Summary: Challenges and Opportunities for Building-Integrated Photovoltaics RFI

State of the Industry and Key Domestic Markets

Market segments actively being pursued

Based on responses received, a variety of product segments were identified as being pursued in the United States. The list includes:

• Roofing products:
  • Roofing systems with commodity solar modules
  • Monocrystalline roofing panels on slopped roofs
  • Standing seam metal roofs
  • Solar shingles
  • Solar tiles
  • Integrated roofing membrane on rooftop with solar
• Covering/Shading products:
  • Parking lot coverings
  • Solar carports with charging stations
  • Awnings
  • Sunshades
  • Solar laminates (without framework) on solar canopies, carports, awnings
• Glass products:
  • Power generating PV windows
  • Opaque solar modules and semitransparent solar modules
  • Building glazing
  • Spandrel
  • Curtain walls
• Vertical products:
  • Cladding
  • Building façades
  • Vestibules
  • Wall-integrated PV
• Other areas:
  • High-performance building envelopes
  • Fiberglass pultruded parts for window reinforcement
  • CIGS panels for building façades, partial window replacements, indirect light awnings
  • Power electronic solutions for rooftop and façades
  • Electrical panels, subpanels, breakers
  • Building microgrids (solar+ESS+EV charging+EMS+VPP operation)
  • Characterization and validation of products

In terms of markets served, most of the respondents indicated a focus on residential or commercial buildings. This was an almost equal split, with slightly more responses giving preference to commercial buildings and the majority pursuing both markets. It was noted by some respondents that their strategy is to initially target commercial buildings and then move to the residential market, as they see more difficulties for the residential segment due to less willingness of owners to pay and lack-of-standardization concerns for BIPV products. Some special segments of the commercial building market, like government buildings, educational facilities, hospitals, manufactured houses, and agricultural facilities were also identified by the respondents as being of interest and of their primary focus. The following segments were specifically mentioned:

• Residential buildings (single and multi-family)
• Commercial buildings
• C&I buildings
• MUSH market: municipalities, universities, schools, hospitals
• Government buildings, higher education, healthcare sector
• Manufactured houses at the factory level
• Agriculture and greenhouses
• Playscapes

In terms of new buildings or retrofits, the vast majority of respondents mentioned being involved in both sectors with few of them only focusing on new buildings.

Market segments best aligned with commercialized BIPV products

A variety of information was provided with respect to the alignment of commercialized BIPV products and market segments. Some responses viewed the topic from the customer market segment perspective and others from the side of the BIPV product and application. It was also noted that, assuming availability of various BIPV products, the type of BIPV should be dictated by the aspect ratio of the building. Larger roof areas (like in warehouses) would naturally be a better fit for rooftop solar, while taller, skinnier buildings (like high-rise office or residential buildings) would be better fit for glazing or façade products.

Overall, most of the respondents considered the extended commercial building market to be best aligned with commercialized BIPV products. This market includes high-end commercial office and retail buildings (which have fewer cost constraints and can use the technology as marketing point), educational facilities, such as schools, colleges, and universities (which consider educational and research benefits of incorporating new technologies, especially in the science and technology sectors), hospitals, hospitality buildings, and warehouse facilities (which consider weight issues and reduced need for puncture of membrane roofs). New construction commercial projects seem to have the most potential.

The residential building market seems to be interested in the appeal of aesthetics of BIPV compared to tradition rooftop PV products. Development of more aesthetically pleasing products would be the best strategy for alignment with this market, though cost is also a significant factor. Multi-family homes and high-rise buildings seem to be the most promising segments. New constructions seem to be perceived as better aligned compared to retrofits.

In terms of products, roofing products are perceived to be best aligned with the market, both for commercial and residential applications. Power generating windows and other glass products are secondary, with more appeal on in commercial applications. However, responses indicate that most of the existing products need further development as they might not be fully aligned with the market needs. Another product category identified is shading elements, awnings, and in particular carports and parking shade covers.

Respondents also provided some insights about differences between the U.S. markets and markets in Europe or elsewhere in the world. It was noted that in the United States, residential and commercial roofs for new constructions align well with existing BIPV products in the space, but elsewhere in the world, many more commercial products are available for building façades for high-rise buildings, offices, government buildings, educational facilities, sports arenas, airports, and public areas. In Europe, there have been large commercial projects integrating BIPV glass as well as several small-scale commercial projects integrating BIPV walls and façades.

Largest market opportunities for BIPV

A variety of information was provided on the market opportunities for BIPV products. Like in the previous question, some responses viewed the topic from the customer market segment perspective and others from the side of the BIPV product and application.

Respondents perceived the largest market opportunities for BIPV to be in the commercial sector; however, residential applications were also considered to present great opportunities. In the commercial segment, corporate offices, retail buildings, storefronts, public buildings, government buildings, educational facilities, hospitals, and light industrial facilities were specifically identified as promising. Opportunities for older buildings with large power needs at places where the grid infrastructure is older were mentioned as well as applications that combine conventional rooftop solar with additional BIPV elements. For the residential sector, multi-family housing and low- and mid-rise buildings with a high ratio of wall-window to roof area were considered the largest opportunities. Incorporation of BIPV into manufactured housing and modular construction production lines was also identified as a promising opportunity. In terms of location, it was mentioned that the state of California would provide a large market opportunity because of the state requirements with respect to climate change and clean energy.

When viewing opportunities from the BIPV product perspective, three product categories were identified as being the most promising in the market:

• Roofing products
• Glass products (windows, glazing)
• Shade elements (awnings, carports, sunshades)

Regarding PV glass and power generating windows, respondents explicitly mentioned the stacking benefits of glass capturing infra-red light and thus also reducing heat transferred into the building.

Respondents also noted that a comprehensive market characterization and assessment is necessary, as the market opportunity will be eventually defined by the adoption and market-pull for these products, not by the theoretical availability of BIPV products that could replace a particular building element. Another view presented was the perspective of using the energy generated to offset the cost of the building element that is required by the building.

Marketing and sourcing of current BIPV products

Respondents approached this topic from various different angles and provided different types of information related to marketing strategies, manufacturing locations, industry composition, and PV cell technologies mostly used by BIPV products. Some respondents noted that marketing efforts are very limited and are done on a project-per-project basis, and this is considered a contributing factor to the limited uptake of BIPV technologies.

• Marketing and sourcing strategies: A typical marketing approach treats BIPV as architectural products that are marketed and sourced as offerings within the construction materials industry. Therefore, marketing starts from approaching architects, engineers, or real-estate developers via a product advertising strategy. Typical media and avenues include:
  • major architectural magazines, websites, or other digital media;
  • social media venues;
  • trade shows, home and garden shows, green building shows, architectural conferences, sustainability expos;
  • networking into specific target market segments.

In cases where developers or designers are more familiar with BIPV products, sourcing would follow the pattern of an interested architect or building developer reaching out to a BIPV product vendor. BIPV products are often marketed as elements of total-building approaches to achieve high LEED or similar scores. They are offered by the supplier to real-estate developers and architects with a promise of return on investment based on the electrical cost offset from the generated electricity as well as on applicable local incentives. Non-electrical benefits, such as acoustics, thermal, safety glazing, or UV light blocking, are also listed but often not included as part of the economic consideration. The dual-use and aesthetic aspects of BIPV compared to traditional PV products is another marketing point typically used.

• Manufacturing locations: Locations mentioned in responses include the United States (mainly for assembly), Canada, and China. Companies seem to have interest in having manufacturing in the U.S. as they believe it could allow them to better serve their customers.
• Industry composition: Respondents perceive the BIPV industry in the U.S. to be highly concentrated with only 5-6 major players, most of them providing roofing products. There is also a number of smaller companies or start-ups, some of which are also focusing on other products (windows, glass, façades, curtainwalls, shading elements, carports, etc.). It was mentioned that the number of startup companies in the U.S. is very small in comparison to Europe, where there are over 30 small companies producing and marketing various BIPV products. There are also cases of big roofing, construction, and window companies that begin to acquire and partner with BIPV companies and then integrating them with their existing offerings and channels.
• PV cell technologies: Cell technologies considered for BIPV products are based on silicon or other thin-film technologies, such as amorphous silicon, (a-Si), multicrystalline silicon (mc-Si), polycrystalline silicon (pc-Si), copper indium gallium diselenide (CIGS), cadmium telluride (CdTe), or organic PV (OPV) cells. Monocrystalline silicon (c-Si) is also used in roofing products, like in solar shingles.

