We’ve all been there – discovering our battery is dead just when we need to make an important phone call while on the way somewhere. The fear of not being online when out and about, not being able to make a phone call, check e-mails or go on Facebook, is widespread – in fact, there is even a technical term for it: “nomophobia”, or no-mobile-phone phobia. Researchers, IT experts and companies around the world are busy developing new autonomous power sources for mobile applications and sensors. “Micro energy harvesting” (MEH) refers to a whole host of different ways to “harvest” energy, potential sources including motion such as that generated during walking or dancing, vibrations like those produced by shock absorbers in trucks or washing machines, and waste heat from engines and industrial facilities. Air flows, braking energy and sound and electromagnetic waves can also be “tapped”, generators of many different types being used. As yet, the global MEH market – encompassing anything from bicycle dynamos and hand crank mini transistor radios to solar-powered parking ticket machines – is still small, turning over only a few hundred million euros per year, according to US industry analyst IDTechEx. All the same, there are increasing signs that a boom is imminent, latest forecasts predicting that 2.1 billion euros could already be generated in ten years. The lion’s share of this is likely to be attributable to entirely novel products – such as shoe inlays which supply power to charge mobile phone batteries, energy-producing jackets and trousers, wireless light switches without a battery, car lights which use the heat given off by car exhaust pipes, or self-sufficient vibration meters on bridges or high-rise buildings.
German energy harvesting projects
In its “foresight process”, Germany’s Federal Ministry of Education and Research identified energy harvesting as one of the fields of technology which could become particularly important this decade – and should therefore be provided with greater funding. A number of German research groups and industrial companies are already working on concrete projects in this sector. A team at the University of Freiburg for example is developing pressure-sensitive trainers which can be used to run a pulse monitor or stopwatch, while the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology (FEP) in Dresden is dedicated to improving and miniaturizing piezoelectric systems which derive power from vibrations. Well-known companies like Bosch have also recognized the potential of MEH, however. Udo Gomez, head of R&D at Bosch subsidiary Sensortec, explains the strategy: “The goal is to design products such that they generate their own energy.”