Outlook - Wind Energy Meteorology: Atmospheric Physics for Wind Power Generation - page 150

Chapter 7
Outlook
This chapter is not designed to summarize the main points from the preceding
chapters. This has already been done in the concluding subchapters of each of the
Chaps. 3 - 6 . Rather we will try to look briefly at possible future developments and
a few limitations for the use of the material in this topic. This concerns technical
aspects as well as assessment methods for meteorological conditions and possible
climate impacts of large-scale wind energy conversion.
7.1 Size of Wind Turbines
The evolution of wind turbines addressed in the introduction has not yet come to a
halt. Larger and larger turbines are being designed and erected (Thresheret al. 2007 ).
Turbines are increasing in hub height as well as in rotor diameter. The former
involves new concepts for turbine towers, the latter depends critically on the avail-
ability of suitable blades (Grujicic et al. 2010 ). This development is fostered by two
aspects. One issue is that the deployment of offshore wind turbines is very expensive
and complicated. The foundation of the turbine masts in the sea floor (see, e.g.,
Wichtmann et al. 2009 ) and the transport by large vessels are still challenging tasks
which have not been solved finally so far (Bretton and Moe 2009 ). In order to limit
deployment costs, fewer but larger turbines are erected offshore. The other issue is
that turbines are being erected more and more in less favourable wind climates,
because the best and windiest sites near the coast are already in use and because wind
power is needed in urban and industrial centres far away from the coasts as well. In
order to get the same harvest from the turbines as in coastal windy areas, they must
have larger hub heights to reach atmospheric levels with sufficient wind speed for an
economically meaningful operation. Both developments lead to an increasing
importance of the exact specification of the meteorological conditions described in
this publication for siting and operation of these turbines. Nearly all new turbines will
operate in the Ekman layer of the atmospheric boundary layer. For example,