Electric scooters recharged online: an experiment in Freiburg to save energy
The Swiss postmen's electric scooters have become the protagonists of a pilot project that combines sustainability and savings. On the one hand, it will allow Swiss Post to reduce its energy costs and on the other, Fribourg's electricity grid will benefit from greater stability. The heart of the entire system is the so-called vehicle-to-grid (V2G) technology, or the ability to discharge residual energy from vehicle batteries into the grid and recharge when tariffs are more convenient . Not to mention the possibility of always using the same batteries as potential energy storage nodes for the local grid - in this case, the municipality of Fribourg. Obviously, this last function is a future perspective since it would require a huge fleet of vehicles. The pilot program, which began at the end of May and will last four months, involves the Federal Office of Energy (FOEN), Swiss Post, vehicle supplier Kyburz Switzerland AG, electricity grid operator Group-E and the Institute of Electrical Engineering at the Lucerne University of Applied Sciences and Arts (HSLU).
In practice, two objectives can be achieved by using bidirectional charging , i.e. charging and discharging the batteries of electric vehicles via a system connected to the grid . The first is to charge the e-scooters when the rates are lowest (i.e. at night); the second is to feed the residual energy of the day (during the day at more expensive rates) and create a sort of virtual power plant to support a more efficient operation of the grid. "As soon as the scooters arrive at the depot in the early afternoon, we calculate the charge and discharge profiles based on the variable Groupe-e rate, to make the most of the vehicles to support the electricity grid," said Severin Nowak , a professor at HSLU. The only insurmountable limit is to ensure that the batteries are fully charged by 5 a.m., when mail deliveries begin.
It should be noted that the energy arbitrage action could allow Swiss Post not only to save money but also to earn something. This is possible thanks to dynamic electricity tariffs , which for example Groupe-e already applies in the Fribourg area. Obviously, the conditional is a must for the economic result because the current fleet of e-scooters is only nine units: these are traditional electric models that have been made compatible with the project. In any case, current projections indicate an added value of 2,500 Swiss francs (at the exchange rate 2,671 euros) per vehicle for the entire life cycle. The experiment will make it possible to understand above all the technical feasibility of bidirectional charging with alternating current – batteries traditionally work with direct current, therefore with a movement of electrons in “one” direction. "This is the key innovation of the project. The on-board devices we are using are the first of their kind", concluded Erik Wilhelm of Kyburz.
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