By Steve Hanley
The Fraunhofer Center for Sustainable Energy, located in Boston, Massachusetts, is a nonprofit applied research and development laboratory whose mission is to foster economic development through the commercialization of clean energy technologies. It is part of the massive German organization Fraunhofer.
Recently, the center announced a breakthrough in solar panel design and installation that will reportedly slash the cost of residential solar PV systems. Christian Hoepfner, the director of the center, says right now that adding solar panels to an existing roof takes many hours of work by an electrician and a roofer. Typically, the final cost ends up being around $4.90 per watt.
But the new system devised by Fraunhofer gets that cost down to just $1.50 per watt — less than a third of the normal expense. To do so, they get rid of the rigid frame that supports most solar panels. Instead, they build their panels on a flexible substrate that is backed with an industrial adhesive. This allows the panels to be affixed directly to the existing shingles. Since the panels weigh no more than an extra layer of shingles, no structural reinforcements of the roof are required. Eliminating the frame also reduces the amount of packaging needed to get the panels from the factory to the job site.
The Fraunhofer PV units can be installed directly by the homeowner, lowering the cost of a PV system even further. They are connected using a “plug and play” system that feeds a DC to AC inverter. When the installation is complete, an electrician removes the electric meter and installs a standard car charging adapter in the meter base. The output from the inverter gets connected directly to the adapter; no rewiring inside the house is required. Except for removing the meter and installing the adapter, home owners can do the whole job themselves.
It takes a lot of creative thinking to combine new ideas with existing building code requirements. Reducing the cost and complexity of residential solar panels is a big step forward for home owners who want to add energy from the sun to their personal space at an affordable price.
However, that’s not to say this approach is without its limitations and weaknesses. “I have some reservations. I don’t think homeowners should be climbing over their roofs without safety harnesses, and hope that they will still recommend professional installations,” Lloyd Alter of TreeHugger writes. “I am not crazy about the idea of gluing things to shingles; are there going to be moisture and maintenance issues? What about freeze-thaw issues? I would have preferred that it actually was inserted under the tab of a row of shingles at the top so that it actually acts as a giant shingle. And what about velcro instead of glue? And there is more to American housing than low-slope roofs on suburban bungalows, what is the cheap and cheerful solution for them?”