Collecting ‘waste’ energy generated as a by-product of other processes and bringing it quickly to more useful application in something of a holy grail among energy technologists. One area with a lot of potential for energy harvesting is in the pipes delivering water to homes and businesses.
New technologies aim to harness excess pressure within water mains, which is caused when water is stored higher than the customers it serves, flowing downhill to reach them. It really is the oldest trick in the book when it comes to tapping kinetic energy, and offers the chance of electricity generation all day, every day.
The pipes under Lower Gwynedd in North Wales are one of the first notable areas of the UK where this innovation is being tested - and the expectation is that the kit will pay for itself within five years. With Environment Agency research suggesting that the water industry accounts for up to three per cent of the total energy used in the UK, but acknowledging huge potential for increased renewable generation, the success of such early applications may determine whether more low-carbon electricity will be literally in the pipeline.
Recovering energy from other everyday processes is an idea that easily captures the imagination. In recent times there have been a number of stories on the potential of various applications. A big favourite is the energy-generating shoe; with a new model utilising electromagnetic induction to harvest from both foot impact and ‘swing’ gaining column inches last month. It’s fair to say, though, that not all pundits are totally convinced by such inventions.
In this piece, Bill Ray,believes that many applications of energy harvesting - particularly those relying on human bodies or the air - are not going to provide the consistent and significant energy a joined-up world needs:
“The problem with energy harvesting is that there really isn't very much energy to harvest...There are many more companies making harvesters than companies making products which use them, for the moment at least... When Things become self-powered it opens up a huge range of possibilities, but we're only just starting to understand how to exploit them.”
He suggests that the future for small-scale energy harvesting is in sensors that generate enough power to tell us about the world around us in a self-sustaining way. He cites smart switches that use the energy of being pushed, a sensor which tells power companies when electricity is being stolen from the grid (without using any itself), and a sensor that gathers data on the performance of trains while powering itself from the vibrations of motion.
Energy harvesting technologies that can communicate data wirelessly could be a building block in the creation of ‘smart cities’ - and industry experts are quick to suggest that such technologies are on the cusp of a major mainstream breakthrough.
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