Octopus said that its Octopus Power Pack tariff will save EV owners who drive 10,000 miles (16,093km) per year more than 850 pounds (USD 1,067) annually. Vehicle-to-grid (V2G) or bidirectional charging has long been seen as a technology with the potential to help balance power grids by using millions of EVs as batteries on wheels that would provide power back to grids when they need it most.