Chasing that 2-year-old from one end of the house to the other may one day help reduce your electric bill. Researchers at the University of Wisconsin-Madison have developed a method of using chemically treated wood pulp fibers — tiny cellulose nanofibers — that produce an electrical charge when they come into contact with untreated fibers.
Unlike solar and wind power that are dependent on weather and require vast amounts of real estate to produce substantial output, the foot-step method of generating electricity, so-called roadside energy harvesting, is a renewable method that could be installed in areas that require flooring anyway.
"Roadside energy harvesting requires thinking about the places where there is abundant energy we could be harvesting," Xudong Wang, an associate professor of materials science and engineering, said in a press release. "We've been working a lot on harvesting energy from human activities. One way is to build something to put on people, and another way is to build something that has constant access to people. The ground is the most-used place."
Malls, stadiums and other high traffic areas are ripe for such harvesting. Wang currently is optimizing the technology and hopes to have a high-profile prototype on campus.
Because wood pulp is cheap and a byproduct of a number of industries, the flooring produced from it would be as affordable as conventional materials in contrast to current materials used for harnessing footstep energy that are costly, nonrecyclable and impractical on a large scale.
Wang’s process uses vibration to generate the same kind of electricity that produces static charges. The electricity produced by the fibers could be harnessed to power lights and charge batteries.
"So once we put these two materials together, electrons move from one to another based on their different electron affinity," Wang said.
"Our initial test in our lab shows that it works for millions of cycles without any problem. 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 research was published last month in Nano Energy.