Given that for every 10 kWh (units) of electricity made 'available for use' in our homes, the distant fossil fuel (coal or natural gas) powered powerstation in Castle Donington or similar has to generate 37kWh of 'heat energy' then surely it makes much more economic and ecological sense for us to generate our own electricity as close to home as possible? (This is beacause 27 units of the 'heat energy' generated at the 'distant' power station is 'lost' in the generation process and in its journey of hundreds of miles over 'lossy' overhead power lines from the 'furnace/boiler/generator' to the wall socket in your home). Similarly, if nuclear power is used to replace the fossil fuel 'furnace' the remaining stages of generation, transmission and distribution are subject to the same 'heat losses' as are involved in those process stages in the fossil fuel case.

The nominal efficiency of the process is further diminished in the use of mains electricicty in our homes to charge up the 400 volt 5/10/22/24 kWh 'battery' in an electric or hybrid electric car, motorcycle etc. Typically between 30 and 50% more electricity has to be used in the battery charging process than is actually stored as useable energy in the battery. Finally the conversion of stored electrical power in the battery to motive force in the car is no more than 85%. Thus 'doing the maths' we can see that the 'conversion efficiency' from power station to 'motive power on the road' is between 10/37 x 1/1.5 x 0.85 = 0.153 and 10/37 x 1/1.3 x 0.85 = 0.177 i.e. the conversion efficicency is between 15% and 18% with a typical value of 16.4% for coal fired generation. In contrast the converson efficiency between petroleum based fuels burnt in an internal combustion (IC) engine and 'motive power on the road' is typically greater than 20%.

If the IC engine had been 'invented' before the electric car and the steam engined car at the end of the 19th Century, then the electric car would probably never have been seriously considered for anything other than certain 'niche' applications such as milk delivery 'floats' as the 'start/stop' nature of this activity is ideally suited to electric propulsion.

P.S. The 'conversion efficiency' of solar energy to 240 volt rms a.c. electricity, using modern roof mounted domestic solar panel arrays is around 15% - makes you think doesn't it ?

Edited by Firmbutfair on 08/07/2014 at 10:14