Transparent solar panels: [The Complete Guide]

Did you know that approximately 2.5 billion m2 of architectural glass is installed in buildings globally every year?

Imagine if this whole area is covered with power-producing transparent solar panels. Wouldn't the world be transformed into an energy-sufficient haven?

Well, this depends on how transparent solar photovoltaic technology will be utilized moving forward. But before we even consider the future, we should first understand how the current transparent solar panels function.

A transparent solar panel is a photovoltaic that lets visible light pass through but absorbs invisible light and converts it to power.

By letting visible light seep through, transparent PVs defy the typical role of solar panels, which is to capture most of all the light energy emitted by the sun.

The efficiency of transparent solar panels is well below the acceptable levels, making this technology so controversial.

Nevertheless, transparent solar panels come with impressive benefits such as high application volume and, of course, the potential to turn every glass surface into a power-producing system.

So, is this the revolutionary photovoltaics technology we’ve all been waiting for?

Are transparent solar panels even a thing?

How are clear solar panels made, and how do they work?

Are transparent solar panels any different from conventional modules?

What does the future hold for this revolutionary solar PV technology?

These questions and any other concerns you might have regarding transparent solar panels are all thoroughly covered in this guide.

Let's get started.

What are Transparent Solar Panels?

Transparent solar panels, also known as transparent photovoltaics (TPVs) or clear solar panels, are solar collectors that harness energy from radiation invisible to the human eye.

Most transparent solar panels work with Ultraviolet (UV)and Infrared rays (IR).

We all know that intense exposure to UV is a health risk, so having clear solar modules deal with this region is already a plus for this technology.

With TPVs, you’ll maintain the main role of your glass surfaces (to let visible light through) while still producing the much-needed power.

Transparent solar panels are designed for application in areas where conventional solar panels can’t be used. Going with this, it’s clear that transparent solar panels are here to benefit solar power consumers a good deal.

So, how did this brilliant innovative idea come about?

In the US, the research about transparent solar panels was kicked off by two professors: Richard Lunt of MSU and Vladimir Bulovic of MIT.

Their 2015 research led to the development of Ubiquitous Energy, a company that pioneered the production of the first truly transparent solar panels in the US.

Today, the company has installed clear PVs as windows at their headquarters in Redwood City, California. The modules produce enough electricity to light up LEDs in the building.

Other pioneers of this PV technology also exist around the world. Additionally, you should expect more and more companies to be involved in the production of transparent solar panels in the future.

Researchers and manufacturers involved in the design and development of clear solar panels have to accomplish the following 3 things for this technology to be commercially viable:

• Improve the efficiency of transparent solar panels
• Reduce the market cost of transparent solar panels
• Design methods to easily integrate transparent solar panels on a wide variety of structures

Types of Transparent Solar Panels

As with conventional solar panels, transparent solar panels are designed in various ways for multiple applications. There’re 3 main types of transparent solar panels:

Thin-film transparent solar panels

Thin-film transparent solar panels are clear solar panels made of lightweight materials. Thin-film TPVs can be flexible or rigid, but they stand out for their narrow design.

These transparent solar panels can be integrated into the glass structure during the manufacturing process and installed on the target surface as pre-made solar collectors.

PROS

• Affordable for their efficiency
• Faster payback of the money invested
• Easy to install hence save on labor costs

CONS

• Shorter lifespan
• Low efficiency

Plastic transparent solar panels

By combining the right plastics, photosensitive elements, and additives, we can now have transparent plastic solar panels that are as good as glass modules.

Plastic clear solar panels are embedded with tiny organic fluorescent particles that collect energy from invisible radiations.

Since plastic is recyclable, these solar panels will be more friendly to the environment than conventional modules.

PROS

• Very lightweight
• Cost friendly in the long run
• Sturdy
• Easy to install

CONS

• High production cost
• Few manufacturers

Organic transparent solar panels

Organic transparent solar panels are solar cells made by combining polymer donors and small molecule acceptors.

An organic solution containing these molecules is crafted into tiny solar panels that can be applied on any glass surface.

Organic transparent solar panels are perfect for existing structures where glass is already installed. These TPVs are also great for flexible devices such as wearable electronics.

PROS

• Highly versatile/unlimited use
• Easy to install
• Availability of materials
• Low manufacturing cost

CONS

• Low efficiency
• Not as stable as glass TPVs

Please note: Transparent solar panels can also be categorized as partial or fully transparent.

The transparency level is just an indication of the amount of visible light transmitted by the photovoltaic.

Popular Transparent Solar Panels Manufacturers

Of all the questions you may have in mind, you probably have this at the top: “Who makes these transparent solar panels?”

