Nanogenerators use ocean energy to power sensors and more
Tsunamis, hurricanes and marine weather are monitored using sensors and other devices installed on ocean platforms to keep coastal communities safe until the batteries on these platforms run out. Without power, marine sensors cannot collect critical wave and weather data, raising safety concerns for coastal communities that rely on accurate marine weather information. Battery replacement at sea is also expensive. What if you could avoid all this by powering your device indefinitely from ocean wave energy?
Researchers at the Pacific Northwest National Laboratory (PNNL) are working to make this happen by developing a new cylindrical triboelectric nanogenerator (TENG). TENG is a small power plant that converts wave energy into electricity to power devices at sea. Larger versions of this generator can be used to power marine observations and communication systems, including acoustic and satellite telemetry.
FMC-TENG, a new nanogenerator, harnesses the renewable energy of open ocean waves to generate electricity. (Animation by Sarah Levine | Pacific Northwest National Laboratory)
“TENG is low-cost, lightweight, and can efficiently convert slow, uniform, or random waves into electrical power. explains PNNL’s Daniel Deng. Lab Fellow and co-developer of his new TENG device.
Deng and his team have taken a novel approach to advancing a cylindrical TENG for use in the open sea. The patent-pending frequency-multiplying cylindrical triboelectric nanogenerator (FMC-TENG) uses carefully placed magnets to convert energy more efficiently than other cylindrical TENGs, resulting in a slow, uniform Converts waves into electricity. So far, his prototype FMC-TENG has been able to generate enough power to power an acoustic transmitter. Acoustic transmitters are a type of sensor often included in ocean observation platforms that can be used for communication. This is approximately the amount of power required to light an LED bulb.
“We are developing FMC-TENG, and everything from ocean observation platforms with multiple sensors to satellite communications harnesses the power of the sea,” said Deng.
Artificial fur, magnets, waves for power
If you have ever been shocked by static electricity, you have personally experienced the triboelectric effect. This is the same effect the researcher uses in her FMC-TENG to generate electricity. Cylindrical her TENG consists of her two nested cylinders, the inner cylinder of which rotates freely. Between the two cylinders are strips of artificial fur, aluminum electrodes, and a Teflon-like material called fluorinated ethylene propylene (FEP). As TENG rolls along the surface of an ocean wave, synthetic hair and aluminum electrodes on one cylinder rub against her FEP material on the other, creating static electricity that can be converted into electrical power.
The more the cylindrical TENG moves, the more energy it produces. So fast, frequent waves can generate more energy than slow, even waves in the open ocean. To come up with his TENG, which could power electronics in the open ocean, Deng and his team set out to increase the amount of wave energy converted to power in the FMC-TENG. The key was to temporarily stop the movement of the cylinder inside the FMC-TENG.
At FMC-TENG, the team placed magnets to stop the device’s inner cylinder from spinning until it reached the crest of the wave, allowing it to build up more and more potential energy. As we approach the crest of the wave, the magnets are released and the inner cylinder begins to roll down the wave very quickly. Faster motion produces electricity more efficiently, and slower waves produce more energy.
Ocean wave energy converter
Today, the FMC-TENG prototype can generate enough power to run small electronic devices such as temperature sensors and acoustic transmitters. As the team iterates on the design for commercial use, FMC-TENG is expected to generate enough power to run an entire open-ocean surveillance platform consisting of multiple sensors and satellite communications. Additionally, FMC-TENG is lightweight and can be used on both free-floating devices and mooring platforms.
“FMC-TENG is unique because there are few wave energy converters that can efficiently generate large amounts of power from low-frequency sea waves,” said Deng. “This type of generator could potentially power integrated buoys with sensor arrays and track open ocean water, wind and climate data using entirely renewable ocean energy.”
Original: New generators come to ocean energy
Than: Pacific Northwest National Laboratory
