On August 9, a thunderstorm caused 1.5 GW of generation capacity to go offline within seconds in the U.K. The incident caused millions of households to temporarily lose power but the situation could have been considerably worse if not for the country’s battery storage reserves.

Parts of London and the English South East were left in darkness as a result of the storm on August 9. The country’s extensive battery portfolio may have prevented worse damage.

Renewable energy company RES claims to have averted disaster in the U.K. – and with parliament ready to go on an enforced break tonight, it isn’t Brexit the clean energy company is talking about.

RES says its battery capacity was instrumental in preventing a complete blackout in the U.K. in the wake of a thunderstorm on August 9.

The Hertfordshire-based company operates an 80 MW storage portfolio in the U.K. which sprung into life when a gas-fired power plant and an offshore wind power station ceased operation after a lightning strike and poor weather conditions. The incident caused trains to halt, traffic lights to stop working and blackouts for nearly a million households and some hospitals. However, it could have been much worse, according to RES.

With a 660 MW gas-fired power plant in Little Barford suddenly stopping after a lightning strike, and the Hornsea 1 offshore wind park subsequently going offline, the grid was 1.5 GW short of electricity within a minute or so.

Battery capacity is theoretically well-suited for such scenarios as the power stored is highly dispatchable and such assets can be mobilized rapidly and accurately. The blackout offered RES and its batteries to show what they could do.

The battery portfolio reacted within seconds to counter the falling distribution frequency. The gas plant failed at 4.52pm and the resulting lack of 660 MW of capacity occurred within seconds. According to RES, grid frequency fell at a rate of 0.144Hz/s but within 25 seconds its batteries kicked in and changed from charging to discharging mode, helping the frequency recover.

Dual benefits

Some 45 seconds after the gas power cut, the Hornsea 1 wind park off the coast of Yorkshire experienced failure and the cumulative energy loss in the system rose to an estimated 1.45 GW, causing frequency to fall again.

Just 76 seconds after Little Barford gas plant went offline, 5% of the U.K. distribution grid decoupled automatically from the rest of the network as a protective measure. Two minutes after the event, however, grid frequency was recovering, and at 4.55pm, the rate returned to the legally prescribed range.

RES’ batteries again proved their worth when the attempt to restore frequency ended with inertia on the supply side, causing grid overloading and prompting frequency to go above the anticipated 50 Hz at 4.57pm. This time the batteries stepped in and switched to charging mode to alleviate the grid of the excess power.

Statera gas claim

RES is not the only back-up power company to hail the performance of energy storage in mitigating the effects of the August 9 blackout. However, rival Statera credited not only its storage assets but used the incident to make the controversial claim flexible gas peaker plants would be critical to back-up a renewable-energy grid. That assertion, made to pv magazine, disputed the claims made by the proponents of storage technologies such as vanadium flow batteries and pumped hydro storage to being able to guarantee security of supply in a truly carbon free grid.

Less controversially, RES said battery storage may have prevented a U.K.-wide blackout last month.

The performance of the storage assets echoed that seen in Australia when the Loy Yang A3 coal unit tripped and left a 560 MW gap in the system, on December 14, 2017. On that occasion, Neoen’s 100 MW/129 MWh Tesla-made battery proved its worth just weeks after inauguration when it stepped up within split seconds to supply 7.3 MW of power which avoided widespread power cuts and restored frequency.

www.pv-magazine-australia.com