It’s been clear for some time that reliance on fossil fuels is being replaced by a search for cleaner energy. One concept for the future is power roads: highways that can turn the very idea of roads as conduits for conspicuous energy consumption on its head.
There are a variety of technologies in development that will allow roads to generate their own power, which can then be used to sustain vehicles and even potentially to contribute to the national grid.
Football leads the way
Plans are afoot to include energy-generating elements into the asphalt. The technology has already been applied to football pitches, shops and airports – tiny amounts of energy are harnessed from the kinetic pressure of footfall to power lights and other related infrastructure.
Power roads can also potentially be used to charge electric vehicles. Economies of scale could make this feasible as electric vehicles become more efficient and more popular, but the idea is already being applied to public service vehicles.
In the South Korean town of Gumi, a 12km length of road was launched in 2013 which allows buses to be charged as they drive along it. Electric cables buried under the road generate electromagnetic fields, which are then picked up by a coil on specially equipped buses and converted into electricity.
A less ambitious system has also been trialled in Milton Keynes but it requires buses to stop for several minutes while the charging takes place.
High cost is still a debilitating factor, but government agency Highways England is continuing to run trials and has revealed long-term plans to install plug-in charging points every 20 miles on its motorway network.
Beyond induction charging
Elsewhere, agencies are employing some complicated calculations to make the numbers work. This involves working out the amount of energy it takes to build the road in the first place and balancing it against the potential payback.
For instance, the Norwegian Public Roads Agency is developing a ‘ferry-free’ E39 highway over the fjords in western Norway. The project will involve a large number of bridges, offering plenty of opportunities for wind, sun and wave-generated energy. It would include solar panels on bridges, wind turbines integrated into key points of the highway and energy derived from water below the bridges.
Key to the project’s success will be the re-use of stone that’s dug up during construction, rather than transporting it to disposal sites, as is often the case in standard road building.
Power roads hold great potential for the future of transport, but there’s still a lot of research and practical trials to go before our roads will be able to produce more energy than we expend on them.
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