This paper presents a framework to find optimal offshore grid expansions using a transportation model of the power grid. The method extends the standard mixed‐integer linear programming approach to the solution of the transmission expansion planning problem to account for fluctuations in wind power generation and load; this makes the method especially suited to identify optimal transnational offshore high‐voltage direct current grid structures for the integration of large amounts of offshore wind power. The applicability of the method is demonstrated by a case study of the North Sea region. Copyright © 2011 John Wiley & Sons, Ltd.

This paper provides an overview of major transmission planning activities related to wind integration studies in the United States and Europe. Transmission planning for energy resources is different from planning for capacity resources. Those differences are explained, and illustrated with examples from several regions of the United States and Europe. Transmission planning for wind is becoming an iterative process consisting of generation expansion planning, economic-based transmission planning, system reliability analysis, and wind integration studies.A brief look at the policy environment in which this activity is taking place is provided. A set of coherent and collaborative transmission planning, siting, and permitting policies and cost allocation method must be developed to achieve the intended objectives. The scale of transmission development envisioned for this purpose will require unprecedented cooperation across multiple jurisdictional boundaries. C 2012 John Wiley & Sons, Ltd.

This paper addresses the role of Norwegian hydro power to provide balancing power to a future wind dominated European power system. Two power market models, one simplified and one detailed are used to model possible responses of Norwegian hydro power to a wind driven exchange pattern for various amounts of exchange capacity. The case analysed assume a 2030 scenario for wind generation in Europe and an increase in exchange capacity between Norway and Europe from 2300 MW to 5800 MW. We find that the generation constraints and the exchange capacity, and not the aggregated reservoir size, are the most important limiting factors for the amount of balancing the Norwegian hydro power system can provide.

Offshore wind farms are gradually being planned and built farther from the shore. The increased integration of wind power, also onshore, and the demand for improved power system operation give rise to a growing need for transnational power exchanges. Grid connection is a critical factor for successful large scale integration of offshore wind power. In this paper a comparison study between two different grid building strategies for offshore wind farms in the North Sea is presented for the 2030 medium wind scenario of the TradeWind project [1] (302 GW installed wind capacity). These two strategies are: i) A strategy based on radial wind farm connections to shore and point-to-point interconnections between countries, called radial grid; ii) A strategy based on the use of offshore nodes to build an HVDC offshore grid, called offshore grid. The comparison addresses different power system aspects, such as the total socio-economic benefit associated with each strategy, power exchanges between countries, offshore wind power utilization, grid congestions and utilization of HVDC cable capacity. We find that the offshore grid gives a total benefit over the economic lifetime of the grid for the European interconnected power system of 2.6 billion Euro compared with the radial grid. Our results show that even for moderate amounts of installed wind capacity, the offshore grid strategy is better than the radial one, assuming the future European power system will have a large penetration of offshore and onshore wind power.Index Terms-Renewable Energy, Offshore wind energy, Power system, Power market.

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