Tsunamis, hurricanes and marine weather are monitored using sensors and other devices installed on platforms in the sea to help protect coastal communities, until the batteries of the rigs it’s boring. Without electricity, ocean sensors cannot collect high tide and weather data, leading to safety issues for coastal communities that rely on accurate weather information. Changing batteries at sea is also expensive. What if all this could be avoided by a device that provides energy forever in the ocean wave energy? A new generator has arrived at Ocean Energy.
Researchers at the Pacific Northwest National Laboratory (PNNL) are working to make this a reality with the development of a new cylindrical triboelectric nanogenerator (TENG) – a small power station that converts thermal energy into electricity and power tools in the sea. The generator can be used to power marine monitoring and communication systems, including television and satellites.
“TENGs are cheap, lightweight, and can quickly convert current, uniform, or random waves into energy, making them well-suited for ocean power devices. Where monitoring and access are difficult and expensive,” Daniel Deng, of PNNL explained, laboratory researcher and co-founder of the new TENG device.
Deng and his team took a new approach to improve cylindrical TENGs for use in the ocean. Their patent-pending Frequency Multiplication Cylindrical Triboelectric Nano-Generator (FMC-TENG) uses carefully placed magnets to convert energy more efficiently than other cylindrical TENGs and convert slow waves into electricity. So far, the FMC-TENG model has been able to generate enough electricity to power a sound transmitter, a type of sensor often included on an ocean-viewing platform that can be used for communications. That’s about the amount of electricity it takes to power an LED bulb.
“We are developing the FMC-TENG to power everything from multi-sensor ocean monitoring platforms to satellite communications, all using the power of the ocean,” said Deng.
Artificial wool, magnets and waves for energy
If you’ve been shocked by static electricity, you’ve experienced the triboelectric effect – the same effect that researchers use to generate power with the FMC-TENG. The cylindrical TENG is composed of two cylinders that are connected to each other, and the inside of the cylinder rotates freely. Between the two cylinders, there are synthetic fibers, aluminum electrodes and a Teflon-like material called fluorinated ethylene propylene (FEP). When the TENG rotates on the surface of the ocean waves, the wool and aluminum electrodes of one cylinder rub the FEP of the other cylinder, producing alternating current that can be converted into energy.
The longer the cylindrical TENG goes, the more power it produces. This is why traveling waves, tend to produce more energy than unidirectional waves. To find a TENG that can power electronics in the ocean, Deng and his team set out to increase the power of the waves that transform into electricity in the FMC-TENG. It turns out that the key is to stop the small cylinder inside the FMC-TENG from moving.
In the FMC-TENG, the team placed a magnet to keep the cylinder inside the device from rotating until it collided with the pulse of the wave, allowing it to store more energy. As you get closer to the opening of the wave, the magnet released from the inner cylinder begins to rotate rapidly in the wave. A faster wave produces more electricity, generating more energy than a slower wave.
A wave energy converter for the open ocean
Currently, this type of FMC-TENG can generate enough power to operate small electronic devices, such as temperature sensors and sound transmitters. While the team reiterates its plans for commercial use, the FMC-TENG should generate enough power to power an open ocean monitoring platform consisting of multiple sensors and satellite communications. In addition, the FMC-TENG is lightweight and can be used in both floating devices and moored platforms.
“The FMC-TENG is unique because there are very few wave energy converters that work well and can generate large amounts of energy from low-frequency waves,” Deng said. “This type of generator can enable ships to connect with sensors to track water, wind and weather data in the open ocean using renewable ocean energy.”
