Many Homes Lack the Capacity to Charge Future Electric Cars, National Grid Says

The utility company believes public charging stations are the better solution.

byStephen Edelstein|
Many Homes Lack the Capacity to Charge Future Electric Cars, National Grid Says

Many electric car drivers rely on home charging stations. Plugging in at night often provides enough juice for daily driving, without resorting to public charging stations. But a major multinational utility company believes future electric cars could present a problem for home charging. National Grid, which manages electricity infrastructure in Great Britain and parts of the United States, claims many homeowners in its area of operations can't charge an electric car and make a cup of tea simultaneously without blowing a fuse. 

But that warning may not be as dire as it seems. The estimation assumes an electric car with a 90-kilowatt-hour battery pack, something that probably won't become commonplace for a few years. Since it's unlikely that drivers will completely drain the pack in regular use, it's assumed that charging takes place with 25 percent of capacity remaining. To charge the car in a reasonable amount of time, National Grid assumed its hypothetical homeowner would use an 11-kilowatt charger.

That charger would require 48 amps, according to National Grid. Since the average U.K. household has a main fuse that supplies 60 to 80 amps of power, that doesn't leave enough room to charge the car and run another large appliance at the same time, National Grid argues. 

Running something like a tea kettle or an oven could trip the house's main fuse, National Grid warns. It claims building up a network of public charging stations is a better option than having people continue to rely on home charging, arguing that would require a "large scale rebuild of the domestic electricity infrastructure."

However, that scenario seems to leave out an important detail. Charging at the rates discussed by National Grid requires a dedicated 240-volt power source, which should have its own breaker and therefore not run on the same circuit as other household appliances. (You can plug an electric car into a standard household socket, but it will take much longer to charge.) Anyone planning on buying an electric car should take a look at their household wiring first to make sure it's in good condition, and should consider a 240-volt power source, known as a Level 2 charger. Home charging does require a little extra planning, but it won't force you to choose between an electric car and electric lights.