A major step in this direction was made on 3 December 2010, when 10European countries (Belgium, Denmark, France, Germany, Ireland,Luxemburg, the Netherlands, Norway, Sweden and the United Kingdom)signed a Memorandum of Understanding on the development of a NorthernCountries Offshore Grid Initiative (NCOGI), in line with prioritieslaid out in the EC communication on “Energy Infrastructure Prioritiesfor 2020 and beyond – a Blueprint for an Integrated European EnergyNetwork”, published in November 2010. Connection to the gridwould help smooth out peaks and troughs in supply and demand, whilemaximising synergy between national investments.
Under the terms of the Memorandum, three working groups comprisingrepresentatives of key stakeholders will look at the major challengesto developing an offshore grid, namely, Grid configuration andintegration, Market and regulatory issues and Planning andauthorization procedures. According to a synthesis report on a workshopheld in Brussels in March this year to review the contribution ofEU-backed technology projects to the development of the offshore grid,priority is being given in the first instance to the first workinggroup (configuration and integration), with considerable input from theEuropean Network of Transmission System Operators for Electricity(ENTSO-e).
Indeed, says the report, "from the wind generator side [...] the onlyobstacle to the massive development of offshore wind farms isconstituted by the limitations for their grid connections." Until now,the majority of national wind farms have been connected independentlyto their respective national coasts – so-called radial connections.According to a 2010 study by Offshore Grid, financed by the EC’sIntelligent Energy Europe Programme, this can be the cheapest solutionwhen the wind farms are less than 50km from the coast – largely because50 Hz alternating current connections can be used that interface easilywith the grid. For longer distances high voltage DC (HVDC) transmissionis more effective.
For wind farms situated 50 km to 150 km from the onshore connectionpoint, hub solutions may be more economical, says the Offshore Gridreport, especially "where the installed capacity within a 40 km radiusof the hub is about the same order as that of the largest availableHVDC technology at the time of contracting." For countries that meetthese criteria, such as Germany, says the report, grid connection costscould be reduced by up to 34% compared to purely radial connections.And for the North Sea area as a whole, clustering wind farms aroundhubs could reduce the costs of connection to the grid by 20% by 2030,according to the EC Blueprint report.
The development of module-based solutions for the grid integrationof large amounts of wind electricity generation is one of the twostrands of the EC’s European Energy Programme for Recovery (EEPR)Offshore Wind Energy Programme, worth some €565 million, launched lastyear. One of the projects co-funded by EEPR – for Kriegers Flak in theBaltic Sea – is enabling the move from a ‘separate solutions’ radialapproach to grid connection, to an integrated approach with additionalconnections between wind farms and a multi-terminal DC link. Meanwhile,the EEPR funding for the Cobra Cable project is enabling thedevelopment of an option for a so-called “Future-proof HVDC cable link”that would permit connection of future wind farms and allowmulti-terminal operation.
The development of the kind of offshore grid envisaged will requireconsiderable investment, though. According to an EC paper on EnergyInvestment Needs and Financing Requirements, published in June thisyear, for the Northern Seas offshore grid, “...it is estimated that about20% of the wind farms to be developed between today and 2020 should beconnected via hubs to shore or via T-connections to internationalinterconnectors, in view of developing an optimised meshed offshoregrid. This represents investment costs of about 10 bn €, out of a totalinvestment of about 30 bn €.” But, by 2020, wind generation fromoffshore facilities in Europe’s Northern Seas will be providing anestimated 40 GW of renewable energy. And, according to figures tobe published this month by the European Wind Energy Association (EWEA)offshore wind energy generation could rise to 150 GW by 2030 –providing over 10% of EU electricity supply.
For further information:
http://ec.europa.eu/energy/renewables/grid
http://ec.europa.eu/energy/infrastructure/strategy/2020
http://www.ewea.org