Solar Roof Tile Exhibition shows developments
in photovoltaic roofing
by Rolf Hug
09/06/2006
In an exhibition the
company Biohaus PV Handels GmbH presents the history of solar roof
tiles over the past 15 years. With its zero-energy office building
the photovoltaic system integrator located in Paderborn demonstrates,
since the beginning of 2005, versatile and innovative solutions
for the integration of solar technology, including thin-film technology,
photovoltaic façade elements and state-of-the-art high-performance
solar cells.
Biohouse building with solar roof tiles on a monopitch
roof, a view of the Solar Roof Tiles Exhibition. Photos: Biohaus
PV Handels GmbH
"With the Solar Roof Tiles Exhibition we want to demonstrate
that solar power generation is not only an ecologically sensible
solution but that the aesthetic component is gaining in importance
too,” Biohaus Managing Director Willi Ernst says when describing
the purpose of the exhibition. The Solar Report presents the most
interesting exhibition pieces, shows some of the systems already
implemented and portrays the history of solar roof tiles from its
earliest beginnings to the present, without claiming to be a complete
presentation.
From a photovoltaic roof tile to a solar building
component
Solar roof tiles are photovoltaic modules that are integrated
into roofing. The individual “tiles” are linked with
electrical plug-type connectors to form larger units and then deliver
clean electricity. Solar roof tiles are being developed and sold
since the early 90’s by different manufacturers to allow
an optically attractive integration of solar roof tiles into the
roof surface. Biohaus also manufactures solar roof tiles and has
become the European market leader with its "BIOSOL InDach" system.
And this was sufficient reason for the Paderborn company to present
these special solar systems within the framework of an exhibition.
Products of various international manufacturers are shown, including
the Spanish module producer Isofoton and the Japanese manufacturer
MSK. The performance of the PV modules included in the solar roof
tiles has been significantly improved over the past years: from
the initial modules with a peak performance of 3 Watt (Wp) per
element up to 200 Wp in the largest solar roof tile offered by
Biohaus today. This development is demonstrated in an exemplary
and very vivid manner in the Eco-Park Exhibition Dören which
is planned to be a permanent exhibition.
Quantum leap: from the early solar roof
tile (BIPV sample IndustrieDach, 12 Wp, 1994) via the "Just
Roof" by the Japanese manufacturer MSK (82 WP, introduced in
1995) and the solar tile "Isofoton teja ceramica" (13,5
Wp, 2000) right up to the solar roof tile Biosol XXL (124 Wp, 2005).
Photos: Biohaus
Beauty comes at a cost
Solar roof
tiles, in the narrow sense of the word, are conventional ceramic
roof tiles with solar cells that are attached mechanically or with
adhesives. In the broader sense of the word, this term is now also
being used for solar roof tiles or solar roof elements that are
manufactured from other materials, e.g. slate, plastics or metal.
The aesthetically very attractive ceramic tile by Gebrüder
Laumans GmbH & Co. KG with its head office in Brüggen
was rewarded with great praise when introduced in 1999, especially
since it allows a very sensitive integration of photovoltaics,
even in buildings that are declared national monuments.
However, the optically very convincing solution comes at a price:
up to 25% additional costs for the tiles with mini modules of 3,75
and 4,55 Watt had to be calculated. To construct a system with
a peak performance of one kilowatt, 400 tiles were required that
were then equipped with linked mini solar modules. Particularly
the cabling and the plug-type connections of the individual elements
led to the price increase. Laumanns discontinued the production
of its highly esteemed system on 31.12.2004, and other manufacturers
of solar roof tiles had to follow suit.
The Swabian tile manufacturer Pfleiderer in Winnenden has also
discontinued production of the “TerraPiatta-Solar” tiles
that were introduced in 1999. However, production will be relaunched
in autumn 2006. These solar tiles with a performance of 55 Wp each
were assembled in a similar manner as the ceramic roof tile “Terra
Piatta” and replaced six surface tiles each.
Top: Solar roof tile TerraPiatta-Solar by Pfleiderer.
Photo: Biohaus.Left: Solar centre in the Manor House Wietow (Mecklenburg)
with TerraPiatta-Solar roof tiles and solar window shutters.
Photo:
Martin Schachinger.
