Transparent Solar Panels Are in the Works

Solar power is a great power source as it’s cheap, green, highly efficient and inexhaustible. Located 150 million km from the sun, earth receives just one-billionth of the sun’s colossal power output. Even that tiny fraction—some 120,000 trillion W—showers earth with more energy in one hour than all the energy consumed by humans in an entire year. However, it has some drawbacks.

For one thing, solar panels tend to be bulky and unsightly, occupying plenty of space. Nevertheless, they no longer have to be. Today, as the push toward renewable energy intensifies, the solar power industry is manufacturing and installing solar modules worldwide at record-setting numbers.

A team of engineering researchers at Michigan State University, in the US, has devised a new type of transparent luminescent solar concentrator. When placed over a window, it can harness sunrays even as it allows people to see through it. It can also be used on cell phones and any other devices with a clear surface to help power them.

The transparent panes that can harvest solar rays use organic molecules developed by Lunt’s team to absorb invisible wavelengths of sunlight. “We can tune these materials to pick up just the ultraviolet and the near infrared wavelengths that then ‘glow’ at another wavelength in the infrared,” Lunt explains. “Because the materials do not absorb or emit light in the visible spectrum, they look exceptionally transparent to the human eye.”

The researchers can adjust these materials to pick up only sunlight in the ultraviolet and near-infrared wavelengths in order to convert these invisible rays into electricity.

The potential for such transparent solar panels is vast. Solar’s quick-paced growth is expected to continue for decades in response to growing global energy demands. In a report published last year, the Energy Information Administration (EIA) predicted that, in the next 25 years, renewable energy sources such as solar and wind will supply roughly 50% of the new energy capacity in the U.S.

In the US alone there is as much as 7 billion square meters of glass surface. Even if a fraction of that is covered in transparent solar panels that could make a huge difference in allowing the country to wean itself off its dependence on fossil fuels. In fact, the researchers say, transparent solar technologies could supply up to 40% of the US’s energy demand, which is equivalent with the potential of rooftop solar units. Taken together, that is a huge potential for solar power.

Despite solar energy’s rapid growth and shiny-looking future, the overall fraction of power currently generated by photovoltaics is tiny. EIA estimates that in 2015, solar energy accounted for just 0.6% of the total quantity of electricity generated in the U.S. Coal and natural gas each supplied 33% of the total, leaving the rest to come from nuclear, hydropower, and other renewables, mainly wind power.

Albeit transparent solar applications are only around a third as efficient as traditional solar panels at converting solar energy into electricity, they do have a marked advantage: they could be installed at vast swathes of ready-made surfaces like windows without being visually intrusive, unlike many traditional panels.