Seabased fine-tuning wave-to-grid electrical system

Swedish wave energy company Seabased is optimising its electrical system that channels inputs from many generators, each absorbing power from different waves, into a single stream of electricity that is ready for the grid.

Photo showing Seabased wave energy generators head for deployment at Sotenas in Sweden (Courtesy of Seabased)
Illustration/Seabased wave energy generators head for deployment at Sotenas in Sweden (Courtesy of Seabased)

Seabased is currently working with the University of Edinburgh and ENAG, a French energy conversion company, to ensure the electrical system is fine-tuned to extract the maximum power in a variety of wave climates, the company informed.

“The electrical system is unique in its ability to passively channel the power from multiple generators through the right inverters at the right instant to create a single stream of grid-ready power”, said Anders Kronberg, Seabased’s lead electrical engineer.

The Seabased electrical system is housed in a marine substation (MSS) on the ocean floor, where it is connected to an array of linear generators.

Each generator has a cable leading to a buoy on the surface. The buoys move with the waves, and this motion lifts and lowers magnets called translators inside the generators, producing power. In a standard array, 20 generators will transmit to one MSS, according to Seabased.

Though the power comes in asynchronously, from several different waves happening at different times, the MSS converts all these inputs into a smooth stream of 33kv DC grid-ready electricity. From the MSS, standard sea cables deliver this electricity to the grid. 

“Optimizing the system entails finding the sweet spot where the generators and the electrical system work together to maximize output without risking excessive wear and tear”, added Kronberg.

A concept for Seabased wave power park (Courtesy of Seabased)
Seabased wave power park concept (Courtesy of Seabased)

What makes the electrical system’s job more complicated is that the power varies in voltage, depending on how fast the translator is moving and where it is in the journey up and down inside the generator when the wave hits.

In addition, the generators are carefully spaced so as catch different waves, so no two generators are producing power the same way at the same time, Seabased said.

When these disparate inputs from multiple generators arrive at the electrical system, they need to be carefully channeled in a way that produces the optimal stream of electricity at any given time.

Laurent Albert, Seabased’s CEO, said: “Our business model is wave-to-grid, not just providing a technology that turns waves into power, but providing whole systems that we can design, build, and install in communities to provide grid power from waves. This optimization is part of the roadmap”.

To remind, Seabased has, in collaboration with the Offshore Renewable Energy (ORE) Catapult, created a new software tool designed to help extract the most power from various types of wave climates.

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The new software tool is expected to help Seabased optimise its wave energy system from wave to grid, while also moving the company toward the anticipated certification of its technology at the end of 2021.