COBRA likely to boost Danish wind power

As the name “COBRA” suggests, the roughly 325-kilometre-long power cable, scheduled to connect the Danish and the Dutch power grids in 2019, will be long and winding, and it will curl like a snake,

When finished, this interconnection, which has been on the drawing board since 2009, will run from Endrup just outside Esbjerg across the North Sea to the port of Eemshaven in the Netherlands.

COBRA – short for COpenhagen-BRussels-Amsterdam – will have a transmission capacity of 700 MW, which is equivalent to the amount of electricity used by 700,000 households. Denmark’s Energinet.dk, in collaboration the Dutch transmission system operator TenneT, is in charge of the grid construction. Siemens will build the two converter stations to be located at each end of the cable, which will be manufactured and laid by Italian cable manufacturer Prysmian.

“The main components of the interconnection are a converter station in Endrup, Denmark, that will convert alternating current (AC) to direct current (DC), an onshore cable and the submarine cable itself, followed by another onshore cable and a converter station in Eemshaven in the Netherlands, where the current will be converted back to AC,” explains Torben Glar Nielsen, CTO of Energinet.dk.

“COBRA is a fairly long cable, and long power links like this are made to carry DC, because there is a limit to how far you can transmit AC.”

Better conditions for offshore wind power in the North Sea

The offshore wind industry will benefit a great deal from COBRA: according to Mr Nielsen, the cable will be a gateway to an attractive market for Danish wind power.

“We expect that power can be sold at a higher price than in Denmark, and this might make it more attractive to construct offshore wind farms.”

This is something that the Danish Energy Association is also very interested in:

“We have a lot of wind in our region – Denmark, northern Germany and southern Sweden – and this production will benefit greatly from improved export opportunities. These opportunities will affect the profitability of offshore wind. The greater the areas that are interconnected, the easier it is to actually integrate a lot of sustainable energy, ” says Stine Leth Rasmussen, department head at the Danish Energy Association.

“If we want our wind power industry to continue and keep growing, it’s important to improve our international connections by creating this North Sea Grid.”

Are cables the right solution?

However, not everyone shares Energinet.dk and the Danish Energy Association’s optimism. Aalborg University energy researcher Brian Vad Mathiesen concedes that it could be a good idea to lay these new cables to gain access to other countries’ power markets, but, in his opinion, the benefit to Danish consumers and society have not been adequately documented.

He also points out that there may be challenges involved in exporting and importing energy from offshore wind in Denmark, for example, because consumption and production are very closely related in the countries connected with Denmark.

“When you have large centres of power consumption that are also major production centres, there is no benefit from interconnecting systems. That is exactly the situation we have in Denmark, and it’s also happening in the Netherlands and the United Kingdom,” he explains.

“You can’t use the cables to balance out the production of wind energy. If we don’t have wind here, then there usually isn’t any wind elsewhere in our region, either, and at times when consumption is typically high in Denmark, it is typically high in other nearby places, too.”

In order for the transition to a green economy to reap the benefits from the cables, Mr Mathiesen believes that a different approach would be preferable:

“Rather than exporting energy to other countries through cables, I believe we should focus more on a strategy of exporting energy to other sectors, i.e. the heating and transport systems,” he explains.

In response, Torben Glar Nielsen of Energinet.dk says: “We support a combination of the two. We believe it’s a good idea to export energy to other countries as well as use it in other sectors, and that both provide socio-economic benefits.”

Higher level of activity at the Port of Esbjerg

Energinet.dk and the Danish Energy Association both stress that COBRA will drive future offshore wind activities in the North Sea and elsewhere.

“The cost of building offshore wind farms is generally coming down, which makes wind power increasingly competitive to produce. This, combined with better opportunities to transmit the power to shore and sell it at a good price, means that our sites off the coast of Jutland are becoming very attractive,” says Mr Nielsen.

Ms Rasmussen agrees:

“The prospects with respect to offshore wind farms in the North Sea are excellent, and there are indications that it would make good sense to build a lot more wind turbines in the North Sea.

It is a win-win situation. As offshore wind farms become less expensive, sites in the North Sea become more attractive. That also makes it more relevant for us to build more connections, and that generates good business for the Port of Esbjerg and others,” concludes Mr Nielsen.

This is a translation of the Danish article published in Port of Esbjerg Magazine 4, 2016.