Environmental Engineering Reference
In-Depth Information
Krewitt
is analysis is for Germany, is based on European
Union regulations for emission controls, and uses German
government numbers for health effects. His comparisons
are for the same amount of electricity generation from
each source, one terawatt-hour (one gigawatt of electricity
for
'
hours), and are supposed to be end-to-end; that is,
to include mining, transportation, fuel fabrication, plant
construction, operation, and the effect of emissions on
public health. The fact that coal is the worst of the major
fuels for electricity generation is no surprise. The biggest
surprise for me was the large number for photovoltaic
generation. Krewitt
is analysis is based on the use of poly-
crystalline photocells which use many toxic gases in fabri-
cation. I would expect the thin-
'
lm cells coming into use
now to be less hazardous, but there are not enough of those
deployed to make a good estimate as yet. The analysis does
not deal with uncertainties as well as I would like and the
numbers give an impression of precision that I think is
unwarranted. Nonetheless, of the major fuels, coal is
clearly the worst, wind the best, and nuclear seems some-
what better than photovoltaic or gas.
The ef
ciency of electricity generation is important in
discussing emissions. The aging
fleets of US coal and gas-
fired power plants run at average ef
ciencies of about
% respectively, while the most modern coal
plants run at
% and
%. Though the
United States prides itself on technology, it is a long way
from the best in the world when it comes to ef
% and gas plants at
ciency of
electricity generation [
]. Denmark is best with coal at
ciency while Luxemburg and Turkey lead the
way with gas at
%ef
%. Honors for being the worst go to
India for coal at
% and Russia for gas at
%.
