Thin Film Solar Panels: A New Generation of Flexible Solar Energy

Thin Film Solar Panels: A New Generation of Flexible Solar Energy

When people imagine a solar power system, they usually picture a flat, heavy glass structure mounted on a roof or a dedicated metal frame. In fact, about 95 percent of the global PV market still looks exactly like this. But today we are talking about the remaining few percent. Thin film solar panels are significantly lighter and do not require heavy supporting structures. They can be installed on roofs with limited load capacity or mounted vertically on building façades. They can also take on more complex shapes, allowing them to be integrated into architectural elements. In some cases, thin film technologies can even be incorporated into car roofs and wearable materials. Read on to discover how thin film solar technology is opening new possibilities for designers, architects, and developers.

Thin, Yet Different

Thin film photovoltaics (thin film PV) are a class of solar modules in which the active semiconductor layer is deposited onto a thin substrate such as metal, fiberglass, or plastic. This layer is 100 to 350 times thinner than a conventional silicon wafer. As a result, the panels can be rolled into rolls and applied to surfaces almost like a sticker, without the heavy frames typical of traditional solar modules.

There are several thin film technologies, each with its own strengths and limitations.

a Si (amorphous silicon)

Experiments with non crystalline silicon began in the 1970s. These modules are lightweight and relatively inexpensive, but their real world efficiency is only about 5 to 6 percent, compared with 15 to 22 percent for conventional monocrystalline panels. Today amorphous silicon is used mainly in small autonomous devices such as calculators.

CdTe (cadmium telluride)

This is a more mature technology. CdTe modules can reach efficiencies of up to about 19 percent, perform well under diffuse light, and maintain stable performance at high temperatures. Despite being classified as thin film, CdTe panels are typically large and rigid. They are well suited for large commercial solar power plants, but their size and the presence of cadmium limit their use in residential buildings.

CIGS (copper indium gallium selenide)

When thin film solar panels are discussed in the context of architecture, CIGS is usually what people mean. This technology combines flexibility with relatively high efficiency, typically between 13 and 18 percent. The modules weigh less than 3.5 kg per square meter and are only about 1.5 to 3 mm thick. They can be applied directly to a surface without additional mounting systems using peel and stick installation. These panels follow the shape of the underlying structure and can withstand wind and seismic loads.

GaAs (gallium arsenide)

Gallium arsenide is one of the most efficient photovoltaic materials, with cell efficiencies reaching up to about 30 percent. However, it is extremely expensive and therefore mainly used in satellites, aerospace applications, and military technology.

Perovskite photovoltaics

Perovskite solar cells are a promising technology currently in the research and pilot production stage. Single junction cells have reached efficiencies of around 25 to 26 percent, while tandem cells combined with silicon have achieved up to about 33 percent.
Compared with conventional monocrystalline modules, commercially available thin film panels are generally less efficient and tend to degrade faster. Amorphous silicon modules typically lose about 0.8 to 1 percent of their output per year, compared with roughly 0.3 to 0.5 percent for monocrystalline modules. CIGS and CdTe panels degrade at around 0.4 to 0.5 percent annually.

At the same time, thin film modules have several advantages. They are lighter, more resistant to vibration, and easier to install. They also perform better under low or diffuse light and are more tolerant of high temperatures. In many cases, the cost per watt is also lower, typically around 0.20 to 0.35 USD per watt compared with about 0.30 to 0.50 USD per watt for monocrystalline modules.

Thin Film Solar in Practice

Lightweight adhesive modules are particularly valuable where traditional solar installations are difficult or impossible due to complex roof shapes or limited structural capacity. One of the largest CIGS projects in Europe using MiaSolé panels is the Maaspoort sports complex in the city of ’s Hertogenbosch in the Netherlands. A total of 418 panels measuring 2.6 by 1 meter and weighing about 3 kg per square meter were applied directly onto the building’s thin membrane roof. The installation generates around 125 MWh of clean electricity per year.

Because thin film panels are significantly lighter than conventional glass modules, they can also be used on older buildings with limited load bearing capacity. In the United States, this advantage was demonstrated at a 3M warehouse in Missouri. The 40 year old building could not support traditional heavy mounting structures, and the risk of roof penetration was unacceptable. Engineers therefore selected CIGS modules. The entire 10 kW system was installed in roughly two hours. Thanks to this approach, the aging building was able to gain solar generation without reinforcing its structure.

Solar energy remains one of the simplest and most effective ways to reduce electricity costs and make a home more energy independent. In this guide, we explain how solar systems work, where to begin, and what to consider when choosing the right solution for your home.

Solar for Lightweight and Temporary Structures

Thin film solar panels make it possible to turn existing canopies into sources of energy. Private and public parking structures offer especially strong potential, providing vast unused surface area that can be used for cost effective renewable power generation.

A good example is the Oakley Executive RV and Boat Storage facility in California, where an existing vehicle canopy was upgraded with solar generation. Lightweight thin film modules weighing less than 2.75 kg per square meter were applied directly onto the corrugated roof of the existing structure. The canopy did not require structural reinforcement, and the panels are virtually invisible from the ground.

