light of this blackout. What is certain by now is the critical role which the flexibility assets play. The traditional generators obviously could not react fast enough. The importance of the batteries and energy storage systems is likely to continue to rise.