The glass we use every day may soon have one function that will revolutionize the way we consume power. Imagine a car that can power itself over and over again or a smart device like a phone or tablet that will never run out of battery life. These are just a couple of examples of what a transparent solar panel will have the ability to do for us one day.
A transparent solar panel is a piece of glass that allows the visible light to pass through while harvesting invisible light such as near-infrared rays and ultraviolet to convert into electricity.
As you might expect this technology can be a game-changer for how we can utilize the clear pieces of glass we already use every day that get a massive amount of sun exposure. This article will take you through how the panels work, their efficiency, potential uses, and how they compare to standard photovoltaic panels already in use all over the world.
HOW DO TRANSPARENT SOLAR PANELS WORK?
Transparent solar panels are quite smart. Professor Richard Lunt, a chemical engineer at Michigan State University, and his team of engineers revolutionized this technology. Transparent solar panels are able to let the wavelengths of the light spectrum we can see pass through the glass, while trapping wavelengths we cannot see, so they can be converted into energy.
The transparent panels are infused with organic material that is able to capture the near-infrared and ultraviolet rays while letting the light we see pass through. Once captured these rays of light bounce up and down the piece of glass until they reach one of the edges where a thin strip of solar cells is placed to convert that energy into electricity.
HOW EFFICIENT ARE TRANSPARENT SOLAR PANELS?
The efficiency of a transparent solar panel is approximately 5% according to Professor Lunt. The most efficient solar panels on the market right now have an efficiency rating of closer to 23%. The average panel you see installed on a rooftop or in a ground-mounted array ranges between 15%-18%. This efficiency rating refers to the percentage of sunlight hitting a solar panel that is actually converted into electricity.
FIND OUT WHAT SOLAR COSTS IN YOUR AREA IN 2020
COMPARING TRANSPARENT SOLAR PANELS AND TRADITIONAL SOLAR PANELS
Transparent solar panels are less efficient per square foot, however, they welcome a whole new way of making our lives more efficient. If we look at efficiency from a different angle we could argue these panels are highly efficient. Currently, the most popular places to put solar panels are on top of buildings or mounted on a plot of land. High-rise buildings and skyscrapers typically found in cities use vast amounts of power and are much taller than they are wide, giving little space on the roof to put panels.
Meanwhile, the sides of these buildings are mostly windows. A plot of land is great if it is in the middle of nowhere and no one is using it at the moment, but that is still land that could be used for other things in the future. Moreover, having the panels way out away from people who use electricity means it has a long way to travel. A large amount of electricity gets lost while moving through transformers and power lines over long distances, so how efficient are the solar panel farms really?
Transparent solar panels provide efficiency on a different level. Most importantly, they can be installed anywhere we are already using clear glass windows or glass screens. Having a “see-through” glass option for solar panels, we can allow light to shine through our windows, making it possible to reduce the use of electric lights in those rooms and buildings. Think about tall skyscrapers.
A building could be 1,000 feet tall by 50 feet wide by 50 feet deep. This building would have a roof space of 50 feet x 50 feet, which equals 2,500 square feet of space for rooftop solar panels. Meanwhile, this same building would boast 1,000 feet x 50 feet of space on each side, which equals 200,000 square feet of surface area. That 200,000 square feet may be made up of mostly windows, which could be converted to power-producing transparent solar panels. Much more power produced in the same amount of space.
On a much smaller scale, all our many smart devices from tablets to cell phones to electronic readers could all be built with a transparent solar panel screen for easy charging whenever outside during the day.
Even though the transparent solar panel currently lacks in light absorption efficiency, it excels in functionality for our world that uses see-through glass surfaces all day long.
HOW CAN TRANSPARENT SOLAR PANELS BE USED?
Transparent solar panels will be most useful for commercial buildings as mentioned above. The other ways they can impact our lives is charging mobile devices with a glass component, a car that could potentially charge itself while driving or parked outside, and perhaps powering greenhouses that could use affordable electric heat.
What about the infrastructure we already have in place? The Michigan State team pioneered the development of a transparent luminescent solar concentrator that when placed on a window creates solar energy without disrupting the view. The thin, plastic-like material can be used on buildings, car windows, cell phones or other devices with a clear surface.
WHO MAKES TRANSPARENT SOLAR PANELS?
Sharp – In 2013, Sharp introduced a transparent, but shaded, solar window using dye-sensitized solar cells. The windows are about 40” tall by either 28”, 45”, or 55” wide. Their production equates to about 6 watts per sq/ft. Since the announcement Sharp has made no further ones indicating anything progress since then.
EnergyGlass – EnergyGlass uses “Patented Inorganic Nano Technology” to create transparent solar windows without any visible lines or dots. EnergyGlass between 1-4 Watts per hour depending on the time of day.
The manufacturer claims that users have a 100% field of vision while the energy can be sent back to the grid or in battery storage. EnergyGlass is the furthest along on this list. They produce 4 different versions of solar windows: a basic laminated version, an insulated version, a double insulated version, and a triple insulated version.
Physee (not yet commercially available) – A Dutch start-up that produces what they call the PowerWindow. It is a solar window similar to EnergyGlass that uses the quantum(organic) dots to tarp the unseen light rays. Currently, the company has only one installed project, it is 300 square feet of PowerWindows on a Dutch bank.
Ubiquitous Energy (not yet commercially available) – A startup out of Silicon Valley. They produce a film that acts as a replacement solar window. The film can be added to a piece of glass and let the visible light through while trapping the invisible.
They call their product ClearView Power and are still in the testing phase so they remain commercially unavailable. They claim they can see a ‘practical’ efficiency of 10%, which would be as close to PAR with as of these transparent solar panels to traditional ones.
SolarWindow (not yet commercially available) – Another company not ready for commercialization, SolarWindow produces a liquid PV coating that can be applied to pre-existing windows.
HOW MUCH IS A TRANSPARENT SOLAR PANEL?
A transparent solar panel cost is not available to the public from most companies who produce them and for the ones that do sell them they are not yet financially practical to the public. The cost of these panels compared to the cost of alternative energy sources is still very high. These solar windows currently take a very long time before you see a return on your investment.
To go deeper into this we will take a look at Sharp’s offering, which actually has some cost information for us. In 2013 they estimated one square meter or 11 square feet would cost approximately $2,000.
To accurately compare we have to take into account what a window and solar panel would cost for the same size since you are essentially getting two functions in one. A typical double-pane window of this size can vary between $150-$250.
The standard panel today on average is a 300-watt panel and the price here can vary quite a bit depending on manufacturer, $200-$400 so we will split the difference and say $300. So if you got a $250 window and $300 panel the total cost would $550. That panel also takes up 15 square ft (3’ x 5’) but we do not need to get knit-picky here. This gives us a difference of approximately $1450!
But wait, there’s more! Not only is it 4 times the price it is about a quarter of the efficiency as well. Depending on the brand a 300-watt panel can produce at 16-20% efficiency. The transparent solar window produces 1%-5%. It is just not there yet for the general population but it is definitely something to pay attention to as the panels progress.
The technology is proven and the future is “bright” for these transparent solar panels. Unfortunately, the future is still a few years away for this technology to be in a place to be mass-produced and introduced to the public. We will stay on top of all new solar and power trends so you can take advantage of them before anyone else.