However, BIPV (Building-Integrated Photovoltaics) is still a niche application of negligible importance measured by total PV installations worldwide. “It is a side line of the PV industry,” explains Gaëtan Masson, Vice President of EUPVTP. Of the just under 40 Gigawatt solar power output newly installed in  2014 worldwide, only about one Gigawatt was accounted for by BIPV – this means the market share of BIPV is as low as 2.5%. One obstacle to market success are the relatively high costs: building laws and technical requirements vary widely from country to country and among regions. This is why modules are customised in relatively small lots locally for local architects, Masson explained. And this used to make the production of higher quantities and economies of scale difficult. 

The BIPV industry would have to focus more on competitive market segments, he felt, in order to profit from economies of scale like conventional PV. “Then companies could start production of pre-fabricated BIPV elements.” The EUPVTP also feels that the political framework has to improve in order to help this industry take off. At present, however, countries are rather “back-pedalling” when it comes to state aid for solar installations. In France, for example, one of the few countries with special subsidies for BIPV, the additional support for in-roof systems is scheduled to end in late 2015.
 
BIPV would help countries to achieve the set climate protection targets more safely; after all, EU member states have undertaken to bring down greenhouse gas emissions by a minimum of 20% against 1990 levels by 2020, to increase energy efficiency by 20% and to achieve a 20% share of renewable energies in total energy consumption. In this context buildings play a pivotal role: new buildings should require next to no energy for heating, hot water, air handling and conditioning from 2020 and cover the remaining energy needs themselves. BIPV would be the solution: wherever modules cannot be installed on the roof they could be integrated into the building skin.
 
Even though the circumstances for BIPV are difficult – on-going innovations raise hopes for an imminent breakthrough of this technology. Modules are becoming more efficient and available in ever more designs. Architects appreciate this newly gained scope for design. “We feel that business is picking up,” says Bernd Sprecher, General Manager of Manz CIGS Technology. This company develops production lines for thin-film modules based on copper, indium, gallium and selenium. Manz manufactures BIPV modules in various, freely selectable dimensions and shapes in the Southern German town of Schwäbisch Hall. Here a sheer, photo-active CIGS layer is vapour-deposited on float glass – a process that by Sprecher’s accounts permits variable module sizes and custom shapes.

For the time being, however, the classic option is still unrivalled in terms of efficiency rates – top modules from mono-crystalline silicon already achieve over 20%. This high degree of efficiency is also a key reason why BIPV specialist ertex solartechnik, a subsidiary of glass producer ertl glas from the Austrian town of Amstetten, predominantly uses silicon cells for its modules. In order to meet the architects’ high demands, ertex solartechnik has joined forces with specialists from the architecture, glass and PV industries to develop modules that are novel in terms of their looks. “Now architects and façade planners have a photovoltaic module at their disposal that fulfils the highest demands in terms of appealing looks and design freedom – like conventional façade elements – but forms a symbiosis with solar power generation,” explains Dieter Moor, Marketing and Sales Manager at ertex solartechnik.
 
According to Moor, the different options result from the possibility of patterning and colouring each layer of the module – from the front glass surface to the back sheet. In this way laminated safety front glass can be designed with various patterns and degrees of transparency, printed glass backs, coloured front glass and encapsulation films, patterned glass fronts, coloured and semi-transparent solar cells as well as coloured solder connectors. “This ensures solar cell structure is next to invisible,” Moor explains.

Thanks to new semi-conductors architects can look forward to even more freedom to design with solar technology. Dresden-based company Heliatek and Belgian flat glass producer AGC Glass Europe are working on BIPV elements that incorporate organic photovoltaic films of different dimensions, colour graduations and levels of transparency in construction glass. Heliatek spokeswoman Kathleen Walter says that these films make elements easier to handle and also suitable for use in irregularly shaped façades. Furthermore, solar films in organic material promise to keep production costs low since there are sufficient amounts of tiny photoactive molecules (oligomers) available and can be precipitated onto the film using an efficient role-to-role process. This is far less labour-intensive than the production of crystalline silicon cells whose “blanks” – the wafers – must first be diced out of a solid block before being processed further into cells.
 
These solar “light-weights” obviously go down very well in the construction industry. “We are virtually flooded with enquiries for pilot projects. This technology definitely promises to trigger a boom,” remarks Walter. But Heliatek has not solved all critical points in the process yet. Films from the pilot production currently achieve an efficiency rate of seven to eight percent. In the glass sector Heliatek has already realised a number of pilot installations and been capturing data since. A façade installation in Dresden achieved an additional yield of 23% over conventional silicon after just one year. In the joint-venture development with AGC the next step is product certification. Currently, all BIPV elements are undergoing final tests. 

This is why the EU is promoting the further development of this technology with an investment of some Euro 3 million as part its “Horizont 2020” programme. The concrete objective of Got Solar (as the research project was dubbed), which involves cell developer Dyesol as well as six European research institutes, is the development of a cell-sealing technology fit for industrial production. After all, perovskite suffers from the same restrictions as Heliatek’s oligomers: it is extremely sensitive and must be protected especially well against outside influences. Dyesol spokeswoman Eva Reuter explains: “It’s all about increasing their stability.” The company wants to start mass-producing perovskite cells in 2018. To this end a new factory with 600 megawatt annual capacity is planned in Turkey. 
 
At glasstec 2016, the world’s biggest and most international trade fair in the glass sector, companies coming to Düsseldorf from 20 to 23 September 2016 will be given the opportunity to exchange ideas about innovations and pave the way for new collaborations. Experts from the solar and glass industries will get together to network about progress made in solar glass and module manufacturing as well as in materials and costs. The Special Show “glass technology live” targets this interface between solar technology and glass. Here the latest developments in façade and energy will be presented, including innovations in PV and solar thermal systems. Interesting insights are also guaranteed by the international “architectural congress”. Speakers from renowned architects’ offices will present their visions with glass here and BIPV is also expected to play a crucial role in these visions.
 
Messe Düsseldorf GmbH
Messeplatz
40474 Düsseldorf, Germany
www.messe-duesseldorf.de
www.messe-duesseldorf.com