Environment

Recovering power from transport and motion

30/05/2016
Recovering power from transport and motion

Capturing kinetic energy, or the energy generated by an object in motion, could prove to be an alternative to energy from traditional sources, such as fossil fuels, in energy efficient systems. Kinetic energy recovery is already used in, for example, Formula 1 motor racing, where the energy generated by racing cars when they brake can be stored and subsequently used for acceleration.

In the United Kingdom, the London Underground tested in 2015 the recovery of energy from braking tube trains. The results showed that such systems could be effective – Transport for London calculated that roll-out of the technology could cut its energy bill by 5%, or £6 million (€7.7 million), each year.

In Portugal meanwhile, researchers are experimenting with the kinetic energy generated by people and cars. A Portuguese university-based start-up, Waydip, developed a prototype paving slab that will depress slightly when people or vehicles move over it. The slight movement – a dip of up to 10mm – is enough to generate a small electrical charge that can go into a battery or be fed into the power grid for later use.

Recycling energy from roads

Waydip researchers installed a prototype similar to a speed bump in a car park access road at the University of Beira, northern Portugal. They tested different vehicle weights and speeds, and found that for vehicles of the same weight, the electricity generated increases at higher speeds, though the rate of increase declines as the speed goes up. Compared to earlier tests, harvesting the kinetic energy generated from people walking across similar devices in pavements, the researchers found that vehicles produce a much greater amount of energy.

From the prototype installed at the University of Beira, during a one hour period of peak traffic about 10.5 watt hours of energy (or 10.5 watts expended for a duration of 1 hour) was produced. It is a small amount of energy – enough to power a low-energy light bulb. However, the power output could be significant if the technology was installed across a whole road network.

Waydip researchers will continue to refine their technologies, which are known as the Waynergy People and Waynergy Vehicles systems. Further testing is planned in pedestrian crossings and on urban roads. In the most recent paper summarising the developments so far, the Waydip researchers concluded that “the enormously high level of traffic on municipal and urban roads will allow the production of a considerable amount of electric energy, reduce the consumption of fossil fuels and thus improve the quality of the environment.”

Further information:

Transport for London information on energy recovery tests: https://tfl.gov.uk/info-for/media/press-releases/2015/september/recycling-energy-from-tube-trains-to-power-stations

“Waynergy Vehicles: an innovative pavement energy harvest system”, paper in Municipal Engineer by Francisco Duarte, Joao Paulo Champalimaud and Adelino Ferreira, November 2015: https://www.researchgate.net/publication/271836659_Waynergy_Vehicles-An_Innovative_Pavement_Energy_Harvest_System