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Monday 6 July 2015

Electric Cars - Would you start from here?

This post started as an attempt to understand electric cars.  My first impression was that electric cars are a set of trade-offs.  On a rough like-for-like basis, electric vehicles are expensive, maybe costing £20k - £30k compared to £10k - £15k for a similar petrol fueled one.  The return is you swap tail pipe emissions for smoke stack emissions but get a more diverse fuel mix which includes nuclear, coal, gas, wind and solar rather than petrol.  Fuel costs are lower, in part due to the lower tax on the fuels used in electricity generation relative to those for automotive use.  The nature of the energy use is significantly different, a high proportion of the energy purchased for electric vehicles reaches the wheels, the conversion losses having taken place at the power station, whilst for a petrol engine the energy loss and related pollution takes place at the vehicle.  A big attraction of electric vehicles is the potential for improving air quality in cities.

Automobiles have been with us for more than a century.  Treat this graph with caution because it was compiled from a random collection of vehicles which I might have owned, i.e. bottom of the range family vehicles.  There is a well established trend of increasing weight and power which has largely been offset by improved efficiency.  A Fort Model T of 1920 weighed in at roughly 500 kg with 20 HP (from a 2.7 liter engine) giving approx. 20 mpg, my Mark 1 Mini (1,000 cc) from the 1970s weighed in at 650 kg,with 35 HP, giving 42 mpg.  The box that my wife uses for her commute to work weighs 1,200 kg and may have a 50 HP engine and returns roughly 50 mpg.  Clearly, there has been a significant advance in petrol engine efficiency over the last century.
The electric equivalent of my wife's box might weigh 1,500 kg and have another 20 HP.  Is this time for a rethink of what we want from a car?

Hi-tech batteries, hydrogen and fuel cells have the potential to partially displace petrol as the dominant automotive fuel.  Exactly how this might take place depends on climate, in Arizona, solar panels work well, in the UK offshore wind offers greater output.  Wind and solar energy sources are weather dependent, but most cars spend 95% of their time parked waiting for something to happen, that something could be the availability of some form of sustainable energy.  With an increased number of charging points and a connection to the internet of things, a parked car could hunt around for an appropriate energy supplier.  Take this one step further and add-in peer-to-peer energy, a parked car might do a deal with the owner of a roof top PV array to buy electricity that might otherwise go unused.  There are a lot of technologies emerging which could be joined up in some interesting ways.

My first impression when looking at electric cars that I might imagine buying was that the manufacturer was trying to safeguard the buyer from change, they just looked like the one that had just been traded-in only the new one came with an electric plug.  Maybe, the optimum electric vehicle is a lockable golf buggy costing less than £10k and a range of 100 miles and very low running costs.  For a lot of people this concept would work.  Most car journeys are short and usually involve one person, maybe up to four on the school run.  This concept would not be attractive to those who see the car as a modern day cod piece, but if I were still a thrusting young project manager, I might lust after a Tesla S.

Back in the 1950s there were a number of small, light cars which were a common sight on the roads, the best known is the Bubble Car:


Variations on the theme included the Messerschmidt KR200.  These vehicles weighed roughly 250 - 400 kg and were powered by small two stroke engines.  Motor cycle and sidecar combinations met the same need, whilst I have met a couple of ladies who liked them, most didn't.  However, real enthusiasts did manage to transport a family of four, dad driving, mum on the pillion and two children in the sidecar.  A lot of motor cycle frames from the 1940s and 50s had sidecar lugs as standard.

A modern day equivalent of the Bubble car might be the Renault Twizzy which would meet the motoring needs of a lot of people, just that they don't know it.

Postscript

By chance I came across this description of what it was like to start a Model T:

"If Mr. Smith's car is one of the high, hideous but efficient Model T Fords of the day, let us watch him for a minute.  He climbs in by the right hand door (for there is no left hand door by the front seat), reaches over to the wheel and sets the spark and throttle levers in a position like that of a clock at ten minutes to three.  Then, unless he has paid extra for a self starter, he gets out to crank. Seizing the crank in his right hand (carefully, because a friend once broke an arm whilst cranking), he slips his forefinger through a loop of wire which controls the choke.  He pulls the loop of wire, he revolves the crank mightily and the engine at last roars, he leaps on to the trembling running board, leans in, and move the spark and throttle to twenty five minutes to two. Perhaps he reaches for the throttle before the engine falters into silence, but if it is a cold morning, perhaps he does not.  In that case, back to the crank again and the loop of wire.  Mr. Smith wishes Mrs. Smith would come out and sit in the driver's seat and pull that spark leaver down before the engine has time to die."

Let's all be grateful that cars have evolved to the point where you push or turn something and pull away.  However, in the process we have lost contact with the engineering on which the car is based and less able to understand and evaluate choices.




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