PREDICTIONS – 10 Years Later - Santa Fe Institute

APPENDIX C
WE CAN BECOME MUCH MORE EFFICIENT
APPENDIX FIGURE 11.2 Historical trends in efficiency for three technologies: engines,
production of light, and production of ammonia. The efficiency is defined in
the classical thermodynamic way as useful output divided by energy input. In spite
of the progress made during the last 300 hundred years, we are still roughly around
the 50% efficiency level of these technologies. The last point on the prime-mover
line (open triangle) and the ammonia-production line (open circle) have been added
by the author. Both updates confirm the trends. ∗
∗ Adapted from a graph by Cesare Marchetti in “Energy Systems—The Broader Context,”
Technological Forecasting and Social Change, vol. 14 (1979): 191-203.
Copyright 1979 by Elsevier Science Publishing Co., Inc. Reprinted by permission of
the publisher.
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