Photovoltaic New Trend: Building-Integrated Photovoltaics

Under the dual pressures of the global climate crisis and energy transition, the construction industry is undergoing a silent yet profound transformation. As a major contributor to global carbon emissions (approximately 38%, according to IEA 2024 data), the traditional building model is in urgent need of disruption. The explosive growth of Building-Integrated Photovoltaics (BIPV) technology is driving a fundamental shift in cities from "energy consumers" to "energy producers."
What is BIPV? Traditionally, solar energy is installed on building rooftops, known as Building-Applied Photovoltaics (BAPV). However, more and more architects are learning how to integrate solar cells and components into building elements such as facades, roof tiles, and railings, which is known as Building-Integrated Photovoltaics (BIPV).
BIPV systems consist of solar cells or modules that are integrated into building components or materials, becoming part of the building structure. In this way, they replace traditional building components rather than being fixed onto them. BIPV components can not only generate electricity but also provide additional functionalities for the building. For example, they can provide sun protection, insulation, sound insulation, or security.

Where can BIPV be installed? Compared to traditional solar panels, BIPV offers numerous advantages First, there are more surfaces available for integrating solar cells or modules—BIPV is not limited to rooftop integration. Solar modules can also be integrated into building facades, skylights, railings, etc. BIPV can also enhance the aesthetics of a building. For example, the materials used in BIPV allow architects freedom in terms of transparency and color. When integrated into ventilated facades, translucent skylights, or windows, BIPV can help keep buildings cool.
What is the cost of BIPV? Generally speaking, BIPV is more expensive than traditional PV systems used in solar power plants. This is reasonable, as BIPV systems do more than just provide electricity. However, because BIPV can perform multiple functions within a building in addition to generating electricity, it can save on material and installation costs.
What technologies are involved in BIPV? The main solar cell technologies for BIPV include crystalline silicon solar cells, thin-film silicon solar cells, and other thin-film technologies such as organic photovoltaic (OPV) and dye-sensitized solar cells (DSC). Crystalline silicon solar cells are the most mature technology, but thin-film technologies are attracting attention due to their flexibility, ease of integration, and responsiveness to indirect light. Organic solar cells are a relatively new technology and are still under development. However, the advantage of organic photovoltaics (OPV) is that it is a lightweight, semi-transparent material that can be coated onto curved surfaces and glass at low cost and can be made in a variety of colors or pure neutral colors. It is also highly sensitive to low light intensity, making this technology very suitable for maritime climates. In addition, this technology has less dependence on the angle of incident sunlight, making it very suitable for applications such as building facade integration.

 

Resource Efficiency and Environmental Impact

Integrating solar panels into buildings can reduce the need for additional materials and space. This means less resource consumption and less waste generation. By reducing the raw materials required for construction and installation, we minimize the environmental footprint and pressure on natural resources. In addition, since solar energy is a green and renewable energy source, it can significantly reduce the carbon footprint of buildings.
 

 

Space Efficiency

In urban environments where space is extremely valuable, building-integrated solar power systems have unique advantages. By installing solar panels directly on building facades or rooftops, there is no need for additional land or space to build large solar power plants. This efficient use of space is particularly beneficial in densely populated areas. By choosing vertical or rooftop solar installations in urban environments, we can preserve more undisturbed land. This approach protects natural habitats and supports biodiversity, whereas large ground-mounted solar power plants sometimes disrupt local ecosystems.

 

Design Flexibility

The aesthetics of a building are closely related to its attractiveness, value, and ability to blend in with or stand out from its surroundings. The development of building-integrated solar panels is not only reflected in their functionality as components but also in their enhancement of architectural appeal as design elements. Thanks to advances in technology and manufacturing processes, building-integrated photovoltaic systems can be integrated into a variety of architectural styles, from traditional to modern. This ensures that the integration of solar panels does not compromise the original design concept of the building but complements or even enhances it. In addition to a flat appearance, BIPV also offers a range of design options, including different colors, textures, and transparency. Some BIPV solutions even mimic materials such as slate or terracotta, allowing architects and homeowners to maintain a unique aesthetic while enjoying solar energy. While rooftops are a common application for building-integrated photovoltaic systems, the adaptability of this technology means it can also be used on facades, awnings, and even as part of a building's shading system. This broadens the design possibilities and allows architects to think creatively about how and where to integrate solar power generation into their designs.

