Environmental Report 2000 - EnBW

Further Information
What goes into the production of one kilowatt hour
of electricity
Electricity generation is a highly complex and elaborate process. But as ecological findings
show, the industry’s impact on the environment can now be kept to a minimum thanks to
modern, state-of-the-art technology.
We can trace the flow of electricity
backwards from the plug in the living
room over the wire that leads to the
house connection line which leads to
the local transformer. From there it
goes via subterranean or overhead
cable to the transformer station and
from there via medium-voltage networks,
substations with transformers,
switching systems and converters
and high-voltage lines all the way
back to the power plant.
In our group this means mainly nuclear
power plants, coal- and gas-fired plants
and hydroelectric generating stations.
The electricity which reaches the end
user through the network is produced
here by the action of turbines in the
generator. We produce the heat and
steam which is essential for this process
by splitting the uranium atom or
by burning coal and gas or by harnessing
the power of moving water to
operate the turbines.
“Ingredients” for electricity
generation
The nuclear fuel uranium is mined
throughout the world from uraniumrich
rock, then treated, concentrated,
inserted in tablet form into fuel rods
and transported to the nuclear power
plant.
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Coal, oil and gas are million-year old
fossil remains of plants and small
animals, transformed and preserved
in pockets in the earth’s crust. Coal is
produced in many regions of the
world. We may get it from Australia,
South Africa or Columbia where huge
bucket wheel excavators extract it
from open cast mines. It is then
shipped to Rotterdam and from there
transported to Germany.
Two million tonnes of coal
in one year
Last year our plants at Heilbronn and
Karlsruhe consumed around two million
tonnes of coal, producing waste
gases such as carbon dioxide, sulphur
dioxide, nitrogen oxide as well as
dust. Highly efficient units can filter
the majority of the pollutants out of
the flue gases with the exception of
carbon dioxide, the basic by-product
of every combustion process. But the
filtered products can themselves have
new negative environmental impacts
if they have to be stored. This is why
we process the gypsum and fly ash
we gain from the filters into materials
for the construction industry. .
Ecological stock-taking
An “eco-breakdown” of our electricity
generating activities provides the following
picture.
For one kilowatt hour of electricity –
the equivalent, say, of one hour spent
using the vacuum cleaner – we require
(based on our 2000 energy mix) 0.001
grams of uranium, 76 grams of coal,
1 gram of natural gas and 1 gram of
heating oil as well as 2 grams of
limestone.
The production of one kilowatt hour
of electricity based on this energy mix
involves approx. 0.005 grams of radioactive
waste material, 225 grams of
carbon dioxide, 0.20 grams of sulphur
dioxide, 0.16 grams of nitrogen oxide,
and 0.005 grams of dust, 0.7 grams
of waste material, as well as 3 grams
of gypsum and 8 grams of fly ash for
the cement industry.
Minimal environmental impact
With the advanced technology we
have installed in our power plants to
protect the environment, we ensure
that environmental impact is kept to a
strict minimum. Even if we take preand
post production processes into
account, the overall picture remains
substantially the same. And the large
quota of nuclear and hydroelectric
power we produce means that our
specific CO2 emission levels are also
relatively low: with 225 grams per
kilowatt hour, we have only reached
about 40% of the national average.
Natural gas is an environmentallyfriendly
fuel for both domestic use
and power stations. When burned,
it only produces little CO 2.
However, reserves are somewhat
limited, and it is thus inclined to be
relatively expensive.