Recent months have seen a number of important developments in the market, including a breakthrough for Seawind’s innovative two-bladed turbine, news that Senvion is planning a 10 MW plus unit and an upgraded 8.0 MW from Siemens Gamesa
Two-bladed offshore wind turbine pioneer Seawind has signed an agreement with wind and solar farm operator WRE Hellas to develop small-scale offshore windfarms in the Aegean Sea.
Seawind and WRE Hellas plan to develop a series of mini offshore windfarms in the deep water in the Aegean under the Clean Energy for EU Islands Programme, a long-term framework to help the 2,000+ inhabited EU islands generate their own sustainable, low-cost energy. The programme was formally launched in September 2017 in Crete by European commissioner for climate action & energy Miguel Arias Cañete.
Seawind will deliver two-bladed turbines with floating foundations for the project. The complete unit will be assembled ashore and installed by a semi-submersible vessel. No lifting is necessary during the installation phase or for operations and maintenance. The complete units – including turbine and support structure – are designed to be installed by sinking them into place.
The innovative design of the turbine, in which the rotor is uncoupled from the shaft using a teetering hinge, means there is no requirement for a blade pitch mechanism, with the added benefit of significantly reduced fatigue and loads. This makes for a much lighter turbine head and tower, which is beneficial for floating wind turbines.
“Development of economic, clean energy sources is of vital importance for many small Greek islands that rely heavily on tourism,” said WRE Hellas’s managing director Victoria Alexandratou. “Seawind’s technology will enable us to meet this objective at a cost comparable to the wholesale price on the mainland and independent from government subsidies.
“It is critical to preserve the environment and landscape of the Greek islands whilst developing independence from fossil fuels and reducing energy costs. Together with Seawind, WRE Hellas will also evaluate various types of energy storage systems to guarantee energy supply 24/7.”
“Seawind’s approach – assembling the entire system onshore and launching at sea by semi-submersible vessels – is the key to bringing down the cost of offshore wind and being able to install one or 100 turbines in a very economical way,” said Martin Jakubowski, chief executive of Seawind Technology.
Seawind’s offshore units have concrete support structures, bottom fixed or floating, and were developed in collaboration with Olav Olsen in Norway. Seawind assisted during basin testing of Olav Olsen’s floating foundation, which confirmed the high degree of stability of the concrete semi-floater design.
Seawind noted that, although the Mediterranean Sea does not have the same kind of winds found in the North Sea, the Seawind 10.4 will produce circa 45M kWh at about 8.5 m/s of wind speed. The company believes it will open up many deepwater sites around the world with medium wind speeds such as in the Mediterranean Sea.
Seawind is currently completing the construction of its 6.2 MW demonstrator in Norway and in 2018 will be implementing the design of a 10.4 MW unit with a 210 m rotor diameter.
A Senvion-led consortium is seeking Horizon 2020 funding to develop a 10 MW+ offshore wind turbine of a more conventional design.
Senvion has confirmed it has submitted an application for Horizon 2020 funding to the European Commission for the development of a ‘new generation’ offshore wind turbine of in excess of 10 MW.
The company is leading a pan-European consortium in the ReaLCoE project that hopes to develop the turbine. The consortium includes utility EnBW and Fraunhofer IWES.
Senvion chief executive Jürgen Geissinger said “Senvion anticipates being a front-runner in the offshore business with double-digit rated capacities. ReaLCoE’s vision is to unleash the full potential of offshore wind energy to be in direct competition with conventional energy sources in electricity markets worldwide.”
Senvion first announced the development of a 10 MW+ turbine for the offshore wind energy industry in May 2017.
The consortium plans to develop, install, demonstrate, operate and test a 10 MW+ prototype platform in an offshore environment.
Siemens Gamesa has unveiled a new 8 MW class offshore wind turbine and a new onshore model, both of which are part of its ‘one segment/one technology’ strategy.
The SG 8.0-167 DD is a direct drive turbine with a rotor diameter of 167 m. Its B82 blades will allow for an 18% greater swept area and up to 20% higher annual energy production (AEP) than its predecessor, the SWT-7.0-154.
The SG 8.0-167 DD utilises proven technology and will thus have a short time to market by reusing components from its predecessor. In January 2017, the first prototype in the 8 MW class unit was installed and commissioned according to plan in Østerild, Denmark. While a testing programme with a focus on the electrical system is performed on this prototype, an additional SG 8.0-167 DD prototype will be installed at Østerild in 2018. With the larger rotor, it will be used mainly for blade tests.
The SG 8.0-167 DD is expected to be market ready in 2020. To accelerate time to market, Siemens Gamesa is collaborating with Fraunhofer IWES in Bremerhaven, Germany. In addition to inhouse testing and prototype operation, the nacelle of the new 8 MW turbine will be tested at the institute’s dynamic nacelle testing laboratory (DyNaLab). A comprehensive programme, including load simulations and grid compliance tests, will start in spring and will be completed by the end of 2018.
“The introduction of the SG 8.0-167 DD shows our continued dedication to industrialising the offshore market,” said Siemens Gamesa’s chief executive officer offshore, Andreas Nauen. “With the rotor upgrade, we can offer our customers even higher energy yields at lower wind speeds. The flexibility of the offshore direct drive platform helps to reduce the levelised cost of energy and at the same time mitigate risks.”
Only the rotor in the new turbine is being upgraded. Siemens Gamesa has designed the 81.5 m long B82 blade with less than a 20% increase in mass compared to the B75. Both blade types are manufactured as fibreglass components, cast in one piece using the company’s patented integral blade process.
As highlighted above, the new offshore turbine and new onshore model are part of Siemens Gamesa’s ‘one segment/one technology’ philosophy announced in early November. By 2020, the company will have one technology per business segment. In the onshore market, the company will streamline its technology approach and focus on geared solutions typified in the new onshore unit, the SG 4.2-145. In the offshore market, it has opted for the direct drive platform.
“The single platform strategy helps the company to transition to a more focused offering in the medium term by utilising economies of scale throughout the supply chain. This is how we will deliver lasting value to our customers,” said the company’s chief executive Markus Tacke.
The new offshore turbine is to be supplied to Vattenfall for a trio of projects that are the subject of a recent agreement.
Vertical axis turbine will have permanent magnet generator
VertAx Wind Ltd and the University of Edinburgh have signed a commercial licensing agreement for the C-Gen permanent magnet generator developed at the university.
The agreement enables VertAx to build the technology into its multi-megawatt vertical axis wind turbine currently under development.
VertAx chairman Peter Hunter said “This allows us to take the next step as we develop our turbine to compete in the expanding offshore market.
“The C-Gen concept is the right generator design for our large-scale vertical axis turbine, and we look forward to successful collaboration and further development of this advanced permanent magnet generator.”
C-Gen is an air-cored, lightweight, ‘no cogging’ design. Its development started in 2005 under the Scottish Enterprise Proof of Concept Programme, and it has since been demonstrated at various scales up to 1 MW.
VertAx’s vertical axis wind turbine design contrasts with the horizontal axis turbines that currently dominate wind power globally. The company’s aim is to further reduce the cost of offshore wind energy while re-establishing wind turbine manufacturing in the UK.