 

Building-Integrated Photovoltaic Applications

The wide range of applications for building-integrated photovoltaics is closely related to architectural imagination. With technological advancements and the increasing urgency of sustainable development, integrated solar panels will undoubtedly have more innovative uses. Its significance lies not only in power generation but also in redefining our understanding of buildings—transforming passive structures into active contributors to a green future.

1. Rooftop Installation: Rooftop installation is the most common application of building-integrated photovoltaics, seamlessly blending with the building's profile. Here, the roof can serve not only as a barrier against the elements but also as a solar power generator.
2. Facades and Exterior Walls: BIPV facades transform building exteriors into energy sources, combining aesthetics with practicality. Large glass facades can be equipped with semi-transparent integrated solar panels that generate electricity while filtering sunlight.
3. Awnings and Canopies: Outdoor structures such as awnings and canopies are ideal locations for building-integrated photovoltaic systems, providing shade while capturing sunlight.
4. Balconies and Terraces: Installing building-integrated photovoltaic systems on balconies or terraces provides both privacy and power generation. With the increasing demand for apartments in urban living, installing building-integrated photovoltaic (BIPV) systems on balconies is an important step towards self-sufficient residential complexes.
5. Greenhouses and Agricultural Applications: BIPV is not limited to urban buildings. Its application in agriculture demonstrates its versatility. Agricultural storage spaces can benefit from building-integrated photovoltaics, providing power for their internal operations and reducing operating costs.
6. Highway noise barriers: These barriers are primarily used to reduce noise pollution from busy roads, but can also be equipped with integrated solar panels, turning long stretches of road into power generators.
    

 

Potentially faster installation

A major inherent appeal of building-integrated photovoltaics (BIPV) lies in its potential for simplified installation.
With the dual functionality of BIPV, the processes of erecting a shading structure and a power generation system can occur simultaneously. This simultaneous installation offers significant advantages in terms of time, manpower, and overall efficiency. Recent studies indicate that conventional solar installations require approximately 6.9 labor hours per kilowatt, while residential rooftop integrated PV installations require approximately 6.4 labor hours per kilowatt on retrofitted roofs and only 3.5 labor hours per kilowatt on new construction sites.

By reducing the labor hours required per kilowatt, BIPV not only accelerates the installation process but also potentially saves costs. Reduced on-site construction time translates to lower labor costs, faster project turnaround, and quicker return to operation for commercial projects. This data is particularly evident on new construction sites, where the installation of PV BIPV requires only 3.5 labor hours per kilowatt. This suggests that if builders and architects plan for BIPV systems from the initial stages of a project, the installation process will be more efficient. This proactive approach ensures that the necessary infrastructure and logistics are in place from the outset, leading to a smoother and faster installation. For retrofit or roof renovation projects in particular, a faster installation process means less disruption to occupants or operations within the building. This is especially beneficial for businesses or organizations that need to maintain daily operations even during construction or renovation phases.

 

Economic Advantages

• Cost Savings: Investing in BIPV systems can significantly reduce electricity costs. By directly utilizing solar energy, reliance on the grid is reduced, leading to lower electricity bills.
• Potential for Additional Income: For buildings that generate excess electricity, there is the possibility of feeding it back into the grid where feed-in tariffs or net metering are available.
• Increased Property Value: Buildings equipped with BIPV are more attractive in the real estate market. As the global focus shifts towards sustainable living, energy-efficient homes and offices become favorable choices for buyers, potentially leading to a higher return on investment for sellers.
• Protection Against Energy Price Fluctuations: BIPV systems offer a degree of protection against energy price volatility. By producing and using solar energy on-site, reliance on external power sources, whose prices can fluctuate due to economic or political reasons, is reduced.

