Environmental Engineering Reference
In-Depth Information
Solar thermal electric systems are expensive, but do
have a potential advantage. Basically, they collect heat
and then turn that heat into electricity just like a conven-
tional electric power plant. The typical ef
%,
better than all but the best (and most expensive) of the PV
cells. Even better, the systems can store their own heat
and use it to produce electricity when the Sun is not
shining. Regrettably, they are more expensive today than
other systems, but if their costs can come down they
would be a winner. At present they are a maybe.
Geothermal is a winner if you have a source of heat
near the surface like the Geysers
ciency is
field in California, or
those in Iceland, New Zealand, and the Philippines.
Enhanced geothermal is all about mining the heat from
deep underground and so far all attempts have failed. It is
a long-shot maybe.
Small hydro is
fine, but there is only a very small
amount of it and it is really irrelevant on a world scale.
Investment in ocean systems is another triumph of
hope over experience. There is only one in the world that
has been producing energy for decades. It is in France
where a river estuary was dammed and turbines installed
that produce electricity when the tide comes in and the
tide goes out. People say they have new ideas so I will give
it a maybe, but secretly I think it is a loser.
Biofuels:
Chapter
reviewed biofuels. The US corn-
based ethanol program should be terminated; it is a loser,
but the federal government is very unlikely to do the right
thing because Congress thinks it likely that votes will be
lost in the corn-belt states if they end it. Brazilian sugar-
cane ethanol is a winner, and the EU
'
is grain-based etha-
nol
is somewhere in between. Phase-
(cellulosic)
is
