Design software supports development of wave energy converter

Oceans cover two-thirds of the Earth's surface, are integral to all life on the planet impacting on climate and weather patterns, and are home to 230,000 known species. They are also one of our greatest assets and now stand to deliver far more to us through wave energy harvesting as we look to a future without fossil fuels.

Heikki Paakkinen was confident his idea of a wave energy converter would create a sustainable source of energy for future generations and founded Wello.

The pioneer programme, the Wello Penguin, is a patented wave energy solution, designed to work in harmony with the ocean to provide an ecological means of tapping into a source of pure, unlimited energy.

A 1:8 scale model survived testing in a 100 year storm in 2010, before a full scale unit was constructed in 2011. This was put under test in Orkney at the European Marine Energy Centre, during which time it was connected to the grid, successfully generating electricity while surviving 12m waves.

The Penguin, which floats on the water, is designed to capture rotational energy generated by the movement of its asymmetrically shaped hull, which rolls, heaves and pitches with each passing wave. This motion is used to accelerate and maintain the revolutions of a spinning flywheel housed inside the hull, which in turn drives an electric generator to produce electricity that is exported via a subsea cable. The vessels are static, so they do not disrupt the water's natural rhythm or disturb marine life, and are proving to be reliable and durable.

The devices produce no visual or noise pollution and can be used on almost any coastal area, with the power to generate enough electricity to power 400 homes from one device. The current device is rated up to 500kW and the Orkney tests in 2013 showed that continuous current control ranges for the device were between 160 to 180 kW with peak performance periods of up to 700kW in sea conditions of 3m and higher.

It is an idea that Wello believes has the potential to make a dramatic impact on the way in which the world can harness the power of the sea.

Like many of the best ideas, Wello's technology relies on its philosophy of making a complex solution simple. The design team has developed a converter that contains only one moving part inside the actual hull of the device. This means the internal parts are not exposed to sea water and are therefore not subject to corrosion. The asymmetrical design of the device is also important to the conversion from continuous rotational movement to electricity, and this is an area in which Wello believes itself to be unique. All other wave energy harvesting devices convert the movement of the waves into a back and forth motion. This drives a piston which feeds the generator. The problem with this is that the energy is not continuous. The Penguin, on the other hand, uses continuous rotational movement, directly converting the motion to electricity without the need for hydraulics, joints or gears.

The Penguin's design also uses off-the-shelf commercial components for the converter and the steel hull and, as the actual device is built like a ship, the manufacturing can be completed locally by ship yards using existing tools and manufacturing processes. In addition, the generator is the same as used in wind turbines. All of this ensures low manufacturing and installation costs, as well as minimal maintenance outlays.

Instead of complex fixed structures which can cause damage to the sea bed, the Penguin converter floats on the surface with only minimal anchoring attached to the bottom, making it also easier to install and disassemble. The 30m x 15m vessel is nine metres in height but since less than two metres are above the waterline, it is barely visible from the shore and floats in a discreet and non-disruptive manner without making any sound.

The actual energy is generated in one step only as there is a direct conversion from the movement of the vessel to electricity which is then fed directly into the onshore grid through a 2km long cable. "The Penguin is a truly unique way to harness the waves with all of the components inside the device, ensuring that they are protected against the force of the sea. Wello has gone from simple conception to technological development and commercial piloting of clean technology and will soon be able to make a difference, not just in the field of clean energy, but in the lives of people who want to make a smart change," claimed Aki Luukkainen, CEO Wello.

Style and substance

Throughout the design process, the team wanted to maintain a balance between form and function, to ensure that any resulting device was beautifully designed and wouldn't take away from the grace of the sea, as well as delivering an innovative solution to future energy shortages. Working within the Autodesk Cleantech Partner Program, and using the free design software which it provided them with, the Wello team was able to achieve this balance, without compromising the success of the project. Working with Autodesk over the past four years, the team of ten engineers and designers used Autodesk Inventor from the Autodesk Product Design Suite to create the mechanical components and mechanisms. The key design challenge for the team was keeping the product simple, with simplicity one of the main elements of the company's philosophy.

Autodesk Alias was used for the form of the design, allowing the innovative three dimensional curved hull design to be sketched using the digital tool. "Autodesk helps with the design and visualisation of innovations, a critical part of the process, as well as creating a beneficial link from design to manufacturing of prototypes," said Luukkainen. "We had to create a new category of wave power converters and having the design tools free of charge thanks to Autodesk's Cleantech Partner Program enables us to use software we wouldn't otherwise have been able to provide to our designers and engineers. This in turn has significantly reduced our time to market."

The company's goal is to install ten Penguin wave converters around the world in the next three to five years. At the end of last year Wello received a financial and psychological boost when Scandinavian utility company Fortum, bought a minority shareholding. Luukkainen viewed the collaboration with Fortum as a natural step as Wello moves from technology development to the commercial piloting phase. "This is an excellent example of a small company partnering with a big company, which can significantly speed up the development of new technology into a commercial product. Together Wello and Fortum can take a significant step in this evolving sector."

Looking ahead, the Wello team is planning to expand on the design tools it uses, particularly drawing on simulation tools to better understand how the Penguin can be refined and rolled out successfully across the globe.