In spite of or possibly because of the solar power boom after the
amendment of the renewable energy law in 2004, only very few roofs
were tiled with the “classical” solar tiles during the
past years. The trend moved towards larger solar power systems, even
on private roofs. The cost-based compensation for solar electricity
fed into the network led to supply bottlenecks for modules and solar
silicium. Many maufacturers noticed that solar tiles moved into the
background and the solar cells demanded were used for traditional
modules to be mounted on roofs or to be used in ground mounted solar
parks systems.
Photo: Biohaus
The fact that solar building elements can compete aesthetically
with conventional roofing is proven by the solar roof tiles by
Biohaus. These high-performance Biohaus modules with thin-film
technology based on UniSolar laminates and with black-coated profiles
and assembly brackets replace conventional roofing and are utilised
as complete solar roofs.
Clean electricity from beautiful roofs
Solar power systems on historical
buildings or on buildings declared national monuments or on roofs
constructed by demanding constructors have shown the possibility
of sensitive integration of photovoltaics. This living proof
includes the various solar tiles by European manufacturers that
did not open
a mass market but are a shining business card for solar power
technology. The small-surface solar tiles on the basis of conventional
tiles
or on slate tiles were manufactured mainly by tile manufacturers
who simply added the additionally purchased modules.
ATLANTIS-"SunSlate",
13,3 Wp, introduced to the market 1995. Photos: Atlantis Energy
Systems, Sacramento, USA.
The manufacturers of the modules, on the other hand, relied on
high-performance solar roof tiles. PhönixSonnenstrom AG may
serve as an example – this company used the Newtec solar roof
tile developed in Switzerland, but had to discontinue production
because of a lack of demand. According to information provided by
the company, Newtec solar power systems with a total performance
of 100 kWp were built – a marginal figure in comparison to
the 1-Megawatt open-space system that Phönix built last year
near Würzburg. Yet the Newtec solar tile is not to disappear
entirely since the company certainly does see chances for the product
and emphasises its aesthetic qualities.
Photos: Solar roof tile "Newtec";
0,864 kWp solar power system in Sulzemoos (left in pic.); right:
solar heating system.
Source: Phönix Sonnenstrom AG
Houses with solar roof tiles can be found throughout Europe, occurring
particularly frequently in Germany, Switzerland and Austria. The
increased costs are justifiable particularly in historical buildings
where conventional solar power solutions would not be authorised.
But exemplary systems were also installed on new buildings: a solar
roof in the Austrian town of Fußach (Vorarlberg) received the
2002 Austrian solar award by EUROSOLAR for its aesthetically successful
and unobtrusive photovoltaic integration. The system boasts a performance
of 2 kWp and forms part of the EU project "Hip – Hip” (House
Integrated Photovoltaic - High-tech in Public).
Award-winning solar roof in Fußach (Vorarlberg). Photos:
Austrian Energy Agency
Experts and solar associations are expecting a further price
reduction for solar modules through an expansion of photovoltaic
capacities
and the end of the current silicium shortage which could in turn
lead to a renaissance of solar tiles. Whilst façade integration
of solar power systems is rewarded by an additional 5 cents feed
in tariff according to the renewable energy law, such an increased
reward system has not yet been introduced for the integration of
solar tiles. The rather small manufacturers surely were not able
to form a strong enough lobby. Sensitive PV integration is supported
and marketed by the German-Italian research project "PVACCEPT".
The results of this project are published in the book "Solar Design" that
was nominated the Solar Book of the Year 2005 on the Solarserver.
PV
roofs are becoming larger, solar roofs also used for generating
heat
A stroll through the 1. International Exhibition of Solar Roof
Tiles
at Biohaus reminds of times when the building of solar power systems
not only made good economic sense but also required a fair amount
of idealism. The system integrator in Paderborn opted for a combination
of performance and optical appearance that also took into consideration
financial aspects. The “real” solar tiles will probably
be found in a niche market in future as well, whereas the trend towards
the solar roof is continuing: the highly advanced assembly systems,
e.g. "SolRif" or the XXL modules by Biohaus can be used for
solar roofing on a large scale. This is proven by the solar power world
record in the Hessian town of Bürstadt: the world’s largest
PV solar roof with a photovoltaic performance of 5 MW was mounted
on bitumen sheeting, protects the vapour barrier and minimises temperature
fluctuations.
5 MW solar power roof in Bürstadt.
Photo. Tauber Solar
Solar roof with 84 square metres of sun
collectors for heat production. Photo: Sonnenhaus-Institut
Solar roofs that are completely covered with thermal sun collectors
play an increasingly important role – for the effective support
of heating systems or for houses that are heated with solar power
only, large collector surfaces are required.
