Piezoelectricity, a technology transforming humans into generators
Dance like you were a super-hero
« There’s enough energy in this world, you just have to use it the right way, ». That’s what Mr Smit said in 2008 about the way his Watt Club in Rotterdam enlightened the dancefloor. In fact, the club -which is deemed to be the first sustainable club in the world- is generating a part of its club’s electricity by harvesting the energy produced by vibrations of people’s steps unleashing themselves on the dancefloor. However, these daily heros have only babies’ super-power : one person dancing produces about 20 watts, which means two persons would only light a bulb.
What is this power by the way ?
The act of generating energy through steps is the piezoelectric phenomenon. Piezoelectricity -comes from the Greek word piezo meaning « to squeeze » or « press »- is the ability of some materials to produce electricity thanks to mechanical pressure. The inverse phenomenon is also true : piezoelectric materials deform when voltage is sent to them. This physical phenomenon was discovered by Jacques and Pierre Curie in 1880 while they where applying some pressure on quartz. In fact, multiple materials have piezoelectric caracteristics, but the most used are crystals (quartz) and ceramic – this last one being the most used in industry because of its cheaper cost.
A green power !
However known for a long time already, the potential of this technology could not be exploited to its maximum until recently because of the lack of money invested in it- as always with technological progress would you say. But, better late than never, with all commitments taken by governments at the end of the last century in order to reduce their carbon footprint and all efforts deployed to fund renewable energy, piezoelectricity projects started to develop. Indeed, this technology, as photovoltaic, is a green and clean one : it uses physical phenomenon already existing on earth, without releasing greenhouse gaz, all this for free ! If you pass over the price of the technology : not less than 1000€ one square meter of the paving stone…
I’m sure, you can do it and save the world
In spite of the uncompetitive price of this tehnology, some examples of use can already be seen, and a way more are to be. The Londonian start-up specialised in piezoelectric paving stone, Pavegen -which had already equiped the Watt club- had the opportunity in 2014 to transform a Brazilian football field into a piezoelectric generator or again, in 2015, to equip SNCF’s Paris office floor with 6 of its paving stones. More recently, in 2017, California’s government funded an experiment willing to harvest cars vibrations into electricity thanks to a piezoelectric road. Will this road be sufficiently powerfull to make profitable the investment ? Indeed, piezoelectric productivity is pretty low : between 1 to 4 joules by step. No matter what, one thing is sure : investing in that clean energy is a politial act betting on the futur.