 

Cost Comparison

When assessing the financial implications of integrating BIPV systems, it is essential to consider the broader long-term savings and added value beyond the immediate outlay. While the initial investment in BIPV may be higher than traditional solar installations, the long-term savings and benefits can offset this cost. It is crucial to view this investment from the perspective of its dual functionality: you are essentially purchasing both roofing material and a solar power generation system. When considering property appreciation, potential energy resale, and electricity cost savings, the return on investment becomes clearer. Modern buyers and investors are increasingly environmentally conscious. Energy-efficient buildings equipped with BIPV are considered more attractive, potentially increasing property value. This appreciation can significantly reduce the initial cost of the system. In areas with net metering, excess electricity generated by BIPV systems can be sold back to the grid. This resale potential can become a steady income stream over time, further enhancing the financial outlook of BIPV. Many governments and local authorities offer incentives, rebates, or tax breaks for sustainable energy-efficient buildings. BIPV systems, due to their environmentally friendly nature, may qualify for such benefits, further reducing the actual installation cost.

 

BIPV Case Studies

In recent years, numerous BIPV buildings have emerged globally. We have selected several representative cases to share with you.

 

Public Buildings

Project Name: China Pavilion, 2019 Beijing World Horticultural Exposition Design Firm: China Architecture Design & Research Group Co., Ltd. Design Period: 2016.9-2017.5 Construction Period: 2017.8-2019.3 Building Area: 23,000㎡ Chief Architects: Cui Kai, Jing Quan, Li Liang In terms of energy utilization, the pavilion's roof and curtain wall are equipped with a solar photovoltaic power generation system. 1024 semi-transparent golden cadmium telluride photovoltaic glass panels were installed, adopting a "self-generation and self-use, surplus to the grid" model to provide power support for the pavilion's lighting, scenery, and other operations. Using cadmium telluride translucent thin-film modules as building components, it possesses the functions of ordinary translucent roofs and curtain walls, such as maintenance, heat insulation, and aesthetics, while also having power generation capabilities. This achieves the green building concept of transitioning from passive energy saving to active power generation. Furthermore, it not only cleverly combines with the building's roof and curtain wall components but can also be made into different sizes, different light transmittance, and different colors according to requirements, perfectly replacing traditional curtain wall glass and truly realizing the replacement of building glass with photovoltaic glass.

 

Commercial Buildings

Project Name: ENERGYbase office, Vienna, Austria
Building Function: Office and experimental educational building
Integrated System: External shielding on inclined facade
Address: Giefinggasse 2, 1210 Vienna
Architectural Design: Ursula Schneider, pos architekten ZT gmbh
Completion Year: 2008
Module Production: SOLARWATT GmbH
Solar Technology: Glass-glass laminated panels
Nominal Power: 48.2 kWp
System Size: 364 photovoltaic modules, approximately 400 m2
Module Dimensions: 1520 x 710 x 9 mm
Orientation: South
Installation Angle: Inclined 31.5°

 

Residential Buildings

Project Name: Best Social Housing Apartments, Netherlands
Building Function: Residential building
Integrated System: Facade
Location: Best, Netherlands
Architect: NB Architecten
Completion Year: 2018
Photovoltaic module: Stion CIGS solar module without frame
Manufacturer: EigenEnergie.net BV
Solar technology: Standard thin-film (CIGS) module
Nominal power: 250 kWp
System size: 750 square meters facade + 500 square meters railing
Module dimensions: 656 x 1656 mm2
Orientation: Three facades of the apartment building
Installation angle: 90° tilt

 

Conclusion

Building-integrated photovoltaics is more than just a sustainable energy solution; it represents a shift in how we view urban development and infrastructure. As the world increasingly leans towards eco-friendly solutions, building-integrated photovoltaics stands out not only for its green credentials but also for its economic viability and aesthetic appeal. For those looking to invest in a future-oriented and sustainable lifestyle, building-integrated photovoltaics is undoubtedly a worthwhile consideration.