To answer this, we’ve compiled the most popular and successful manufacturers in producing transparent solar panels:

Onyx Solar

Onyx Solar specializes in TPVs for buildings. They use heat-treated safety glass for their solar panels, which is exceptionally sturdy and great at heat and sound insulation.

Onyx transparent solar panels come in various shapes, colors, and sizes, meaning that they can be applied in a wide range of designs and projects.

Heliatek

This is a German company that specializes in the production of organic TPVs. The average efficiency of Heliatek solar panels is 11-15%. Impressively, these solar panels can be applied on building windows and automobile glass surfaces.

The company is working on improving the efficiency of its transparent solar panels.

Ubiquitous Energy

As mentioned earlier, this is one of the pioneers of transparent solar panels. Over the years, Ubiquitous Energy has gained a reputation for producing the best clear solar panels.

Ubiquitous transparent solar panels are indistinguishable, powerful, energy-efficient, and cost-effective.

Brite

This is a nanomaterials company that leverages deposition techniques to craft transparent solar panels and other glass building materials.

Clear solar panels from Brite reduce the energy footprint of buildings by providing power for heating, cooling, and lighting. Brite aims to make transparent solar panels suitable for greenhouse farming.

Amerisolar

Since 1993, Amerisolar has been perfecting the design and production of high-efficiency solar modules.

Recently, they introduced transparent solar panels with the aim of illuminating buildings while producing electricity and offsetting some of the energy demands of buildings.

Amerisolar offers a great selection of transparent solar panels, and they guarantee the best solar panels possible.

Transparent Solar Panels vs. Conventional Solar Panels

Is a semi-transparent solar panel different from a transparent solar panel?

Currently, semi-transparent solar panels are a type of transparent solar panels whose light transmittance is below 100%.

While some companies are producing fully transparent solar panels (100%), semi-transparent modules are the most common in the market today.

Semi-transparent solar panels are perfect for application in building windows and greenhouses where some light still needs to be filtered.

However, they may not be ideal for use in devices such as smartphones where 100 light transmission is needed.

When switching to solar, which panels should you choose?

To make a sound decision, you need to ask yourself the following questions:

Where do you want to install the solar panels?

Transparent solar panels are perfect for areas where conventional solar panels can’t be applied, such as on windows or as a cover for a greenhouse.

Is aesthetics a major concern?

Unlike conventional solar panels, transparent solar panels have no significant impact on the look of a structure. So, guided by the aesthetic change you want, you can choose transparent or conventional solar panels.

How much power do you need?

Currently, conventional solar panels have a high power production efficiency, so they’re better if you’re looking to produce a good amount of power.

However, despite their relatively low efficiency, transparent solar panels are the better option if you have a large glass volume.

How are Transparent Photovoltaics Made?

Here are the major components that make up transparent photovoltaics:

• Glass or plastic- Outermost layers that act as the housing for the light-sensitive molecules.
• Absorptive layer/ Luminescent concentrators- This contains the materials that get excited by invisible radiations and later release the electric current to the solar cells.
• Electrodes- Connect the solar cells with the external PV system.
• Reflective back layers- Installed on the back layer (on glass or plastic) to reflect IR and UV radiations.
• Anti-reflective coatings- Prevents any other reflections on the surface of the transparent PV.

Transparent solar panels have luminescent concentrators of either organic salts or quantum dots (nanoparticles made up of semiconductor material).

These particles are lined throughout the surface of the tiny modules, and their primary role is capturing the UV/IR radiations.

At the edges of transparent solar panels are the tiny solar cells. The solar cells collect the radiation’s energy and convert it to solar power. Between the luminescent concentrators and solar cells are electrodes that conduct the electric current produced.

All the other components are used to optimize solar power production by reducing energy losses.

To produce transparent photovoltaics, getting the right balance of light absorption and light transmission is essential. It is for this reason that partially transparent and fully transparent panels have been developed.

Why organic materials?

Conventionally, solar panels have been made from silicon. This material is excellent due to its high efficiency in producing solar power.

However, it’s not transparent, so it can’t work in glass-covered areas where solar power is still needed.

Transparent solar panels leverage carbon-based and organic materials to capture energy. The configuration of these light-converting materials can be altered to achieve transparency when integrated into solar modules.

In a nutshell, the making of transparent modules must incorporate these three elements:

• Optical design
• Molecular design
• Device optimization

Transparent Solar Panels: A Cost Analysis

Transparent solar panels cost around $25 per square foot. A similar size of conventional solar panels goes for about $5.

So you may ask: Are clear solar panels expensive?

Clearly, transparent solar panels are 5 times more expensive than conventional solar panels. However, considering that they’re installed in areas where conventional solar panels can’t be installed, they’re certainly worth the money.

