The multimillion-dollar question about BIPV is this: what will convince customers — architects, builders, and homeowners, even construction materials suppliers and financing entities — to justify the extra expense in a BIPV application? Companies and organizations continue to improve and innovate around the technologies involve with building-integrated photovoltaics (PV), from new cell designs and technologies such as PERC, metal wrap-through, and “smart wire” structures, to new and improved materials from thin-film CIGS to dye-sensitized and organic PV, and the latest solar PV wonder-material perovskite. Standardization will help reduce the complexity (and thus costs) of BIPV installations; this already has made some headway in the U.K. for products such as roof tiles and shingles. These are needed progress in performance and cost reductions, but they’re not enough.
NanoMarkets believes the answer lies in other factors to consider:
Multifunctional BIPV: If on-site energy generation is the only or overriding goal, c-Si panel arrays bolted onto a rooftop will beat out BIPV applications as the most economic option for the foreseeable future. What BIPV must demonstrate are other capabilities and features that go beyond energy generation, which can aid or directly result in a faster return-on-investment and justify higher costs. A multifunctional BIPV skylight or curtain wall allows a building to generate energy for 25 years, control natural day lighting, harvest ultraviolet/infrared harmful radiation, and provide acoustic and heat insulation, among other functions. Examples include semi-transparent arrays of c-Si cells that create diffused natural lighting; roofing systems with details such as flashings, capping, and roof penetration; hollow glass to provide heat and sound insulation.
Aesthetics and flexibility: To some customers, a typical flat rooftop array of c-Si panels simply lacks visual appeal, especially on structures with unique design emphasis such as prestige buildings. Frameless BIPV modules offer both uniformity in color, and variety in form and structure, including transparency and flexibility for curvature. Options here include thin-film CIGS and CdTe PV and thin c-Si metal foils. Dye-sensitized and organic solar cells (DSC/OPV) promise not only low-cost processing on glass and performance in less-than-ideal lighting conditions, but also can incorporate colors.
Monolithic integration: We note that monolithically integrated BIPV roofing, in which there’s no clear distinction between the energy and roofing subsystems, still hasn’t really emerged, though there are monolithically integrated modules available. Similar monolithic integration is coming for BIPV glass; products that are self-tinting, self-cleaning, and self-healing; such products, based on still-developing technologies and most notably DSC, could capture nearly half the market, NanoMarkets believes.
Tracking BIPV’s Market Emergence
Overlaying the current benefits of today’s BIPV systems and technologies into what works in the marketplace, here is where NanoMarkets sees the best near-term inroads:
“Prestige” buildings: For these higher-end buildings such as offices, BIPV glass is considered ideal for both the “image conscious” clientele and architects, to experiment with their creativity while emphasizing the “green” aspect of the buildings. The most likely areas for application of BIPV in prestige buildings include windows, roofing, and building façades.
Government buildings: These aren’t quite considered “prestige,” and appearance often isn’t the most important factors. But government entities increasingly have to adjust to meet sustainability mandates, and BIPV can help meet a building’s energy objectives.
Commercial buildings: It seems obvious to affix solar roots on flat-top commercial structures that sit baking in the sun all day. Among the growing examples are carports and gas-stations. One such BIPV example is a Southamption, U.K. project installed by PolySolar which is expected to generate more than 400 MWh of electricity over its expected 25-year lifetime. NanoMarkets tracks other applications of BIPV on buildings, such as Trony Solar’s projects of glass curtain walls at the Shenzhen Nanshan Software Park, Shenzhen Institute of Building Research, and the Guangzhou TV Tower.
Residential: NanoMarkets sees three segments of the residential market where some BIPV can be found. In expensive high-end homes, the cost of both the hardware and installation of BIPV glass may not be an obstacle. Multi-family dwellings more or less have the same characteristics as commercial buildings, and increasingly are becoming attractive for sustainability. And there are small installations, even to the level of an owner-installed BIPV window.
Retrofits: While the vast majority of BIPV revenue will come new construction over the next several years, NanoMarkets predicts the burgeoning market for retrofit BIPV, building add-ons such as awnings, balconies, and additional stories, will catch up to new construction by the end of the forecasting period. In Europe, demand for BIPV lies in the retrofit market; NanoMarkets believes in a few years its market share will go up to 40%.
The Secret Answer Is: Zero
A zero-energy building (ZEB), commonly understood as an energy-efficient grid-connected building that can generate onsite green electricity, uses multiple integrated renewable sources to compensate for its energy demand. Until recently BIPV was not commonly used in ZEBs; building-applied PV systems, wind turbines, and energy-efficiency emphases such as lighting were predominant. Moreover, ZEBs typically aren’t scaled up to the sizes of prestige buildings, and total area for PV on them is not as much.
ZEBs are fast gaining momentum, thanks in part to policy and subsidy support. In Europe, there is great enthusiasm for sustainable architecture: all new buildings must be nearly zero energy buildings (ZEBs) from the end of 2020. The R2CITIES project, for example, aims to develop and demonstrate an open, easily replicable strategy for designing, constructing, and managing large-scale district renovation projects for achieving nearly zero-energy cities; it is targeting three residential districts involves more than 57.000 m2, more than 850 dwellings and more than 1500 users, with a potential of energy consumption reduction close to 60%. Industrial partners specializing in the provision of materials are Onyx and Ezinc for BIPV applications. In the U.S., federal government buildings must reduce energy use by 30% by the year 2015. Building industry estimates suggest the number of net-zero-energy buildings across North America will double in 2014 compared to 2012. In Japan, the government wants to meet 50 percent of residential power requirements through BIPV systems, which favors the application of BIPV glass in conventional homes.
NanoMarkets sees the increasing number of net zero energy buildings, and regulatory support for them, as a catalyst for growth in the BIPV market, both for glass and non-glass BIPV. We project zero net-energy buildings will overtake prestige buildings by 2019 as the biggest consumer of both BIPV types. Other commercial and government buildings also will increase adoption of BIPV products, making this segment the second-highest revenue generating market for BIPVs. Residential buildings will start growing fast as the BIPV manufacturers start offering cheaper products.