Tokyo hopes ‘solar roads’ lead to greener power grid

TOKYO >> The Tokyo government intends to introduce new “solar road” technology to collect energy from the sun via solar panels installed beneath the surface of roads and “power-generating floors” that generate electricity by utilizing the vibrations created by people walking.

The effort is aimed at promoting Tokyo as an eco-friendly city ahead of the 2020 Olympics and Paralympics. The new technologies, which have been attracting attention, are expected to be introduced on a trial basis at facilities owned by the government as early as next year.

In late May, 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 automobiles to drive over the panels. Solar roads have been deployed as 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 percent of the entire electricity the store consumes.”

The Tokyo government has focused on technology to advance renewable energy sources.

It set a goal of having renewable energy account for about 30 percent of Tokyo’s power consumption by 2030, compared to about 12 percent in 2016.

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 $5.8 million to install .6 miles of solar road.

Therefore, the government plans to pick locations at metropolitan government-owned facilities such as parking lots, where the amount of electricity gained by installing the system would justify the cost.

Power-generating floors are created by using 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 132-pound 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, passageways can be lit so people can walk safely. A major home builder and a road construction company have already introduced the new technology.

This summer, illuminated power- generating floors will be installed on sidewalks and bridges that don’t have streetlights in Brazil as part of the Japanese government’s official development assistance program.

The Tokyo government is discussing introducing power-generating floors in locations such as metropolitan 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 Corp. President Kohei Hayamizu said, “I hope our product will lead to realizing a society that utilizes energy that would otherwise be wasted.”