If it is possible to refurbish energy-intensive businesses with an energy index of 750 kWh/m2a to PEB, why should it not be possible to realise all future European average buildings with ten times lower energy indexes of 40 to 70 kWh/m2a as PEB as well? Furthermore, if in Pudong at the Huang-Pu river of Shanghai apartment and business buildings with altitudes of 350 to 420 m are built in a weekly rhythm, why should it not be possible in European cities and towns to enlarge buildings or building groups by some aAlpiq solar wall: In Geneva, the technological department of Alpiq presented a solar wall with micro-amorphous solar cells from Oerlikon-Solar and designed in cooperation with SUPSI. Installed on the facade, this wall produces approximately 85 kWh/m2a. With mono-crystalline Sunpower solar cells (offered in 2009) with an efficiency factor of 19.1%, an energy-production of ^ 130 kWh/m2a would be possible (see also Swiss Solar Prize 2009, Bennau, p. 32/33). bScientific American loc. cit, p. 60; Spectrum of science, 12/09 p. 84 ff.
floors? Adaptations of roofs and facades with an integration of PV installations allow an optimum use of solar energy. If 25 years ago, solar-powered light vehicles were able to drive across whole continents, and projects of CO2-free hotels and business buildings were realised (see Figs. 44.1 and 44.50), these environmental – friendly technologies should finally be implemented on a large scale, especially in the building sector. Not only new buildings should be PEB, but also refurbishments should result in PEB by preserving the appearance of the townscape.