Domestic manufacturing opportunities

There is a growing interest in U.S. manufacturing, as evidenced by the number of foreign-owned companies that have opened or are opening plants in the U.S., in addition to U.S.-owned companies that already have manufacturing facilities. The U.S. has established itself as a leader in the manufacturing of rooftop-integrated solar, but other companies could be incentivized to develop manufacturing capabilities that include PV integrated into windows, building façades, and other substrates. In addition, a growing number of innovative BIPV ideas have emerged across smaller companies and startups in the United States. Respondents, however, have noted that currently there are insufficient economic incentives for the development of domestic manufacturing of BIPV products and their respective supply chains in the United States. Tax incentives or grants to support BIPV manufacturers who wish to manufacture in the U.S. and for businesses to procure these products could be a driver for adoption.

In general, it is ideal to manufacture components as close to the market as possible as this reduces costs and speeds up development. The impact to the cost of the final product could be lowered, if the bulk of the raw materials and final assembly are completed domestically or regionally (especially if tariffs are considered). It is customary for the building industry to use local manufacturing and source materials locally, so it would be meaningful for BIPV to follow the same paradigm. Many building materials used in such products are large and heavy enough that makes sense to produce domestically and even regionally throughout the country to reduce transportation costs and logistics, which could account for 10-15% of the cost, in some cases.  Other benefits include manufacturing to order, reduced inventories, on time delivery, quick deployment within the region, quality control, and the ability to better meet various sustainability requirements, while also ensuring supply chain security. It was also identified that cybersecurity of BIPV systems, as it pertains to their electronics and control hardware and software, provides another argument for domestic production.

The roofing industry lends itself to domestic manufacturing, with shipping costs being a major reason. The main challenge to the development of BIPV roofing is sourcing of materials and manufacturing of the non-industry standard-size solar roof tile. There currently exists very limited domestic capability for this need. The specific glass used in PV modules is made only in Asia today and is difficult and costly to source. Manufacturing equipment and facilities do not currently exist for specific solar tile sizes, and this not only increases cost but also lengthens development time. This creates needs and opportunities for developing domestic manufacturing capabilities.

Glass is also produced close to the consumption site due to high transportation costs because of the brittleness and weight of the product. Most windows are manufactured domestically, and insulated glass units (IGUs) follow this same pattern. IGUs are primarily ordered and manufactured regionally/domestically, due to custom specifications, sizes, and lead times. By extension, it is reasonable to conclude that solar windows and other glazing-based PV products are well-suited for domestic manufacturing. Solar windows are unlikely to be exported globally from a single manufacturing site as this could be cost prohibitive. If the integrated photovoltaic function does not involve fabricating semi-transparent solar cells over the entire window area, but rather only employ commercial solar cells (e.g. crystalline Si based) outside the window viewing area and thin-film coating techniques, then it is very feasible to integrate the photovoltaic window manufacturing/assembly alongside the existing window manufacturing facilities. It could also seamlessly integrate into the existing IGU supply chain (glass fabricators can apply PV coatings), which further ensures domestic manufacturing and that the revenue uplift from the value-added BIPV window product is captured domestically as well. Semitransparent OPV power generating windows also have a significant opportunity for domestic manufacturing.

Respondents also identified a few additional, more specialized opportunities for domestic manufacturing, such as cadmium telluride (CdTe) as the semiconductor for PV modules, pre-engineering and assembly of unitized curtainwall panels, manufactured homes incorporating BIPV, and emerging products that rely on advanced manufacturing like quantum dots.

Advantages to regionalization of product manufacturing with end markets

Respondents described a variety of advantages that regional BIPV product manufacturing would provide. Such benefits pertain to:

• Development of a stable domestic supply chain less susceptible to political interruption or other disruptions.
• Reduction of transportation costs.
• Reduction of carbon footprint.
• Improvement in the pace of product development.
• Decrease in product lead times.
• Reduction in inventories.
• Enhancement in customer perception.
• Local sales support and logistics.
• Creation of more local jobs.
• Creation of regional educational opportunities.
• Fostering of innovation.
• Enhancement in community engagement and relations.
• Fulfilling regional architectural preferences that are best addressed with local production.
• Capturing market share by calibrating products and applications to meet specific regional customer environmental characteristics.
• Customization of locally manufactured products to regionally specific building code requirements.

It was also noted that this topic should be more thoroughly addressed within an economic framework that will consider factors like the costs of building and operating regional manufacturing facilities, the cost and availability of raw materials at a distributed scale, projected long-term product demand per region, the ability of a smaller manufacturing facility to adapt to new products and production equipment, and how the latter stacks up against projected savings in transportation and breakage costs.

Product Requirements

Most competitive current BIPV products on the market

Respondents pointed out that a variety of BIPV products exist on the market, but many of them are still not mature enough to be considered truly competitive, pointing out a few reasons for this assessment. Currently there exists a tradeoff between the cost of BIPV and the aesthetics of a system. The cost is a function of the difficulty in sourcing components as well as the complexity of installing the system. Installation complexity of the most aesthetically pleasing systems appears to be high. Products have not been successful so far either because of aesthetics improvements not being substantial to justify the higher cost or because of limited support services provided to the installers to sell and design these products. Products that have excellent aesthetics have often been too expensive for adoption beyond early adopters. In addition, BIPV systems do not seem to payback within an assumed 20-year lifespan of the product, based on energy generation. This is attributed to insufficient solar to electric power conversion efficiency combined with suboptimal solar orientation, and it makes the business case for BIPV weaker. It was also identified that the BIPV market is currently unstable as it is largely supported by a few specialty manufacturers who could abruptly withdraw, causing an entire market segment to collapse.

Nevertheless, respondents identified specific BIPV product categories and commercial products that in their opinion are the current most competitive ones on the market:

• Roofing products: In general, roofing BIPV is more competitive than other types, due to increasing mass production and relatively lower customization levels compared to other product custom-made designs (but not in comparison to regular PV panels). Modified solar panel frames made of metal or a combination of metal and plastic, similar to those on typical large solar panels, can be very competitive. BIPV roofing panels are usually cheap to produce, easy to install and their matching dummy tiles can be cut on site with no need to pre-design them, thereby reducing manufacturing and material costs. PV roofing shingles is another competitive product. They may prove to have the lowest barrier to entry because their main application space (residential rooftop PV) is one that the broader ones that the market already accepts. Furthermore, the expected lifespan of a PV shingle roof and conventional silicon PV modules are well-matched at about 30 years. Many of the integration challenges associated with this type of product (e.g., wiring, module to module interconnects, power optimization, etc.) either have reasonable solutions developed for the retrofit rooftop market or seem to be near-term solvable. A concern that was brought up is that matching of products from different manufacturers may be an impediment to one or more of the products finding a large market, because the dimensions of the BIPV module (e.g. tile or shingle) may not match other manufacturers products on the roof, except for the roof system(s) the BIPV modules were designed around.
• Glass products: BIPV products like solar glass windows or glazing products are also considered quite competitive, though not as mature yet. Products that are based on glazing or structural elements may find greater barriers to adoption due to concerns about longevity and interconnection.
• Conventional solar modules on building façades are currently the most cost-competitive vertical products on a strictly levelized-cost-of-energy (LCOE) basis because they use commodity PV panels for source components. However, such products are not optimally customer-competitive because of the poor architectural “fit” of the modules and their aesthetics, so there is need for modules that better integrate with complex building features. It was pointed out by respondents that the U.S. significantly lags the rest of the world with respect to façade-integrated PV. A recent IEA Task Force 15 Report was referenced, which profiles 25 BIPV projects worldwide, including two in Canada but fails to identify any project in the U.S. While there are challenges with respect to façade-integrated PV (performance, shading, lifespan replacement costs), the dramatic drop in the cost of installed solar, the need to grow dual-use application spaces, the pace of innovation, the pressure to de-carbonize the electricity sector, the increase in severe weather events that adversely impact ground-mounted PV, and the increasing corporate interest in BIPV, suggest the U.S. should be moving faster toward BIPV diversification.

