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Materials Mobility

349: Photovoltaic road surfacing

Problem:

Perhaps the most common and useful characteristic for roadways around the world is the enormity of their surface area. Roadways which could generate electricity for even a fraction of the day, could contribute to local power demands.

Solution:

In 2014, Colas, a world leader in transport infrastructure teamed up with the INES (French National Institute for Solar Energy) to install 710 ft² (66m²) of solar road which they called Wattway on a carpool area in Narbonne (Highway A9, exit 38). The goal of the installation is to provide a clean energy, stored and then used to power roadside equipment locally (here, the light for the pedestrian path).

Wattway’s panels are thin polycrystalline solar cells, and each module is composed of 28 cells. Even after being embedded in resin, the cells are thin enough that they won’t peel off the road during normal expansion and contraction.

The next pilot test was undertaken in a small town with a 1-km stretch of solar pavement. This one section produced enough power to light the village’s street lamps and cater to its 3,400 residents. In fact, 215 ft² (20 m²) of these panels can supply the electricity requirements of a single home. In 2019 Wattway presented their product at the “francophone village” at CES Las Vegas 2019 and among 80 startups and companies, Wattway won the silver Smart City award as well as the second “Grand Jury Prize”. (wattwaybycolas.com)

In December 2017, China opened its 0.6 mi (1km) solar highway in the Shandong province’s capital Jinan, south of Beijing. It spans 63,234 ft² (5,875 m²) and is capable of generating up to 1GWh every year – enough to power 800 homes. However, the Chinese government plans to use the electricity created by its solar highway to power street lights, billboards and CCTV cameras, as well as to heat the roads surface to melt any snow that gathers on it.

In its first 14 weeks in operation, the road generated 96 megawatt-hours of energy. Once completed, the road will be able to use the sun to generate electricity, which will be transmitted into the grid. Its peak power generating capacity is 817.2 kilowatts, over a designed service life of 20 years.

Funded by Qilu Transportation Development Group and built by Pavenergy, the Chinese solar road was developed by chief engineer Zhang Hongchao at Tongji University’s College of Transportation Engineering.

Solar roads can also provide energy to electric vehicles. ElectReon Wireless in Israel has developed a dynamic wireless power transfer (DWPT), which enables energy exchange between all vehicles moving along the road. This technology combined with a renewable source (such as solar panels) could provide a nearly endless power supply to various EVs.

It is capable of both powering vehicles without a battery and charging a battery connected to the vehicle. A major advantage of this technology is the high efficiency and safety: DWPT operates with more than 88% efficiency and has no safety concerns for surrounding wildlife or human users. The system began trial testing in March 2016 in Tel Aviv.

Additional tests are up-coming, with a public transportation use-case and a commercial development installation. A trial section laid down on a coastal route of Bett Yanai, Israel succeeded in transferring 8.5 kW of energy with a 91% efficiency recharging a Renault Zoë in transit. ElectReon has signed an collaboration agreement with Renault-Nissan-Mitsubishi alliance.

ElectReon will also supply their DWPT system for a 1 mi (1.6 km) electrified road as part of a 2.5 mile (4.1 km.) highway between their airport and Visby on the island of Gotland. In February 2020 ElectReon successfully wirelessly charged a fully electric 40-ton truck and trailer at a test facility in Sweden. The next step will be to charge the truck through dynamic wireless power transfer on the public road in Gotland, Sweden. (electreon.com)

Discover Solution 350: Steel production using solar power

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