One Step At a Time

Piezoelectric tech can make the most of every little bit of energy

Every step you take is full of potential. It’s not just in what you can accomplish, but with physical energy. With or without a pep in your step, each time you set a foot down, you release energy into the ground. Harvesting that piezoelectric energy is the mission of Pavegen, the maker of tiles that can absorb that energy and turn it into lasting power. The industry’s mission doesn’t end there, though, as the technology might scale to bridges and roadways, soaking up the power that cars and trucks vibrate into the surface.

First Steps

Pavegen’s kinetic floor tiles, made almost entirely from recycled tires, produce between 2 and 5 joules of energy per step, enough to power an LED streetlight for 30-60 seconds. Installed in high-traffic areas, they can generate enough energy to light the space. Scale that up enough, and you’re starting to see some real energy savings. That’s why piezoelectric energy works so well in places where people gather.

A dozen tiles Pavegen placed near London’s Olympic Park during the 2012 Summer Games attracted more than 12 million footsteps, keeping the lights on in a nearby tube station for five hours each night. At the Abu Dhabi Airport, which sees 2 million passengers pass through annually, Pavegen tiles light interactive displays and data screens. At Berlin’s 2017 Festival of Lights, 176 tiles powered a 26-square-meter light installation for 10 days. Pavegen triangular tiles lit up a purpose-built mini-park in Washington, D.C.’s, Dupont Circle. On their own, these projects are small. But they pave the way to something greater.

“Imagine this on a large scale, in cities with millions of people walking over it every day,” deputy British ambassador to the U.S. Patrick Davies told the Washington Post. “Whatever your views, it’s generating power for low cost, and it’s completely renewable because people are going to walk along here all the time. So what’s not to like?”

Part of a Smart City

That’s the dream for Pavegen, which strives to be part of the smart city infrastructure. Take installations such as the one at Hong Kong’s Quayside, where an indoor track made from Pavegen tiles helps people connect their own well-being to the city’s sustainability, making citizens an integral part of their city’s vibrancy. They can help power transport hubs, which highlights and encourages use of public transport. At schools, they can impress upon children the importance of renewable energy sources while providing fun as they jump on the tiles to see how much energy they can produce.

“The smart city is one where everyone communicates with each other, and power is directed to where it is needed. Energy harvesting is a technology that can both produce the power and send the data that’s needed to link everyone together and use energy more efficiently,” Pavegen founder Laurence Kemball-Cook told the Guardian.

For now, much like the Energy Floor kinetic dance floors that have helped power Coldplay concerts, Pavegen’s tile installations might have more of a symbolic function rather than making a major difference in terms of renewable energy usage. Where piezoelectric energy might make more of a tangible impact is on roads and railways.

Where the Road Might Go

Proof of concept for harvesting piezoelectric energy from cars has happened in Israel, where Innowattech collected 2,000 watts per hour on a 10-meter platform in regular traffic conditions on the country’s main north-south highway. The cars’ weight, motion, vibration, and temperature all contributed kinetic energy, which batteries on the side of the road stored. In theory, a complete four-lane highway with such technology under the surface could capture a megawatt-hour of energy, enough to power 2,500 homes. Calibrating the collection sensors on a large scale has proved an obstacle, however.

That vibrations can provide harvestable energy is a welcome development. It means that any machine in any factory can be a source of piezoelectric energy. Perpetuum, a U.K.-based company like Pavegen, has found a way to harvest it, from manufacturing machines and train cars. The vibrations power sensors that monitor the machines’ performance and for predictive maintenance that saves energy, emissions, and productivity. Perpetuum’s tech caught the eye of Hitachi, which bought the company and made it part of its rail division in 2020.

“Being part of Hitachi will present vital opportunities that only a global transport giant can offer,” Perpetuum CEO Steve Turley said.

Scaling up piezoelectric energy can add important contributions to the further development of renewable energy and pave the way for net-zero communities. The journey of 1,000 miles begins with a single step. And there’s energy in each one.