In terms of competitive PV cell technologies used in BIPV products, respondents indicated that monocrystalline Si panels (similar to those commonly used for BAPV) are the most competitive due to cost, efficiency, and reliability. Silicon products have advanced more than other thin-film products for BIPV, but BIPV provides unique opportunities for thin film. Currently, a-Si is the dominant player in the market, because it is a mature, scalable, and relatively low-cost technology. Organic PV (OPV) cell technologies were also mentioned, mainly for windows and other glass applications. Respondents also provided information on this topic in the “Marketing and sourcing of current BIPV products” section of this report under the “State of the industry and key domestic markets” category.

Respondents also identified specific companies and products in the BIPV space that they consider to be the most competitive in the current market. The companies and products referenced were:

• Tesla: Solar-roofing products
• GAF Energy: Roof-integrated products
• Certainteed: Roof-integrated products
• SunTegra: Roof-integrated products
• Luma: Roof-integrated products
• Sunnova: Asphalt shingle with retrofit solar
• Citadel: Asphalt shingle with retrofit solar
• Semper Solaris: Asphalt shingle with retrofit solar
• Solaria: Frameless solar modules
• Lumos Solar: Frameless solar modules
• Onyx: PV glass
• Ubiquitous Energy: PV glass
• Sunpreme: Bifacial double glass
• Sunflare: Lightweight, flexible solar systems
• SolaBlock: Solar masonry units
• GismoPower: MEGA carport

Key product requirements for given markets

Respondents overall identified that a number of factors such as performance, cost, lifetime, reliability, code compliance, supply chain integration, design process integration, aesthetics, and installation process are all important factors in the requirements for the BIPV industry and overall market. Responses were provided considering BIPV products in general and specific product categories.

The following overarching requirements, spanning all BIPV product categories were identified:

• Performance and cost: Performance and cost are key factors for BIPV. Due to the dual function of such products, the performance would be expected to last the lifetime of the building. The reduction in solar panel performance over time (about 25 years), which is not as long as the expected life of the building (over 50 years) causes some concerns with respect to planning on the maintenance or replacement of BIPV products, given that such products are not always easily replaceable. BIPV modules may also not face an optimal direction, therefore achieving reduced energy yields over their entire lifetime. The payback period achieved based on costs and PV performance would play a significant role in wide-scale adoption. However, a different opinion was also presented saying that while high PV performance is one of the most important requirements for conventional PV, the requirements for BIPV might be much lower. The main driver for customers buying traditional solar technologies primarily comes down to LCOE, while the drivers for customers investing in BIPV might be broader and include things like aesthetics, architectural trends, public perception, LEED certifications, as well occupant comfort and occupant demands.  Customers would compare BIPV products to other building product options rather than other energy generating technologies.
• Aesthetics: Aesthetics need to be as attractive and as flexible as the traditional building product options.
• Process integration: Design process integration and installation process are key requirements for BIPV. This includes ability to show value to the end customer in terms of offsetting energy needs or providing aesthetic improvements versus traditional solar products and easy installation of the product by the installation team.
• Reliability, durability, and safety: All three are important requirements for BIPV products and need to match traditional options both in the building and solar industries. Validation of the field performance and reliability of emerging technologies and products is needed, under controlled experimental conditions and across different operating climates that align with the market’s objectives and application spaces. BIPV may often be installed in places where there is insufficient air ventilation to dissipate heat, therefore causing reliability, durability, and safety concerns. The BIPV certification requirements were noted by a number of respondents. The mandate that BIPV products are certified to UL 61730 is considered very challenging since product sizes are typically customized for every project. The current certification protocols are dependent on a tested size of a BIPV panel with a potential size deviation allowance of up to 20%.  All of the standards are currently focused on applications that typically use a common size.  Roof-top or field array PV panel applications use a standard size, and many manufacturers test and offer only a couple of sizes for this standard application. In contrast, many BIPV requirements for a typical building application can have a variety of sizes to meet the design requirements of the project.  UL 61730 testing takes approximately 5 months to obtain results.  Every project could require the making of true to size samples of every size and perform UL 61730 certification testing for every size on a given project.  This is not practical from a timing or cost perspective and presents an insurmountable commercial challenge to BIPV products being successful in architectural applications.
• Supply chain integration: Currently BIPV manufacturers are facing supply chain issues and having difficulties finding reliable suppliers for their parts or having to perform different stages of production at different locations or even countries. Such complex supply and production processes are prone to disruptions. Therefore, proper supply chain integration is a key requirement for successful products.

Identified (ideal) requirements for BIPV roofing products include:

• Uniform aesthetics.
• Installation time comparable to conventional panel and roofing (or re-roofing).
• Reliability, troubleshooting, and maintenance equivalent or superior to conventional panel systems.
• Energy generation performance equivalent or superior to conventional panel systems.
• Comparable cost to new roof with conventional panels.
• Compatible with design and quoting software used by contractors.
• Simple permitting.

Identified requirements for glass products (windows, insulated gas units, glazing) relate to:

• Photovoltaic performance and manufacturing cost (as compared to conventional windows) resulting in acceptable payback period.
• Reliability, durability, and safety similar to traditional windows.
• Functionality of traditional windows, in that the transmittance in the visible spectral range, the uniformity across the entire window area, and the thermal insulation ability should be comparable to existing glass windows.
• Perceptible appearance for their lifetime.
• Aesthetic features including color, visible light transmission (VLT) and level of transparency, uniformity, and haze.
• Ability to achieve various tints to maintain the aesthetics.
• Desire to have dynamic solar control with independent control of near infrared and visible light.
• Proper supply chain integration.
• Ability to be manufactured and sold by existing glass fabricators.

Challenges with building material performance requirements and rating metrics

The majority of the respondents identified standardization and code compliance as the major challenge that BIPV are facing with respect to performance requirements of building materials. More specifically, responses revolved around the following issues:

• Existing requirements and standards: There are currently no singular standards specific to the BIPV industry. Presently, using multiple existing standards is the fastest way to certify a new BIPV product, with multiple levels of certification, inspections, and approvals needed. Most BIPV products span both the construction world and the solar world and are burdened with not only meeting UL and California CEC requirements for safety and productivity, but also ASTM International and other building codes for building-construction acceptability. As an example, there are no relevant standards identified for solar windows and instead solar windows must simultaneously comply to ASTM International standards for traditional windows and traditional PV modules. This creates added costs and uncertainties affecting the commercialization of BIPV products. The development of homogeneous codes and standards commensurate with BIPV products will streamline the process and speed up the ability for new BIPV products to reach safety certifications for use in these markets. Respondents also thought that this could be an opportunity for industry standardization.
• Standardized protocols for quantifying benefits: The lack of standardized protocols for characterizing and presenting the benefits of PV generation, when integrated in the building envelope, makes it challenging to convince consumers that the results are credible to get the benefits of products acknowledged. There is also no means to directly compare the thermal performance of a BIPV product when it is used in place of a standard building product to capture the additional energy benefits of BIPV improving the overall building thermal performance. Tested metrics for energy benefits, both energy saving and generated energy, are needed for use in building design energy modeling software, so that local code requirements can be met. Provisions should be made to consider the combined thermal performance and power offsets of BIPV. In addition, no rating system exists to compare available products in the marketplace or to provide a standard means to communicate performance, so that products could be compared on a level playing field.
• Terminology standardization: The language used by technology and research scientists often does not align with what building designers and builders use.
• Design challenges: Respondents indicated that there is not clear federal regulation on permitted designs for BIPV roof and façade products. There are no clear guidelines for issues like required ventilation shafts, hurricanes, or severe wind resistance requirements for a roof. If they were available, it would be simpler to design compatible products and would be less risky from a business standpoint, as designing solutions for standards that may later change is undesired. The DC electrical system design required by BIPV products is also not standard and could impose challenges to both designers and installers. A suggestion was also provided to potentially use micro-inverters with all BIPV components.

Alignment of performance requirements with BIPV applications

Respondents indicated that the alignment between performance requirement and BIPV applications might depend on the product and the product design in a particular category as well as the specific requirements for the category. However, there are some common themes that emerged from the responses.

