See-through solar materials represent a huge source of untapped energy and could store as much energy as bigger, heavier rooftop solar units.
See-through solar-harvesting applications, such as this module pioneered at Michigan State University, could potentially produce 40 percent of U.S. electricity demand. (Credit: Michigan State University). The authors argue that unrestricted use of such highly transparent solar applications, together with the rooftop units, could nearly meet U.S. electricity demand and drastically reduce the use of fossil fuels.
Highly transparent solar cells represent the wave of the future for new solar applications. Their potential has been analysed and shows that by harvesting only invisible light, these devices can provide a similar electricity-generation potential as the bulky rooftop solar panels while providing supplementary functionality to improve the efficiency of buildings, automobiles and mobile electronics. Lunt and colleagues at MSU pioneered the development of a transparent luminescent solar concentrator that creates solar energy without disrupting the view. The thin, plastic-like material can be used on buildings, car windows, phones or other devices with a clear surface.
The solar harvesting system uses organic molecules developed by Lunt and his team to absorb invisible wavelengths of sunlight. The researchers can "tune" these materials to pick up just the ultraviolet and the near-infrared wavelengths that convert this energy into electricity. Moving global energy consumption away from fossil fuels will require this kind of innovative and cost-effective renewable energy technologies. Only about 1.5 percent of electricity demand in the United States and globally is produced by solar power.
But in terms of overall electricity potential, the authors note that there are an estimated 5 billion to 7 billion square metres of glass surface in the United States. And with that much glass to cover, transparent solar technologies have the potential of supplying some 40 percent of energy demand in the U.S. - about the same potential as rooftop solar units. The complimentary deployment of both technologies could get the US close to 100 percent of their demand if they also improve energy storage.
Highly transparent solar applications are recording efficiencies above 5 percent, while traditional solar panels typically are about 15 percent to 18 percent efficient. Although transparent solar technologies will never be more efficient at converting solar energy to electricity than their opaque counterparts, they can get close and offer the potential to be applied to a lot more additional surface areas. Right now, transparent solar technologies are only at about a third of their realistic overall potential.
While traditional solar applications have been actively researched for over five decades, we have only been working on these highly transparent solar cells for about five years. This technology offers a promising route to economical, widespread solar adoption on small and large surfaces that were previously inaccessible.