What just happened? Operators have flipped the switch on Europe's largest battery energy storage system, bringing online a system capable of storing enough electricity to power 300,000 homes for up to two hours.

The facility, located in Cottingham, East Yorkshire, UK, was overseen by renewable power company Harmony Energy Limited and utilizes Tesla Megapack technology. The system can store up to 196 MWh (megawatt hours) of electricity in a single cycle and will provide balancing services to the energy grid while also allowing for fossil fuel sources to be replaced by renewable energy sources like solar farms and wind turbines.

The battery energy storage system was built adjacent to the Creyke Beck substation, which is where the Dogger Bank offshore wind farm is slated to go live next summer.

Each Tesla Megapack can store over 3 MWh of energy, or enough to power an average of 3,600 homes for one hour. Harmony didn't say how many Megapacks it deployed in the build but based on simple math and the construction photo accompanying the press release, there are at least several dozen units at the site.

Harmony said the project was originally intended to become operational over two phases – one in December 2022 and the second in March 2023 – but they decided to bring everything online now in anticipation of the challenging winter period.

Last month, the office of gas and electricity markets (Ofgem) said the UK could experience a gas shortage this winter due to the war between Russia and Ukraine. Gas is responsible for generating between 40 percent and 60 percent of the UK's electricity, and a shortage could have a major impact on power production.

The facility will be run using Autobidder, a real-time trading and control platform from Tesla that allows utility companies to monetize battery assets. Autobidder is already overseeing several other battery storage projects including the Hornsdale Power Reserve (HPR) in South Australia.

Harmony said this is the first of six similar projects it intends to deliver in the coming years.