Accelerating grid expansion and reducing costs

According to a recent German study, technical innovations, standardisation and optimised planning will save time and costs for offshore grid connections. (Photo: DOTI 2010 / alpha ventus)
According to a recent German study, technical innovations, standardisation and optimised planning will save time and costs for offshore grid connections. (Photo: DOTI 2010 / alpha ventus)

A recent study carried out by the German Offshore Wind Energy Foundation shows that significant acceleration and cost reduction can be achieved in the area of offshore grid connections. It also proposes improving network utilisation to quickly eliminate bottlenecks on land.

The study examined acceleration and cost reduction potential for offshore HVDC grid connections in Germany during all phases of a project, including planning and approval, tendering and contract awarding, and implementation. The analysis shows that 8 to 14 months can be saved during the tendering, contract awarding and project implementation phases. The acceleration potential during the planning and approval phase is 6 to 9 months. Time savings between 10% and 25% can be achieved during each phase.

During the approval process, for example, time can be saved by using standardised application forms, and on the technical side, cost reductions of up to 30% can be achieved using innovative connection concepts. These include concepts for connecting wind turbines directly to the converter or using smaller, decentralised converter units. The study recommends designating special areas for demonstration and pilot projects to test technical innovations.

In order to implement these technological innovations, it is very important to increase the flexibility of the technology and connection concepts defined in the German spatial offshore grid plan as well as eliminate the rigid separation of system performance and operating voltages, according to the study. Increased competition and transparency during the tendering and contract awarding phase can also reduce costs and accelerate projects. Disclosure obligations related to the awarding of contracts could be expanded. This, however, would require legislative changes.

Utilising and expanding power grids on land

"Acceleration and cost reduction are not only necessary for grid connections at sea, but also for grids on land", the clients of the study stated. Grid bottlenecks on land, which are currently also making it difficult to transmit offshore wind power in critical situations, would need to be overcome in the short term using dynamic real-time processes until sufficient transmission capacity is available. In addition, an increased utilisation of hybrid lines might be practical. Above all, however, the currently available technical options for improving the usage of existing grids (online Dynamic Security Assessment) must be rolled out quickly in existing grids.

The study concludes that offshore wind power has successfully established itself in the energy mix for the energy turnaround in Germany, and that slowing down offshore grid connections would not be appropriate. The clients stress: "In order to be able to implement the continuous expansion promised by the German federal government, the offshore wind industry will need the annual implementation of a grid connection system after 2020 as well. The NOR-3-3 connection in 2021 comes first. This must now be urgently confirmed by the Bundesrat and Bundestag in the Renewable Energies Act 2016."

The German Offshore Wind Energy Foundation and Wirtschaftsverband Windkraftwerke e.V. (trade association for wind power plants) jointly commissioned the study together with the following organisations and businesses: AGOW, OFW, OWIA, VDMA Power Systems, WAB, 8.2 Consulting AG, ABB AG, ADWEN GmbH, ENOVA Energieanlagen GmbH, GE Energy Germany, Nordwest Assekuranzmakler GmbH & Co. KG, PNE WIND AG, Siemens AG, Strabag OW EVS GmbH, WindMW GmbH, and wpd offshore solutions GmbH.

The short and the long version of the study can be downloaded in German from the German Offshore Wind Energy Foundation's website:


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