Electric road

Irisbus Cristalis trolleybus using overhead power lines in Limoges, France, 2015

Bordeaux tram using ground-level rail power supply near the Roustaing tramstop, 2006

OLEV bus using ground-level wireless dynamic charging, 2016

Overhead power lines have been used for road transport since at least 1882 in Berlin with Werner von Siemens's trolley buses. Over 300 trolley bus systems were in operation in 2018. Power to trolley buses is normally delivered using a pair of trolley poles positioned on top of the vehicle which extends to the overhead power lines. Implementations for highway vehicles have been developed in the late 2000s and 2010s[5]^: 15 but they are not suitable for non-commercial vehicles such as passenger cars.[2]^{: Appendix D}

Ground-level power supply in the form of electrified rails is similar to overhead power lines in implementation. Instead of an arm or pole extending to overhead power lines, a mechanical arm extends from the bottom of the vehicle and aligns with a rail embedded in the road. The rail is then powered, and power is transferred through the arm to the vehicle.[5]^: 16 Ground-level power supply is considered aesthetically preferable to overhead wires[5]^: 20 and it is suited for all types of vehicles.[2]^: 24

The concept of a wireless ground-level power supply for vehicles was first patented in 1894. A static-charging system for shuttle buses was demonstrated in New Zealand in 1996.[5]^: 13 Similar systems have been implemented by Conductix-Wampfler and Bombardier PRIMOVE, which were later developed from static charging at bus stations to dynamic charging while driving.[2]^{: Appendix B}

Development of electronic road systems has grown significantly from the late 1990s through the 2010s.[2]^: 12–22 Several companies have developed and implemented electric road systems in the 2010s.[2]^{: Appendix B}

A report generated by TRL in association with the Swedish Transport Administration listed available electric road systems, of which KAIST OLEV, Siemens eHighway, Elways, Elonroad, Bombardier PRIMOVE, and Electreon were found to be the most commercial-ready, with OLEV and eHighway already possessing a complete system in 2018.[2]^: 13–15 The project funded electric roads with overhead power lines, and ground-level conductive rails and inductive coils.

Overhead power lines were first tested through the project, using Siemens eHighway technology. The road was opened in June 2016 in Sandviken municipality near Gävle in central Sweden. A 2-kilometre stretch of the E16 motorway was fitted with trolley wires 5.4 metres above its surface, which supply power at 750 volts DC. Trolleytrucks can connect the power pickups, mounted on mechanical arms or trolley poles, while driving under the wires. The trolley poles allow for a degree of lateral movement, but if the lorry is steered into the outside lane, the trolley poles are lowered automatically and the lorry switches to battery or diesel power.[8] The system is capable of delivering 500 kW of power and has a maintenance period of 20 years.[2]^{: 140–144}

Electric truck driving on a public road with Elways ground-level power supply, near Arlanda airport, 2019.

Ground-level conductive rails, i.e., electric rails in the road that transmits energy to a vehicle through a conductive pickup under the vehicle, were tested from 2017 to 2019, using technology by the company Elways and a rebuilt 18-t DAF truck. A 2-kilometre stretch in one direction of road 893 between Stockholm Arlanda Airport cargo terminal and the Rosersberg logistics area 12 kilometres away was fitted with embedded conductor rails as part of the eRoadArlanda project. The project involved major international companies, small local businesses, national government agencies, local government, local property owners and academic partners.[9] Short sections of the rails were energized when a compatible vehicle approached and disconnected once the vehicle had passed. The system measured the energy consumed, so that the vehicle owner could be billed.[2]^{: 146–149} Buses and trucks were tested on the road,[10] but the system could also be suited for electric cars. Safety tests were run to ensure that the rail was safe to touch even when the road was flooded with salt water.[11] The system was capable of delivering 200 kW of power and had an expected maintenance period of 20 years.[2]^{: 146–149}

Ground-level conductive rails are scheduled to begin testing in 2020 using technology by Elonroad, a Swedish startup located in Lund. The project EVolutionRoad is a three-year test and demonstration project that will run 2019–2022.[12] The first stretch of road was inaugurated in June 2020[13] and is the first electric road system placed in an urban environment. A conductive pickup under the vehicle connects to the rail via sliding contacts, and the rail is only active one meter at a time when covered by the vehicle, making it safe in a city environment. The system measures the energy consumed, so that the vehicle owner can be billed. The system is capable of delivering up to 300 kW with 97% efficiency while driving.[14]

Ground-level inductive coils are scheduled to begin testing in 2020 using technology by Electreon, an Israeli startup.[15] The system is similar to the eRoadArlanda project, with short sections made of copper coils that energize when a vehicle is driving over them and disconnect when it is passed that enable the use of power metering and a billing system for the energy consumed. The system is capable of delivering 50 kW of power and has a maintenance period of five years.[2]^{: 171–172}

A 2019 report by the Swedish Electromobility Centre estimates the annualized societal costs of the entire Swedish automotive fleet under each of the three systems. Overhead power lines, despite having the most mature technology and least expensive infrastructure, are the most expensive overall because they only allow tall commercial vehicles such as trucks and buses to charge while driving, while non-commercial vehicles cannot use the wires to charge while driving, so they will have to use static charging that requires larger batteries with higher capacities than batteries required with the use of dynamic charging. Ground-level power supplies allow dynamic charging for all vehicles, which greatly reduces the required battery capacity and size since the battery is charged while it is being used. The reduced battery size and capacity reduces cost by about five billion euros annualized for the entire Swedish automotive fleet. The two types of ground-level power systems are estimated to have equal costs for all the components in aggregate other than infrastructure; the conductive rail infrastructure is estimated to cost about 1 billion euros annualized, while wireless inductive infrastructure is estimated to cost about 2.8 billion euros annualized.[1]^: 10–11

The Indian Government is planning to trial an electric highway (e-highway) on the under construction Delhi–Mumbai Expressway within the next three years to boost electric mobility in the country.

Bombardier conducted a dynamic wireless power transfer trial in Mannheim, Germany, in 2013.[16]^: 9 Germany launched an overhead power line electric road in May 2019 on a 10 km (6.2 mi) section of Bundesautobahn 5 south of Frankfurt. The project is operated by the ELISA consortium which includes Siemens and Scania.[17]

Highways England began a dynamic wireless power transfer project in 2015[18] but the project was cancelled in early 2016 for budgetary reasons.[19]

In May 2023, ENRX won a contract to build a one-mile wireless charging system capable of charging at up to 200 kW on State Route 516 near Orlando, Florida.[20]