Minesto is an innovation company with a unique solution for sustainable energy production. The idea is to harness the energy found in tidal currents. The challenge is obvious, since the equipment is permanently submerged underwater.
An underwater kite
Minesto’s tidal energy turbine functions just like the kind of kite that most of us have played with at the beach. We noticed that when the kite moves laterally, it also moves quickly – far faster than the wind does. And that is precisely the effect that Minesto exploits. Our energy solution is an underwater kite anchored to the seafloor.
The turbine is installed in the front of the kite and is pushed through the tidal current as the kite moves constantly in a figure-of-eight pattern, several times faster than the speed of the tidal current. Its movement is meticulously controlled by the kite’s built-in control system.
High-speed data over long distances
“We’ve used an EtherCAT solution,” relates Henrik Person, who developed parts of the system. “The reason is that we have exceptionally high demands on high-speed data transmission and secure transmission, so real-time execution is vital.”
Since the turbine’s power and efficiency rating depend on an optimal movement pattern, the system also includes a number of sensors and actuators which all work with real-time data. Controlling and steering the kite in the tidal current is an intricate optimisation task.
Quality and operational reliability are crucial
“There are several reasons why we chose EtherCAT,” explains Henrik Persson. “rt-labs, which developed the software platform, has broad-based experience of EtherCAT in applications where the demands on robustness are particularly high.” And the system truly has to be robust. Once the kite is launched it simply has to work and continue delivering power for many years. Here Minesto has benefited from both the robust software platform and the abilities offered by EtherCAT.
Scalability offers unique test potential
“We’ve conducted plenty of tests with a quarter-scale prototype,” explains Henrik Persson. “Thanks to high performance, we could gather enormous quantities of data in the analysis phases. We didn’t even have to choose – when we needed to analyse in some other way, we were able to simply select other data series.”
Scalability has thus been of immense benefit. With Minesto now moving to full-scale units, some of the necessary tests and validations have already been carried out. “Since we were able to conduct so many and such comprehensive analyses, we were also able to verify our simulations. And that of course gives us the extra security of knowing that everything works as intended before we launch the unit into the ocean,” concludes Henrik Persson.