Scientists at U.S. National Renewable Energy Laboratory (NREL) have developed a transparent glass material capable of converting sunlight into electricity, a new step toward reliance on renewable energy sources.

Unlike solar panels that rely on opaque materials to absorb energy, the new thermochromic window is transparent, changing to a darker tint with sunlight exposure. As the glass darkens, it absorbs energy and generates electricity.

"There is a fundamental trade-off between a good window and a good solar cell," explained NREL scientist Lance Wheeler. "This technology bypasses that. We have a good solar cell when there's lots of sunshine and we have a good window when there's not."

Regular solar panels use dark-colored silicon or polycrystalline solar cells to capture energy. To make a transparent panel, scientists combined single-walled carbon nanotubes and an experimental material called perskovite.

According to NREL, the glass changes color when exposure to sunlight pushes molecules of methylamine out, enabling it to generate electricity. The panel cools when not exposed to sunlight, naturally absorbing methylamine back into it and turning it translucent.

Scientists found the panel's prototypes yield a solar power conversion efficiency of 11.3 percent.

The research group is now working to improve longevity and stability of the devices, which have been found to decline in effectiveness over time.

NREL hopes to integrate the new technology, once completed, into homes and vehicles to unobtrusively generate an effective power supply.