The turnaround in the PV (photovoltaic) sector has been visible since the second half of 2013. And while 2013 was not a great year the solar industry, including BIPV (Building-Integrated Photovoltaics) in general and BIPV glass in particular is beginning to pick up. While many firms offering BIPV glass have gone under, the ones that emerged from the solar bust are still faced with the same problem; how to get their products into the mainstream construction market and not just prestige buildings.
The conventional use of architectural glass range from the mundane—windows and skylights—to the exotic, like building facades, curtain walls, atria, pergolas, and canopies. In any of these applications, BIPV glass could substitute for regular architectural glass. BIPV glass is the largest part of the BIPV market, but BIPV itself still represents a tiny share of the solar panel market itself, so that isn’t saying that much. In addition, despite its many advantages, BIPV (again including BIPV glass) has never managed to break out of the premium building product category and is used primarily on large corporate headquarters and homes of wealthy individuals.
It is quite possible to imagine that BIPV glass will stay that way—there are plenty of building products that never drop below the premium pricing that characterizes today’s BIPV glass. However, such building products tend to support mostly medium-sized businesses that have little opportunity to grow. Or sometimes these premium building products are supplied by small divisions of larger companies, but typically the same modest expectations apply to these divisions too.
However, the expectation has always been that BIPV—glass or other—was the way forward to get PV into a wide variety of buildings. The main driver here was supposed to be aesthetics—a BIPV building is said to look nicer than one with large and very visible panels on the roof of a building. Not all architects agree with this statement, but a lot of BIPV advocates hope that BIPV glass can actually help sell a building.
But for now, what everyone agrees on is that the cost of BIPV glass can be prohibitive. Sharp, recently showcased solar window and balcony railings at PV Japan 2013. The windows will cost around $2,000 per square meter. Clearly, to drive BIPV into the mainstream, costs are going to have to drop considerably and/or functionality will have to increase. Both approaches are plausible strategies.
In this context a number of approaches suggest themselves. At one end of the scale, an obvious thought for BIPV glass firms is to bump up their marketing dollars for reaching architects; the main decision makers when it comes to BIPV glass. At the other end are fanciful multifunctional strategies that combine (say) lighting and PV into a single panel and therefore spread the cost across several functionalities. Although this kind of thing is on the cusp of being commercialized, it isn’t here yet.
Cost Strategies for BIPV Glass: Design and Technology Strategies
Cost and design: Since all BIPV glass buildings are custom designed at the present time, cost can be reduced based on thoughtful design prior to the BIPV glass being built in. For the reasons given above, it is hard to find a completely conventional building that has taken advantage of this, but an example of where design has helped reduce cost is the Future Business Centre, a new purpose-built business innovation center in Cambridge (U.K.) aimed at supporting the growth of environmental and community enterprises.
The cost per square meter of PV glazing in this building is said to be only marginally higher than the conventional glazing on the building, Polysolar (U.K.), a local company, installed the solar PV glass façade, a curtain wall in the stairwell, using Polysolar’s double glazed amber tinted PV glass, and an opaque rainscreen cladding system to supplement the rooftop solar array.
This is not to say that the Future Business Centre is in some way unique, but is indicative of a hope that the very high current costs of BIPV glass can be designed out without making any very elaborate arrangements.
Cost and technology: Another way to reduce cost is to use low cost fabrication and materials strategies. In this context we note that Pilkington has an alliance with Dyesol to create BIPV glass using DSC PV. Meanwhile, Heliatek, a German OPV firm, has signed a BIPV glass joint- development agreement with AGC Glass Europe.
These arrangements have several implications. One is that really big glass firms are sufficiently interested in BIPV glass to become at least this involved. The other is that OPV and DSC have been chosen, since this is a prima facie case for thinking that solution-processed PV layers are being considered as a way to lowering the cost of PV.
Color and Lack of It as a Way to Differentiate BIPV Glass
Meanwhile, differentiating BIPV glass in the marketplace is not easy to do, since from the perspective of a building owner the BIPV glass per se may seem an undifferentiated commodity. Long-term, many product/market strategies may be devised that will help differentiate BIPV glass. However, at present NanoMarkets believes that two of the main differentiators are—paradoxically—enhanced transparency and enhanced color!
Colored BIPV: BIPV glass is now available in various designs and colors. Obviously, the less plain vanilla a BIPV glass product is, the more appealing it can become to possible customers. This strategy may not turn BIPV glass into a mass market, but it does stand a chance at least of expanding the addressable market.
An actual example of how this might work is SwissINSO, which has formed a joint venture with Acomet Solar (Switzerland) which is expert in metal and glass façade constructions. The duo plan to offer colored solar panels to eliminate the problem of poor panel aesthetics that has hindered the development of PV and solar installations on roofs, building facades and architectural projects in general. They recently completed the first installation of light blue PV panels on a building façade, with several other projects contracted in Switzerland and the UK.
Another example is provided by the solar windows made of colored amorphous silicon solar panels at Barcelona’s Schott Iberica building. Geneva Airport also provides another instance of where colorful BIPV glass panels have been installed.
Transparency as a selling point: Somewhat ironically, while color and tint may be a selling feature for BIPV glass, so might transparency. The point here is that no BIPV glass can be completely transparent, since it must absorb light to function as a PV panel. That said, a BIPV window that is more transparent rather than less is more likely to achieve larger markets.
Transparency is normally achieved either (i) because the PV cell are so thin or laser grooved that it is possible to see through or (ii) because crystalline solar cells on the laminate are spaced so that light filters through the PV module and illuminates the room. The problem is that while more transparent panels are more likely to be acceptable to the end user, they are also more expensive.