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

• Split Design scenario: An overall grid design built on
the hub case scenario as described in chapter 4.5.3.
Cable circuit length and number of installed
DC converters
The installed AC and DC cable circuit length for each
scenario is displayed in Figure 4.36. The “worst
case” Radial reference scenario, in which all offshore
wind farms are connected individually, exhibits with
42,000 km the largest overall circuit length to be installed.
The circuit length is dramatically reduced to
28,000 km for the Hub Base Case scenario 2030 in
which the offshore wind farms are connected to hubs.
The Hub Base Case scenario served as the starting
point for the overall grid design development. The additional
circuit length to develop these was 3,000 km for
the Split Design and 3,800 km for the Direct Design.
The overall circuit length for the overall grid design is
31,000 km for the Split Design and 32,000 km for the
Direct Design, 10,000 km of which are AC cables in
each of the cases. Note that these figures show the
circuit length. As AC circuits use 1 x 3 core AC cable
and DC circuits use 2 x 1 core DC cables, the total
cable length is higher.
TAblE 4.7: UTIlISATION OF WINd FARM cAblES
connection
Hub Base Case (Step
0)
Direct Design (Step
2, before mesh)
Direct Design (Step
3)
Split Design (Step 2,
before mesh)
Split Design (Step 3)
40 For Germany onshore connection points have been chosen far inland. This approach is based on the detailed national study dena-
Netzstudie I (dena grid study I). The connection points far inland increase the overall connection costs to certain extend.
OffshoreGrid – Final Report
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The DC converter numbers for each scenario exhibit
the same characteristics for the different scenarios.
In the Radial reference scenario almost 300 DC inverters
are installed, but the the number is largely reduced
to 206 for the Hub Base Case.
In the final Direct Design the overall installed converter
number is 235. In the Split Design 226 converters
are used.
Overall costs of the different scenarios
Finally, Figure 4.38 summarises the overall costs and
lists the overall electricity generation costs. It is important
to highlight that the costs should always be
compared taking into account the system benefits of
reduced electricity generation costs due to larger trade
capacities via the additional infrastructure. Please
note that the infrastructure costs have only been assessed
up to the onshore connection point. 40 Costs
for onshore grid reinforcement needs are not included.
• Costs and benefits of the Radial reference scenario
It is clearly most expensive to connect all offshore
wind farms individually without considering hubs
connections. Including the ENTSO-E TYDNP interconnectors,
the investment costs until 2030 would
amount to €92 bn.
Ljm_5-NL
Cap MW 1,800 1,800 1,800 1,800 1,350 990 900 1,710
Util % 53.8 53.6 53.0 53.4 53.3 56.5 57.1 55.0
Cap MW 1,800 1,800 1,800 1,800 1,350 990 900 1,710
Util % 53.8 71.3 68.4 67.7 68.4 59.0 57.1 65.2
Cap MW 1,800 1,800 1,800 2,800 1,350 990 900 1,710
Util % 53.8 81.8 59.7 77.1 53.3 74.8 57.1 62.8
Cap MW 1,800 1,800 1,800 1,800 1,350 500 500 1,710
Util % 53.8 53.6 59.3 53.4 53.3 85.1 85.2 55.0
Cap MW 1,800 1,800 1,800 2,800 1,350 2,010 500 1,710
Util % 78.3 79.1 55.8 73.0 53.3 79.7 81.5 62.8
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