National Grid has welcomed the plan to make electric or zero-emission cars and vans account for all new sales from 2040, but said the government and industry now faced big decisions on how the extra power was provided and demand for it was managed.
The grid recently warned that, by 2030, electric cars could require 3.5-8GW of additional capacity, on top of the current peak demand of 60GW.
By comparison, the nuclear power station being built at Hinkley Point in Somerset will add 3.2GW of capacity to the system.
By the middle of the century, when it is assumed almost all cars will be electric, that extra peak demand could be up to 18GW.
The lowest estimates of extra demand assume that drivers charge their cars at off-peak times. Smart meters and time-of-day tariffs could incentivise owners to charge when wind and solar power are plentiful and electricity is cheaper.
Energy networks could also manage demand via automatic time-shift charging, whereby a car plugged in at home at 6pm is not actually charged until the early hours of the morning, when demand is low.
Ministers have already urged drivers to think carefully and avoid placing extra pressure on the grid.
James Court, head of policy at the Renewable Energy Association, a trade group, said: “We need smart vehicle charging and price-reflective tariffs if the future electric fleet is to be a huge benefit and not a hindrance to our grid.”
Regardless of how sensibly the extra demand is spread across the day, electric cars will require investment in new power generation.
The energy analyst Wood Mackenzie estimates that if one in three cars sold in 2035 is fully electric, the vehicles would collectively account for 3% of the UK’s total electricity demand. Building 400,000 charging points for them all would cost £30bn, the group has said.
National Grid said the extra power would be generated from gas, windfarms, imports and nuclear reactors – not from coal, which is scheduled to disappear from the UK’s power mix by 2025 at the latest.
And the switch to electric vehicles could even provide an eventual boost to the grid.
The government recently announced £20m of funding to support research on vehicle-to-grid technology, where the grid could call on the power stored in the cars’ batteries to help cope with fluctuations from intermittent wind and solar farms.
