Environmental Engineering Reference
In-Depth Information
CHAPTER 9
Clive Lewis
Converteam UK Ltd., Rugby, Warwickshire, UK.
There are plans for a large expansion of offshore wind energy, particularly in
Northern Europe where there is limited space for onshore turbines. One means to
reduce the cost of offshore wind energy is to build wind farms with fewer larger
turbines, reducing the number of costly offshore foundations. The emerging next
generation of HTS technology, which offers the prospect of low cost high vol-
ume HTS wire production, can be used to build compact and lightweight genera-
tors at high rating and torque. These new generators will become the enabler for
very large, direct drive wind turbines in the 10 MW class. Direct drive turbines
also offer an improvement in reliability
and
effi ciency by removing the gearbox,
which has been a troublesome component in many offshore wind farm projects,
and replacing it with a much simpler mechanical system that is not sensitive to
the misalignment or to fl uctuations in the shaft torque. Reliability is particularly
important in offshore turbines where access is diffi cult and expensive and often
prevented by weather conditions. Converteam UK Ltd. are in the fi nal stages of
a project to design a direct drive HTS generator for this class of turbines, and
to build and test a scaled prototype. Following on from this project will be the
manufacture of a full size prototype and its demonstration on a 10 MW turbine. An
economic analysis during earlier stages of the project calculated a reduction in the
cost of energy of 17% from a 500 MW offshore wind farm by the use of this class
of HTS direct drive turbines compared with the baseline case of 4 MW conven-
tional DFIG turbines. This analysis did not include any additional cost reduction
due to improved reliability and availability.
1 I ntroduction
The wind turbine market is large and rapidly growing; while at the same time there
has been a trend towards larger and larger turbines. Larger turbines are attractive
Search WWH ::
Custom Search