Offshore Electricity Infrastructure in Europe - European Wind Energy ...

esults
Overall design comparison
Figure 4.35 compares the cumulative net benefit
for the Direct and Split offshore grid designs on an
absolute and relative basis (benefit-to-CAPEX ratio).
Although the net-benefit of the Direct Design is larger
and outweighs the one of the Split Design by €3.1
bn, this does not mean that the Direct Design is
more efficient. In fact, this only proves that the Direct
methodology has gone further in the development:
more is invested in the trade of energy in order to
reduce the system cost more. The relative comparison
is more interesting here. Even though both designs
are highly beneficial and the difference between them
is small, the Split Design returns 297% of the initial
investment as benefits over 25 years, while the Direct
design only returns only 280% of system benefit per
invested euro. When evaluating this figure, it should
be kept in mind that the Split Design is build based
on mirroring the interconnectors in the Direct Design.
A complete optimisation starting with split wind farm
connections might yield higher benefits when the
same overall investment is done.
FIGURE 4.38: TOTAl cOSTS FOR ThE OvERAll GRId dESIGN
Split offshore grid design
Direct offshore grid design
4.5.5 Infrastructure investment –
circuit length and total costs
The previous paragraphs have analysed the additional
costs for adding the Direct Design or Split Design to
the Hub Base Case scenario. To complete the analysis,
this paragraph gives an overview of the total costs
of an offshore grid in Northern Europe. Furthermore
it is instructive to have a look at the overall circuit
length and the number of DC inverters that are implemented
in each design. The following scenarios will
be compared:
• Radial reference scenario, where all 2030 offshore
wind farms are connected with individual connections.
The ENTSO-E TYNDP direct interconnectors
are included. In this scenario no hub connections
are realised.
• Hub Base Case scenario, where the 2030 offshore
wind farms are connected via hubs where beneficial.
The ENTSO-E TYNDP direct interconnectors
are also included. As mentioned before, this is the
base case used for most comparisons in the whole
document.
• Direct Design scenario: An overall grid design built
on the Hub Base Case scenario as described in
chapter 4.5.2.
Reference scenario
bene�ts due to reduced
Infrastructure
cost (€bn)
electricity generation costs
over 25 years (€bn)
100
Reference and base case Overall grid design
100
90
80
92
83
78
86
84
90
80
70
69
70
60
60
50
50
40
40
30
30
20
€ 21
€ 16
20
10
10
0
Radial Base case Hub Base case
Direct Design
Split Design
0
ENTSO_E interconnectors
Hub wind farm connections
Individual connections
Annual generation bene�ts
74 OffshoreGrid – Final Report