Energy from waves: Data analysis with SQL4automation at sea

The wave energy converters developed by CorPower AB — inspired by the pumping principle of the human heart — harness ocean wave movements and convert them into electrical energy using phase-controlled oscillation. This achieves an energy density up to five times higher than conventional wave energy converters without phase control. With this new technology, a considerable amount of electrical energy can be generated in a relatively compact system. "We are currently working on a system that achieves the same energy harvesting effect at only one-tenth the volume compared to conventional buoys," explains Jakob Sagatowski, Senior Software Engineer Control & Communications at CorPower Ocean AB in Stockholm, Sweden.

Clean energy from waves

The converters integrated into buoys could generate 2,000 TWh to 4,000 TWh of energy per year. As much as 10% to 20% of global electricity consumption could thus be generated more efficiently, cleanly and economically, contributing to the conservation of resources. The challenge specifically in wave power utilization is "on the one hand, to design a device that is robust enough to withstand even the harshest storms," says J. Sagatowski; on the other hand, enough energy must be generated to make it economically viable. "With our new converters, this is possible," he reports proudly. "Our goal is to create a new generation of devices for the effective use of wave energy for power generation that can compete with established energy resources."

PC-Control based on TwinCAT 3 from Beckhoff Automation is used as the control technology. Two of these controllers are integrated in each Wave Energy Converter. "One TwinCAT PLC collects all sensor data, the other is used for data processing," explains J. Sagatowski. From there, the collected information is transferred via the also integrated SQL4automation Connector to an SQL database, so that it can then be used for system optimization. "A large number of values must be captured and considered for the analysis and optimization of the system," continues the automation specialist. "Among other things, temperature values, measurements from pressure and humidity sensors, flow velocity and, not least, the generated electrical energy are recorded in order to make a reliable statement regarding efficiency." The movement of the buoy is also captured using acceleration and vibration sensors.

Up to three times more effective with data analysis

The SQL4automation Connector is used "for several reasons," says J. Sagatowski: "On the one hand, a great deal of sensor data must be captured to ensure the correct functioning of the system." Extensive testing is required for successful practical deployment. This also includes the mechanics: for example, the temperature in the cylinders is monitored. He continues: "On the other hand, the technology itself must be continuously optimized. We are essentially working with a constantly self-optimizing model to maximize energy yield." According to the specialist, the system becomes up to three times more effective with the help of data analysis.

"Constant monitoring of system parameters is essential for continuous built-in tests. This not only serves to optimize the system but also reduces susceptibility to faults and potential system errors," adds the automation specialist. This also makes it possible to guarantee customers that the system is running smoothly and optimally.

"Of course, the buoys are also visually observed, but in order to optimize the complete system with all its functionalities and influences, processing and recording of all data is required. SQL4automation provides the most practical way to do this. We capture approximately 3 to 4 GBytes of data per day," he explains further. The standard version for up to ten connections is used.

The data helps to continuously optimize the system and thus increase performance. In addition, the system itself is monitored, as it is exposed to considerable temperature and environmental influences. "The combination of Beckhoff control technology and Inasoft data technology is a perfect fit for our requirements and offers advantages," says J. Sagatowski.