Biofuels in Perspective

4 Biofuels
Table 1.2 Estimated world production and prices for renewable feedstocks and petrochemical base
products and intermediates
Estimated world production Indicative world market
(million tons per year) price (euro per ton)
Renewable feedstocks
Cellulose 320 500
Sugar 140 250
Starch 55 250
Glucose 30 300
Petrochemical base products and intermediates
Ethylene 85 900
Propylene 45 850
Benzene 23 800
Caprolactam 4 2000
effort, it is clear that renewable raw materials are going to win over fossil resources in the
long run. This is particularly true in view of the perspective of increasingly rarer, difficult
to extract and more expensive fossil resources.
1.3 Comparison of Bio-energy Sources
1.3.1 Direct Burning of Biomass
Traditional renewable biofuels, such as firewood, used to be our most important energy
source and they still fulfill an important role in global energy supplies today. The use of
these traditional renewable fuels covered in 2002 no less than 14.2 % of the global energy
use, far more than the 6.9 % share of nuclear energy (IEA). In many developing countries,
firewood is still the most important and locally available energy source, but equally so in
industrialized countries. The importance is even increasing: in several European countries,
new power stations using firewood, forestry residues or straw have recently been put
into operation and there are plans to create energy plantations with fast growing trees or
elephant grass (Miscanthus sp.). On the base of net energy generation per ha, such energy
plantations are the most efficient process to convert solar energy through biomass into
useful energy. An important factor in this respect is that such biofuels have (in Western
Europe) high yields per ha (12 t/ha and more) and can be burnt directly, giving rise to an
energy generation of around 200 GJ/ha/yr (Table 1.3).
1.3.2 Utilization Convenience of Biofuels
The energy content of an energy carrier is, however, only one aspect in the total comparison.
For the value of an energy carrier is not only determined through its energy content and
yield per hectare, but equally by its physical shape and convenience in use. This aspect of
an energy source is particularly important for mobile applications, such as transportation.
In Europe, the transport sector stands for 32 % of all energy consumption, making it a very