Future of Wind Energy - Wind Energy Systems for Electric Power Generation - page 164

Chapter 8
Future of Wind Energy
8.1 Off-Shore Wind Energy Generation
8.1.1 General
Off-shore wind energy generation is considered as the techniques of dynamic
development in the future. Existing off-shore wind parks in Europe such as
Middelgrunden and Horns Rev have collected first practical experience. Studies sug-
gest that worldwide offshore wind potential is larger than the electricity consump-
tion [Ack02]. Currently a large number of wind parks are being in the planning and
approval procedure.
Taking Germany as example, there are (as per end of 2007) a number of wind
park projects licenced by the authorities in the exclusive economical zones of the
North Sea (16) and in the Baltic Sea (6). The distances to coast are 13 ... 100 km,
water depths at park location are 15 ... 40 m. Planning foresees an installed offshore
power of 2900 MW until 2011, both in the North Sea and the Baltic Sea. Really
large offshore wind parks are expected for the time after 2010.
8.1.2 Foundation
The foundation of the wind systems is the foremost technical issue, and will require
a large portion of cost compared with on-land systems. Depending on the distance
from shore of the location for erecting a WES and the water depth, several founda-
tion methods have been investigated. [Mus05]
- Gravity foundation
Gravity foundation features a flat base. It is stiff but heavy and has a larger foot-
print compared with the monopole. The construction must take care of stress due
to ice, e.g. by providing an ice-breaking cone in height of the water surface level.
The maximum water depth for which the solution is suitable is under discussion.