PROJECT DESCRIPTION
BACKGROUND
Climate change was the main priority of the Swedish Presidency of the European Union in 2009. According to the European Environment Agency (EEA Report No 5/2008, 16 October 2008), the EU15 was on track to meet its Kyoto Protocol commitment of an 8% reduction of emissions by 2012. However, additional measures would be required if the EU27 is to meet the subsequent goal agreed by EU leaders of a 20% emissions reduction by 2020. Emissions have been reduced in all main sectors except transport. The continuing expansion of public transport is expected to add to the challenge of reducing emissions in this sector. But increasing electrification is likely to be beneficial, as the source of the energy required is flexible and the amount of energy used for transportation can be reduced.
OBJECTIVES
The main aim of the SLIDE IN project was to demonstrate how greenhouse gas emissions, and other forms of air pollution, can be reduced through the introduction of a unique ‘SLIDE IN’ concept for public transport that allows batteries to be charged while the vehicle is in use. The project would furthermore show how this concept can be used in Europe to establish a flexible and cost-effective bus system, using existing infrastructure. It was expected to have considerable advantages over ordinary diesel buses in terms of emissions, noise and reliability.
The SLIDE IN concept would be tested in two cities in Sweden – on the trolley bus electric lines in Landskrona, and on the electric tram lines in Lund. During the project, the SLIDE IN concept would be demonstrated on a specially equipped bus. During the first stage of the project, the SLIDE IN bus would be tested on the electric lines currently used by a couple of trolley buses in Landskrona. The bus route would be organised to make sure that the SLIDE IN bus operates on battery alone for about 10 km, before returning to the electric line for a period to recharge the batteries. In the second stage, two years into the project, the bus would be adapted so that it can slide into a tramway system. The bus can be recharged by the existing electric lines of a tramway system. No new infrastructure investments would be required. The bus would also be equipped with a fleet management system in order to keep track of data, such as battery capacity, temperature and driving distances.
To ensure its sustainability, the concept would be analysed from an economical and a human perspective. SLIDE IN is expected to reduce energy use for transportation by more than 50%, while also eliminating the use of fossil fuels. The fleet management system continuously monitors the energy used by the bus, allowing for assessment of the future potential of implementing SLIDE IN technology for all types of road transportation in Europe, including cars, buses and trucks. The project planned to train at least six bus drivers in driving the SLIDE IN bus and in ‘eco-driving’.
RESULTS
The SLIDE IN project showed that the SLIDE IN bus containing the prototype battery can be effectively employed on a trolley bus line. The concept of transferring electric energy to a vehicle while it is moving, recharging its batteries and enabling it to travel farther on battery power alone was demonstrated in a real-life environment. The buses were shown to be quieter and less polluting than regular buses, providing a better working environment for drivers as well as those in the city. The buses were also shown to be reliable, having the same capacity as diesel or gas buses, and affordable. Given that they can also drive off the network of electric lines, the buses can also be said to be flexible.
The beneficiary fully implemented the first stage of the project on the trolley bus electric lines in Landskrona, but the bus was not trialled on a tram line in Lund as the tram way had not been built during the lifetime of the project. The project used existing trolley-bus infrastructure consisting of overhead wires in Landskrona to test the recharging of the bus batteries. The bus was equipped with adjustable trolley-poles on the roof, a control system inside the cabin and a battery package. The size of the battery in the bus was equivalent to the battery capacity that some of the existing premium electrical cars offer today: 60 kWh. A measurement system continuously transmitting wireless data to the project team was also installed on the bus. During a normal day the bus would run for a total of 170 km, of which 70 km was in trolley mode – i.e. connected to the overhead trolley line and charging while driving. The other 100 km was thus run in battery mode. A total of 10 battery cycles were performed per day.
After nearly three years of operation the battery performance was tested by technicians from Altairnano, an energy storage expert and the manufacturer of the battery, along with technicians from the bus manufacturer and assembler Solaris and Skoda (bus chassis), in June 2016. The results showed that the battery seemed nearly unused, demonstrating an excellent battery lifetime and a clear difference to fast charging technologies, which drain the battery heavily.
The demonstration value of the project is high: the battery type that charges while running for short periods of time was not in use anywhere else. Importantly, the SLIDE IN technology can be installed in any type of vehicle deemed suitable, such as delivery trucks, and it has already been replicated. Four busses have been operating in Esslingen, Germany since May 2016. The concept has also been trialled in the Dutch city of Arnheim as well as Zürich, Switzerland. A follow-up initiative financed by the Swedish Energy Deartment, Elonroad, is currently aiming to show that a vehicle can be charged from a track in the road.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).
