Life-Cycle-Assessment for Stoves and Ovens - ESU-services Ltd.

4 Interpretation
The life-cycle-impact-assessment gives interesting insights in environmental impacts caused
by various cooking options. A first result is the large gap between the results for electric
cooking in Western-Germany and Switzerland due to the differences in the electricity production.
Power generation in Switzerland is mainly based on nuclear fuels and hydro-power
whereas in Germany fossil fuels have the highest share. The comparison between gas (CH)
and electricity (D) shows a clear preference for the first.
There is not such a clear outcome if the alternatives are compared for the situation in Switzerland.
A comparison based only on the method of Eco-indicator 95+ does not provide satisfying
results because the impacts of electricity production in Switzerland in some categories,
e.g. radioactive releases and land use are not valued. From a valuation using the additional
impact categories radioactivity, space use, waste heat (as an indicator for the use of energy resources)
and eoctoxicity, cooking with natural gas is better considering radioactive releases
and space use. With regard to terrestrial ecotoxicity and waste heat the impacts caused by a
gas stove are higher than those of using electricity. In other categories the impacts of gas use
are about the same.
Considering the uncertainty of data (e.g. efficiencies of different stoves) and methods (impact
assessment for indoor pollution) the differences of the two possibilities do not lead to a clear
ranking. The overall environmental impacts of cooking with gas or electricity in Switzerland
are assessed here to be about the same.
The impacts of cooking with wood depend mainly on the question whether or not the waste
heat of the stove is used for room heating. Thus the stove achieves a high overall efficiency.
Cooking with wood is an ecological alternative to the other options if the heat of the fire can
be used for room heating. Cooking on a 3-stone fire shows to have relative high environmental
impacts. Especially the toxic effects 28 to human being should be considered while
valuing this option.
Cooking with LPG might be a theoretical alternative to the other types of energy. But from an
environmental point of view there is no clear constraint for it. The use of kerosene for cooking
is also not environmentally friendly in comparison to the other alternatives.
It should be taken into account, that the environmental impacts depend considerably on the
efficiency of the stove used and on the energy consumed due to the users' behavior. Thus for
all types of stoves further developments towards a higher efficiency and proper roles for the
consumers' behavior are desirable to minimize the environmental impacts of cooking.
To compare the cooking alternatives more reliable, further methodological improvements are
necessary for the inclusion of land use and radioactive releases in the method Eco-indicator
95. Further on a separated valuation of indoor air quality effects is necessary to assess the
health effects of pollutants released during cooking in more detail.
The data investigated in this report are satisfying in regard to the inclusion of the environmental
impacts of cooking in further LCA studies. But to compare different cooking alternatives
in detail more information is necessary regarding the efficiency of stoves and a good
method to compare it. An other data gap are the measurements of emissions available for the
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The figure for the environmental effect human toxicity (8940 kg) is about three times higher than this for the
second worst option electric stove in Germany.
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