If current trends are anything to go by, in future we will no longer produce all our electricity in large, central power stations. Small-scale local electricity generation will gain in importance. Sander Mertens, a post-doctoral student at TU Delft, developed the aerodynamic design of a wind turbine which is specifically suitable for built-up areas. Compact, mobile, low-noise, and vibration-free, it is the ideal alternative for use on top of high-rise office blocks, where wind speeds can easily reach twenty percent more than with the same height away from buildings. The electricity can be fed straight into the buildings power system, saving on energy transport costs and losses, and producing high feed-in yields. Prototypes have already been installed on the town hall in The Hague (designed by Richard Meier), on an apartment block in Tilburg, on an office block in Breda, and on top of the Delft ChemTech faculty building. Interest has been generated in London and Leicester in the UK, New Mexico and New York in the USA, and in France and Canada.