Environmental Engineering Reference
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example of the problem. If it is required that
%of
electricity come from wind, what do you do when wind
is blowing hard and output is
% of capacity? Since
there is no emission-free energy storage (pumped storage is
a limited exception) I must either turn off part of the wind
system or turn off everything else. German utilities are
already having problems with the stability of the German
power grid at a lower level of wind power. Wind is a winner
if it is a relatively small part of the electricity supply (arbi-
trarily I set this at
%) and a maybe for anything larger.
What is needed is low-cost emission-free energy storage.
We do not have it, and there is little investment in its
development. This is the problem that led the CCST
'
s
study of California
s Energy Future to conclude that the
goal could not be met solely with renewables.
The problems of solar are different from those of wind.
The capital cost of
'
per kilowatt is the same as that
of a nuclear power plant, but the output is only
$
%of
capacity for photovoltaic in a sunny part of the country. If
a nuclear plant puts out power
% of the time and a solar
PV installation puts it out
% of the time while they
both have the same capital cost per capacity kilowatt, you
know whose electricity is lower in cost. Nonetheless, PV
does have a place. If you are in a poor country with no
grid and need energy for your farmers to charge their
cellphones so that they can get the best prices for their
products, or where you want your schools to get educa-
tional broadcasts from your capital, the high cost of
PV systems may be well worth paying. In places like
California where daytime electricity costs are very high,
PV may save you money. In places where the costs of
daytime electricity are not charged a premium, PV is a loser.
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