Building-integrated Photovoltaic (BIPV) : Beyond the Value and Challenges of the components Themselves

Building-integrated photovoltaic (BIPV) is often regarded as an area where photovoltaic products with insufficient competitiveness attempt to enter the market. But Bjorn Rau, the technical manager and deputy director of PVcomB at Helmholtz-Zentrum Berlin, believes that this view may not be fair. He pointed out that the missing link in the deployment of BIPV lies at the intersection of the construction industry, the construction sector and photovoltaic manufacturers.

From PV Magazine

The rapid development of the photovoltaic industry over the past decade has brought its annual new installed capacity to a global market size of approximately 100 gigawatts (GWp), which means that about 350 million to 400 million solar modules are produced and sold each year. However, integrating it into buildings remains a niche market. According to a recent report from the EU's "Horizon 2020" research project PVSITES, only about 2% of the installed photovoltaic capacity was integrated into building envelopes in 2016. This tiny figure is particularly striking because over 70% of global energy consumption and approximately 40% to 50% of greenhouse gas emissions come from urban areas.

To address the greenhouse gas challenge and promote on-site power generation, the European Parliament and the Council introduced Directive 2010/31/EU on building energy efficiency in 2010, with the core concept of "Near Zero Energy Buildings (NZEB)". This directive applies to all new buildings constructed after 2021. The directive came into effect at the beginning of this year for new buildings that will accommodate public institutions.

The instruction does not stipulate specific measures for achieving the NZEB state. Building owners can consider energy efficiency measures such as insulation, heat recovery and energy-saving solutions. However, as the overall energy balance of buildings is a regulatory goal, active power generation within or around buildings is crucial for meeting NZEB standards.

Potential and Challenges

There is no doubt that photovoltaic applications will play an important role in future architectural design or the renovation of existing building infrastructure. The NZEB standard will be the driving force for achieving this goal, but not the only factor. Building-integrated photovoltaics (BIPV) can be used to activate existing areas or surfaces for power generation, thus enabling the addition of photovoltaic applications in urban areas without the need for additional space. The potential for clean electricity generated by integrated photovoltaic systems is huge. As the Becquerel Institute discovered in 2016, in Germany, the potential proportion of BIPV power generation in total electricity demand exceeds 30%, while in more southern countries (such as Italy) it is even close to 40%.

But why do BIPV solutions still only play a marginal role in the solar energy business? Why are they rarely considered in construction projects up to now?

To answer these questions, the Helmholtz Centre for Materials and Energy (HZB) in Berlin, Germany, organized a seminar last year and communicated with stakeholders from various fields of BIPV, conducting a requirements analysis. The results show that the problem does not stem from the lack of technology itself.

At the HZB seminar, many professionals in the construction industry engaged in new or renovation projects admitted that there was a knowledge gap regarding the potential of BIPV and its supporting technologies. Most architects, planners and building owners simply do not have sufficient information to integrate photovoltaic technology into their projects. Therefore, people have many concerns about BIPV, such as insufficient design appeal, high cost and excessive complexity. To overcome these obvious misunderstandings, the needs of architects and building owners must be given top priority, and understanding how these stakeholders view BIPV should be prioritized.

The transformation of thinking mode

BIPV differs from traditional rooftop solar systems in many aspects, which neither require multi-functionality nor aesthetic considerations. If manufacturers are to develop products for integration into building components, they need to rethink. Architects, builders and building users initially expected the building envelope to have conventional functions. From their perspective, power generation is merely an additional attribute. In addition, developers of multi-functional BIPV components must also consider the following aspects:

    • Develop cost-effective customized solutions for solar-active building components with variable sizes, shapes, colors and transparency;

    • Set standards and offer attractive prices (preferably applicable to mature planning tools such as Building Information Modeling (BIM));

    • By integrating building materials and power generation components, photovoltaic components are integrated into the new type of facade components.

    • Has a high tolerance for temporary (local) shadows;

    • Ensure long-term stability, pay attention to the long-term attenuation of power output, as well as the long-term stability and deterioration of appearance (such as color stability);

    • Develop monitoring and maintenance plans that adapt to specific on-site conditions (considering installation height, replacement of defective components or facade components);

    • Comply with legal and regulatory requirements, such as safety (including fire prevention), building codes, energy regulations, etc.