The future is electric

SIR – John Hay-heddle (Letters, January 15) says “electric cars are woefully inefficient… not better than 15 per cent overall, compared to 40 per cent or slightly less for a diesel hybrid”.

In fact, modern electric vehicles are typically around 70 per cent efficient at converting electrical energy from the grid, via battery storage, into forward motion. It would be more accurate to say that electric vehicles are between two and four times as efficient as those powered by an internal combustion engine – hybrid or otherwise. Mark Scott

Sherfield-on-loddon, Hampshire

SIR – The recent publicity given to the proposed Hyperloop transport system is in some ways a reminder of one of Brunel’s early inventions, the Atmospheric Railway.

This eventually failed in 1848 after even Brunel’s genius failed to find a way of preventing rats from eating the tallow-lubricated leather seals used to maintain a vacuum in the pipe containing the propelling piston, which lay between the tracks.

While one can imagine that a Hyperloop might be possible for relatively short distances, the power required to maintain low pressure in a large-diameter tube covering the 400 miles between London and Edinburgh, and the difficulties that intermediate stopping points would present, suggest that any investors would lose their money. John Bowden

Macclesfield, Cheshire