piezoelectric roads

Around the world, several projects have proved that it’s possible to generate electricity from traffic – including moving vehicles, cyclists and even pedestrians. These projects involve the use of solar or piezoelectric roads.

What are piezoelectric roads?

Piezoelectric roads use crystals embedded in asphalt to convert pressure and vibrations into energy.

The crystals, placed about 5 centimetres below the surface of the asphalt, slightly deform when traffic travels across them. This produces energy.

Theoretically, the system can produce one kilowatt hour (kWh) of electricity for every 12 metres of road. To achieve this rate, the system must be implemented on fast, busy roads.

Piezoelectric systems in use

In 2008, a piezoelectric system was installed in Tokyo by the East Japan Railway Company.

A piezoelectric floor in Tokyo Station, pictured, uses energy from footsteps to power ticket gates.

piezoelectric systems

Source: Inhabitat

In 2009, Israeli firm Innowattech ran a pilot project along a stretch of highway in northern Israel.

It claimed that its piezoelectric devices, if planted along a one-kilometre stretch of road, could provide an average of 400 kW of power, enough to power 162 homes. 

Nightclubs in San Francisco, London and Rotterdam have each used a piezoelectric system under “green” dance floors. The diagrams below show how the dance floors generate piezoelectric energy.

dancefloor power

dancefloor power

Source: The Green Optimistic

Piezoelectric road testing – what was the outcome?

A number of studies have been conducted to assess the energy production capabilities of piezoelectric roads, including studies in the UK, Italy and the US.

The Israeli project claimed that if planted along a one-kilometre stretch of road, piezoelectric devices could provide an average of 400 kW of power, enough to power 162 homes.

Yet, according to Stanford University researcher Rex Garland, data suggesting that piezoelectric energy harvesting is a competitive, clean alternative energy source is exaggerated.

Garland believes that generating capacity is considerably less than studies report.

He says the data in the Israeli study is over-estimated and that it would generate enough energy to power about 15 homes at most.

He adds that there are other “costs” to consider besides the extensive financial costs of manufacture and installation, such as the environmental impact of manufacturing the piezoelectric crystals.

Garland says that while piezoelectric devices are gaining popularity, they’re less capable than previously hoped.

Solar roads and how they work

Another way to harvest energy from roads is placing photovoltaic modules or sheets on top of a road to capture solar energy.

In theory, just 20 square metres of solar road should be able to generate enough electricity to power a single household.

The world has more than 16-million kilometres of tarmac roads that could be utilised.

car on solar road

Source: Science Alert

Examples of solar roads and pathways

A 2,800 square metre stretch of road in France, pictured above, has been converted into what is thought to be the first solar road in the world.

The road is covered in solar panels that are protected by thin sheets of silicon in order to handle the weight and wear of the traffic.

In the Netherlands, a bike path with photovoltaic cells embedded in the concrete generated 3,000 kWh in its first six months – enough energy to power a household for a year.

The challenges of solar road technology

Roads have to be able to take a massive amount of wear and tear from vehicles.

Any photovoltaic surfaces that are placed on the road have to be able to handle the same amount of daily stress.

The solar road in France, pictured below, started cracking after three years and parts of it had to be demolished.

cracked solar roads

Source: Science Alert

The energy production fell short of expected levels, making the expense of implementing the system on a broader scale unjustifiable until the technology improves.  

Motor graders and new road technologies

All kinds of new technologies are starting to influence the ways roads are designed, built and maintained. Along with making electricity from traffic, researchers continue experimenting with new road materials and increasingly sophisticated road-building tools.

One thing hasn’t changed, though – it still takes a trusty motor grader to get road grading done!

At KH Plant, we specialise in restoring Caterpillar 140G, 140H and 140K motor graders and components to as-new condition – so you can get the benefits of a new motor grader at a fraction of the cost of a new machine.

Contact us for more information or to discuss your needs.

Contact us for more information