Background Up to 60 percent of the global CO2 emissions are caused by the heating of buildings. The reduction of these emissions is therefore a major priority for EU environment policy. Renewable energy sources offer a potential to reduce these emissions and geothermal heat is the only renewable energy that can be used as an alternative to fossil fuels across Europe all year round. RWTH Aachen was preparing the construction of a new student service centre called "SuperC" comprising all academic administration and conference amenities, meeting rooms and exhibitions. The architects planned a very efficient technical concept for the heating and cooling of the building whilst university staff with expertise in mining developed a geotechnical concept for an environmentally friendly energy supply of the building by geothermal heat. Objectives The “SuperC” project aimed to demonstrate the economical and ecological advantages of using geothermal energy to heat and cool large buildings. Taking the Students' Service Centre of the RWTH Institute of Technology at the University of Aachen as its demonstration site, it planned to develop an installation which would provide the energy required for the heating and cooling of this large building with a 95 percent reduction in CO2 emissions. Using a deep geothermal heat exchanger (GHE) designed to operate without a heat pump over a period of 40 years, the demonstration project sought to save about 340 tonnes of CO2 per year in heating and cooling. Based on a self-contained water circulation system, the installation would be free of corrosion and easy to maintain. The project aimed to reduce drilling costs by 20 percent through the use of innovative technology. It furthermore aimed to provide technical and economic data that could be used as a reference for future European projects. It sought to stimulate public debate on the issue of CO2-free heating through the nature of the building and the public relations infrastructure of the project partners. Results The “SuperC“ project succeeded in installing a deep geothermal heat exchanger in the inner-city location of Aachen University. DG Environment of the European Commission rated the project as an outstanding demonstration project with a high potential of reproducibility and the government of North Rhine-Westphalia highlighted it as one of its major renewable-energy pilot projects. The project drilled to a depth of 2.5km, thereby installing a geothermal well of 22cm diameter. In doing so it demonstrated the possibility of realising an inner city deep drilling project. The project met the national noise pollution restrictions and was able to accommodate national mining law, which regulates the search for and exploitation of sub-surface resources. The project designed the heat-distribution system with coaxial pipe, closed water circuit and no heat pump. This was based on the concept of cascade-like heat utilisation for radiators, ceiling and floor heating and tap water. Thermal heat will also be used for cooling, using an absorption refrigeration system. It is foreseen that the well will produce 620 MWh per year of heat in a sustainable and environmentally friendly way, covering 80 percent of the total heat consumption of the Students’ Service Centre. The well will have a peak capacity of 450 kW and 70°C. The enclosed pipe system contains 300 m³ of fresh water without any toxic additives. This means the GHE water will not contaminate the surrounding environment and aggressive thermal water will not enter the pipe system thanks to its impermeable concrete shell and steel casing The project used an optimised drilling technique based on an in-hole hammer. This gave some promising results, but could only be operated for a short time due to a blockage and this technology will therefore need to be developed further. The SuperC plant has a high transfer potential since geothermal energy is available everywhere. Although a long-distance heat supply would still be cheaper in the short- and medium-term, it is estimated that, given the operating time of 40 years and rising gas and oil prices, the geothermal heating plant would reach break-even point after 16-20 years. The project was accompanied by broad dissemination activities and the building itself (which is currently - in July 2007 - still under construction) will be open to the public as a "hands-on" example of geothermal energy deployment. This project has been selected as one of the 21 "Best" LIFE Environment projects in 2007-2008