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The vision of building-integrated photovoltaics vision is often stunning: "high-performance buildings" sporting photovoltaic "skin," their roofs, glass, and walls alive with the steady, daily flow of photons being converted to electrons, the structures' energy needs more than met by the e-juice provided by the PV integrated into their own construction materials.

But the reality is, even though there is a lot of BAPV (building-applied PV) out there--think roof-mounted racks of crystalline modules--and many beautiful solar-powered homes and businesses have been built, we are at the dawn of the true BIPV age, where PV technologies not only integrate with the builder's materials, but actually replace the envelope of systems and surfaces on homes, warehouses, factories, and other structural edifices.

A smallish but mighty group of attendees at Infocast's recent BIPV Summit, which took place within wagering distance of the Del Mar Racetrack near San Diego, represented a decent swath of the entire value chain that will be necessary to make true building integrated solar work. There were building trade folks, solar installer/integrators, thin-film and crystalline silicon manufacturers and a handful of their tool and materials suppliers/partners, architects, money guys, utility company managers, and even a lobbyist or three and a Marine Corps officer at the event.

This was the kind of eclectic audience that Michael Gumm of SolarPower Restoration Systems had in mind when he said during a panel discussion that we are entering a new era where PV and building professionals have to work together in order for BIPV to succeed--something those disparate forces are beginning to do.

The challenge, as Gumm and others noted, is the fragmentation of all these stakeholders (who also include the utilities, government agencies, and others), who often know little about each other's businesses, and their ability to collaborate effectively. The disconnects are many between the disparate industries, starting at the macro level. As Global Solar's Mark McIntyre explained, PV ultimately benefits from scale (and the economies thereof), while the building/construction business--although not immune to scale--also must deal with inherent customization.

In a twist on the old "if you can't beat 'em, join 'em" chestnut, Suntech's Leonard May suggested that the solar side could learn more from the building folks by hiring more of them. Kurt Roth of the MIT-Fraunhofer Center for Sustainable Energy Systems spoke of the need for PV products to be optimized for building integrated applications, polinting out that adapting standard cells or modules for BIPV is not the best solution.

Roth's point has been taken to heart by companies--like May's and others--that are designing and manufacturing solar tiles, integrating flex TFPV with modified biumen membranes, and treating architectural glass with photovoltaic glazing.

Suntech already makes more than pocket change from its efforts in the sector. Its BIPV division (loosely named, given there seems to be more BA than BI involved) accounted for 4% of the company's overall revenues last year, or about $80 million out of $2 billion, according to May. The Chinese solar manufacturer hopes to double its BI biz this year and again next year, and has a dedicated plant manufacturing its BI/BAPV products.

This emerging second phase of BI products, where the PV is directly integrated into the roofing membrane itself and not applied in the field or where optimized thin films turn architectural glass into semitransparent or transparent solar-powered glass, offers architects and contractors a whole new range of options for green/solar design schemes. The suite of sloped and flat roof, canopy, curtain wall, and skylight BIPV approaches is growing, with both thin film and crystalline silicon being used in aesthetic, creative power-producing ways.

But the new goodies could also be the cause of more potential headaches: what if the lifetime and reliability of the flexible PV roof, because of mediocre adhesives or barrier encapsulants, do not meet the same specs as standard construction materials? Or the built-in microinverters in a complex glass-facade BIPV system begin to fail and relatively easy service access was not designed in?

Consider the horror story offered by keynoter and solar pioneer Steve Strong of Solar Design Associates. Among many often-elegant examples of solar PV applied onto or integrated into a variety of structures going back to the early 1980s, he showed a photo of the side of a building in sunny Santa Monica where the architects/designers put a vertical PV facade in the shade--an example of what Strong calls a "disintegrated solar concept."

To avoid these kind of missteps and bone-headed moves, there has to be that aforementioned cross-discipline understanding and cooperation among the various players, or the chances of BIPV connoting "badly implemented photovoltaics" could grow.

BIPV may have tremendous upside for the future, but for now it's a relatively small slice of the solar tart. Energy Insights' Nadav Enbar, who sees "huge potential for the mass deployment" of building-integrated solar, noted in his market overview that the sector only accounts for about 70 MW of the cumulative PV installed--a pittance compared to the overall base of more than 13 GW.

But with millions of square meters of available public, commercial, and residential roof surfaces with PV conversion potential in Europe, Asia, and the U.S., the market should grow in megawatt leaps and mutimillion-dollar bounds.

Enbar concluded his talk with the outlook for BIPV. He said that although the technology is still hindered by high prices, there are many reasons to be bullish about the increasing integration of solar into building envelopes:

• Growing government mandates/incentives are stimulating sector investment.
• Thin-film PV development is powering a growing variety of modules and laminates.
• BIPV is leading to increased property values, improving home sales.
• Downstream building materials suppliers, builders, and utilities are beginning to invest in BIPV.
• A growing manufacturer/installer partnership and collaboration with architectural firms seems likely to multiply with increasing commercial deployment.

As the segment makes inroads in the market and costs become more competitive, integrated solar rooftops and then fenestration and façade-integrated systems will become more prevalent, and with the approach of PV grid parity, he believes that BIPV's aesthetic, multifunctional market-differentiating attributes will position the products for greater acceptance.

There's certainly more to the BIPV beat than one blog post can handle. The impact of the volatility of the overall PV market on this emerging sector; the role of government policies like incentives, feed-in tariffs, and building requirements; and utilities' acceptance or reticence to embrace such a distributed power-generation concept all deserve consideration and analysis. Then there's the whole kettle of fish known as BIPV project financing, which is a topic category unto itself (and one that SolarNet's Keith Rutledge did his best to explain at the conference).

So stay tuned, comrades, for further explorations of and ruminations on BIPV, one of the most appealing and compelling sagas of the photovoltaics revolution.