This environmental impact assessment for Kriegers flak ... - Vattenfall

44 ALTERNATIVE LOCATIONS
8. Alternative locations
The sea around Sweden’s coast is sensitive and certain areas are particularly sensitive and
extra worthy of protection. Due to this, the choice of location for offshore wind power plant
is very diffi cult and a comparison with alternative locations is of great importance to be able
to chose the location with the best advantages and that at the same time causes the least
obstruction and inconvenience.
In the 6th chapter, § 7 of the EC, it states that an EIS should contain an “account of alter-
native locations, if these are possible, and alternative solutions together with the motivation
of why a certain location has been chosen”. Due to this a site study has been made and is
presented below.
8.1 Important criteria for choice
of location
The criteria that are important for choice of location
are presented below.
a) Offshore-based
The area should be offshore. The advantage of building
wind power offshore is primarily that there is more
wind in comparison to onshore, the wind energy per
square meter can be up to 40 % higher than onshore.
Offshore wind power is also less intrusive on the landscape
as turbines are placed far from the closest buildings.
Offshore wind farms also allow the advantage of
having larger farms built. This is due to the fact that
larger areas can be claimed and that the transport of
large components, such as rotor blades, is easier at sea.
b) Within Sweden’s borders
As the energy being delivered is going to Sweden it is
required that the area is within the territorial border or
within Sweden’s economic zone.
c) Scope
The area should be large enough to allow a large
number of wind turbines for the project to be Þ nancially
proÞ table. The number of wind turbines needed
for Þ nancial proÞ tability depends among other things
on the cost of the plant at the location, which in turn
depends on water depth, seabed conditions etc. A very
important factor is the cost of the grid connection that
will be very high if the area is far from the shore. For a
normal wind power project the cost for grid connection
seldom exceeds 7-10% of the total cost of the project
but for a project based far out at sea, such as Kriegers
Flak, the cost is 13-15%. This is due to the fact that 1
km of sea cable is approximately Þ ve million SEK. In
other words, when building offshore wind power you
need to build a relatively large amount of turbines and
thereby claim a large area in order to Þ nance the grid
connection.
d) Water depth
Offshore wind farms should be built at a depth between
10 and 40 meters. If built deeper than 40 meters