Electric car drivers in the UK are unlikely to be able to rapidly charge their vehicles at home at the same time as boiling a kettle, National Grid has warned.
The operator of Britain’s electricity transmission system has cautioned that using a powerful and fast electric car charger at home will trip a main fuse if vehicle owners simultaneously utilise other “high demand” energy items, such as kettles, ovens and immersion heaters.
The warning is contained in a National Grid “thought piece” document which considers some of the potential challenges around the UK’s ambition for a mass rollout of electric vehicles.
National Grid assumes in future most electric cars will need to have a battery capacity of 90 kilowatt hours (kWh) for drivers to make long-distance journeys of about 300 miles.
The ability to travel greater distances without stopping to recharge will be a “must have” if vehicle owners are to abandon their petrol or diesel cars entirely.
An average-size battery charger of 3.5kW would take 19 hours to fully charge a 90kW battery even when it is already 25 per cent full, according to National Grid’s calculations.
A more powerful 11kW device could power up, for example, a Tesla Model S with a 90kW battery in six hours if it was already 25 per cent charged, but owners would be unable to boil their kettles during that time without blowing a fuse, said National Grid.
“The average household is supplied with single-phase electricity and is fitted with a main fuse of 60-80 amps,” added the company.
“If one were to use an above-average power charger, say 11kW, this would require 48 amps. When using such a charger it would mean that you could not use other high-demand electrical items . . . without tripping the house’s main fuse.” – (Copyright The Financial Times Limited 2017)