Energeia. Bulletin de l’Office fédéral de l’énergie OFEN Numéro 6-Novembre 2010 In a world first, the road construction company COLAS Geneva operates with an unprecedented solar thermal technology from CERN to heat and maintain its asphaltic bitumen at a temperature of 180 ° C. The pilot plant, working since May 2010, has been done mainly through support from the Federal Office of Energy.
Geneva is best known as home to CERN, a giant of international scientific research, which by its insolation. However, when the first gets ready a technology using the second to produce energy, this leads to a very promising results. These results are visible from May 2010 on the roof of one building of the road construction company COLAS Geneva. The project is presented as an area of 80 square meters of flat solar panels, with ultra high vacuum, being able to reach temperatures higher than 300ºC, an unprecedented feat for solar panels. The technology has been developed by the Hispano-Swiss company SRB Energy from a patent of CERN.
"In the sector of the roads construction, is used a lot of energy, explains Adriano Guzzo, director of the company COLAS Geneva. Being the most part of the used energy of fossil origin, this makes us very vulnerable to market prices fluctuations. Moreover when we cannot simply pass these fluctuations on the prices of our products. This is why we thought from long time ago to diversify our energy sources”.
 
Sustainable Development Award of the Canton of Geneva

Effectively, environmental management of COLAS Switzerland is not new. "We started in 1984 with the development of our freight transport by rail” Adriano Guzzo recalled. Later, in 2004, COLAS Switzerland signed an objectives agreement with the Swiss Confederation, under the auspices of the Energy Agency for the economy (AEnEC). This commitment encourages Colas Switzerland company to reduce CO ₂ emissions by 25%, by the end of 2010. One year later, in 2005, COLAS Geneva launches to solar adventure outfitting caravans and containers work with solar panels. "These caravans have earned our company the Sustainable Development Award 2007 of the Canton of Geneva”, proudly recalls the company’s director.
"From the beginning, our objective was to integrate solar energy in our industrial processes, particularly at the preparation of bituminous conglomerates which require temperatures near 180°C”, explains Marc Maranzana, Materials director in COLAS Switzerland. A conglomerate is a mixture of inert materials -95%- and bitumen -5%- which covers the top of the road surfaces. The coating is prepared according to the needs and bitumen required for each case is stored in tanks and maintained at a constant temperature between 150°C and 200°C, to prevent hardening or decompose.

A very promising technology

The performance of the COLAS Geneva solar thermal installation has been possible by the support, among others, the Federal Office of Energy (OFEN), ScanE), Geneva Industrial Services (GIS) and the Geneva Committee for new renewable energies (COGENE). "The return on this investment is far for now, says Adriano Guzzo. Without our “partenaires”, we would not have been able to do the installation. We still need 40% of subsidies to become profitable.”However various arguments can be adduced in favor of a return in the coming years. "In the future, clarify Marc Maranzana, we wish we could also take advantage of temperature ranges between 80°C and 150°C, for example, to heat our buildings. Currently, we only exploit the heat of about 180°C, with an average yield of 30%. The price of the panels should also go down over time. Finally, an innate characteristic of the bitumen, its high thermal inertia, could give to this kind of facilities another surprising and interesting role from the economic point of view: energy storage.

Economy 6 tons of CO₂ per year

According to current estimations, the Geneva facility would produce 26 megawatts per hour of heat per year. This would allow to COLAS Geneva company reduce CO ₂ emissions in about 6 tons per year, this is a savings equal to 2200 liters of fuel oil. The potential extension of these facilities in COLAS Geneva center or others is important.
Leaving apart economic and environmental considerations, the two COLAS officers claim to have learned a lot and taken advantage of this collaboration work necessary to make the pilot installation. "The collaboration between specialists from research, economy, road construction and management has been very constructive”, says Marc Maranzana.
With an idea launched in 2005 and a materialization in 2010, these are long term projects.” And Adriano Guzzo concludes: "There is still a lack of a clear desire to do something else. With the rising price of oil, I'm sure this will change very soon”.

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