A visionary new technology wants to upend the way we power society by harvesting solar energy
from windows on your home, the windscreen of your car, and even from the screen of your smartphone.
Transparent solar panels offer a clear solution to the problem of where to put
new photovoltaic cells. The plan is architects going forwards can simply
coat the next generation of skyscrapers with high-tech panes of this groovy generative glass.
Can it really be that simple? Join us as we look into the potential
for transparent solar panels to be the future of energy.
Hang on a second, you’re probably thinking. A window’s one job is to let light pass through it,
right? How can it do that, and simultaneously harvest our sun’s bountiful energy?
Well, there’s a lot more to sunlight than the parts you and I can see. Indeed, the so-called
visible spectrum of light is a comparatively small subset of all electromagnetic frequencies.
Transparent solar cells typically rely on devices known as transparent luminescent
solar concentrators or TLSC. TLSCs are composed of clever organic salts which
absorb invisible portions of natural light – infra-red and ultraviolet,
basically. These salts then proceed to ‘glow’, in a manner of speaking, and this glow powers narrow
photovoltaic strips which are discreetly situated at the very edge of the windowpane. The resulting
power is then converted into electricity and fed into the local building or grid.
These nifty see-through cells are capable of operating at an efficiency of around 10%,
which is roughly half that of a regular opaque solar cell. And even though that might sound,
well, a bit rubbish, researchers are at panes to point out what matters with
transparent solar isn’t the efficiency per se, but instead the potential scale for deployment.
Right now, experts reckon, the United States alone has between five and seven
billion square meters of glass. One-tenth of that is still a pretty big deal – capable,
according to some estimates, of meeting perhaps 40% of the nation’s annual energy requirements.
And okay, fair enough, it’s not as if every single existing window is about to get retrofitted to
work with see-through solar. But when you remember some two-and-a-half billion square
meters of new architectural glass is installed on office blocks and shopfronts around the world
each and every year, the potential for growth in this sector is crystal clear.
Several startups across the globe are vying for a slice of this new-minted industry.
Ubiquitous Energy, which began life as an academic project at MIT,
has received millions of dollars in grants from the California Energy Commission for its patented
UE Power technology. By scooping up power in the infra-red spectrum, Ubiquitous’s solar coating
can not only generate electricity but can help block solar heat and save air-conditioning costs,
paving the way for the dream of net-zero buildings. The firm has already partnered
with leading glass manufacturer NSG Group, who were so impressed with the technology on display
they installed it in the lobby of their own headquarters in Northwood, Ohio.
ClearVue, a solar company based in Western Australia, uses a slightly different
technique. Its transparent luminescent solar concentrator takes the form of a spectrally
selective polyvinyl butyral interlayer sandwiched between two panes of glass.
Infrared light is still transmitted to photovoltaic cells in the frame,
the only difference is it isn’t a coating on the exterior. So far ClearVue’s tech has
been successfully installed in the glass atrium of a suburban Perth shopping mall.
Solar Gaps, a European team, take a slightly different tack, installing solar blinds
inside – or just outside of – office windows. The great advantage of blinds is they can be
mechanically oriented to make the most of whatever sunlight is around. And for every square meter
installed they claim they can generate 100 watts of power or roughly enough to power three laptops.
The most innovative use of clear solar is on, of all places, a Swiss strawberry farm.
A new four-year pilot project has replaced plastic polytunnels commonly used in agriculture
with a bank of Theia's, or Translucency and High Efficiency in Agrivoltaics.
These panels not only hoover up vital photons for power generation
but can alter the extent of their tint to optimize the level of light getting through
to the precious plants inside. This should, if it works at least, help those delicious crops
photosynthesize and produce better yields, crucially using the same land footprint.
One particularly intriguing potential day-to-day application of this technology is in smartphone
screens. A team led by Professor Joondong Kim at South Korea's Incheon National University
has demonstrated that their tech, harnessing a clever blend of titanium dioxide and nickel oxide,
could create power at phone-sized scales. Maybe not enough for a full charge, for now at least,
but at least sufficient for a helpful battery boost in the middle of a busy working day.
Transparent solar is not without its critics, many of whom claim the technology has been supposedly
forthcoming for the better part of two decades now with precious little commercial success.
Such skepticism is healthy, so long as regulators and investors are well-informed enough to spot
dodgy transparent solar projects and see right through them if you will.
It’s pretty unlikely to be a panacea for the energy crisis, let’s say.
But working alongside other clean energy sources,
transparent solar could help drive out towns and cities towards carbon neutrality,
without sacrificing the all-important aesthetics of 21st-century architecture.
What do you think? Would you get transparent solar installed in your home?
What about your car? Let us know in the comments,
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