By Bryan Hay

Use of solar energy, along with other renewable energy sources, is steadily increasing, with massive arrays of solar panels appearing on warehouse roofs, across open fields and deserts, even in space.

But the solar tree, a more portable sun-powered unit that unfolds like a large beach umbrella, some fashioned with artistic elements, is catching on in public areas, allowing people to plug in to recharge phones, tablets, and other personal electronics.

Students working on a senior design project with Jonathan Steffens, visiting assistant professor of mechanical engineering, are creating a more affordable, single-branch solar tree, with the original hope of installing it and testing its usability at sun-swept Metzgar Fields. The project began before the COVID-19 outbreak, and work on the solar tree continues remotely. The current plan is not to finish the actual physical construction of the tree, but to create an open source design document that anyone could use to construct a similar product.

When fully built with four 100-watt solar panels as its sun-absorbing foliage, the tree will store energy from photovoltaic cells in a 12-volt, 100-amp battery, capable of producing 1.2 kilowatt hours of energy.

“So to put that into perspective, compared to a laptop battery, this is 25 to 30 times its size,” says Simon Curtis-Ginsberg ’20 (mechanical engineering). “Even on a day where there’s not that much sunlight it would be able to completely fill this battery. And then the idea is we’ll have outlets and USB ports so people can charge phones and laptops from it.”

And while many solar trees cost between $30,000 and $50,000, the Lafayette model is being built with a budget of about $3,000, says Holly Routledge ’20 (mechanical engineering).

Another point of distinction is that it’s outfitted with a solar tracker, a device that keeps solar panels oriented toward the sun as it rotates from east to west.

“We couldn’t find any trees on the market currently that were able to track the sun,” Steffens says, adding that the Lafayette tree blends aesthetics and improvement over conventional designs.

“The idea is to have this solar tree in a park or public space,” he says. “It blends in with the environment around it.”