area 122 | sustainable way

architect: Renzo Piano Building Workshop

location: Rovereto, Italy

year: 2011

The new wind generator belongs to the “mini wind turbine” category; it is compact but nevertheless produces about 55 KW. The design features a light and transparent structure with some parts in steel and others in carbon and polycarbonate, so that it tends to disappear in the sky, just above the treetops. Its strength lies in its simplicity. These generators will tend to merge into the landscape, but those who manage to recognize them will have the opportunity to admire a product of advanced structural technology and sophisticated aerodynamic engineering. The beauty is that of an organic machine that, unlike the current ones, always moves like an agile, suspended little dragonfly. And this will facilitate its distribution.
The image will remind of the thin, ethereal rigging of sailing ships. The axis of the turbine is horizontal, and the height of the tower about 20 metres. Unlike the present structures, the latter will be much thinner, with a diameter of only 35 cm thanks to the use of a system of pre-tensioned wires, while the diameter of the rotor blades is 16 metres. All the structural and mechanical parts, blades and gondola have been re-designed, simplified and rendered very light, thus reducing friction and internal consumption. The machine has obviously been designed with an eye to the costs, to assure the final product is reasonable and not too expensive.
One of the features that contribute to reduce the visual impact of the machine is the vertical alignment of the blades, which appear as a part of the tower when there is no wind. Innovative technical solutions comprise the use of high-performance carbon fibre and polycarbonate for the blades, an active control of the angle of incidence of the blades, the connection of the blades which derives from aeronautics, the double aligned generator used to produce the specified power, which makes it possible to reduce the frontal volumes, and the tail rotor which also produces electric energy. The aerodynamic shape of the extremely light blades and the system of active control of the pitch make it possible to start the machine even with very little wind, thus limiting periods of inactivity and increasing annual energy output. There are three generators that produce electricity: two main ones aligned on the main axis of the gondola, which are connected both mechanically and electrically in sequence. The third, smaller one is in the hub of the tail rotor. Both main generators are connected to an independent converter/inverter pair, to guarantee the redundancy of the electrical apparatuses and thus greater reliability.
When the wind is strong the management of the transistors, and thus the operation of both generators, is activated.