Finding ways to harness the everyday sources of energy all around us is a concept called "roadside energy harvesting." Scientists are continually looking for new ways to capture and use this energy. From piezoelectric sidewalks to energy harvesting-revolving doors, the idea is that our movements and actions are an untapped source of energy and putting in place energy-harnessing technologies to take advantage of that needs to be a key part of clean energy infrastructure.
Researchers at University of Wisconsin-Madison have developed a new technology that could make our homes energy-generating spaces, with or without solar panels. The team has found a way to create wood flooring that produces electricity from our steps.
What makes this possible is the wood pulp. Scientists have known for a while that the cellulose nanofibers in wood pulp can be treated to produce an electrical charge. They've also previously been tapped for use in safer and more eco-friendly batteries. By putting these fibers in wood flooring, you end up with electricity-producing floors that could power a home's lights and other low-power appliances and because wood pulp is a waste product of many industries, the cost of this new flooring technology would be competitive with regular wood floors.
A key difference between this new technology and existing step-harnessing materials is that instead of being a piezoelectric device, the flooring is a triboelectric device, taking advantage of static electricity from friction. Each piece of flooring has a functional layer less than a millimeter thick containing two differently-charged materials and there could be several layers in each piece to maximize output. People walking across the floor create friction between the two materials.
The transfer of electrons between the two materials creates a charge imbalance and an external circuit harvests the electrons trying to return to create a balance. All contained in durable flooring.
“Our initial test in our lab shows that it works for millions of cycles without any problem,” said Xudong Wang, an associate professor of materials science and engineering at UW–Madison. “We haven’t converted those numbers into year of life for a floor yet, but I think with appropriate design it can definitely outlast the floor itself.”
The next step is to create a prototype of the flooring and install it in a high-traffic area of the university's campus to demonstrate the concept and show its potential. Wang believes that this type of flooring in areas with heavy foot traffic could produce a lot of electricity and unlike solar or wind, it wouldn't depend on the weather or time of day.
If this type of thing could be installed in our homes, the lights or the charge for our iPhones could be powered by our steps and maybe it would even encourage us to get up and move around more.