The role of energy harvesting is now better understood than ever

Over the last two or three years I have seen a rapid maturing of industry’s understanding of the potential, pitfalls and practicalities of energy harvesting technology.

This process has paralleled the development of use cases for the Internet of Things, and this isn’t surprising, as it is largely for IoT applications that energy harvesting will be developed. If millions – or billions – of devices are going to be connected to the Internet, mostly doing pretty basic things like measuring and communicating a value for one or two specific physical characteristics, then it would be hugely helpful if they didn’t all need wiring up, or need their batteries changing every few days or weeks.

Energy harvesting – the extraction of usable power from the environment to reduce or eliminate the need for external power sources or batteries – comes in many flavours. The sources of energy can be electromagnetic (from heat at one end of the spectrum, through light to radio waves), mechanical (vibration and other cyclic motion, and single impulses), and can make use of many physical effects to convert the energy into usable electricity. Often the electricity is used to carry out some active sensing and to communicate the sensor data wirelessly over local or wide-area communications networks, and wireless communications must be thought of as an intrinsic part of energy harvesting design.

The challenges of capturing and using harvested energy are formidable. One place that developers of energy harvesting concepts have struggled in the past is the need to design a solution as an end-to-end system, so that due care can be taken to ensure that energy is not wasted anywhere. This is harder to achieve in practice than it sounds. For instance, power management circuitry is often designed on a bespoke basis for each application and manufactured in relatively low volumes, meaning that costs can be high. For some IoT applications designed for mass-market consumer or business use, such an approach is unsustainable and more integrated solutions or the use of commodity low-power processors and power management chips will be needed.

I am encouraged at the IDTechEx Show in Berlin that companies across the value chain understand these issues – even if they don’t always have a holistic view, or capability, in-house. One exhibitor that certainly does have end-to-end expertise is the University of Exeter’s Energy Harvesting Research Group, led by Professor Meiling Zhu. Her team has not only developed a novel adaptive power management module that has performance benefits over commercial alternatives (and which is being further enhanced currently) but it also has a system-level test-bed to help in developing energy harvesting for new products and solutions, and has demonstrated innovative work in aerospace applications.

Energy harvesting is developing well: IoT has given it  a real impetus. I will return to energy harvesting in future posts, where I will round up the most interesting developments from IDTEchEx Berlin, and give more analysis of individual technologies and their uses and commercialization status.

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