• Certification and code requirements: It was clearly noted that the certification requirements are very poorly aligned with BIPV applications as the codes are more directed to passive building standards, creating excessive cost and complexity for satisfying such requirements. For BIPV panels, custom sizes are needed to satisfy architectural requirements, and this creates complexity with the certification processes. Performance requirements are not specifically defined for solar windows; rather, they are borrowed from traditional PV systems and traditional windows, creating misalignment and additional burdens. Façade-based solar products must be tested at the same tilt requirements as conventional solar, even though such products will not be installed on a tilted basis, thus skewing mandated rated power statements. Wall BIPV systems are also mandated to adhere to the same rapid disconnect requirements as roof-mounted modules, even though such products will not expose firefighters or others to the similar hazards. BIPV codes around electrical grounding and fire testing need to be reviewed to ensure requirements are not unrealistic as this can slow down the pace of innovation and also lead to increased costs that will slow adoption. It was also mentioned that aside from minimal energy code compliance, architects are tied to LEED as a “quality” measurement of performance; however, BIPV applications get only limited points in LEED calculations for innovation.
• Cost and benefit requirements: Considering cost (or cost per watt) as a requirement, BIPV is often compared with traditional monocrystalline silicon projects or silicon costs, and this sets the tone for how the market will be priced. This affects whether BIPV projects can win out against traditional applications, even if those applications are incapable of providing the same range of benefits that BIPV could. This area needs to be further investigated within the broader context of services and benefits delivered by BIPV as well as the long-term economics, which include the benefits of substituting building materials that also generate electricity for traditional building materials.
• Cybersecurity requirements: Though broader than specifically BIPV, it was noted that missing from the requirements is cybersecurity designs built-in and maintenance of security as well as updates to firmware or software based on new efficiencies or optimizations extending the life of the installed products supporting BIPV. Ongoing successful products include flaw mitigation processes, which become more important during the longer lifecycles of the product.

Key Barriers and Perceptions

Factors limiting uptake of BIPV technologies

Respondents identified a number of factors and perceptions that are weakening the value proposition for BIPV and are thus limiting the uptake and faster deployment of such technologies. These factors are grouped in the following areas and summarized below:

• Costs/Price was the main factor mentioned by a number of respondents. BIPV systems are currently perceived as a more expensive solution compared to more traditional rooftop PV solar systems. Several reasons have been identified for the higher costs:
  • certification and product complexity issues;
  • non-standard size PV modules do not yet have the economies of scale associated with conventional panel systems and hence the costs remain high;
  • development of aesthetically attractive systems is difficult to do in a cost-effective way.
  • early-stage development and lack of production scale, which creates a cycle of high price -> low demand -> no investment in manufacturing -> high price;
  • new technologies and supply chains have not caught up to the scale and deployment of traditionally installed solar panels.

Costs are a significant barrier, particularly in the lack of tax credits or other incentives.  The resulting high cost and long payback period make it challenging to cost-justify BIPV into new or existing buildings and structures.

• Technical complexity barriers revolving mainly around the electrical design of the BIPV system. Currently many electrical engineering firms do not design solar systems, so if there is not already BAPV in the building design, the inclusion of BIPV will add an additional solar contractor who must do the design and installation, which adds to the cost and complexity of the project. BIPV systems also face building and electrical integration challenges, such as DC electrical system design or non-optimal cabling and inverter designs and may require extra skills and expertise to do the integration. They are considered customized installation jobs and a lack of NEC rules to govern such electrical installations was also identified. This increases costs and purchaser fatigue.
• Expertise shortage is another important factor. This ranges from the lack of professional expertise among architects and engineers to the lack of qualified BIPV manufacturers and installers. End users and architects need to recognize BIPV systems as suitable options for building skins and view BIPV products as building elements. BIPV implementations are challenging because existing installers have been trained and are experienced in the technologies with mass adoption, like BAPV systems with silicon solar panels with standard mounting mechanisms, but not with more novel BIPV products. There is also lack of trained staff necessary to maintain systems after the initial installation.  Hands on training and experience working on actual systems in the field could help overcome this challenge.
• The issue of certification is perceived as a significant barrier, since the BIPV products are customized and thus require new certifications, if they do not fall within the size tolerances of previously certified products. Every new change, improvement, or evolution requires new certification. The current certification process was developed for standard sizes and a unique mounting system. The growing possibilities of BIPV applications require the needs of a certification and testing system that is not based on a specific size. In order to meet the current electrical building code, every size would need to be tested and certified before it could be legally installed.  Therefore, the current certification process is not practical for a building design or application that does not use a standard size that has been previously tested and certified.  This severely limits the freedom for architects and design professionals to utilize their skills for a project’s needs and limits the use of BIPV products in architectural applications.  A certification process needs to be developed that allows for the full testing and certification of various size BIPV products for use in building envelope applications. In addition, BIPV products must currently conform both building codes and electrical system codes because of the dual role. Simplification of codes and standards and/or establishing codes and standards that are specifically targeted for BIPV products would be significant factor towards alleviation of these barriers.
• Permitting challenges due to imposed and inconsistent standards that were designed for conventional solar (variations and inconsistencies from multiple revisions of standards, regions and interpretation of inspectors). There appears to be a lack of clarity around performance and durability assessment and requirements for stakeholders.
• BIPV performance is identified as another important barrier. Poor performance could relate to lower efficiencies and reduced energy yields because of limited optimization due to building orientation. This could result in higher LCOE and longer payback periods making it difficult to convince end users to pay higher upfront costs of BIPV systems. Installing only based on energy generation potential might not make economic sense especially in regions or buildings with low solar resources. Many successfully implemented BIPV projects, especially vertical projects, have relied on entities with exceptional interest to display onsite renewable energy generation and to showcase their commitment to sustainable design to the public, understanding that the investment may not pay back.
• Aesthetic considerations are an important factor of BIPV, especially for residential applications. The poor aesthetics of many past or currently available offerings significantly limit market interest from both architects and building owners, especially for vertical applications, and the performance/energy generation has not been enough to overcome the poor aesthetics and garner interest. Some respondents indicated that the aesthetic variety of BIPV products is now large enough to enable the use of BIPV in any construction project, but construction companies and architects are not familiar with the entire range of options, and, therefore, do not usually promote BIPV in their projects.
• Lack of financial incentives specific to BIPV, such as dedicated subsidies for BIPV, better financing options such as mortgages that include BIPV roofs or special loans in favorable terms, or innovative business models for new builds that include BIPV and can act as distributed generators or virtual power plants. Being an early-stage technology, BIPV faces lack of confidence from funding and financing organizations that tend to be risk averse and slow to fund such product development and deployment. BIPV uptake requires subsidizing, either from government sources, utilities, other groups to be financially sustainable and be successful.
• Another limiting factor is technology awareness both in the building and solar industry. Many potential end users (both in the residential and the commercial segments) as well as building designers and architects may not be aware of the possibility to install BIPV, and therefore do not even consider it as part of the building design process. Similarly, a respondent suggested that the solar industry’s focus on conventional, rectangular, rack-mounted modules could lead to thinking that PV installations will always only be rooftop or distributed PV arrays. The public knowledge of the advantages of installing BIPV in buildings, both commercial and residential, is also rather limited.
• Disconnects between necessary partnering groups is another identified factor. This issue of BIPV is inherently inter- and trans-disciplinary, encompassing the domains of architecture, diverse traditional branches of engineering, materials science, manufacturing science, decision engineering, and systems engineering. However, it has been approached in a siloed rather than in a wholistic way.
• Complicated processes that negatively affect the customer experience is perceived as another identified barrier. A building owner trying to calculate savings from BIPV installations and then advancing a project requires overcoming many hassles navigating through technical and regulatory processes and collaborating with a number of different parties.
• The limited availability of products and product reliability issues is another important barrier. Some products, like solar windows, are still regarded as unproven to be considered reliable. They may also not provide credible and reliable warranties. The lack of a clear path from the laboratory into manufactured products as well as of standard and regulatory reliability testing procedures presents a barrier to adoption of consumer-acceptable products. Early adopters, government incentives, and exposure to products can expedite the process of consumer acceptance and adoption.
• Operation and maintenance issues are also viewed as an adoption barrier. Given the dual use of BIPV products, it is more challenging to replace a failed component integrated into the building and also serving as a structural element. Regular monitoring procedures are crucial in order to identify any component failure or degradation and maximize performance.
• The supply chain reliability of BIPV was also identified as a perceived barrier. Currently such products may not be sourced via the well-established building material chains. It would be critical that BIPV products integrate with and utilize existing supply chain sales relationships and trusted brand names to lower perceived risk and improve customer perception.
• Lack of educational resources, training material, and knowledge base. Information on BIPV is still lacking in the public. Although this is improving, it has been slow on the uptake.
• Lack of demonstration projects at scale showing the technical aspects as well as the potential economic and other benefits from BIPV installations is a barrier.  Such demonstration projects would provide valuable information to the product developers, the architects and building designers, the builders, the installers and other contractors, the end users, owners, and operators, as well as the investment community, which is currently not very receptive to BIPV.  The low acceptance rate can be turned around for individual BIPV products if they can be demonstrated to be feasible, cost effective, and safe. BIPV products have a double hurdle as they have to be proven both as base building products and as solar products. Such demonstration can be an invaluable source of data and neutral, trusted analysis that demonstrates the values of these BIPV products relative to other materials typically used in the construction process and can serve as basis for further development and deployments by industry-trusted champions willing to take the next step.
• Lack of sales, estimation, and other decision support tools that allow stakeholders to consider whether BIPV can cost-effectively meet their needs as compared to traditional racked and mounted PV products. Existing tools do not enable integrated solar PV models.
• Existing silos in operating and business models of various affected groups and slow development of coordination/cooperation between multiple stakeholders (both in engineering and trades) is another factor hindering uptake of BIPV. Scoping a solar system into a building might come late in the design process, when decisions about the building elements have been finalized. Preliminary engineering work would be a good way addressing such issues that limit design of new systems. Installers also are not incentivized to integrate and typically work under siloed business models. Trade and union disputes over project scope may also arise with technologies that involved multiple trades that might have traditionally worked separately.
• Lack of fundamental research available on BIPV technologies. The U.S. has not prioritized BIPV to the same extent as Europe and Asia, so there has been relatively little R&D in this space.

