Don’t bank on electric cars avoiding a big rise in peak energy demand

SIR – The letter from Thérèse Coffey, the Environment Minister (August 24), illustrates the danger of a vision with no credible plan to achieve it. Her claim that the proposed all-electric car nirvana will only mean an 8 per cent increase on today’s peak demand is misleading.

The National Grid’s Future Energy Scenarios 2017 covers four scenarios for energy production and use. The 8 per cent figure comes from the hugely optimistic “two degrees” scenario, which, for a start, assumes average gross domestic product growth of 2.1 per cent, along with 50 per cent of electric vehicles being shared autonomous vehicles.

But three other scenarios are described, and a fifth hidden away in Section 5.3, which sounds more realistic and would create an increase in peak demand of some 50 per cent.

I urge all interested readers to download the FES 2017 and consider its assumptions about our future. Dermot Flaherty

Upham, Hampshire SIR – Michael Liebreich, the founder of Bloomberg New Energy Finance, in supporting electric cars (Comment, August 23) advocates abandonment of government subsidies.

In markets such as Denmark and Hong Kong, when subsidies to buy electric vehicles have been removed, sales have fallen dramatically.

Following sales of 3,700 Teslas in Hong Kong in the first quarter of 2017, none at all were sold in April after the ending of tax breaks. Only five Teslas were sold in May. No subsidy, no sales. Mike Post

Marlow, Buckinghamshire

SIR – Your leading article (August 22) on the National Grid’s report on the impact of the proliferation of electric cars was wrong to claim that: “It would take 19 hours to charge the average battery to drive 300 miles – but owners would be unable to boil their kettles or cook a meal during that time without blowing a fuse.”

This took the 19 hours that it would take the smallest (3.5 kw) charger, but applied to it the warning that the National Grid issued on using other electrical appliances while using a larger 11.5 kw charger. The National Grid said: “If one were to use an aboveaverage power charger, say 11 kw, this would require 48 amps. When using such a charger it would mean that you could not use other high-demand electrical items (such as kettles, ovens, and immersion heaters) without tripping the house’s main fuse. Using an 11 kw charger would take six hours to fully charge a Tesla Model S, which also has a 90 kwh battery, from the 25 per cent full state.”

So it is not true that current drivers taking 19 hours for charging are unable to boil a kettle at the same time. Sam Richards

London SE1

SIR – Would the addition of lithium to drinking water (report, August 24) enable me to boil a kettle while charging my electric vehicle? Barry Horswell

Southampton