UK electric vehicle (EV) drivers will soon be able to take advantage of cheaper public charging when green energy is abundant, as energy supplier Octopus Electroverse, a subsidiary of Octopus Energy, launches “plunge pricing”.

These “plunge pricing” events take place when there is a high supply of cheap renewable power to the grid, coupled with low demand. EV drivers will receive discounts of between 15% and 45% per kWh for charging their cars at these times. According to Octopus Electroverse, which operates over 700,000 chargers in the UK and Europe, “Plunge Pricing” could save EV drivers up to 250 pounds a year.

Matt Davies, director of Octopus Electroverse, said: “This is a massive milestone: for the first time, drivers can power up and pay less on the public charging network when green energy’s abundant. It isn’t your average discount—it’s revolutionising public charging and something that could never be done with petrol. We’re geared up to work with more chargepoint brands so we can bring this to even more people.”

Octopus Energy, which was recently declared the UK’s largest electricity supplier just eight years after entering the market, has major ambitions regarding the role of EVs in a modernised grid.

Intelligent Octopus Go, Octopus Energy’s EV tariff, now manages a cumulative 1GW of EV batteries. Through this tariff, 150,000 EV batteries are combined to form virtual power plants (VPPs), which allows customers to automatically shift their EV charging to cheaper and greener times of day, saving them money and providing the grid with much-needed flexibility at times of low demand.

In February, Octopus Energy launched the first mass-market vehicle-to-grid (V2G) tariff in the UK, providing free charging to its EV customers. While the tariff, named Octopus Power Pack, is currently in beta, the company claims it could save the average EV driver 850 pounds each year in charging costs.