Factors limiting collaboration/partnering between solar and building industries

The information received under this question was rather limited. Respondents identified a few factors that are limiting collaboration and partnerships on BIPV technologies between members of the solar and the building industries. These factors are grouped in the following areas and summarized below:

• The architectural, building construction, and solar industries are not integrated into a cohesive group.
• Ownership and protection of IP both from the PV side and the building industries.
• Competitive environment with limited original technologies competing for the same early adopters. This leads to a more segregated, individualized approach rather than expanding the industry knowledge by sharing breakthroughs and data from successful applications.
• The building and solar industries have historically been separated with each industry focusing on its own problems and objectives. Cross-functional training across the industries has not been done and partnerships between major companies in these two industries has not been developed so far. There is no financial incentive to building industry/owners to spec solar during the development phase. In addition, most of the larger solar companies that produce PV modules are focused on the larger commercial solar farm projects and have not focused on this segment. BIPV products can fall into an unfortunate gap that the PV industry considers them a building technology and building industry considers them a PV application.
• Architectural firms and schools of design have not yet fully embraced BIPV, in part because it seems largely like a black box.
• The lack of a trusted clearinghouse/database/national resource that would
  • provide information, share data and best practices;
  • drive R&D; and
  • function as a catalyst for innovation by bringing stakeholders together to collectively drive the deployment of BIPV.
• The cost/risk to try something new with few prior examples of success might be too large. Home builders are unfamiliar with the long-term viability of BIPV. High cost and lack of awareness are key barriers between technology companies and the building industry.
• Limited desire within each industry to learn something new. There is little incentive to expand knowledge, if the existing market they operate in is considered large and they can find efficiencies in the economies of scale in deploying existing products.
• Limited learning opportunities. Adoption of BIPV is currently limited and sparse, reducing individual installer companies to learn on their own on new and innovative solar products and technologies.
• Limited opportunities to work across both industries, especially for installers. Sales & lead generation companies do business with either building construction (e.g. roofing) or solar, but they do not do both.
• Disconnect between BIPV product development and product installers. BIPV products are not necessarily being developed for building contractors and with input from building contractors and installers, therefore often making it more difficult for them to use.

The way to increase the collaboration/partnering on BIPV technology needs to educate the solar and building industries about BIPV products and then provide incentives for their use through programs or building code accommodations. Once customers understand the value of BIPV, a market will be created, and collaboration will follow. Academic research can define the benefits of BIPV to the solar and building industries. By providing local governments grants or additional funding, the early projects can be launched and highlighted to encourage future collaboration.

RDD&C Needs and Opportunities

Limitations in current modeling tools for BIPV systems

Some work has already been performed in modeling of the production cost, installed system cost, and energy yields for BIPV technologies and systems in conjunction with partners and experts across the supply chain, including NREL, and the DOE. The most important next step to improve these models is to demonstrate and test them in real world production. This would also result in obtaining realistic field data also addressing the issue of unavailability of such data, which was identified as an important limiting factor of the current BIPV modeling. Nevertheless, it appears that in practice there are still information gaps, issues to be addressed, and improvements to be made and respondents have identified the following limitations in regard to the current modeling of the production cost, installed system cost, and energy yields for BIPV technologies and systems:

• Production cost modeling: The production cost modeling was identified to be difficult for BIPV as the cost is a function of the system components and the manufacturing. Limited information was provided, and some respondents mentioned that they are unaware of any comprehensive modeling tools for specific products or components. It was suggested that some models may exist but may be proprietary and not in the public domain. It was also proposed that projecting scale up costs of product production could be possible once some initial data from small production levels are obtained.
• Installed system cost modeling: Limited information was provided with respect on installed system costs. Some responses suggested that the installed system cost follows from production cost to a degree. However, understanding what factors can affect installed system cost is probably complex, as it depends on interactions between manufacturers, builders, and owners as well as specific technical components of a project. In addition to upfront costs, future replacement costs might also need to be considered. Some tools exist for cost estimation, but they are separate for solar installation estimates and for building construction estimates. No unified tools for BIPV projects seem to exist. The limited number of installed systems and publicly available data was also mentioned as a limitation for creating and validating cost models for BIPV systems. Respondents thought that cost information is hard to come by and a cost database for products, inverters, and other BOS costs would be very useful.
• Energy yield modeling: Most of the information provided by respondents pertains to modeling of energy production from BIPV systems as well as quantification of overall energy benefits achieved using BIPV. Some respondents believe that energy yields and energy efficiency benefits of BIPV are generally known and are the easiest to evaluate by using existing models and programs to simulate such systems and perform techno-economic analysis. However, the majority of respondents described several limitations that exist claiming that accurate simulation set up for BIPV energy yields is not available in most commercially available software. Such limitation include:
  • Accounting for the impacts of shade and indirect sunlight due to adjacent buildings and objects, especially in urban areas.
  • Accounting for the impact of temperature on energy production, which becomes more challenging for an integrated product.
  • Accounting for reflection losses impacted by aesthetic elements.
  • Considering 90° tilt for vertical BIPV products, like façades.

Most of the current PV modeling software is designed for modeling of ground-mounted or rooftop solar systems applied to buildings. Such PV performance models do not accurately capture the unique aspects of the BIPV package and, therefore, do not give accurate information for performance or cost when used in conjunction with BIPV applications. These limitations could be overcome to some extent by adding new models within existing production modeling software, instead of developing custom production software for BIPV. However, it was also pointed out that gaps in current modeling tools for BIPV are also largely due to the fact that most BIPV tools are either standalone software or part of distribution grid simulation software. It would be more effective for BIPV models to be an integrated part of building simulation software to leverage the existing capacity and resources in building energy modeling tools and study the impact and control of BIPV together with other building energy assets.

Taking it even further, more complex, physics-based models, which run thermodynamic simulations to estimate the energy consumption and capture the physics-based heat transfer relationship between heating, cooling, temperature and energy consumption and generation could be used, especially for more advanced research studies. But such models are computationally expensive and require very detailed input data, which might typically be unavailable for most buildings.

Overall, it appears that there is need for both high- and low-fidelity simulation models. High-fidelity simulations, coupled with field work or experiments, could support research purposes, and should be used to validate the coarser tools developed for engineers/architects. Ideally, an integrated modeling system would be developed that spans length scales and unites PV cell/module properties up to building performance and large-scale deployments with many buildings or cities.

