WindEnergyUpdate speaks to Nexans’ wind energy team about the future direction of the wind market and some of the challenges – and solutions – in bringing offshore wind power online.

By Rikki Stancich

In recent years French cable provider, Nexans, has realigned its focus, placing renewable energy at the core of its strategy. Within this market, onshore and offshore wind projects promise to play a pivotal role.

An early player in offshore wind projects, Nexans has supplied and installed submarine, inter-turbine and export cables to bring power from offshore wind parks onshore for some of the most high-profile wind projects in Europe.

WindEnergyUpdate speaks to Rémy Le Fur, Nexan’s Renewable Energies expert, Olivier Angoulevant, specialized in HV submarine cables and Carsten Schroeder, talking about active networking systems, to find out where the new market opportunities lie for OEMs and to discuss some of the challenges and solutions for bringing offshore wind power online. 

WindEnergyUpdate: The renewable sector suffered a lot this year, experiencing an overall contraction in demand. Can you comment on when demand is likely to pick up again and regionally, where that demand might come from?

Rémy Le Fur: This year the renewable sector, including the wind market, suffered due to the financial crisis and credit crunch. Investment in renewable energies fell this year by around 30 percent, following after five years of continuous growth.

Nevertheless, we believe the wind market will show an overall positive growth of around 8 percent this year. The offshore market is finally about to take off, with 40GW of installed capacity expected in Europe in 2020.

However, that overall figure must be viewed with caution given the predicted growth in China of more than 40 percent this year.  This could result in original equipment manufacturers (OEMs) shifting out of Europe towards China and North Africa, respectively. This year we have already seen some major players reducing their capacity in Europe and shifting their focus to the Chinese market

This shift will give Nexans a strong opportunity to enhance its market share by the wind turbine manufacturers.  The predicted compound annual growth rate (CAGR) for the global wind energy market for the next 4years is around 13 percent, which makes wind a very strategic market for Nexans.

Olivier Angoulevant: For the offshore wind market, Europe and the North Sea are the most important markets. Denmark has built the first major projects like Horns Rev and Rodsand but the UK is clearly the number one market at present – we were recently awarded several big contracts in the UK. There is also big potential in Germany and in the North Sea in general. Outside the EU, China, the US and Canada are starting to show interest, however some years are expected before projects are actually built.

WindEnergyUpdate: What are the challenges associated with achieving secure distribution links with offshore turbines?

Olivier Angoulevant: The key issue with high voltage submarine cables is that you are using very high tech, long-length ‘spaghetti’ cabling, which requires specific production facilities. Only a handful of companies can provide HVAC and HVDC and we have a very long track record on this.

Installation is also a key issue, when you consider we are working in very windy conditions and in rough seas. Generally we bury cables at a one-metre depth, which is sufficient.  

However, conditions or regulations occasionally demand that we lay the cables at depths of up to 3 metres, which can create significant cost, risk, time and compliance issues. In each country the regulations are different and are sometimes difficult to comply with in certain conditions.

From a cost-saving perspective, the key lies in having an experienced contractor. In the early days the developers opted for cheaper contractors and ended up facing higher costs further down the line. If you start out with an experienced contractor, you ultimately save money.

We have our in house installation department, including specialized marine installation equipment, as well as jointers to connect the offshore and onshore cable ends. Among several barges/vessels that we operate, we own the biggest cable-laying vessel in the world, the Skagerrak, which has a 7,000 tonne payload turntable, which we use to transport and lay the cables. We also have the CapJet 1MW trenching system, which we use to bury the cables.  

We also offer expertise and experience in operating in an offshore environment.

WindEnergyUpdate: Can you expand on Nexan's Windlink cable solutions - what are its advantages over other cables?

Rémy Le Fur: Windlink is a now a recognized brand in the wind OEM market, despite having been launched only two years ago.  All the cables under the Windlink brand name are specifically designed for wind turbines, such as the loop power cables, control cables, electronic and data transmission cables , ommunications cables, accessories and fiber optics. We can also supply complete kits to respond the demand of OEM’s.

Currently there is a trend among wind turbine manufacturers to place the transformer on top of the turbine (usually on the higher power above 2.5MW output turbines). In this case you would need a medium voltage loop cable. We can produce these to handle different levels of torsion.

We have strong expertise in metallurgy and in developing cables to support a high level of constraint. The advantage here is that our loop cable, low or medium voltage, is designed to handle high torsion. To test these cables alongside the specifications of our customers, we have developed in situ test operations, providing our customers with a high level of warranty.

WindEnergyUpdate: Are project developers demanding any new features or add-ons from a maintenance perspective? If so, what?

Olivier Angoulevant: There is increasing demand for fiber-optic installations within wind turbines. To this end, we use a combined power and telecommunications cable to enable onshore control of offshore turbines.

Carsten Schroeder: We have also developed a comprehensive line of ethernet switch systems for harsh environment applications. We also recently introduced a new, intelligent Fast/Gigabit Ethernet switch system for multiple applications such as monitoring, service telephone, camera surveillance, diagnostics of rotor blades, access control via just one optical fiber.