last edited 2009/04/12 02:51 (*
It came to my attention as it made it to the blog news-scene about the Tesla Roaster which ran 390km (241 miles) without recharging from the town of Valance in France to the Principality of Monaco as part of a "E-Rally" called Rallye Monte Carlo d'Energies Alternatives
and covers a mixture of trunk roads, motorways and single-carriageway roads that wind through the mountains.
A closer look at the "roadster":
Take 1,150 kg metal box, a so called "car" and ..
.. put a 450kg heavy battery in it and use an electric engine . . .
Which makes up 1,600kg heavy vehicle; in the worst case to transport one person (80kg) which makes 20/1 vehicle/body ratio - in other words, 95% of the energy is used to move the vehicle, and 5% of the energy to move you.
Calculating a 5.1L gasoline equivalent per 100km or 46 miles per gallon reveal that this isn't a revolutionary step in efficiency - instead of fussil fuel is will use (or waste) just the equivalent in electric power.
One may argue, in order to establish alternative transportation away from fossil fuels, one has to make small steps, which means to keep the heavy vehicles and only replace the engine . . . even if the engine efficiency itself is much higher than in a gasoline based engine, if you still use 95% of the energy to move the vehicle, this isn't worth it. If you reach a 1/1 ratio between vehicle and to be transported body or goods, then it gets interesting, and you gain an energy efficiency by the very fact you are not wasting it to move a heavy vehicle anymore!
As I wrote in Mobility, a fully loaded truck has a very good vehicle/body ratio, but it's a waste if the truck driving empty.