Limitations in current evaluations of BIPV systems

Respondents identified several limitations that exist in current evaluations of BIPV systems compared to traditional building applications for energy performance, electricity generation, and carbon emission reduction. Such limitations are grouped in the following categories:

• Models and tools: Though some respondents indicated that current tools are sufficient for BIPV analysis, most responses indicated that there is lack of quantifiable models to evaluate the cost benefits of deploying BIPV, as accurate simulation set up for BIPV energy yields is not available in most commercially available software. Traditional building applications for energy performance, electricity generation, and carbon emission reductions are generally well understood including product options in the marketplace, however, BIPV and ancillary-structure PV systems are less well-known. Evaluation of BIPV energy performance and electricity generation require modeling that reflects the nature of the solar technology being applied to the built environment. Factors such as change in insulation, heat gain, light levels that a BIPV might change need to be taken into account for these calculations. Some BIPV technology also performs differently than traditional solar cells under low angle light or diffuse light from cloudy skies. Finally, a point was made that new modeling and analysis tools for BIPV should be able to inherently account for uncertain quantities to more effectively allow stakeholders to confidently design, build, and operate robust systems gaining broader acceptance.
• Comprehensive assessment of benefits: The solar industry mostly focuses on LCOE as the arbiter of performance modeling for PV, penalizing BIPV products that provide energy production for a building while also displacing building construction materials and labor. The major limitation is the lack of modeling tools and metrics that include all costs and benefits of diverse BIPV technologies and could develop a successor to LCOE. To effectively compare BIPV products with more traditional building-applied PV systems, like rooftop PV, it requires a broader assessment of the benefits BIPV provides in addition to electricity generation. This includes aesthetic benefits, the performance of the BIPV products as structural building elements, and thermal performance. However, efficient building-BIPV thermal models do not exist. Unlike the traditional thermal model of an HVAC-integrated building, it is difficult to find high-fidelity and computationally efficient models describing the complicated coupling between BIPV and building thermal dynamics. The building envelope modeling for air transfer does not account for the heat load that can be generated by PV devices, inverters, and storage devices that could be part of a BIPV system. More understanding of the impact (positive or negative) to the heat load produced by these devices within the building envelope and more research into how much energy is produced versus the increase in thermal load to the building is needed. In addition, it was noted that thermal performance analyses and power generation calculations are typically approached by different people as different studies. There is a need to bridge modeling systems, tools, and methodologies used by the building and solar industries and create a more unified approach. Architects could play a role in integrate the criteria during modeling, though a more dedicated role within a project team might need to be created at the early project stages.
• Availability of data: Performance data for typical system applications are needed to support current evaluation, but energy performance data for BIPV systems is scarce and often largely proprietary; such data could be collected across multiple installations and technologies in both the residential and commercial sectors but would require a concerted effort at the national level. That effort might be better led by a trusted organization with the expertise and capabilities to collect and analyze the data, while also ensuring anonymity. Standards for measuring such product data also need to be developed. Some manufactures can supply rough approximations of performance, but these can vary widely between manufacturers.  There are no rules to ensure performance values are generated and presented in the same way to ensure fair comparison between products.  Effective, fair, accurate, and credible rating programs need to be developed to be able to rate and compare the thermal and optical properties of BIPV products used in building envelope applications. Development of a central database of existing PV products would also facilitate planners to identify and evaluate options and compare opportunities.

Another key limitation with respect to data is lack of standardized data sources of city-scale building data that are needed for evaluating BIPV systems. Those data sources should include various levels of building characteristic such as basic properties (e.g. use type, year built, change history, building permits, etc.), geometry (e.g. footprint, height, number of stories, total area, etc.), location and climate, energy systems (e.g. HVAC, lighting, internal loads, service hot water etc.), building envelope information (e.g. construction type, insulation for walls and roofs, window properties, etc.), and actual energy consumption data and utility bills. Besides the data for individual buildings, several other datasets are required for BIPV system evaluation, including weather data, local building energy codes and standards, utility rates, and cost data of building technologies.

• Consideration for O&M costs: O&M plays an important role in determining the cost-effectiveness of renewable technologies in general and this becomes a limitation for BIPV. There is lack of O&M service-related data for BIPV as well as lack of software to evaluate initial costs and maintenance requirements over time for different BIPV systems.
• Educational opportunities: There appear to be very limited educational and training opportunities for designers for evaluating best fits and for other affected and interested stakeholders in the industry.

Additional research, development, and demonstration needs

Respondents have noted that very little research or development has been performed on BIPV technologies in the U.S. which could address the numerous challenges identified. Therefore, several areas for research, development, and demonstration have been identified:

• Need for testing facilities and demonstration projects: Most of responses clearly presented the need for testing facilities and demonstration projects. Although, multiple test beds exist for demonstration and validation of performance and operation of traditional PV and CSP systems, no comparable facilities exist for testing of new BIPV modules or BOS components. Field testing of BIPV technologies to measure performance, degradation rates, and ensure long-term reliability under different operating conditions is an essential step for further development and deployment. Full size demonstration projects would be used for showcasing aesthetics and installation options and processes, gathering and distributing field data and performance metrics for modeling, and making diagrams available for pre-engineering of components and installations. Accurate data allows extrapolation for energy savings and energy production and would be invaluable when evaluating building energy performance. Demonstrations could also be used to aid in certification of BIPV products and also serve an educational role. Development and demonstration should also target demonstration of production processes for BIPV products.
• Efficiency and energy yield improvements: Continued improvement in performance is needed for BIPV products and R&D efforts could help in this direction. This includes improvements in efficiency and costs of various PV cell technologies, focusing on novel material solutions that that could be promising for BIPV applications, such as various thin-film technologies, OPVs, and multi-functional PV (MFPV) for bi-facial energy collection/generation (inside and outside). Development of low-cost, high-efficiency cell technologies are essential for BIPVs due to the inherently sub-optimal orientation and finite areas available. Reduced loss of efficiency over time and adequate durability at higher temperatures are two other important factors. Improvements of the overall power conversion efficiency, beyond the PV cells, should be considered. In addition to efficiency, research needs also exist in improving shade tolerance as well as diffuse and low-light performance of BIPV to improve their energy yields.
• BIPV modeling: Availability of accurate and practical models of BIPV systems and tools for simulation and analysis is a great challenge identified by respondents and R&D efforts would be valuable in addressing this challenge. Such models should account for suboptimal solar orientations, shading, indirect sunlight, reflected light, thermal performance, etc. as extensively described in the previous two sections of the report. Development of new tools or updating existing performance software and combining building performance analysis with electricity generation would be a huge asset in fully capturing the energy benefit in adding BIPV to a building and assisting the uptake of such technologies.
• Thermal management: Development of control strategies of operating temperature of BIPV is important to maintain solar cells efficiency levels, improve durability and prolong the solar cells life, and help reduce cooling loads on buildings and/or reduce urban heat island effects. Method and best practices could be developed from designing the mounting so that air can circulate underneath to designing the module to reject sub-bandgap light to ensuring good emission of thermal IR to help cool the panels.
• Improved BIPV product designs: Design improvements revolve around improving product aesthetics, module optimization to improve power output, durability, and costs, as well as functionality improvements considering ease of installation and serviceability at the individual module level.
  • One of the significant advantages of BIPV is the improved aesthetics compared to conventional PV panels, which are only ok for rooftop installations, but not aesthetically appealing for façades, walls, or windows. Specific new BIPV materials and technologies will need to be developed to provide the necessary aesthetics, especially rich colors and uniform looks, (even at the expense of some loss of efficiency) to create market appeal and enable a broader adoption of PV products in or around buildings.
  • New BIPV systems must be designed and be manufactured with a flexible form factor. Consideration must be taken for issues like access to electronics and easy replacement upon failure or other building issues. Monitoring systems could be developed, and several factors could be optimized, like water ingress and heat transfer properties. There is significant research opportunity for the development of factory-integrated “plug-and-play” components that leverage next-generation solar technology and consider the wiring and required electronics. Module-level power electronics seem more suitable for many BIPV applications, due to the uneven radiation and shading. Such products would make the site installation look more like an assembly process simplifying installation and reducing the need for workforce education. Streamlined installation and training addresses soft costs that will yield a reduction in system cost and increased deployment. Standardization and interoperability of similar products across vendors would be an important topic for such systems.
• Installation and maintenance processes: R&D activities could help improve several aspects of BIPV installation and maintenance. These include:
  • Effective and safe electrical integration of BIPV into the building could be pivotal to reducing costs, improving overall system efficiencies, optimizing wiring management both for installation and maintenance, and minimizing the impacts of electrical faults and other contingencies. The system design could consider DC distribution networks or BIPV-friendly module-level power electronics, which might be more suitable for many BIPV applications, due to the uneven radiation and shading.
  • Safety and damage avoidance procedures could be developed to minimize injury risks for installers and product damage. The fact that BIPV also serve a structural role in the building might require modified installation processes, more aligned with building construction processes, compared to traditional rooftop PV systems.
• Systems integration: BIPV deeply couples with the energy consumption profile and thermal dynamics of a building. This integration could potentially further expand to energy storage systems (ESSs) and thermal energy storage (TES). A hybrid approach that integrates solar (both electric and thermal) with other building systems could maximize the potential of solar technologies. Hybrid solutions that incorporate both solar thermal and solar electric integrated with HVAC systems have the potential to completely remove the HVAC load of a building from the grid. Research and improvements on building energy management systems that can provide coordinated control of all the above systems will also be needed.
• Wildlife impacts: A trend in commercial construction has been the adoption of codes for bird-friendly design elements in the façade. There is no known work investigating the impact of BIPV in the area of bird-friendly rating and the need exists for development of module designs that ensure BIPV will be able to comply with these new codes.
• Cybersecurity: Additional research with BIPV providers as partners in cybersecurity includes baselines of systems; creation of more automated cybersecurity models that include a ranking of priority of cyber issues; software bill of materials for supply chain documentation; creating sustainable cyber mitigations and extending product install base.

