What is Building Integrated Photovoltaic (BIPV)?

Fast read

Building-integrated photovoltaics (BIPV) is a technology that integrates solar cells into building materials, such as windows and roofs. This has the potential to generate electricity while also providing aesthetic and structural benefits.

However, several challenges have prevented BIPV from becoming more popular, including lower efficiency, not ideal for all orientations, higher costs, technical challenges and lack of direction via Government policies.

Despite these challenges, there is growing interest in BIPV technology. As the cost of BIPV systems decreases in future years and the technology becomes more mature, BIPV will likely become more widely adopted.

Why do we not see more windows, house walls and high rises with solar panels built into them?

I’m often asked why windows do not have solar cells. Why the side of buildings, particularly glass-covered skyscrapers and towers, do not act as a solar PV generator? It would make sense that all the surfaces could generate electricity to power the buildings. Solar cells are made and integrated into the glass for use within windows, walls, etc. This technology is known as Building Integrated Photovoltaic (BIPV). However, companies offering this technology have not taken off for several reasons.

Low efficiency means reduced PV output

As the solar cells and surface are designed to be transparent, this reduces the opportunity to place the conventional cells. If a different technology is used, this is usually a lower-performing technology, e.g. thin film. Thin film solar technology has lower efficiency and therefore reduces the potential output. Therefore such windows, for example, have reduced performance compared to standard panels.

Building with solar panel windows
Some building-integrated solar can enhance the aesthetics of the development

Not an ideal angle and direction to the sun

Solar panels work best when angled so that the surface directly faces the sun. As windows are vertical, they will not work efficiently as the sun will not be at an angle that maximises power generation. Additionally, many buildings are not oriented to maximise solar performance. Only 1 or 2 sides of the building would be most suitable, as shade will be a significant issue. New technologies, such as Enphase-like microinverters, are hoped to improve this situation in future years.

Retrofitting will cost a fortune

While gaining much sunlight, many existing high-rises and homes do not have building-integrated photovoltaic technology added. Retrofit windows and facades and integrating the generated solar into the building’s electricity infrastructure will be expensive. It is most likely not economically viable. On the other hand, the Government could mandate that all new high-rise buildings include some aspects of the BIPV technology.

New home builders could be compelled to design and construct a solar-friendly roof and dedicate the north-facing wall to some solar technology. We predict that in future years, such policies will be considered by the Governments of the time.

BIPV has higher costs

As the materials and technologies are currently not produced in sufficient mass, the cost of their components is also high. So such systems, due to position restriction, produce less solar than conventional PV but are quite a bit more expensive, putting pressure on the economic viability.

Considerable technical challenges

Another problem preventing the widespread adoption of solar-integrated building materials is technical challenges. To withstand handling during construction and daily use, the integrated windows or panels must be robust and weatherproof.

The design and manufacturing procedures must become more sophisticated to meet these requirements while keeping their ability to generate energy. Furthermore, it cannot be easy to incorporate solar panels into older buildings that weren’t designed with solar integration in mind. Such constructions may need extensive structural and electrical system changes to retrofit solar panels and batteries. Such additional work would increase the cost and complexity of the project.

Standard solar panels for homes, businesses and solar farms are already highly efficient. The solar industry is growing and offers many opportunities for conventional installations. The benefit of adding solar to glass and building panelling over rooftops solar is just not that economical right now. As such, the retrofitting of  BIPV will unlikely gain penetration in the market for some time.

It’s a bit like a catch-22, the technology is expensive as it is only produced in small numbers, and it is only implemented in small numbers because it is expensive.

building integrated photovoltaic on business building
More and more developments in the future will integrate solar into their facades

There are advances on the way for BIPV 

Despite these obstacles, the development of Building Integrated Photovoltaic materials has advanced. The effectiveness, robustness, and attractiveness of solar panels created expressly for integration into building surfaces are the subject of numerous worldwide research initiatives.

New solutions like transparent solar cells or PV windows are being developed to address energy generation and aesthetics.

Additionally, solar integration is becoming more economical because of the falling price of solar technology and cells. Increased efficiencies and ongoing improvements in PV manufacturing techniques also help.

The obstacles to overcome for Building Integrated Photovoltaic

Obstacles, including cost, efficiency, aesthetics, technical difficulties, and policy considerations, have prevented the widespread implementation of solar-integrated windows, solar-generating house walls, and skyscrapers; the future might see this change.

Ongoing research and development initiatives are tackling these issues. We anticipate a rise in the use of solar-integrated buildings as technology improves. Future cost reductions and supportive policies are also in the pipeline. This will help create a more sustainable and energy-efficient future.

The price of solar-integrated building materials is anticipated to reduce further as the demand for renewable energy rises and economies of scale take effect. So in 20 or 30 years, new buildings will most likely have to have building integrated solar as part of the infrastructure. BIPV could be as common as a lift or a balcony, and the new generation of energy users will wonder why we did not do it on a large scale earlier.

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