Offshore solar park supports low wind regions

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TKI Wind op Zee
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Start-up SolarDuck has developed a floating offshore solar platform that can withstand hurricanes, strong currents and high waves. Its innovative triangular platform is intended for sun-drenched but generally wind-poor regions around the equator, such as the Caribbean and Southeast Asia. A demonstrator was recently launched in the Dutch river the Waal. CEO Koen Burgers and his team benefit from their many years of experience in shipbuilding.

For which problem have you found a solution?

“To reduce greenhouse gas emissions, the world is fully engaged in the energy transition. In the Netherlands, it will largely work with offshore wind. However, a large part of the world's population lives in urban areas on the coast in wind-poor regions. And when it blows, it is immediately extreme. There is little space on land for large-scale solar parks. The most logical and responsible solution is an offshore solar plant. A handful of companies are now working on this. Existing floating solar parks on inland waterways are not suitable. It is complex to develop a platform that works for a long time under the harsh conditions at sea. SolarDuck has succeeded in developing a cost-effective solution."

What is de core of your solution?

“We have designed a platform that takes four factors into account: wind, waves, currents and costs. The platform has a triangle shape measuring 17 x 17 x 17 meters on which 40 standard industrial solar modules are mounted in a fixed east-west configuration. This triangle shape is ideal for absorbing the dynamic forces of waves; for example, this geometric shape is also used for floating offshore wind turbines. Numerous platforms can be linked together in any desired shape to form an offshore solar park. The platform is elevated three meters above the water surface, floating on ‘pillars’. The solar plant is anchored to the sea floor. A single platform has a peak power of 16-20 kW, enough for a small residential area. An island with an area of 300 times 300 m² means a peak output of 10 MWp, comparable to a large wind turbine. This surface area seems a lot, but a wind turbine needs ca 3 km² all around.”

What is so ground-breaking about your solution?

“Our design is based on three technological innovations. The triangle shape is a relatively simple but innovative solution to handle waves. SolarDuck patented this shape. The advantage is that the sides of linked triangles always stay together, despite wave movements. With a rectangular shape, the sides separate from each other, just like pavement stones that are pushed up by roots. This simplifies the ability to connect the platforms together, because there is no need to take height differences into account. It also increases safety when people walk from platform to platform for cleaning and maintenance. The dimensions of 17 meters and a height of 3 meters ensure that the solar modules and cabling remain dry when the platforms experience short but steep waves with peaks of three meters. Higher waves are longer: the platform will move along with the waves and stay dry as well. What is also innovative is that our solar plant can withstand strong currents thanks to the patented floater design. The larger the island, the higher the forces on the platform and anchoring. We have designed floats that have three times lower resistance compared to beam floaters and they require less mooring, which saves costs. The third innovation is hurricane resistance. Floating solar parks on inland waterways have a plastic construction. In high winds, they behave like an airplane wing and can therefore be lifted from the water surface. To withstand wind and lifting forces, the construction must be relatively heavy and the panels must be positioned in such a way that the wind does not have a grip on them. There are tricks to realise that. Thanks to our background at Damen Shipyards, we have a lot of maritime knowledge. According to the calculations, the island withstands wind speeds up to 65 m/s or over 200 km/h.”

What are the benefits of your offshore solar park?

“The climate crisis also affects areas around the equator and there are currently hardly any sustainable energy alternatives available, while there is plenty of sun. It is a very logical solution to bring solar offshore. We help the energy transition a step forward. Energy costs will not increase. Ultimately it will be cheaper than fossil energy sources. In addition, it can be transported with containers and assembled at the site, it is scalable, maintenance-friendly, operational costs are low and the output is reasonably predictable.”

How far are you now?

“We started in 2019 with a team of seniors from the maritime sector with a large established network. In mid-April we towed our first demonstrator plant over the Dutch river Waal to its project location at IJzendoorn. There it has been producing electricity since April 30th. It concerns four platforms with 156 solar modules. The first success was that the construction endured a trip of 11 hours being pulled behind a tugboat across the river Waal. The structure will never encounter those currents while operating at sea. We work together with large parties. Damen assembled the platforms. The solar cells come from the Chinese Astronergy and DSM supplies an innovative moisture-resistant back sheet. Norsk Hydro supplies the aluminium parts, Akzo Nobel the coating and Engie has connected the park to the grid.”

What are your challenges?

“It's a completely new market. We are a start-up. In a very short timeframe we have designed, manufactured and installed a seaworthy solution. Now we enter the scaling phase in which we will industrialize our approach. This of course requires considerable financing, but the market outlook is very good. We are on the right track.”

What are your next steps?

“With the knowledge we are now gaining, we want to install a plant of 13 platforms off the coast of Ostend or the Canary Islands next summer. We are now discussing it with potential customers. We will deliver our first commercial system by 2023. The main customers will be utilities, but private regional off takers are also showing interest.”

What is the added value of TKI Wind op Zee?

“We have not yet had close contact yet. We are of course not an offshore wind company. We have made use of subsidies such as the Dutch MIT-scheme and European subsidies. We like to work with organizations such as TKI Wind op zee. The North Sea is very congested. For an optimal use, collaboration and technical integration are required. We think that the TKI Wind op Zee could facilitate this very well. We are convinced that offshore generated wind and solar energy are highly complementary in many places of the world. Within SolarDuck we focus to gain speed. We are already working together with numerous partners in the TKI program and we would very much like to intensify this in the near future.”

This article has been prepared in cooperation with the Offshore Wind Innovators.

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