Today, let us find a place for the heat of the sun.
The University of Houston's College of Engineering
presents this series about the machines that make
our civilization run, and the people whose
ingenuity created them.
"Fear no more the heat of
the sun; nor the furious winter's rages," said
William Shakespeare. In fact, our bodies are very
closely matched to the heat of the sun and to the
cold of its absence. Sunshine pours just about as
much energy upon us as we can bear. It can provide
all the energy we really need. The heat of the sun
has given us most of the energy we've ever used.
Yet we pay the sun very little heed when we want
energy for everyday use. We exhaust the store of
energy that the sun has heaped up for us. We burn
our ancient coal, oil, and gas, while we overlook
the direct use of the sun itself. We forget the 170
trillion kilowatts that steadily rain down upon us.
We forget a hundred ways we can lay our hands on
that energy. Hydroelectric power is sun-driven. An
engine can draw heat from the warm ocean surface
and reject it to the cold ocean deeps. We can
arrange for the sun to warm our homes directly. We
can burn fast-growing plants for fuel. We can tap
the energy of the wind and ocean waves. We can
microwave energy down to earth from solar
collectors in space. Photovoltaic cells can change
the rays of the sun straight into electricity.
None of this is free. The capital costs of solar
systems run high, even if the sun's rays do not.
And solar systems can lay a heavy hand on the
environment. The watershed behind a dam eats huge
tracts of real estate. The dams that've collapsed
have wrought as much havoc as the worst natural
But the real threat to our well-being isn't the dam
or the nuclear reactor or the coal furnace. What
threatens us are the terrible concentrations of
energy in our power systems. To save ourselves, we
must put our eggs in many small baskets. We must
divide our attention. We must put a nuclear plant
here, a dam there, and a windmill in our back yard.
That's hard thinking for us. We make heroes and
villains of energy systems. We forget everything
but the cheapest source at any moment. As prices
change, so does our short attention span. We lurch
from oil to coal to the sun to natural gas.
Right now oil is so cheap that we've put everything
else out of our minds. We're apt to see solar
energy as the posing of flower children. It is not.
It is a rich gallery of possibilties and the least
assailable long-term alternative.
Solar energy is no knight on a white horse. By
itself, and on the same scale as our other power
plants, it can be just as dangeous and expensive as
they are. The sun belongs in a more diverse and
sophisticated equation of energy use. The heat of
the sun is subtle stuff, and it will serve subtle
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds