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

esults
• Very large wind farm hubs may even be close to
the shore and still have a positive net benefit for
interconnecting between them instead of installing
a direct interconnector. This is for two reasons:
– the interconnector cable (established via the
hub-to-hub connection) is less constrained by
the wind farm connection cables as these have
larger capacity, and
– although there is need for extra equipment
offshore, no onshore substation and onshore
equipment are needed.
Sensitivity analysis
An extensive sensitivity analysis is performed on
these results. A summary is given in Table 4.4. More
details from the sensitivity analysis with clear graphs
can be found in Annex D.II.II on www.offshoregrid.eu.
Conclusions
The case-independent model confirms that hub-to-hub
solutions can be beneficial, and provides concrete guidelines.
In general, the following conclusions are important:
• If the capacity of the hub-to-hub interconnector is
small, it will help to send the electricity from both
wind farms to the highest price area. Larger interconnector
capacities are interesting when the price
difference between the countries is high, but they
should not exceed the connection capacity of the
wind farms to the onshore point of connection.
• If the price difference between both countries
is not balanced, it is worth over-sizing the shoreconnection
of the wind farms to the country which
FIGURE 4.19: IdENTIFIEd SEvEN cASES
usually has the highest price during the lifetime
of the interconnector, and under-sizing the hub-toshore
connection to the other country. This way the
electricity can flow to the area with higher prices. It
is the most optimal solution for overall European
welfare.
• For meshed grid nodes with more than two lines
coming together, similar conclusions can be drawn.
The links to the country with the highest prices
(over the lifetime of the interconnector) should be
largest, and the other ones can be dimensioned
smaller. The most efficient solution would occur if
the sum of all country connection cable capacities
equals the sum of the connected wind farms. This
way the additional investment in integrated platforms
and joints brings interconnection between
three countries. If larger interconnection capacity is
needed, some of the cables can be over-sized.
The case-independent model can be used to provide
quick support to find a tailor-made solution out of the
many possible configurations. The analysis in this
section demonstrates the possibilities of choosing
the optimal solution by taking into account various
factors such as the distances between the shores,
the distances between the wind farms, the distances
between the wind farms and other connection hubs,
the capacities of all cables, the market conditions in
every country, the price differences and price difference
profiles between the countries, as well as the
other interconnectors and integrated solutions, either
existing or planned. The model provides clear guidelines
for such parameter considerations and thus for
the design to be chosen.
Case 1 Case 2 Case 3,4,5,6
Case 7
54 OffshoreGrid – Final Report