One major hurdle to wide-scale solar energy deployment is having enough space for solar panels, especially in cities where land and roof space on buildings is in short supply. In high-density locations, producing enough solar electricity to power a building from just the rooftop is difficult, especially when mechanical systems occupy space. But what if the glass itself could generate clean energy with transparent solar panels?
Michigan State University (MSU) developed the first fully transparent photovoltaic (PV) panels in 2014. These panels are suitable for clear windows and even touch screens on devices because they don’t absorb visible sunlight, creating a new paradigm for solar power.
Although clear solar panels are less efficient than monocrystalline and polycrystalline solar cells, there are many potential applications due to their functionality, such as the windshields on cars, the glass in high-rises, and even the touch screens on cell phones. Researchers are working to advance transparent solar panel technology to be commercially viable on a large scale.
The History Of Transparent Solar Panels
Researchers at MSU used organic salts to absorb invisible wavelengths of light, including infrared and ultraviolet light. This approach allows the solar glass to perform like typical glass, while it also generates solar energy because the visible light passes through. Then in 2020, researchers from the United States and Europe developed clear solar panels with 100% transparency.
“Highly transparent solar cells represent the wave of the future for new solar applications,” said Richard Lunt, the Johansen Crosby Endowed Associate Professor of Chemical Engineering and Materials Science at MSU. “We analyzed their potential and show that by harvesting only invisible light, these devices can provide a similar electricity-generation potential as rooftop solar while providing additional functionality to enhance the efficiency of buildings, automobiles and mobile electronics.”
Unfortunately, the efficiency of transparent solar panels is quite low and is currently around 1 percent, but it has an estimated potential of 5 percent. Although this is very low, the potential applications in solar glass mean it could be widely used in numerous applications, making it incredibly practical in other ways.
“MSU has our first installation external to the company,” Lunt said. “We have dozens of projects that are now getting installed around the world from our pilot line. We’re now gearing up for commercial-size production lines, which will be truly transformative.”
Partially See-Through Solar Panels
A German startup named Heliatek GmbH developed partially see-through solar panels, which absorb 60 percent of the light they receive. The efficiency of partially transparent solar panels, also known as partially transparent solar panels, is 7.2 percent, which is still significantly lower than traditional solar panels.
Translucent solar technology has a lower efficiency because 40 percent of the light is not absorbed, thus making it partially transparent. However, partially transparent solar glass can be ideal for specific applications where tinted glass is desirable, such as solar windows on the south face of buildings.
Semi-Transparent Solar Panels
Semi-transparent solar panels are a specific type of transparent solar panels that have a light transmittance below 100%. Although there are fully transparent solar panels available, semi-transparent modules are currently more commonly found in the market.
These semi-transparent panels are particularly well-suited for applications such as building windows and greenhouses, where some level of light filtration is desired. However, for devices like smartphones that require 100% light transmission, semi-transparent panels may not be the ideal choice.
How Do Transparent Solar Panels Work?
Solar panels absorb sunlight (photons) and convert them into electricity (electrons). This see-through solar panel technology functions as a transparent solar concentrator and absorbs light that isn’t visible to the naked eye, including specific UV and infrared wavelengths. However, visible light passes through, so potentially, any glass window could be converted into a photovoltaic cell.
Transparent solar panels typically consist of multiple layers. These layers are designed to capture sunlight and convert it into electricity while maintaining transparency. The specific composition and number of layers may vary depending on the manufacturer and the technology used, but commonly include transparent conductive layers, semiconductor layers, and protective coatings. These layers work together to enable the panel to generate electricity while allowing light to pass through.
What Are Some Uses of Transparent Solar Panels?
See-through solar panels allow light to pass through while generating electricity, and have a range of potential applications, including:
Building-integrated Photovoltaics (BIPV): Glass solar panels can be integrated into windows, facades, and skylights of buildings, turning them into functional energy-generating surfaces without obstructing natural light.
Greenhouses: Clear solar panels can be incorporated into greenhouse structures, allowing plants to receive sunlight while generating electricity to power the greenhouse's operations.
