Enabling the Offshore Wind Supergrid
In 2010, world leading companies in offshore wind came together to form The Friends of the Supergrid - an association that advocates for an efficient, interconnected and resilient electricity grid to complement existing national transmission infrastructure.
A supergrid is a wide area transmission network that makes it possible to trade high volumes of electricity across great distances. The European supergrid is a possible future supergrid that would ultimately interconnect the various European countries and the regions around Europe's borders – including North Africa, Kazakhstan, and Turkey – with a high-voltage direct current (DC) power grid.
The MEDOW project is advancing research on multi-terminal DC grids, which are considered the key technology to connect offshore wind farms to such a supergrid.
MEDOW (Multi-terminal DC grid for offshore wind) sets out to train a new pool of researchers, to cross-fertilize expertise in DC grids and to study operational issues related to their adoption in offshore wind farms. These include questions related to DC power flow, DC relaying protection, steady state operation, dynamic stability, fault‐ride through capability and impacts of DC grids on the operation of AC grids and the power market.
The project is scheduled to conclude in March 2017, and MEDOW coordinator Jun Liang of Cardiff University discussed early results and the project’s expected impact on the realization of the supergrid:
How is a multi-terminal DC Grid a key enabler for the European Super Grid?
High-voltage DC technology has already proven to be a highly efficient solution to transmit large amount of electric power over long distances and in applications such as carrying offshore wind power to shore, cross country interconnectors and AC grid reinforcements.
As the number of these point-to-point connections increases, it could be beneficial to connect them directly rather than through AC corridors, forming a multi-terminal DC grid. This is raising interest in the pan European Super Grid, where more renewable energy resources can be integrated.
Furthermore, the number of high-voltage DC connections is not so small in Europe, with a foreseen growth of 30+ high-voltage DC connections within the next five years, starting with undersea connections, but later on even with longer overhead lines. The only possible solution to meet energy needs in the long-term lies in multi-terminal DC networks connecting the whole continent and the renewable energy sources in the North Sea via offshore grid — which is commonly called the European Super Grid.
The key benefit of high-voltage DC grids is a chance to obtain very reliable, mostly clean energy almost everywhere in Europe. Moreover, the power lines can be either ‘invisible’ (cables) or rather compact compared to standard AC lines.
What can you tell of the project's most notable results so far?
The MEDOW project’s most important contribution is how it managed to bring together academia and industries to work on multi-terminal DC grid development, towards a sustainable Europe. In addition, this collaborative project provides the platform to train and develop early career researchers in order to fill the shortage of skilled and experienced work force in the field of power systems.
The MEDOW project’s contribution to the technical community can be summarized with one book on high-voltage DC grids, one patent (pending acceptance), 60+ technical research papers in top academic journals and notable international conferences along with engagement with local communities. Most of the research output has received high appreciation from industry partners. They are very keen to take up these outcomes and use them in practical applications.
The success of the project has motivated the consortium to consider applying for future funding to continue the project under MEDOW 2.
Overall, do you expect the project results to impact the development of offshore DC grids?
Yes, I do believe the outcomes and findings of the MEDOW project can be used as a roadmap for the development of future offshore DC grids. Through the MEDOW project we were able to tackle most of the uncertainties standing in the way of technological progress and to nurture a strong workforce capable of dealing with the new age mixed AC/DC power system. The outputs of the MEDOW project can be effectively used to reduce the timeframe for the realization of a pan European grid.
Friends of the Supergrid released the 4th update of its Roadmap of the Supergrid Technologies here.