Tokyo hopes solar roads lead to a greener power grid

The effort is aimed at promoting Tokyo as an eco-friendly city domestically and abroad ahead of the 2020 Olympics and Paralympics. The new technologies, which have been attracting global attention, are expected to be introduced on a trial basis at facilities owned by the Tokyo government and other locations as early as next fiscal year.
In late May this year, a solar road was installed in the parking lot of a 7-Eleven store in Sagamihara, Kanagawa Prefecture.
The solar road comprises a system of solar panels installed on the road, with the surface of the panels covered with a special resin to enhance durability making it possible for cars to pass over them. Solar roads have been deployed on motorways in France and as cycling roads in the Netherlands.
A manager at the 7-Eleven store said: “[The solar road system] can generate 16,145 kilowatt-hours of electricity annually, covering about 9 per cent of the entire electricity the store consumes.”
The Tokyo government has focused on the new technologies as potential renewable energy sources.

High cost
It set a goal of having renewable energy account for about 30 per cent of Tokyo’s power consumption by fiscal 2030, compared to about 12 per cent in fiscal 2016.
The Tokyo government said there were no restrictions in terms of locations for installing the solar road system, which increases the possibilities for expanding renewable energy.
The problem with introducing solar roads is the high cost. As the technology has not spread widely, its components are not mass-produced. In France, it is said to cost about 5 million euro (about Bt188 million) to install one kilometre of solar road.
Therefore, the metropolitan government plans to pick locations it owns, such as parking lots, where the amount of electricity gained by installing the system would justify the cost. This will be part of preparations for the trial introduction of the technology, which is scheduled for fiscal 2019 or later.
The metropolitan government hopes that putting Tokyo at the forefront of the technology will help the spread of solar roads across the nation.
Another new technology the Tokyo government is considering introducing is power-generating floors. The technology uses special ceramics that produce voltage when pressure is applied, converting the vibration of footsteps into electricity.
According to Soundpower Corp, which developed the power-generating floor, when a 60-kilogram person walks on the floor at two footsteps per second, it generates an average current of about 2 milliwatts of electricity. The energy of each step can momentarily light up 300 to 400 LEDs, said the company, which is based in Fujisawa, Kanagawa Prefecture.
By installing power-generating floors on stairs and in hallways inside buildings, even during power outages caused by disasters, the floor will be lit at night so people can safely walk there. A major home builder and a road construction company have already introduced the technology.
This summer, power-generating floors are scheduled to be installed on pavements and bridges that don’t have streetlights in Brazil as part of the Japanese government’s official development assistance programme.
The Tokyo government is discussing introducing power-generating floors in locations such as hospitals and exhibition facilities.
“The amount of electricity generated by the floor is small, but its energy-saving effect would be huge,” an official  said.
Soundpower president Kohei Hayamizu said, “I hope our product will lead to realising a society that utilises energy that would otherwise be wasted.”