Cheap and constant energy without visual impact from the shore
Everyone is aware that the energy potential of wind blowing out at sea should be harnessed if we want a renewable future. Good locations inland with available wind resource are limited, and wind at sea is more constant and has much more laminal flow. However, in some countries, such as in Spain, seabeds get deeper and deeper very quickly from the shore, so it is impossible to dig the foundations of a wind turbine there.
That is the reason why experts in numerous disciplines are making progress in the development of floating wind farms to harness wind energy. There are several R&D projects in which companies, universities and research centres work together to get the total economic feasibility of floating offshore wind farms, so they can generate electricity as cheaply as other renewable sources. Some of these projects have received and are receiving financial support from Demowind 1 & 2, which distributes funds from the European Union’s Horizon 2020 programme.
One of the central issues in developing a floating wind turbine is the system employed to produce floatability. An optimal design should achieve stability for the wind turbine, an immunity to the effects of sea swell, longevity and, of course, manufacturing and deployment costs that are financially feasible. There are different concepts of floating platforms, such as those developed by Flowocean, Ideol, or X1 Wind. The design patented by Flowocean consists of a semi-submersible platform holding two wind turbines at the same time and uses TLP —Tension Leg Platform— technology.
The platform designed by Ideol can be constructed with concrete or steel in locations near the plant. It is a ring-shaped platform and can support many designs of wind turbine without need for modifications. Finally, the Spanish engineer Carlos Casanova created the conceptual design for the X1 Wind patent. It consists of a very light platform —also submergible and with TLP— that does not need wind turbine towers as wind strikes the blades from behind —downwind—. Such an innovative project has received funds from Horizon 2020 and is backed-up by InnoEnergy. They plan to install a prototype off the coast of Gran Canaria in the Canary Islands.
The key to make floating platforms cheaper is to reduce the mass of the wind turbines. So, their design must be optimized, and in some cases, technologies must evolve. This is reflected in the work conducted by the Compact Holistic Efficient Floating Turbine project, led by the British company Magnomatics and in which Norvento is contributing our expertise in the design and testing of electric generators. In this case, the technology is highly disruptive and could drastically reduce the mass of the electric generator, reducing the structural requirements of other elements such as the chassis or the tower and making them lighter.
Even though there are a lot of projects being developed, there are just a few examples of floating off-shore wind farms worldwide; such as the ones in Fukushima or Hywind Scotland, with a surprising capacity factor of 65%. Some experts foresee that they will be commercially available at Spain in 2025 and we predict a huge trajectory with vast stretches of sea covered by wind turbines and without visual impact from our shores. Cheap and safe energy for the consumer.
Inmaculada Saboya Bautista
Inmaculada holds a PhD in Electrical Energy from Universidad Pontificia de Comillas and forms part of Norvento’s microgrid and grid studies team. Contact Inmaculada.