BIPV - Building Integrated Photovoltaic

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Milland Church

BIPV architectural system: 
Opaque roof
Tilted roof
Building use: 
BIPV integration year: 
Between 2005 and 2012
Eurac Research
Milland Church BIPV system installed on the SE-facing slope (Eurac Research)
Via Campill, Bressanone (BZ), Italy

The first step was to obtain the religious institution’s permission to install such an innovative technology on a holy building. Once the priest has defined the PV plant configuration thanks to the technical advice of the team Von Lutz and the architectural design of Arch. Claudio Paternoster, Elettropiemme Srl was entrusted with the BIPV system electric design and installation. At the suggestion of Elettropiemme Srl, the American SunPower Corporation was chosen, having a product with the right colour and a good energy performance (Don Vijo Luigi Alois Pitscheider). The works were concluded in 2008.

Aesthetic integration

The PV system is a pitched roofing solution integrated into a metal sheets roof. It represents an interesting example of retrofit of a church built in 1984– 1985, where the original building shape, composition and main colours are respected. The roofing system is divided into six triangular parts. The PV plant, installed on the south-west facing part, is made of dark modules with black rear side base in order to keep homogeneity in surface and colours.

Energy integration

The BIPV system annually produces an electrical output of around 22,000 kWh (as monitored in 2011 by Eurac Research). It supplies most of electrical energy need of the church, the parish centre and the rectory (Don Vijo Luigi Alois Pitscheider).

Technology integration

87 PV modules (SunPower Co., SPR-220 BLK) are integrated 14.5 cm far from the outside roof layer with a gap of 2.5 cm among the module arrays. The air gap allows natural ventilation of the PV modules and thus slightly reduces the power losses caused by the increased operative temperature. The chosen module typology eliminates standard metal gridlines, since metal contacts are placed on the back of the solar cell, out of sight. The fixing system is made of metal rails and clips.

Decision making

The main reason that leads the priest Don Vijo Luigi Alois Pitscheider to strongly want the integration of the photovoltaic system into the Milland Church roof was making a practical contribution to promote the use of renewable energy, serving an example for the community. Using one of the most sun-exposed roof parts to produce electric energy was also an opportunity to enhance the modern church features. Once the feasibility and cost effectiveness of the intervention were assessed, the priest succeeded in overcoming an initial disagreement with the local government (Don Vijo Luigi Alois Pitscheider).

Lesson learnt

The chosen PV technology, based on back contact technology, combines an esthetical appeal (homogeneous black appearance) with the energy performance (the PV cells are entirely exposed to solar radiation without any covering due to standard front contacts). Fake modules play an important role in the finishing of the BIPV system. In order to respect the roof geometry, several fake modules have been installed around the perimeter of the PV system. First fake modules which have been installed resulted to be too reflective and did not match very well with the active PV modules in the considered operative conditions. They have thus been removed and replaced with less reflective ones in order to provide a more homogeneous and coherent aspect. This experience underlines the importance of finishing details, which can make the difference to reach high quality in BIPV systems.



Project type: 
Building function: 
Integration system: 
Opaque tilted roof


Module type: 
Standard modules
Solar technology: 
Monocrystalline silicon
System capacity [kWp]: 
System size [m²]: 
Module size [mm]: 
1,559 x 798
Tilt [°]: 


Total cost [€]: 


SunPower Corporation
Rio Robles San Jose 77, California


Via Campill, Bressanone (BZ), Italy

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