Challenges to demonstrating and validating the durability and performance of BIPV systems

Respondent input was limited but overall, the following issues were identified:

• Performance metrics: BIPV performance metrics need to be calibrated for BIPV systems and not just borrowed from conventional solar. The value to the building needs to be part of the demonstration and validation. One of the key challenges in demonstrating performance is not just assessing the energy generation potential, but the thermal benefit from preventing solar heat gain, insulating, etc. New metrics for BIPV should be developed beyond metrics used for PV to take in far more value-added attributes than LCOE.
• Performance testing: BIPV do not have dedicated performance testing standards. Durability testing for BIPV not only demonstrates long-term power generation, but that the products can maintain structural or other building performance requirements over the expected product lifetime.  While IEC 61215 and UL61730 are the only common standardized certification tests in the solar industry, those tests probe only certain failure mechanisms and by themselves are poor for establishing bankability and/or long-term stability. Current U.S. standards (e.g. UL 7103 for BIPV) are based on safety, and do not directly address performance durability.
• Lack of tools: There is lack of simulation programs that match results of real-life case studies, which are needed to show building owners that an investment in BIPV is worth the total burdened cost of installation/maintenance of products. Additionally, there is lack of tools to quantify damage tolerance in performance and durability.
• Regulatory issues: There is an increased number of qualification and type tests needed for a mixed-use product (e.g., building code and safety tests plus PV module tests) to achieve certification.  Unified, standardized and accepted tests and certifications for BIPV windows would be greatly beneficial.
• Variability in usage conditions: The requirements and processes for demonstrating and validating performance and durability would vary significantly for various BIPV products. Building platforms for demonstrating, characterizing, and validating, BIPV technologies, which range from fairly well-established roof-integrated solar shingles to colored glass, and multi-directional, multi-angled building façades is quite challenging. Existence of a trusted “one-stop shop for BIPV” would be very valuable to startups trying to engage labs in valuing their technologies. This could be a task that DOE and the National Labs could consider.
• Economic issues: High manufacturing costs can make it difficult for new products to get beyond the prototype stage. This may affect the validation efforts if not enough pieces can be reasonably made without larger investments. However, uptake of the BIPV industry requires moving rapidly from laboratory-scale demonstrations to large-scale demonstrations in realistic outdoor and building environments. This will require a considerable increase in government and private sector investment, as well as participation from neutral third parties for “pressure testing” the technologies in a scaled, operating context. Feedback to the researchers and other stakeholders is urgently required to sustain their advances.
• Logistical issues: The R&D community and the end-user community are relatively silo-ed, with building designers, developers and owners having an ad hoc relationship, at best, with researchers. Outreach to establish trusted channels of communication and create collaborative platforms is essential.

Permitting-related barriers

Regulatory compliance was one of the key barriers that respondents have identified for BIPV deployment pertaining to both the product certification as well as permitting requirements. This topic was also covered by responses to the third category about key barriers and perceptions. The following issue were identified by the respondents:

BIPV technologies requiring both construction and solar technologies code compliance and, therefore, face greater barriers than solar alone. The multiple testing protocols needed for a base product and potential repeated testing for customized products add time and expense in getting the required certifications. Some of these processes may require assistance form third-party laboratories which can further increase the costs. The burden of meeting these requirements impedes innovation. In addition, solar certification standards (e.g. UL and IEC) are developed for rack-mounted conventional PV technologies making it difficult for BIPV products to comply. Similarly, the certification and testing process of building products developed for traditional passive building products and is not designed for BIPV. There is, therefore, no clear path for a BIPV company to adhere to guidelines while being innovative. BIPV deserves to be considered as an independent category with dedicated standards that trim away aspects not relevant but burdensome to the technology developers.

Regarding permitting barriers, it appears that local regulations have not caught up with BIPV technologies and there are no codes or standards specifically addressing BIPV. Given BIPV products are rapidly evolving, there is a mismatch with the fire, electrical, and structural codes enforced, the newest model codes, and the newest BIPV products. NEC code requiring rapid shutdown, voltage limitations of 80V, and fire set-back requirement were mentioned as relevant examples. These challenges continue to the inspection phase of the permitting process, where the inspector enforces the code implemented at the local government. BIPV may face challenges if the inspection process and sequence is not explicitly understood by jurisdictions and builders alike. Variations and inconsistencies from multiple revisions of codes and interpretation of inspectors are also frequent. This reality results in delays and inefficiencies that influence BIPV product installation processes, timelines, and costs.

Another impediment referenced by respondents are utilities placing maximum PV limitations per account, which limit a portion of the value proposition needed to advance adoption.

Stakeholder Engagement Processes

Areas of information and knowledge gaps in the industry

Respondents indicated that there are significant information and knowledge gaps in the industry that mainly relate to either limited awareness of the BIPV technologies and their full potential by specific groups of impacted stakeholders or the fact the BIPV industry sector is currently siloed, and each group of stakeholders has limited visibility and understanding of the state and activities of other groups. More opportunities for open discussion between silos are greatly needed and taking the discussion to other professional forums would be most useful. End-users or impacted stakeholders also operate under the mindset of segregating the structural aspects from the energy generation aspects of buildings, viewing them as two separate types of activities and not considering more comprehensive and holistic approaches. Respondents also identified specific groups of stakeholders, where knowledge and information gaps appear to be more prominent. The key groups identified include (i) architects/designers, (ii) builders/contractors, (iii) asset owners/operators, and (iv) regulators.

Specific lack of knowledge and informational gaps have been identified in each of the following areas:

