Building Integrated Photovoltaics & Sustainable Architecture

Building-integrated photovoltaics (BIPV) are photovoltaic materials that can replace conventional building materials such as windows or facades. They are an important element in sustainable city building projects as a primary or secondary source of electrical power. A BIPV system can turn a whole building into a power plant. Often, they generate far more solar energy than a simple rooftop system.

In this article, we cover the concept of building integrated photovoltaics as well as their history and current market situation. Furthermore, we discuss various BIPV applications for new buildings and retrofit solutions for already existing buildings.

What is a Building Integrated Photovoltaic System?

BIPV Explained

Building-integrated photovoltaics s the use of solar glass on a building’s surface area for windows, roofs and facades. It is increasingly being used in the construction of new buildings as an electrical power source. However, it is also suitable for retrofit solutions on existing structures.

BIPV vs. BAPV

There are two ways to fit a building with photovoltaic materials. Integrated (BIPV) and building applied photovoltaics (BAPV), which is the more prevalent way of attaching panels to existing structures. Generally, BAPV solutions are more expensive. This is because it is more difficult to attach PV materials to an existing building design.

In both cases, however, the fundamental advantage is that it transforms a whole building into a solar power plant. Buildings can thus generate electricity on-site, often in sufficient amounts to become self-sufficient.

What are the Advantages of BIPV?

• Save money on building materials.
• Free electricity.
• Energy-efficiency through insulation.
• Aesthetic design.

BIPV materials provide the same function as the traditional building materials they replace (for example, cladding or roof tiles). Thus, they save money on those materials and offer the functions of PV system at the same time. The BIPV system then generates free solar power, which provides a return on investment. A building that is completely clad in PV materials can generate enough electricity to fully sustain itself.

Solar glass also helps in making a room additional energy efficient. Due to it’s insulating characteristics, it keeps a room cool during summer and warm during winter.

By integrating PV technology with a building’s structure, it gains additional architectural appeal through eye-catching solar glass or shading structures. It also provides more artistic freedom, as the panels can be produced and placed to be as unobtrusive as possible. Furthermore, BIPV itself sends a message by emphasizing a dedication to green technology.

BIPV Technologies

The modern PV market is dominated by two main PV glass technologies:

1. Solar cells produced from crystalline silicon, either as single or poly-crystalline wafers. They deliver roughly 10-12 watts per square foot.
2. Thin-film products consist of thin layers of PV material put on glass or metal substrates. They offer around 4-5W/ square foot.

Thin-film technologies provide the promise of cheaper prices while being more friendly to the environment.

Building Integrated Photovoltaics Journals

BIPV is an interdisciplinary field that sits at the cross-section of cutting-edge technology. It is directy tied to research on semiconductors, electrical engineering, architecture and city building. Therefore, there are a number of scientific journals that cover BIPV technology from different angles.

• International Journal of Development Research
• MDPI
• BIPV Adoption
• Technology Frontiers of BIPV
• Building Integrated Photovoltaicss – A Handbook PDF

History of BIPV

BIPV made it’s first appeareance in the 1970s. Aluminum-framed PV modules were attached to or installed on isolated buildings that had no connection to an electric power grid. In the 1980s, the first large-scale roof-mounted PV modules were installed. These PV systems were often put on grid-connected buildings in locations with centralized power plants.

By the 1990s, BIPV solutions started entering the free commercial market. The scientific publication Economic Assessment of BIPV postulated that BIPV will pose economic value for exchanging renewable energy credits (RECs). Despite technological potential, there are still obstacles to wider adoption, such as integration with high-density urban planning.

An economic study asserts that there are still major technological difficulties to solve before the cost of BIPV will be competitive. However, there is a growing consensus that, BIPV systems will become more widely commercialized. In Europe, they are the backbone of Europe’s zero energy building (ZEB) plan.

Building Integrated Photovoltaics Market

BIPV Market Overview

The global market for building-integrated photovoltaics is currently valued at USD 14.4 billion. It’s predicted annual growth rate until 2028 is around 3%, which is still a conservative estimation. Government support programmes are expected to fuel the industry during the next seven years, so higher returns are likely.

With a market share of over 67%, thick crystal technologies are the most popular among building integrated photovoltaics manufacturers. However, thin film technology has less environmental concerns and a lower overall cost. Therefore, it’s market share is expected to surpass thick crystal technology in this decade.

In terms of applications, roofing systems account for 60% market share. Demand for residential roof installations is predicted to rise in countries such as the UK, Germany, and France. Furthermore, increased deployment of energy storage systems will support demand for off-grid PV systems.

Commercial BIPV applications have the largest share in the BIPV market. Ⓒ Grand View Research

BIPV Market Segments

With more than 40% of the global BIPV market, industrial applications had the highest revenue share. Government actions aimed boosting renewable energies are projected to propel the industrial sector.

The expanding number of utility-scale projects in many nations also contributes to the industrial segment’s growth. Due to increasing awareness of zero-emission green infrastructure, the commercial sector is expected to increase significantly.

BIPV installations enhance the aesthetic appeal of building facilities while also saving significant amounts of money on electricity. Thus, they encourage product adoption across the commercial market.

BIPV Applications

Pitched & Flat Roofs

Roof tiles with integrated solar modules are known as solar roof tiles. They increase roof life by shielding insulation and membranes from UV radiation and water deterioration. Thin film solar cells incorporated into flexible polymer roofing membranes are the most common use of BIPV.

Metal pitched roofs are fitted with PV capabilities. This can be done in two ways. One way is through bonding of free-standing flexible modules. The other way is of the CIGS cells directly into the substrate through heat and vacuum sealing.

Solar Curtain Walls & Solar Facades

Solar curtain walls or facades are often used in high-story buildings to increase energy efficiency in an aesthetic manner. Due to better performance at vertical angles and under shadows, thin film solar glass is most commonly used for this purpose. Multilayered solar glass also provide noise and temperature insulation.

Colored solar glass can be deployed to match existing structures or to achieve a certain look. Standard colors are blue, black and brown. To generate more diverse colors, layers of colored laminate or glass can be used. Colouring the modules does result in a slight decrease in output.

Solar Windows

When roof space is restricted, solar windows can be used to generate power as well. Solar windows and skylights can be entirely opaque or up to 50% transparent and come in a range of colors. Aside from energy generation, solar windows reduce glare and improve temperature insulation, both of which are critical in sustainable buildings.

Infrared light is reflected by PV glazing, limiting heat transmission through the glass. This keeps heat out during summer and in during the winter, resulting in a more stable inside temperature. This is a major reason why low emissivity glass is frequently used in workplaces.