What is the payback period of TPVs?

This depends on the glass area that the transparent PVs are installed in.

A large transparent solar panels project (A good example is installing clear panels on a skyscraper with extensive glass surface) can recoup the money invested even before hitting 5 years of operation.

However, if you install clear solar panels, say on your home’s windows, it may take up to 10 years to recover the initial money invested.

Where to buy transparent solar modules?

You have 3 options when it comes to buying transparent solar panels:

• Transparent photovoltaics companies- Check out the manufacturers’ section above.
• Online retailers- Best option to buy transparent solar panels since you have a wide variety of options to choose from.
• Local solar shops- Most convenient if you can find the clear module type you want.

Cost of transparent solar windows

The average price of transparent solar windows is $40 per square foot. This number increases when you factor in the cost of additional components such as framing.

The installation costs– which vary depending on location– also dictate the final cost of the project.

Like the panels themselves, solar windows with clear solar panels are definitely more expensive than conventional non-solar windows.

Even so, considering the benefits such as electricity production that solar windows come with, it’s sensible to incur the initial cost.

How do Transparent Solar Panels Work?

Transparent solar panels operate in a completely different way from conventional panels. Instead of capturing visible light and turning it into energy, clear solar panels convert invisible light into solar power.

Here’s the basic working process of transparent solar panels:

1. Light from the sun hits the transparent solar panels
2. Shorter wavelength radiations are absorbed by the quantum dots/organic particles
3. Visible light passes through the clear solar modules
4. The radiations absorbed by light-absorbing particles are later emitted in longer wavelengths. For the case of organic salts, they glow to release the radiations
5. The side pane of the transparent PV reflects the radiations back
6. The re-emitted radiations travel the whole length to the edge of the solar panel (the quantum dots/ organic salts can’t interact with the longer wavelength radiations)
7. The tiny solar cells on the edge of the solar panels absorb the solar energy
8. Energy from the solar cells is carried by tiny wires and conveyed to a meeting point
9. The total solar energy from the solar panel is then fed into an existing solar PV system
10. In the case of smaller devices, the energy is channeled directly to a load

So you may ask, how does visible light pass through the transparent solar panel?

To allow visible light through, the transparent PVs material is made in a way that the energy gap between the light active elements is greater than light photons.

Therefore, the electrons don’t interact with the visible radiations of the electromagnetic spectrum.

Efficiency of Transparent Solar Modules

The efficiency of transparent solar panels is one of the most contentious topics regarding this PV technology.

Usually, solar panels have an efficiency of around 20% and this is because they harness visible light. Transparent solar panels let visible seep through and capture invisible radiations thus reducing efficiency significantly.

The average efficiency of most transparent solar modules is still below the 10% mark. We’ve seen clear solar panels with efficiency as low as 1%.

Obviously, a lot has to be done to at least match the efficiency of clear solar panels to that of conventional solar panels.

Even so, solar experts argue that transparent solar panel potential is high due to the availability of space to install them. However, if you assume a 1% efficient solar panel is installed on a cellphone, it won't make sense since the PV will barely charge the battery.

Do transparent solar panels overheat?

Due to the clear nature of transparent solar panels, they do not absorb much heat.

However, if the sun is intense, they can still overheat. Depending on the temperature coefficient of the solar panel in question, an efficiency reduction occurs accordingly.

So when installing transparent solar panels, it’s crucial to consider factors such as shading which are likely to contribute to overheating.

How can transparent solar panels be made more productive?

A very practical hack is stacking several transparent solar panels. A stack of solar panels increases the distances for absorption of the invisible light, thus the amount of solar power produced per square foot of clear solar panels.

But let’s face it, the efficiency of transparent solar panels is below the acceptable threshold, meaning they’re currently not viable for small-scale use.

Applications of Transparent Solar Panels

For greenhouse

Integration of transparent solar panels on greenhouses optimizes photosynthesis and makes food production season-independent.

With transparent solar panels, the light transmitted to plants can be controlled (smart shading), therefore canceling out the effects of extreme temperature changes.

The energy captured by the solar panels can also be turned into electricity and used to power other activities in the greenhouse.

Note: Semi-transparent solar panels can also be used in greenhouses. Literally, any solar panel with at least 70% transparency is perfect for greenhouses.

Also Read: Transparent solar panels for greenhouse food production.

For skyscrapers (solar windows)

Solar windows are a type of building-integrated photovoltaic meant to illuminate the inside of buildings (especially multi-floor buildings) while still generating energy to power basic functions, such as charging.

