The North Seas Countries' Offshore Grid Initiative - Initial ... - Benelux

. Flow based optimisation, using both an optimisation tool and iterations with local
experts and decentralised flow based simulations challenging and reviewing the outputs
of the optimisation tool to create revised cross border capacities. These new capacities are
loaded into the market model to identify the trading benefits resulting from the
additional investment. Some refinement of the configurations can be carried out at this
stage to take account of the detailed benefit calculations.
2.5 Grid Simulations
Optimised outline grid designs are confirmed as viable and refined with more targeted
network and market simulations.
While the outline grid designs have been optimised based on combined on and off shore
grid costs, the configurations must then be checked in detail by local grid experts to
identify in more detail the impacts of the new power flows on the internal grids including
e.g. lower voltage levels of each country. This is done to ensure that the grids adhere to
transmission standards as outlined in Appendix 3 of TYNDP 2012 [3], among these the
requirement for power flows not to violate thermal limits of any part of the grid, with all
circuits in service (i.e. the “n” condition) or with any one circuit out of service (i.e. the “n-1”
condition). At this stage the requirement for some additional internal reinforcements may
be identified.
Other more complex and time consuming tests, such as testing the dynamic stability of
the proposed networks, are normally done to support real investment decisions and to
ensure that the selected solution will be operable. In the case of this study, where general
concepts are being tested but no investment decisions are being made, these additional
analyses are not necessary or justified, instead some expert assessment was deemed
sufficient.
2.6 Market Modelling II
Explores how the market would be expected to evolve and what benefits arise as a result
of the grid expansion strategies proposed in the previous stages.
Once all modifications to the grid design, both onshore and offshore, have been
completed, a further market model analysis is carried out to validate and review the level
of interconnection and assess how the market behaviour might evolve as a result of the
grid expansion strategies proposed in the previous stages. Any changes in the cross
border capacities as a result of this investigation are fed back into the grid analysis for
further investigation.
Once this is finalised – a comparison of costs and benefits is carried out, delivering the
quantifiable part of the benefits. A set of non-quantifiable benefits is mentioned in
Chapter 5.1.4
A detailed description of the process is presented in Appendix A 1, including statistics on
the model parameters, technologies and the candidates used for both designs.
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