Vattenfall E-Mobility R&D program is currently working within several projects with the aim to develop, investigate and evaluate future charging solutions for electric vehicles.
One important and technically challenging field is electrification of heavy transportation. Vattenfall (coordinated via BD Sustainable Energy Projects, BU R&D Projects) is a partner within an on-going ERS (Electric Road Systems) development and demonstration project called “Slide-in - technology for continuous transfer of energy to electric vehicles”.
Slide-in Electric Road Systems
Slide-in Electric Road Systems can be described as electrified roads that support dynamic power transfer to the vehicles from the roads they are driving on. The basic principle is to power an electric engine within the vehicle from an external power source that is built into the infrastructure of the road. The electric power is transmitted while the vehicle is in motion, through a “pick-up” (current collector) mounted on the vehicle. The electric roads would be accessible for both vehicles with ERS-propulsion as well as conventional vehicles. Further on, the ERS-vehicles would be equipped with a small battery and a smaller internal combustion engine, which allows the vehicles to also drive on conventional roads outside the ERS network.
International project cooperation for development of ERS solutions
Volvo GTT is together with Alstom responsible for the development of a conductive energy transfer solution, while Scania CV and Bombardier together are responsible for the development of an inductive energy transfer solution. The project is partly financed by the Swedish Energy Agency.
Vattenfall has within this project analysed and proposed a solution for the distribution grid connection of a “Slide-in road” between Stockholm and Gothenburg (446 km) and together with the project partners estimated the total investment cost for the required grid infrastructure. This part of the project has been carried out in cooperation between Vattenfall R&D, Vattenfall BU Distribution and the consultant Pöyry Swedpower.
Additional partners in this project are the Swedish Transport Administration, Svenska Elvägar, Chalmers University of Technology, Lund University and KTH Royal Institute of Technology.
The goal of this project is to investigate whether it is possible to create a continuous energy transfer from the road to the vehicles that is safe, robust and utilizable both for heavy-duty vehicles and personal vehicles. Two different Slide-in solutions based on conductive and inductive energy transfer are developed, demonstrated and analysed regarding energy efficiency and cost.
Project objectives and scope
Both solutions are to be demonstrated in full-scale tests in a realistic environment, which means that two test tracks are being built. Measurements are made during the same conditions and with settings from a common scenario. As no solutions for Slide-in ERS are commercially available today, similar existing solutions used within other transport sections, such as the tram industry, have been adapted for road vehicles. Furthermore, the vehicles have been adapted to be able to connect to the ERS and utilize the energy transferred. Most of the adaptations concern the pick-ups, which are specially designed within the project.
An increased proportion of vehicles utilizing an ERS would demand new infrastructure to supply the electricity. Computer models have therefore been made by Lund University to simulate the energy demand for both solutions. The business model has been designed by KTH, who has also identified the actors for the ERS.
Proposed solutions are also discussed with the Swedish Transport Administration and other relevant administrative authorities. The aim is to reach solutions that affect the roads function and durability as little as possible, and at the same time meet the future requirements on ERS.
A fixed scenario has been defined
The generic scenario description, for both subprojects, includes the main parameters required to calculate or simulate the:
- Energy demand per road km
- Infrastructure required to supply the demanded energy
- Energy transfer efficiency from road to vehicle
- ERS construction and safety
- Vehicle demands required to be able to utilize the ERS
- Total Slide-in ERS solution costs.
The project started in October 2010. A first edition of the report from phase one will be delivered in December 2012. The second edition, including all the test results, will be delivered in June 2013. A phase 2 of this joint development and demonstration project is under discussion. The project results and conclusions will be summarised in a Vattenfall E-mobility newsletter during 2013.