This interesting BBC article talks about an economist’s efforts to chart the efficiency of light production from the discovery of fire to the LED.

Yale Professor William Nordhaus studied the amount of hours of labor required to produce 1,000 lumen-hours using fire, oil lamps, candles, and light bulbs. He found the labor once required to produce 54 minutes of light now produces 52 years.

Hooray for human progress!

Click here to read it.