Mechanical ‘trees’ generate energy by swaying in the wind


New tools for harvesting wind energy may soon look less like giant windmills and more like tiny leafless trees.

A team of engineers at Ohio State University are testing whether high-tech objects that look a bit like artificial trees can generate renewable power when they are shaken by the wind – or by the sway of a tall building, traffic on a bridge or even seismic activity.

If the initial tests are successful then the future of renewable energy could be powered by a tree’s ‘sway’ in the breeze.

This is just one aspect of the Ohio teams research. The idea is that by studying how energy can be generated by swaying motions, the theory can also be applied to the vibrations generated by buildings and bridges, and potentially converting those vibrations to energy as well.

The idea may conjure images of fields full of mechanical trees swaying in the breeze. But the technology may prove most valuable when applied on a small scale, in situations where other renewable energy sources such as solar are not an option, said project leader Ryan Harne, assistant professor of mechanical and aerospace engineering at Ohio State, and director of the Laboratory of Sound and Vibration Research.

The “trees” themselves would be very simple structures: think of a trunk with a few branches—no leaves required.

1-2Early applications would include powering the sensors that monitor the structural integrity and health of civil infrastructure, such as buildings and bridges.

Harne envisions tiny trees feeding voltages to a sensor on the underside of a bridge, or on a girder deep inside a high-rise building.

“The project takes advantage of the plentiful vibrational energy that surrounds us every day,” he said.

“Buildings sway ever so slightly in the wind, bridges oscillate when we drive on them and car suspensions absorb bumps in the road.

In fact, there’s a massive amount of kinetic energy associated with those motions that is otherwise lost. We want to recover and recycle some of that energy.”

The research was published In a recent issue of the Journal of Sound and Vibration