BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

4.2 European results: biofuels compared to fossil fuels 59
4.2.8 Wheat straw versus light oil / natural gas for district heat production
Use of fossil fuels
Greenhouse effect
Acidification
Eutrophication
Summer smog
Nitrous oxide**
Human toxicity**
* How to interpret the diagram
Advantages for
biofuel
Advantages for
fossil fuel
Light oil
Natural gas
-1000 -500 0 500 1000 1500
European inhabitant equivalents* per 100 TJ
The figure shows the results of comparisons between complete life cycles where light oil and natural
gas respectively are substituted by wheat straw for heat production. The unit refers to an amount of 100
TJ of heat. This is equivalent to the average heat requirement of about 4,000 inhabitants of Europe in
one year or a wheat straw production of about 1,300 ha/a. In this case for example the amount of fossil
fuel saved if light oil is substituted by wheat straw is equal to the amount which more than 700 European
citizens would on average consume in one year (this is what is meant by “European inhabitant
equivalents”).
Remarks and conclusions
The results show that both wheat straw as well as light oil and natural gas have certain ecological advantages
and disadvantages.
• Advantages of the biofuel: use of fossil fuels, greenhouse effect, compared to natural gas also summer
smog (very small)
• Advantages of the fossil fuel: acidification, eutrophication, compared to light oil also summer smog
• Low or no significance: –
The data for ozone depletion and human toxicity tend to have a high uncertainty. Therefore these categories
should not be included in the final assessment. (**See Chapter 4.1.2 and for details on all impact
categories 3.3 and 3.4)
A further assessment in favour of or against wheat straw or light oil / natural gas cannot be carried
out on a scientific basis, because for this purpose subjective value judgements regarding the individual
environmental categories are required which differ from person to person.