Focus on electric Postbuses
Local, emission-free transport with electricity from Switzerland
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Our current focus is on electric Postbuses with electric battery drive systems. This technology is the most advanced, it has proven itself in practice in Switzerland and abroad, and battery-powered buses are already available on the market in a wide variety of models from many different manufacturers.
However, battery-powered buses are not yet suitable for all topographies, either because their range is not sufficient or because the strain on the battery and drive system would be too great. For this reason, PostBus has made a conscious decision to remain open in its choice of new technology, while closely following the development of fuel cell technologies and synthetic fuels.
How a battery-powered bus works
Battery-powered buses have electric motors that obtain their drive energy exclusively from a battery. The battery is recharged once or several times a day via the electricity grid. At present, the average range of battery-powered buses on a single charge per day is around 250 kilometres. The range can be increased to over 300 kilometres or more if the battery is recharged several times a day. This occasional charging is done either in short intervals with high power at the terminal stops or during breaks in the depot throughout the day – for example, at lunchtime.
All PostBus battery-powered buses obtain 100 percent of their electricity from renewable energy sources in Switzerland.
Battery technology and the range of battery-powered bus models are developing very quickly. In the next few years, a significant boost to battery capacity is expected, with a corresponding increase in the range and economic viability of battery-powered buses.
How we charge Postbus batteries
PostBus has different charging systems in place for battery-powered vehicles:
- Depot chargers: the Postbus battery is recharged once a day – usually overnight.
- Occasional charging: recharging during sufficiently long stops while on the road, at a terminal stop or in the depot. This kind of top-up charging is currently done using a plug or pantograph that is lowered onto the vehicle from above.
How we’re conserving resources
Our electric Postbuses are powered by lithium-ion batteries (Useful information about electric vehicle batteries). The cathode material consists of nickel, manganese and cobalt oxides (NMC), the anode of graphite coated on a copper foil. There is an electrolyte between the cathode and anode that enables the transport of electrons. The electrolyte consists of a solution of lithium salts.
In general, the raw materials are not geologically in short supply, but they may have limited availability due to restricted production capacities and geopolitical conflicts.
The amount of lithium required for a 3-tonne bus battery is approximately 50 kilograms. In 2021, 104,800 tonnes of lithium were produced worldwide, with 50 percent coming from Australia and a quarter from Chile. Global lithium reserves are estimated to be 14 million tonnes.
Each bus battery requires around 80 kilograms of cobalt. The production process is technically difficult. Global annual production of cobalt stands at just 124,000 tonnes. However, as there are known reserves of around 7 million tonnes, the raw material is not classified as being in geological short supply. Because batteries are becoming less dependent on cobalt and richer in nickel, demand for cobalt is expected to decline, leading to an easing in the supply situation.
A bus battery requires around 200 kilograms of nickel. Today’s global reserves are estimated at 95 million tonnes. In 2021, around 2.7 million tonnes were produced worldwide. The most important mining country is Indonesia, with 771,000 tonnes annually, followed by the Philippines with 334,000 tonnes. As a result of the trend towards high-energy batteries that are less dependent on cobalt and richer in nickel, demand for nickel is almost certain to increase in the coming years. Nickel is also an important alloying component of stainless steel. However, most nickel required can be recovered from recycled batteries.
A bus battery requires around 110 kilograms of manganese. In 2021, 20,000 tonnes of manganese were extracted globally, one third in South Africa and one sixth in both Australia and Gabon. Global reserves are estimated at approximately 1.5 million tonnes.
In 2021, global production of natural graphite was about 1 million tonnes, with 80 percent coming from China. Current global graphite reserves are estimated at approximately 320 million tonnes. For economic reasons, there is no recycling of graphite from lithium-ion batteries at present, but research is already underway. There are also currently efforts to replace graphite with silicon as anode material. The volumetric energy density of silicon is almost three times greater than that of graphite.
The extraction of raw materials and the production of batteries make up a significant amount– around 20 percent – of the total environmental impact from a battery bus. The biggest environmental impact is caused by the extraction and drying of the lithium and the electricity needed to assemble the battery. Even now, the total environmental impact over the lifetime of a battery bus is only 40 percent higher than the impact of a diesel bus.
From a social point of view, the extraction of cobalt is the most problematic aspect. The politically unstable Democratic Republic of the Congo controls half of the world market. Unfortunately, a third of Congolese cobalt has particularly questionable origins. It comes from unofficial production, in which workers risk their lives in unsophisticated small mines. There is a cross-industry initiative in place to improve the working conditions for these workers. Due to the high price, battery manufacturers are also constantly working to reduce the proportion of cobalt in the cathode. The first completely cobalt-free batteries are expected in the next few years.
- We intend to further increase our commitment to responsible procurement in the future.
- We require our suppliers to have a plan for recycling batteries in place in an effort to ensure that as much lithium, nickel, manganese and other metals as possible are recovered.
- In our bus procurement, we look for batteries that are less dependent on cobalt.
- We monitor technological developments and incorporate our findings into our bus procurement.