Many of the problems we face today are
not so new as we think they are. And some of our modern solutions are not so
new, either. The problem of energy shortages and the solution of using solar
energy go back at least to early Greek cultures. The climate in the coastal
areas of Greece 2,500 years ago was characterized by cool winters, much as it is
today. At that time, the Greeks heated their homes with small, charcoal-burning
heaters. In other words, wood (which is used to make charcoal) was their primary
source of energy. However, by the fifth century B C fuel shortages had become
common be- cause, in many parts of Greece, the firewood in the forests had been
depleted. Once the supply of fire- wood from the local forests ran out, people
began to use the wood from olive groves as fuel. But this solution had its own
problem. It reduced the olive crop, a valuable resource to the Greeks. By the
fourth century B C, the city of Athens banned the use of olive wood for fuel.
Wood had to be imported from farther and farther away, making it more difficult
to obtain and more expensive to use. About this time the Greeks began to build
their houses facing south, so that the low sun in winter could penetrate and
help heat the interiors. Excavations of ancient Greek cities suggest that large
areas were planned so that individual homes could take maximum advantage of
passive solar energy.