Consumer Electronics: Transparent solar panels can extend battery life or provide supplementary power in electronic devices such as smartphones and tablets.
Automotive: Clear solar cells can be integrated into vehicle windows or sunroofs, contributing to the electrical power needs of electric or hybrid vehicles.
Outdoor Furniture and Shelters: See-through solar panels can be applied to outdoor structures, such as bus shelters, benches, or pavilions, providing shade while generating renewable energy.
Portable Chargers: Clear solar cells can be incorporated into portable chargers, enabling users to harness solar power to charge their devices on the go.
Military and Emergency Applications: Glass solar panels can be used in military and emergency applications, providing power to field operations, shelters, or communication devices.
Aerospace: Clear solar cells can be integrated into the surfaces of spacecraft or satellites, contributing to their power needs in space.
Consumer Products: Various consumer products, such as wearable devices, backpacks, and even clothing, offer a discreet way to generate power from see-through solar panels.
Public Spaces and Infrastructure: Transparent solar PV panels can be integrated into public spaces, such as bus stops, walkways, or canopies, combining functionality with sustainable energy generation.
Companies Making Transparent Solar Panel Products
Several companies are actively involved in the development and manufacturing of transparent solar technologies. Some leading manufacturers in the transparent solar panel industry include:
Ubiquitous Energy - Transparent Solar Windows
California-based company Ubiquitous Energy has made significant advancements in the development of transparent solar cells for commercial applications. Their ClearView Power™ technology is designed to offer transparent solar windows for buildings. The company has focused on enhancing the transparency and efficiency of its solar cells, making them well-suited for architectural integration.
Polysolar - Transparent Solar Carports
In the United Kingdom, Polysolar specializes in transparent photovoltaic glass tailored for building integration. The company has been actively involved in various projects, including the installation of transparent solar canopies and solutions for building-integrated photovoltaics (BIPV) in urban environments.
Onyx Solar - Solar Glass
Based in Spain, this company is known for its innovative building-integrated solar products and solar panel windows solutions. Onyx has been dedicated to creating transparent solar panels suitable for use in skylights, canopies, and facades. These solutions enable the generation of electricity while permitting natural light to pass through.
Bright Solar - Solar Glass
Bright Solar, a forward-thinking company, has made significant strides in the development of solar glass products tailored for commercial applications. Their cutting-edge technology aims to provide innovative solutions for building integration. Bright Solar has focused on enhancing both the transparency and efficiency of its solar glass, making it ideal for seamless architectural integration.
SolarScape Enterprises - Transparent Solar Panels
SolarScape has emerged as a leader in the development of solar glass products designed for commercial applications. Their transparent solar panel technology aims to revolutionize building integration solutions. SolarScape is dedicated to enhancing both the efficiency and transparency of solar glass for seamless architectural integration.
Xiamen Solar First Energy Technology - BIPV Products
This company is a prominent player in the renewable energy sector, particularly in the field of BIPV. The company has demonstrated a commitment to innovation in developing cutting-edge BIPV products that seamlessly integrate solar technology into architectural elements, including solar glass curtain walls and sunrooms.
SolarWindow Technologies - See-Through Solar Panel Windows
Known for its transparent electricity-generating windows, SolarWindow Technologies works on developing flexible, thin coatings that convert ordinary glass into electricity-generating solar panel windows.
Future Applications Of Transparent Solar Panels
It’s estimated that there are 5 to 7 billion square meters of glass surfaces in the United States, so the opportunities to use solar glass are nearly limitless. This means that the windshields and sunroofs on cars, smartphone screens, curtain walls, and canopies on buildings can all generate solar power.
“Once you realize you can do this, you can make a solar cell that looks just like a window, it really sparks your imagination,” said Lunt.
If this new technology is implemented in the glass on skyscrapers, there is a greater potential to generate a significant amount of solar energy because there are so many vertical surfaces on tall buildings. Also, the angle that the sun hits transparent solar panels isn’t so critical.