If transparent solar panels are to be installed on windows, there’re some crucial factors to consider:

Shading

Shading is a big hurdle when it comes to the efficiency of clear solar panels– it leads to localized hot spots on the surface that lead to a decrease in overall efficiency.

So, if a building is to be integrated with transparent PVs, it must be in a place clear of obstacles. Also, considering the shading effect, PV technology is only effective for buildings that are well spaced out.

Total footprint

The footprint of a building determines the number or size of clear solar panels needed for the project. This gives an estimate of the cost that'll be incurred.

If the building isn't all glass, then the total surface area of the window glass should be used as the total footprint.

Energy demands of the building

Transparent solar windows should provide enough solar energy to power a typical building's devices.

However, if the building is a heavy power consumer, there should be plans beyond installing solar windows. A more promising alternative to solar windows is embedding solar cells on window blinds.

For pergola or patio

A pergola or patio is a brilliant expansion of the living space to the outdoors.

While these spaces can work without roofs, it makes sense to add a cover for weatherproofing purposes.

The good thing with transparent solar panels is that they let in light to the space while weatherproofing and producing power.

Also Read: Solar pergolas, and patio covers.

Transparent solar panels are most effective when used on buildings and greenhouses. Other possible applications of transparent solar panels include:

• In cars as power-producing windshields/ sunroofs- The power produced in this scenario can be used to run the AC of an automobile.
• In cell phones to charge batteries- The glass surface on cell phones is quite small, so the efficiency of clear solar panels has to be improved if they’re to work for this application.

In light of these applications, we can conclude that solar panels are made for areas where conventional solar panels aren't feasible.

Transparent Photovoltaics’ Maintenance

Like conventional solar panels, the most essential maintenance practice of transparent solar panels is cleaning.

Any other special maintenance procedure (especially for solar panels installed on small devices) should be well documented in the manufacturer’s guidelines.

So, how should you generally clean transparent solar panels?

Use clean water and a soft brush or cloth to clean your transparent solar panels. If stubborn grime has accumulated, you can add in some mild dishwashing soap and a soft brush to deal with it.

Luckily, there’re no sensitive components on the surface of a transparent photovoltaic that will be scraped out during the cleaning process.

All in all, you should still be gentle when cleaning your transparent PVs to avoid other issues such as breakage. Avoid using rough-abrasive brushes to clean your transparent solar panels.

It is vital to properly maintain transparent solar panels to ensure that they reach their expected lifespan. Even more importantly, proper maintenance keeps the solar panels' warranty compliant. TPVs usually have a warranty period of 15-25 years.

Benefits of Transparent Solar Panels

Little or no aesthetic change

Since transparent solar panels are clear like glass, they can be retrofitted into windows without changing their original look.

And it's not just about the look; installing transparent solar panels won’t mess with any architectural aspects of your building.

In fact, transparent solar panels increase the value of buildings, so this is a project that real estate investors should embrace.

Converts harmful UV rays to power

Transparent PVs absorb UV light from sunlight, saving you and your property from the damage that these harmful rays cause.

The sunscreen effect is especially beneficial when clear photovoltaics are installed on windows– solar windows still allow light to pass through but filter it from these harmful rays.

Highly versatile

Clear solar modules have unlimited uses and are made for areas where conventional solar panels can’t be installed.

Though novel applications such as integrating solar cells into smartphone screens have not yet been refined, transparent solar panels have already shown great potential in terms of versatility.

Drawbacks of Transparent Solar Panels

Poor efficiency

Transparent solar panels only harness ⅓ of the spectrum's radiations, limiting their power production efficiency.

Low efficiency is a big hurdle for transparent PVs, and it's only when this problem is solved that the technology will be rendered partially successful.

High cost

Despite the low production efficiency, clear solar panels come at a high initial cost.

While this cost will quickly be recouped when the modules are installed in a large glass building, it can be a challenge for individual homeowners looking to install TPVs.

The Future of Transparent Photovoltaics

Moving forward, you should expect to see the following innovations in the field of transparent solar panels:

• Design tuning to increase the modules' efficiency.
• Integration of transparent PVs with conventional solar panels for enhanced power production per unit area of solar panels.
• Flexible transparent solar panels that can be installed on a wide variety of surfaces.
• Clear solar panels made from recyclable glass for cost reduction purposes.

Frequently Asked Questions

Conclusion

Transparent solar panels are no doubt a futuristic PV technology but as it stands for now, so much has to be done to render it practical.

To say the least, the efficiency of these solar panels is one primary factor PV manufacturers have to crack as soon as possible.

All in all, transparent solar panels have the potential to transform the world into an energy harvesting system the versatility of these solar panels has already proved that. The world is getting eco-friendlier. Be part of the revolution!