Energy harvesting everywhere
Energy is everywhere, and its wasted everywhere.
small fans could be build in the drain, water- tap (like the fans already used for measuring the water consumption), everywhere where a fluid or a gas flows.
small generators could be build in door knobs, knobs of basins, in exercise machines of gyms, everywhere where something is turned.
piezoelement could be build in floors, walkways, streets, everywhere where something is pushed.
Solarcells could be attached to walls, car tops, and all sort of devices.
What do you think, besides of the robustness of these small generators, is the biggest challenge for these devices to penetrate our daily life? Cost? Compatibility? Ease of use? Market acceptance?
I think one big challenge would be to make the devices fit existing infrastructure easily (eg flexible dimensions for different diameters of drains) and the energy / battery management. since different devices would produce different, and also fluctuating electricity, electronics to adjust the current and battery (cost and size as challenge) for the storage would be needed. a solution of that could be to not use a central energy management, but use the energy where its created, eg use the energy of flowing water to directly heat it again.