Athletic
power
(brief output) steady output
1 kWh in 10 hours
1 kWh from a utility |
A well conditioned athlete can produce much more
than a horsepower --- during a short time interval.
The same athlete, asked to produce a steady output of power over a period of a day (10 hours, say) will produce perhaps 100 watts of useful power, if connected to a machine the most efficient way, via bicycle pedals. The athlete thus produces one kilowatt-hour of useful work in 10 hours. How much would you pay him (her)? To obtain one kWh of energy from a utility costs a bit less --- about a dime. |