3 ms·

Oil power stations are around 33% efficient[1]. Electric drives have up to 80% efficiency[2]. Given those rough figures, even when powered by oil stations batt

Oil power stations are around 33% efficient[1]. Electric drives have up to 80% efficiency[2]. Given those rough figures, even when powered by oil stations battery-powered cars can theoretically be more efficient at using oil than a car with an ICE. [1]http://en.wikipedia.org/wiki/Oil_power_plant#Heat_into_mechanical_energy http://en.wikipedia.org/wiki/Oil_power_plant#Heat_into_mecha... [2] http://en.wikipedia.org/wiki/Electric_car#Energy_efficiency http://en.wikipedia.org/wiki/Electric_car#Energy_efficiency

colanderman 15y ago
Not disagreeing with you, but the point of an electric car is not drivetrain efficiency. It's regenerative braking and emission consolidation.
rdtsc 15y ago
However does the efficiency offset the inefficiency (physical and economic) to store enough electricity to make it feasible.
gvb 15y ago
You also need to account for the transmission line efficiency[1], the charger efficiency (typically 90-95%), and battery efficiency[2] (80-90%). If we assume the transmission lines are 98% efficient, the charger is 95% efficient and the battery is 90% efficient, the motor controller is 95% efficient, and the motor is 95% efficient (drive efficiency of 90% instead of 80% of the parent quote)... 0.33 * 0.98 * 0.95 * 0.90 * 0.95 * 0.95 = 25% efficient, with efficiency numbers somewhere between "best case" and "optimistic". ICE in an efficient car is competitive with that. A hybrid will beat that. [0] How Stuff Works estimate: http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell4.htm http://auto.howstuffworks.com/fuel-efficiency/alternative-fu... [1] Nobody knows for sure what the transmission line (including step-up and step-down transformers) is in actual practice. Note the Wikipedia article says "efficiency" several times, but never pins an estimate onto it: http://en.wikipedia.org/wiki/Electric_power_transmission http://en.wikipedia.org/wiki/Electric_power_transmission [2] http://en.wikipedia.org/wiki/Lithium-ion_battery http://en.wikipedia.org/wiki/Lithium-ion_battery

colanderman 15y ago

Not disagreeing with you, but the point of an electric car is not drivetrain efficiency. It's regenerative braking and emission consolidation.

rdtsc 15y ago

However does the efficiency offset the inefficiency (physical and economic) to store enough electricity to make it feasible.

gvb 15y ago

You also need to account for the transmission line efficiency[1], the charger efficiency (typically 90-95%), and battery efficiency[2] (80-90%). If we assume the transmission lines are 98% efficient, the charger is 95% efficient and the battery is 90% efficient, the motor controller is 95% efficient, and the motor is 95% efficient (drive efficiency of 90% instead of 80% of the parent quote)... 0.33 * 0.98 * 0.95 * 0.90 * 0.95 * 0.95 = 25% efficient, with efficiency numbers somewhere between "best case" and "optimistic". ICE in an efficient car is competitive with that. A hybrid will beat that. [0] How Stuff Works estimate: http://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/fuel-cell4.htm http://auto.howstuffworks.com/fuel-efficiency/alternative-fu... [1] Nobody knows for sure what the transmission line (including step-up and step-down transformers) is in actual practice. Note the Wikipedia article says "efficiency" several times, but never pins an estimate onto it: http://en.wikipedia.org/wiki/Electric_power_transmission http://en.wikipedia.org/wiki/Electric_power_transmission [2] http://en.wikipedia.org/wiki/Lithium-ion_battery http://en.wikipedia.org/wiki/Lithium-ion_battery