THE PRICE OF ILLUMINATION IN LUMENS
THE PRICE OF ILLUMINATION IN LUMENS. Nordhaus has a table on page 49 of his paper which shows the prices of different lighting technologies in terms of illumination in cents per thousand lumen-hours. He begins with open fires; then neolithic lamps using animal or vegetable fat in the period 38,000 B.C. to 9000 B.C.; then Babylonian lamps in 1750 B.C. Nordhaus doesn’t include price estimates for them in the table but in an appendix he reports on an experiment he conducted with a Roman lamp certified as dating from Roman times.
The big changes in the technology of light begin in about 1800 when tallow candles and sperm-oil candles are developed. While the Nordhaus table has listings and estimated prices for a number of technologies in the years after 1800, data points for tallow candles in 1800 and a filament lamp from the late twentieth century are sufficient to make Nordhaus’s important point. I have eyeballed the Nordhaus figures. A tallow candle in 1800 had a price of about 40,000 cents (four hundred dollars) per 1000 lumen-hours and a modern filament lamp had a price of about 400 cents (four dollars) per 1000 lumen hours).
Nordhaus (p. 63) concludes that “the growth in the frontier volume of lighting has been underestimated by a factor of between nine hundred and sixteen hundred since the beginning of the industrial age.