Offshore Wind and Meshed Offshore Grid(s) to Benefit Energy Security in EU

Offshore wind farms in combination with meshed offshore grids and cross-border interconnectors, powered by appropriate regulatory frameworks, can largely contribute to energy security in the European Union.

There are two main reasons for offshore wind being viewed as a big contributor to energy security. One is that variability of this clean power source is lower than that of onshore wind, as wind at sea is more constant and stronger. Combined with current forecasting tools – which are continuously getting better – this makes offshore wind even easier to predict than wind on land. With capacity factors of 50 per cent and more offshore wind farms can deliver twice as much power than onshore projects in continental Europe.

The other reason is that offshore wind is a domestic energy source as wind farms are built in a country’s waters. Viewed in terms of the EU, the generation capacity in the North Sea and future cross-border connections also make offshore wind a European energy source.

“Offshore wind is a domestic, clean and affordable energy source, whose costs are rapidly decreasing, as the latest tenders have shown,” said Andreas Wagner, CEO of German Offshore Wind Energy Foundation (Stiftung OFFSHORE-WINDENERGIE), in an interview with Offshore WIND.

The future use of interconnectors and especially meshed offshore grids will make the energy generated at sea even more reliable, according to Wagner.

At this time, interconnectors in the EU such as NorNed, NordLink, COBRAcable and interconnectors between the UK and continental Europe are driven by the electricity market in general and not directly by offshore wind. Connecting offshore wind farms to planned or existing interconnectors via hybrid projects is also one of the key areas that the North Sea Energy Cooperation, launched two years ago between the European Commission and North Sea member states, is currently looking into.

This is specifically the focus of the Cooperation’s Support Group 2, which is also investigating cross-border connections of offshore wind farms with specific interconnectors and other similar solutions such as TenneT’s long-term vision of a North Sea Power Hub.

So far, the first concrete step taken in terms of interconnectors and integration of offshore wind farms is in the Baltic Sea with the Combined Grid Solution (CGS) developed by Denmark’s TSO Energinet and German 50Hertz. The CGS will connect two offshore wind farms – the Danish Kriegers Flak project (Vattenfall) and the German project Baltic 2 (EnBW) so the electricity can flow both ways, when the turbines are not running or not running at full power, the connection will serve for trading electricity between the two countries.

“These are the first steps, but further initiatives are needed, especially when it comes to regulatory framework. This is something we are focused on within the Horizon 2020 PROMOTioN project, in which Stiftung OFFSHORE-WINDENERGIE is also involved as a partner. TenneT is leading the work packages dealing with the regulatory framework required to make meshed offshore grid solutions possible,” Andreas Wagner said.

PROMOTioN (PROgress on Meshed HVDC Offshore Transmission Networks)revolves around demonstration and testing of HVDC technology that can be deployed for transporting large amounts of offshore-generated electricity over long distances across the North Sea. The project is studying and testing different technologies, such as HVDC circuit breakers, HVDC gas insulated switchgear, and HVDC network protection systems.

A meshed grid at sea would allow for diverting electricity through a different cable if there is a fault on one part of the connection, just like it is being done with transmission systems on land, which would significantly increase reliability of offshore wind energy and lead to overall economic and energy system benefits, according to Wagner.

“We currently have radial or point-to-point connections in offshore wind, and the next logical step would be making offshore wind generation in the North Sea and the Baltic Sea even more reliable by mitigating faults. If built across a larger geographical area involving more than one country, a meshed offshore grid would also enable balancing power distribution and sending the electricity where it is needed, since the wind does not blow equally strong everywhere all the time,” Andreas Wagner said.

Adrijana Buljan, Offshore WIND

Energy security and offshore wind are one of the session topics at the Offshore Wind Conference 2018 (22 October – 23 October).

Find out more about the conference at www.offshore-energy.biz.