• Understanding of the dual use and, therefore, dual value that BIPV products provide. Often end-users mistakenly compare the cost of BIPV products to the cost of more traditional solar systems only, making it hard for BIPV products to compete.
• Awareness of the differentiation in BIPV products compared to traditional building materials and rooftop solar products by the current certification bodies and clarity in the requirements of certifications for BIPV products.
• Clarity of BIPV market needs, primarily due to “siloed” approaches to market sectors. Market demand needs for BIPV need to be identified and documented for current and future requirements. The existing power delivery infrastructure needs to be documented to confirm how power needs can be met; subsequently, BIPV’s role in this new ecosystem view can be properly targeted.
• Alignment between BIPV providers, the existing business ecosystem that serves the building/construction industry, and the end customers. BIPV providers are often separate trades from traditional building trades, like roofing, glass, and building design and there is a business model knowledge gap between all these groups. Such groups are aware of one another, but happy in their own business model and not interested in the opportunities of combining them and are lacking the knowledge of operating as a combined business model. Identifying pathways to more effectively incorporate BIPV into existing business models of impacted trades will require additional collaboration among the trades. Building relationships among these trades is essential for BIPV products to gain market share and be presented to consumers. Another challenge is that these impacted industries are often diffuse, with many firms competing for market share and very few comparatively, dominant players. Finally, homeowners would much rather work with a single contractor than having to coordinate among multiple different ones.
• Involvement of multiple stakeholders in each phase of a product design. Architects and other end-users rarely engage with other experts (like materials scientists, chemists, manufacturers, power engineers) to define the performance parameters and needs. In the limited examples where this has occurred, the result has improved environmentally and economically, and has stronger potential for market adoption and societal impact.
• Understanding of the power generation potential of BIPV products at the very large scale.
• Knowledge and understanding of soft benefits, like occupant alertness and wellness in the workplace, and hard benefits, like increase in value and rent potential, when a building contains advanced technologies like BIPV.
• Access to objective information regarding system assessment by homeowners or building owners.
• Excessive focus on energy cost payback from funding agencies. There is an order of magnitude gap between what the funding agencies had concluded and recommended for the roadmap vs. what is happening in reality.
• Benefit calculation and evaluation mechanisms that could provide an acceptable basis for project comparison, especially for funding evaluations of R&D projects. The LCOE is the primary concern in most evaluations, but other cost benefits and savings, like energy cost avoidance, are not considered heavily.
• Specialized tools for BIPV modeling, costing, and bidding. Tools for building or solar modeling and bidding do either product quite well, but integrated projects do not have any tools that manage both aspects well.  The same is true for construction and project management tools.
• Understanding cost structures and markups in BIPV products (especially in the glazing and fenestration industries) to better identify where the cost savings exist or are being lost.
• Manufacturing supply chain requirements. Lack of local manufacturing and development using domestic materials for self-reliance was identified as one of the industry gaps.
• Education on BIPV including product availability, cost estimating, and performance modeling for designers and builders.
• Understanding of optimalelectrical integration details of BIPV products along with other systems like EV chargers and battery storage. BIPV could be used for direct current (DC) applications such as powering LED lighting, computers, and other appliances. This could involve DC power distribution and development of additional components and equipment, such as combined DC/AC electrical panels that divide such loads, can split critical and non-critical loads, and can include relays or other control functions instead of trying to retrofit into an existing AC wired home.
• Information and experience troubleshooting and maintaining installations by asset owners or operators.  These skillsets are needed to minimize O&M costs and maximize system uptime.
• Understanding of cybersecurity concerns and risk mitigating strategies and future look into emerging cybersecurity concepts to the BIPV community.
• Identification of the optimal technological approaches for meeting BIPV needs and the most critical technical hurdles yet to be overcome.
• Identification of ways to move the best technologies from the research phase to commercialization and of the right groups of manufacturers to move the technology forward to the consumer.
• Identification of the major manufacturing and cost challenges to be met and the size of the investment needed to scale various BIPV technologies.
• Discovery of the initial consumers and of ways of engagement with the customer base.
• Ways to inform the public of BIPV potential and benefits.
• Workforce training and preparing.
• Government regulations and support needed to encourage technology adoption.
• Development of product definitions and guiding standards within the industry.
• Design resources and guides for realistic BIPV systems would be incredibly helpful. Current designs are often “too ideal” and there is a fair bit of reconciliation required between design and implementation, which may end up reducing the system energy output and increase implementation costs.
• Wholistic understanding of how building energy efficiency and generation affect the building systems and overall performance is important for new construction.
• Decision comparison points for home and commercial building owners for various products. When combining energy efficiency and energy production, the payback analysis is not typical.  The financial analysis makes more sense when looking at total cost of all components involved minus energy savings, generation, and incentives. Product lifetime and life cycle costs of BIPV versus other traditional PV installation might be different and should be evaluated when making a purchase decision. The increased understanding of the life cycle and performance of the building materials where energy-production technology is applied can transform applicability, end-use, and multi-functionality.

Underrepresented stakeholder groups

Respondents have identified a variety of stakeholder groups that are considered underrepresented in current conversation related to BIPV technologies. Increasing active engagement from such groups could improve the exchange of information and alleviate some of the identified challenges of BIPV adoption. Such underrepresented stakeholder groups include:

• The architectural community, including professional associations, private firms and schools of architecture and design. Engaging more with this community could have a significant impact as architects can create the demand for BIPV products by offering more BIPV options to their customers in their designs.
• The construction industry is perceived as possibly the biggest stakeholder group that is not yet at the table. This includes developers, builders, roofing contractors, solar Integrators, etc.
• Manufacturers and product implementation teams in the US. As an example, for glass BIPV products, glass manufacturers seem to be getting more engaged, with less evident awareness and interest from the domestic semiconductor industry. Also, companies along the supply chain (materials and chemical manufacturers) need to be engaged along with these other key participants.
• Relevant trade associations and organizations, which would be well-suited to support stakeholder engagement as they consist of many individual entities that make up these organizations.  They are also able to get communications out to the industry as codes continue to develop over time.
• Local/state regulators (as well as governments) and other Authority Having Jurisdictions (AHJs). Regulators can help increase the demand for BIPV by clarifying the requirements for BIPV projects and passing legislation or regulations to encourage market acceptance. AHJs authorize permits for any major renovations for a building. AHJs in cities and counties need to be pulled into these conversations as they are a stakeholder that may be lacking education and awareness around BIPV.
• Investors needed to mainstream novel BIPV products.
• Power-electronics companies, as the energy conversion and distribution requirements of BIPV products and system designs might vary significantly compared to traditional rooftop PV systems.
• Software developers of tools for bidding, energy modeling, management, and other aspects of BIPV projects.
• Cybersecurity professionals to ensure proper data network integration. Since the operation of such distributed energy sources is based on intelligent electronic devices and software, which could potentially interact with other systems by the use of common data networks in buildings and residences, they could pose cybersecurity challenges and threats.

It was also noted by the respondents that in order to increase the acceptance of BIPV, a more wholistic view of the market needs to be developed rather than focus on individual segments. “Siloed” approaches to market sectors have resulted in a lack of clarity of BIPV market needs and lack of communication and exchange or information between these segments. An approach that allows for cross-pollination between these segments and viewing BIPV under a system-design (or building-design) approach, rather than individual component designs could provide stronger potential for the industry sector.

Outreach mechanisms

Respondents have recommended a variety of mechanisms that could be developed and used to effectively engage interested stakeholders in the BIPV space allowing for better exchange of information and addressing some of the identified challenges of BIPV adoption. Such mechanisms include:

• Publishing case studies, which provide implementation details and modeling data on performance of BIPV under different conditions. Such case studies could be used as templates or baselines for evaluation, design, and planning of new BIPV projects providing guidance and alleviating some of the involved risks.
• Supporting and promoting demonstration projects of BIPV technologies across the United States to provide designers, builders, asset owners/operators, and regulators a hands-on feel as well as serve educational and workers training purposes. University campuses could serve as testbeds and proving grounds for implementation, testing, and education by engaging various institutes and centers, building case studies, and developing academic courses and service-learning.
• Establishing dedicated BIPV conferences, seminars, workshops, working groups, and other training events for the greater industry. Such events should invite representatives from various impacted or interested groups to discuss challenges on implementation, hindrances in developments, and next steps to be taken to improve technology development and deployment, promoting both knowledge transfer and collaboration between different stakeholders.
• Proving the technology at industry trade shows and teaching installation best practices and investment-evaluation methodologies and tools.
• Creating a steering committee to make recommendations for specific certification standards for BIPV or special accommodations for BIPV within existing standards.
• Providing research funding to universities or other R&D organizations across the country to work on the problems that the industry faces. This could be modeled after existing funding processes and mechanisms (e.g. engineering research centers, industry-university cooperative research centers).
• Providing funding opportunities for commercializing BIPV solutions by enabling partnerships between solar companies, building companies, electronics companies, and software companies.
• Instituting BIPV rebate programs or financial incentives.
• Creating a coordinated national effort on BIPV that includes industry, research entities, and academia, like establishing a U.S.-based consortium, similar to BIPV Boost in the EU, as a valuable pathway to connect all impacted or interested parties. This consortium could serve as a clearinghouse to house relevant information about BIPV and further support the decentralized stakeholder collaborative processes needed to ensure BIPV markets scale.
• Developing software platforms that could network builders and solar installers as well as platforms that could serve as integrated planning and sales tools.
• Developing websites dedicated to BIPV, like websites for solar and energy efficiency, addressing solar technologies, building technologies, and energy efficiency in combination.
• Promoting early-stage innovation with small-scale, low-burden incentives and prizes, similar to the American-Made Network Competitions, which are very successful in getting attention for innovative concepts.