by MrMambo » Sun 26 Nov 2006, 08:05:10
$this->bbcode_second_pass_quote('pup55', 'E')lectricity in most of the US ranges from 5 cents to 12 cents per kwh.
The problem with your calculation is that in order to turn the "energy contained in crude oil" into electricity you have to burn it, boil water, and run a turbine, all of which causes heat loss and other inefficiencies. So, you need to know what the energy balance (oil in and electicity out) for a power plant is. If you could figure out how to extract the energy from oil, or any other object, 100% efficiently, you would really be onto something.
I don't think thats a problem with my calculation at all. I think we agree more than you think. I mentioned that you can get a lot more work done for the same amount of KWh in the form of electricity than you can from the same amount of crude oil. To generate work from oil you use either a combustion engine or a heat engine. If you have a really really efficient heat engine or combustion engine you might be able to translate 40% of the energy in the oil in a regular engine you get less than 30%. While for an electric engine you can expect an efficiency of way over 90%.
The consequense of this is that if you are going to buy energy to get work done you can choose between bying crude oil /gasoline etc for close to 4 cents/KWh. and then have maybe 0,3KWh translated into real work. How much electricity would you have to buy to get an electric motor operating at 95% efficiency to do 0,3 KWh of work? 0.3/0.95 = 0.316 ( kontroll: 0.316*0.95 = 0.3).
How many more KWh of crude would you need to do the same work as one KWh of electricity (1/0.316 = 3.16 times)
This means that for uses where you need mechanical work done you can afford to pay 3.16 times as much for electricity than for crude oil, assuming you can choose between a 30% efficient oil-engine and a 95% efficient electric engine.
I know all theese assumptions doesnt translate perfectly well to the automobile sector. But still for short trip driving you get more miles per KWh of grid electricity than for KWh of gasoline.