Imagine a public library which is also one of the most advanced solar power generators in Europe: a building that can satisfy its own energy requirements with a totally clean form of electricity.
What may sound like so much wishful thinking is about to become a reality in Matar", a small town in northeast Spain.
Due to be opened in December, the Pompeu Fabra Library can generate 70 megawatts of electricity per hour by means of solar panels built into the angled roof and facade of the building. The complex is in turn plugged into the national grid allowing surplus power to be sold on to the local electricity company or any shortfall to be made up.
The project is part of the European Union Joule 11 programme and is led by panel manufacturer Teulades i Facanes Multifuncionals, with help from the University of Barcelona and French and German research institutes.
Antoni Lloret, research director at the National Scientific Research Centre, Polaiseau, France, and professor of physics at the University of Barcelona, said: "We wanted to prove that solar power is not a utopia, but a perfectly tangible reality - one which can be applied in an urban setting."
He believes the idea of using walls as part of a building's solar capacity is particularly suited to urban environments where a square metre of building land is at a premium but the vertical space of facades is of negligible value.
This technique is also appropriate for northern European countries where "the sun is much lower and so shines on facades more than on roofs", says Professor Lloret.
The library uses three different kinds of photovoltaic cell - monocrystalline, polycrystalline and amorphous silicon - made by French, German and Hispano-British manufacturers; thereby acting as showcase and testing ground for the latest in European solar technology. Their performance will be monitored by a University of Barcelona team over the next two years.
However, possibly the biggest innovation is represented by the building materials themselves. The modules of the facade are designed so that the rows of iridescent photovoltaic cells provide an attractive finish to the exterior and partially shaded light inside the building. Air, trapped in the chamber behind the cells, is heated by the sun and sucked into the ventilation system to provide heating on cold days. It is estimated heating costs can thus be reduced by 30 per cent.
The panels allow for quick and easy assembly: the facade of the Pompeu Fabra Library was built in under three days. Above all, these multifunctional modules represent a standard, aesthetically-pleasing solar building material for environmentally-conscious architects.
Solar power remains expensive, but environmentally-friendly. In the case of the solar library, it is around six times cleaner than energy generated conventionally. Professor Lloret believes that new generations of engineers and scientists are beginning to take solar power more seriously. Nevertheless, he believes that it is up to governments to take the initiative if this new, clean technology is to really come into its own.