National Grid underplays concern that electric vehicle popularity will overload power networks

Last month the government said it would ban diesel and petrol vehicles by 2040 as part of efforts to tackle air pollution and climate change. 

The move led to suggestions that charging a large fleet of UK electric cars could dramatically push up peak electricity demand. This comes on top of concerns that the UK could already be subject to energy blackouts as old coal plants are shut down, with little to replace them.

A recent analysis from National Grid said as much as 30 gigawatts (GW) of additional power could be needed at peak times by 2040, which is the equivalent of almost 10 Hinkley Point C nuclear power stations. 

Yet in a new “myth-buster” document, National Grid said such a situation was an “outlier”, and more likely scenarios predicted much lower extra peak demand by 2040.

The extra 30GW would only be needed in a world where there were no petrol or diesel cars on the road by 2040 as a result of plummeting electric vehicle costs, there was little thought for environmental concerns such as tackling climate change, and society was rich enough to allow widespread charging of cars at peak time and peak prices.

Currently electricity production at night eclipses demand due to the necessity to have baseload power stations on the grid that output at a constant rate. With electric cars most likely to be charged at night, the network would be able to handle extra capacity during these times.

National Grid’s set of four “core” scenarios outlining the likely potential impacts of electric vehicles found that peak demand for electricity could rise by between 4GW and 10GW by 2040.

In its new document, the company said the government’s bid to ban petrol and diesel cars and vans by 2040 made the scenario in which the UK is taking effective steps to tackle climate emissions the most probable.

That would mean most cars are fully electric vehicles by 2040, and they would push up peak demand by around 5GW, around an eight per cent increase on current levels.

The assessment said in such a scenario, people would be using “smart” chargers which would know how much electricity cost throughout the day and when drivers would need their vehicle to be fully charged.

There would be “time of use” tariffs which make electricity more expensive during peak times, so smart systems would power up car batteries out of peak hours where possible to save money, reducing impact of car charging on the grid.

National Grid also said building new nuclear reactors would be a difficult and costly way to meet short periods of peak demand, as they give constant output and cannot be turned on and off easily.

Ten nuclear power stations would supply around 10 times what would be needed for the annual electric vehicle demand in 2040.

Last week Ofgem said that National Grid would create a spin-off company to separately operate its electricity system by April 2019.