Traditional PV Panels Vs. Clear Solar Panels
Because the two technologies are so different, so are their ideal applications. For example, if a solar contractor wants to generate as much energy as possible in a limited space, traditional solar PV panels are a better option because they are much more efficient. Yet, when a see-through PV product is needed, transparent solar has a clear advantage. If clear solar products become widespread, it will be difficult to tell them apart from conventional materials.
“The realities of climate change mean we need to find more ways to use renewable energy,” Lunt said. “Transparent solar glass expands the options of solar power tremendously and changes the way we think about generating power. There is no longer a tradeoff between aesthetics and renewable energy. You could turn nearly every surface of a building or landscape into a solar array and generate power right where you use it without even knowing that it’s there.”
However, transparent solar panels are still rapidly advancing, so what might be true today might be different a decade from now. For example, engineers at MSU have now developed transparent solar panels with a zinc-oxide layer they expect will last for three decades, so the potential lifespan of both technologies is comparable.
Like traditional solar modules, clear solar panels produce no greenhouse gas emissions when producing energy and help reduce reliance on polluting fossil fuels. Currently, just over 3 percent of the electricity in the United States is generated from the sun. But as the world transitions to cleaner forms of energy, innovation is needed to enable solar power to produce a larger share of the total energy mix.
Although traditional solar panels are excellent for rooftop applications and solar farms, there are other applications where they falter, especially in high-density areas when lightweight solar cells are needed. In addition to more widescale deployment, energy storage capabilities are also needed to ensure that solar energy can provide baseload power throughout the day, regardless of the weather.
Advantages of traditional solar panels
Superior energy conversion efficiency with solar panels on the market that exceed 22 percent efficiency
A more mature technology that has been extensively tested for decades, which means real-world performance is easier to predict
Available for widescale implementation today due to a robust manufacturing capacity across numerous countries
Transparent glass solar panels need to be handled with more care than traditional solar panels to avoid breakage because glass is more fragile
Advantages of transparent solar panels
Ideal for urban areas where space for traditional solar panels is limited because all the see through surfaces of a building could generate power
Aesthetic advantages because solar glass seamlessly integrates into buildings and other applications, so the difference between traditional glass and fully transparent solar glass is undetectable
The angle of the sun to the surface isn’t important, expanding the options for deployment
Mobile electronics can use ambient light to partially recharge their own batteries, which would be attractive to consumers
Solar glass can fulfill two functions when integrated into buildings, thus using resources efficiently
The transparent solar cells themselves are lightweight and portable (before applying to glass)
Are There See Through Solar Panels?
Transparent or see-through solar panels, often referred to as solar windows, are emerging technologies in the field of solar energy. Researchers are exploring various approaches, including organic photovoltaic cells, thin-film technologies, dye-sensitized solar cells, transparent silicon, and quantum dot solar cells, to create solar panels with varying degrees of transparency. However, although there is progress towards fully transparent solar panels with high efficiency were not widely commercially available.
Are Transparent Solar Panels As Efficient As Traditional Solar Panels?
No, see-through solar panels are generally less efficient than traditional solar panels. While they offer the advantage of translucency, allowing light to pass through, this feature often comes at the cost of lower energy conversion efficiency. Researchers are actively working on improving the energy output of transparent solar technology, but as of now, it is not on par with the efficiency of conventional opaque solar panels.
What Do Transparent Solar Panels Mean For The Future Of Solar Power?
If transparent solar panels become widespread, their potential uses are endless. It will be necessary for engineers and solar professionals to understand how to effectively implement this technology in electronics, automobiles, buildings, and other applications. Likewise, architects and contractors will need to know how to incorporate see-through solar products into building facades to maximize renewable energy production.
As the solar energy industry advances, solar professionals must stay current on the latest technology to help drive innovation. There are numerous promising solar technologies on the horizon that could alter the future of the clean energy movement, including liquid solar panels and using perovskite as a semiconductor in solar modules to replace or minimize the use of silicon. Thus, future scientific breakthroughs will shape the future of clean energy across the globe.
Want to learn about other evolving trends in clean energy? Check out the GreenLancer blog!
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