Going flat with electric cars

Written by Peter Morgan on .




I read with interest your feature on Commander Heron-Watson's electric car.  The national press has been awash with almost hysterical copy on the terrors of petrochemical fuelled cars recently, so here's an engineer's more pragmatic viewpoint.  We all want improved air quality, but not at any cost.

The fundamental flaw of the purely electric vehicle (EV) is that it relies solely on batteries.  Many EVs use batteries that contain rare metals such as lithium, cobalt and nickel.  These are energy costly to extract, manufacture and are consequently expensive to the end user. They also have unstated disposal issues at the end of life.  A Lithium battery powers your mobile phone and given phone battery life gets shorter and shorter with every charge (a characteristic called hysteresis), an EV with the same batteries will suffer the same fate.  Given a small EV might struggle to cover 90 miles at present (so is suitable only for short commutes), after a few years that range will be significantly lower.  Battery anxiety is the elephant in the room that everybody in the EV business doesn't talk about and will ensure the depreciation of such cars is very severe.

The other problem is charging the batteries.  Commander Heron-Watson mentions his solar panels. As a user of these for over 10 years, I can categorically say that they could not be relied upon to do a regular overnight charge. Ignoring the fickle weather, you would need battery packs and special transformers to make the output suitable for an EV.  It simply wouldn't be practical in an urban situation and the payback on such an investment wouldn't be worth it.  That rolls the issue right back to the question of the National Grid overloading at peak times.

EV proponents suggest fast charging might take as little as 30 minutes (if you win the fight to get your car on a compatible public charging point that is actually working).  That compares with perhaps 2-3 minutes to refuel a current small car with a range of perhaps 350 miles.  And nobody is yet talking about the very real issue of safety of the public chargers in wet weather.

Commander Heron-Watson and I do agree on the most important point however - that the future lays with the electrically driven hybrid car, as pioneered by his 'range extender' option.  Development is only in its earliest stages but crucially, this could be applied also to vans and trucks (unlike purely electric).  Watch out for the concept being taken forward by leading automotive engineers Prodrive in Banbury.  They are working in conjunction with Transport for London and Ford to develop a pilot fleet of Transit vans, using just such a powertrain.

Purely electric cars will remain a very expensive novelty. The general public - already sceptical after being misled over the diesel engine - isn't likely to embrace a technology that in its present form is so obviously unsuitable for their requirements.



Peter Morgan C(Mech)Eng, Member of the Guild of Motoring Writers