Electrical Energy from Stretching Yarn

by Emil Morhardt

Well, yarn, sort of. This yarn is made by twisting carbon nanotubes until they become so twisted that the coil up into a helical spring-like configuration. You can do the same thing with cotton yarn or string. When the South Korean researchers (Kim et al., 2017) put the coil into an electrolyte then stretched it what they got was electrical current. Not a lot, but these are small laboratory-scale experiments and what the researchers had in mind was generating small amounts of energy to power sensors, for example, sewn into a shirt or gloves that are stretched and released under normal activities, but that wouldn’t work very well if the subject had to be immersed in an electrolyte. Or would it? They tried immersing the device, which they call a twistron, into the Gyeonpo Sea off South Korea where the temperature was 13ºC (a chilly 55ºF) and the sodium chloride content was 0.31 M, a nice electrolyte solution. But instead of sewing the yarn into a diver’s wetsuit, they attached it between a floating balloon and a sinker on the seabed to see if they could harvest ocean wave energy. Yes! They got it to light up a green LED whenever a wave came by. Continue reading

How Puerto Rico’s Energy Sector Can Revitalize the Island’s Struggling Economy.

by Byron R. Núñez

The Commonwealth of Puerto Rico has more than $70 billion of debt, most of which can be attributed to the United States’ decision to cut corporate tax breaks. The current financial crisis has created a mass exodus by U.S. companies and people from the Island. To ameliorate the situation, President Barack Obama signed the Puerto Rico Oversight Management and Economic Stability Act (PROMESA), which led to the creation of a committee design to manage the island’s finances. This economic instability has forced Puerto Rico’s energy sector to reinvent itself and become more cost-effective and efficient. Currently, Puerto Ricans pay two to three times more for electricity than average Americans. The strongest factor for the island’s high energy costs is that 80% of the energy used on the island comes from imported petroleum as the island itself does not produce nor refine crude oil. Sustainable energy is key to Puerto Rico’s future as the island hopes to comply with a Renewable Energy Portfolio Standard (REPS) that hopes to supply 20% of electricity with green energy by 2035. One company that is hoping to revitalize the island’s struggling economy though the energy sector is Green Kinetic Power (GKP), LLC. Continue reading