Thin film panels are also well suited for temporary pavilions, tents, and foldable structures. Systems built on fabric substrates can be used for festival tents and outdoor cafés, where they can be installed quickly and removed just as easily when needed.

Solar Power in Transportation

Flexible solar modules have long been used on yachts, recreational vehicles, and even passenger cars. One of the best known examples is the flexible solar roof of the Fisker Karma hybrid sports car.

The vehicle features a spherically curved solar module with a capacity of 120 W that also functions as the roof. At the time of its release in 2010–2012, it was the largest curved automotive solar module ever produced. The panel charges the auxiliary battery and demonstrates that solar generation can be integrated into a sleek sports car design without compromising aerodynamics.

Experimental Uses of Thin Film Solar

University laboratories and startups continue to experiment with thin photovoltaic “skins.” For example, the HelioSkin research group at Cornell University is developing a solar surface that can change its orientation by tracking the sun. In a pilot project, the team plans to build a portable canopy of about 150 square feet that can deform to optimize light capture. Although such solutions are still largely confined to laboratory research, they point to the future direction of flexible photovoltaics.

In many real world projects, both types of modules are combined: conventional panels are installed on surfaces with optimal orientation, while flexible modules are used in areas where shape constraints or weight limitations make traditional technologies impractical.

What Is BIPV (Building Integrated Photovoltaics)?

Building Integrated Photovoltaics (BIPV) refers to the use of photovoltaic elements as building materials. Instead of being mounted onto a structure, these systems replace parts of the building itself such as roofing, canopies, façade cladding, or glazing. In this way, solar generation becomes an integral part of the architectural concept.

A striking example is the Copenhagen International School campus in the Nordhavn district of Copenhagen, Denmark. The school’s façade is covered with about 12,000 solar panels with a total area of more than 6,000 square meters. Individually oriented modules create a dynamic pattern that evokes the surface of the sea, while optical filters produce different shades of ocean blue without significantly reducing performance. The system generates more than half of the electricity consumed by the 25,000 square meter educational complex.

In Milan, the insurance company Unipol built a 120 meter tower with a façade made of around 1,000 solar panels that function as adjustable louvers. The modules can change their angle, regulating both daylight and energy generation.

Integrated solar generation inevitably involves trade offs. Designers sometimes sacrifice part of the energy yield for the sake of form, color, or architectural expression. For example, the panels on the Copenhagen school façade operate at non optimal orientations. Yet in public spaces or premium residential projects, aesthetics can be just as important as maximum power output. The engineer’s role is to find the right balance between beauty and performance.

The Limits of Flexible Solar Panels

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Not Always the Right Choice

If a roof can accommodate conventional panels that are cheaper and more efficient, traditional modules are often the better solution. Thin film systems are most suitable when architectural form, weight limitations, or structural constraints make conventional installations impractical.

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• Lower Efficiency and Larger Surface Area. CIGS panels typically achieve efficiencies of around 16 to 18 percent, while monocrystalline modules range from about 15 to 22 percent. To generate the same amount of power, a larger surface area is therefore required.

• Degradation. Amorphous silicon panels lose about 0.8 to 1 percent of their output per year. CdTe and CIGS modules degrade at roughly 0.4 to 0.5 percent annually, while monocrystalline panels typically lose around 0.3 to 0.5 percent per year.

• Cost. Although the price per watt can be lower, typically around 0.20 to 0.35 USD per watt, lower efficiency and more specialized manufacturing often make the overall system more expensive when calculated per kilowatt hour generated.

• Materials and Environmental Considerations. Some thin film technologies use materials such as cadmium or selenium, which require careful handling and proper recycling procedures at the end of the system’s life cycle.

• Not Always the Right Choice. If a roof can accommodate conventional panels that are cheaper and more efficient, traditional modules are often the better solution. Thin film systems are most suitable when architectural form, weight limitations, or structural constraints make conventional installations impractical.

The Engineer’s Role in Architectural Solar Projects

Integrating solar panels into architecture is always a complex undertaking. Flexible modules still require careful engineering, including structural load calculations, mounting design, electrical safety planning, lightning protection, and proper heat dissipation. Architectural creativity without engineering support risks turning an ambitious idea into a costly mistake.

Siriteja’s engineers work at the intersection of design and safety. In development projects, our role is to understand the architect’s concept, evaluate the building’s geometry and materials, recommend the appropriate technology such as monocrystalline, CdTe, CIGS, or a combination of systems, and design the electrical architecture of the installation.

We believe that involving engineers at an early stage saves both time and money. Close collaboration between architects and engineers helps identify potential risks early and ensures that the final project achieves both aesthetic and technical goals.

Conclusion

Thin film solar panels open up a new palette of possibilities for architects and developers. They are not a revolution or a replacement for traditional technologies, but rather another tool in the designer’s toolkit. With them, it becomes possible to cover curved surfaces, integrate power generation into canopies and façades, and create colored “solar skins.”

At the same time, a realistic engineering assessment shows that their efficiency is lower and the overall cost can sometimes be higher. The right choice is always a balance between aesthetics, functionality, and economics.

Working on an architectural project that integrates solar energy? The engineers at Siriteja can help assess where flexible solar panels make sense and where a conventional solution may be the better option.

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