The concept of electric highways

The concept of electric highways

The concept of electric highways has been spread all over the world since 2012 by Siemens.
According to the manufacturer, the idea promises contribution to higher efficiency and
saving fuel and emissions. What is an eHighway and how does it work?

The first electric highway was opened in Sweden as a part of the Siemens’ project
eHighway. It was created to cut the toxic emissions released to the atmosphere by
traditional trucks. The outcome is not bad - a truck in this kind of highways can reach the
speed of 90 km per hour.

The basis for the energy supply system of electric highway was the technology from railroad
electrification, which means that a reliable energy supply for the eHighway truck is ensured
by the two-pole catenary system. The catenaries lead to a level contact wire that provides
stable current transmission, even if trucks move at high speeds. In order to work, the
overhead contact lines must be supplied with energy from substations equipped with
medium voltage switchgear, power transformers, rectifiers and controlled inverters. The
latter is related to receiving information about the electric energy gained from regenerative
braking.

Then, the energy from the overhead contact lines is transmitted to the electric motor of the
eHighway truck with the help of the active pantograph. It can be easily connected and
disconnected from the contact wire at speeds that vary from 0 to 90 km/h. However, the
driver doesn’t have to worry about it too much - the actions is done either automatically or
manually at the push of a button. Because the active pantograph compensates for any shifts
in position within the lane, steering an eHighway truck connected to the overhead contact
lines is no different to driving a diesel truck. Whenever there is an evasive maneuver or the
driver signals movement by using indicators, the pantograph automatically disconnects.

The electric motors in eHighway trucks are powered by the overhead contact lines and the
active pantograph on electrified routes. For traditional roads, the eHighway truck has a
hybrid drive. As for the type of hybrid drive, all types can be implemented without
restrictions: depending on the application and customer requirements, there can be used
serial and parallel concepts with internal combustion engines, battery solutions, fuel cells
and so on. Also, the recovery of the vehicle’s braking energy is enabled by the electric
motors of the eHighway trucks.

The aim of this project is to use the mix of electric mechanics with natural gas or compressed
air with this service in the future.

Since may this year, Germany has started testing the eHighway and the tests are said to last
until 2022. The electrification system went into effect on 10 km of autobahn, allowing trucks
with the necessary equipment mounted to their roof to use the electrified cables to travel at
speeds up to 90 kphwithout needing to burn any diesel fuel, converting back to
diesel-powered internal combustion once they leave the electrified stretch.

Also, The United Kingdom wants to try these kind of highways. They want to begin by
installing a lane able to recharge electric cars in order to encourage the use of electric cars
for longer trips. The lanes are to be installed by the highways and the national roads from all
over the country to increase their use.

What are the advantages and disadvantages of electric highways? First of all, the eHighway
concept can be installed in any kind of built road and it won’t create obstacles for the
remaining vehicles. It means that those vehicles and trucks which aren’t electrified will still
be able to use these roads’ lanes without problems.

The installation for these kind of roads requires traffic free stretches vertically and at the
same time it limits a height for the lanes. The type of roads said to be the best candidates to
be turned into this kind of road, are routes with a lot of trucks with cargo. This system is able
to move trucks from 40 to 60 tons with a higher efficiency than conventional vehicles.

However, the vehicles should be adapted and have electric drive in order to make use of this
technology. Because of that, the eHighways are not a good solution for all kinds of vehicles.
Another thing is that implementation of electric highways is a big investment that needs to
be calculated carefully.

What changes need to be done to electric vehicles to enable them to be charged wirelessly?
Although Tesla is already working on batteries that allow cars to run for 400 km, vehicles
that would use electric lanes would not need such great capacity. Instead, the creation of
batteries should be focused on the weight, space and cost. The crucial requirement is the
installation of systems able to catch the electricity underway and at different speeds.

For a start, electric highways are going to be built in areas where there’s a great traffic
density in order to prioritize its use for the trucks which would help achieve greater
environmental advantages. It is unknown yet if passenger cars will also be prepared to use
such roads.

There are also speculations about the payment for using such highways and what the best
way is to calculate the energy obtained by trucks. In this case, a traditional toll would be an
imprecise solution. There are ideas of using GPS information, but before that is
implemented, first there has to be developed a system for protecting personal data.


Source: detea.es , new.siemens.com