> The 300MW Thurrock Storage project, developed by Statera Energy, is now energised and delivering electricity flexibly to the network across London and the south east.

> With a total capacity of 600MWh, Thurrock Storage is capable of powering up to 680,000 homes, and can help to balance supply and demand by soaking up surplus clean electricity and discharging it instantaneously when the grid needs it.

Unless they updated the original post, that all sounds correct to me. It's a 2-hour battery, rather common in the industry.

EDIT: Ah, you mean the https://stateraenergy.co.uk/news/thurrock-energisation is wrong, with the fantastically outrageous statement of "delivering its full output of up to 600MWh within seconds."