A solar farm has provided National Grid ESO with reactive power overnight in what is being lauded as a UK first.

Solar inverters at one of Lightsource BP’s solar plants were used to provide a reactive power service on Monday 4 November.

The solar inverters are capable of providing reactive power – the ability to maintain voltage levels on electricity transmission systems – by reducing or increasing voltage levels. This then delivers the voltage change necessary at the grid point.

National Grid ESO said this is the first instance of a solar asset providing the service at night, when a solar farm would ordinarily be inactive. The trial means solar could be providing reactive power overnight, utilising the asset when it would otherwise be sitting idle, a move which would help increase capacity on the network without the need for infrastructure upgrades.

It has the potential to provide up to 4GW of power capacity in the South East and save energy customers over £400 million by 2050.

The trial comes as part of the ‘Potential Power’ project run by National Grid ESO and UK Power Networks (UKPN), looking into the creation of a new reactive power market for distributed energy resources (DERs) in the South East.

It follows three years of testing and development and was coordinated with UKPN’s control engineers to ensure safety and reliability of the network.

Kareen Boutonnat, chief operating officer at Lightsource BP, said innovation is “key” to addressing future growth of the energy sector and the trial proves solar plants can “play a larger role” across the electricity network.

“With electricity demand increasing so rapidly we have to be in a constant state of evolution in order to solve the problems of the future.”