Environmental Engineering Reference
In-Depth Information
are ready for mass production. Compared to the size of the systems available
today, the traditional windmills and sailing vessels seem like toys (Figure 8.9). They
even dwarf large airliners such as the Boeing 747, which has a wingspan of about
60 m (195 ft), and the mega - airliner A380 with its 80 m (261 ft) wingspan. Apart
from their size, the performance of modern wind turbines is also impressive. For
instance, a single 6-megawatt system can supply all the electricity requirements
for several thousand households in industrialized countries like Germany and
Britain.
5000
kW
1500
kW
500
kW
200
kW
Ø 115
m
90
kW
Ø 65
m
Ø 40
m
Ø 30
m
Ø17
m
Figure 8.9
Size development of wind turbines.
However, there are physical limitations to increasing the size of wind turbines. As
the size increases, there is a disproportionate increase in the material requirements.
Furthermore, there are major logistical problems in transporting building parts for
such gigantic structures. Based on current conditions it is therefore highly unlikely
that turbines of over 10 megawatts will be built.
Wind power is currently one of the most effective technologies for combating
climate change. Even the largest wind turbines can be erected in just a few days. A
concrete foundation provides a secure base (Figure 8.10). In places with soft subsoil
posts are used to support the foundation in the ground.
There are three different types of towers that can be used: tubular steel towers, lattice
towers and concrete towers. Years ago lattice towers similar to electricity pylons
were normally used. For aesthetic reasons tubular steel towers then became more
popular. Because of rising steel prices and growing problems in transporting the
large tubular segments needed for the biggest types of turbines, concrete and lattice
towers are now being used more and more. As the size of the turbines grew so too
