Since late 19th century cities have started introducing trams, metros and trolleybuses, in their effort to enable massive reliable urban transportation in the beginning and reduce pollution, caused by widely used buses with combustion engines during the last years. However, a century-long experience convincingly shows that constructing and maintaining the street electric infrastructure for such vehicles is hugely expensive. No need to mention the “zero” flexibility of such means of transportation when it comes to modifying existing routes.
That is why wireless and rail-less electric solutions have come to bother the minds of engineers and have entered the development plans of leading technology companies, such as Siemens (Germany), and ABB (Sweden and Switzerland), which are testing in cities like Vienna and Geneva wireless electric bus solutions. Chinese and European bus builders has designed and are marketing some all-electric buses powered by batteries. Most of such solutions are partly or fully based on batteries. But batteries technology reveals numerous downsides:
• toxicity of batteries poses environmental problems;
• low efficiency at temperatures about and below 0 degrees; this requires additional investment of energy to warm the batteries in order to enable their functioning during the winter,
• too heavy and too big – in order to enable the daily operation of the bus, the batteries pack has to weigh between 4 and 4,5 tons and certainly has a volume of a few cubic meters (which grossly reduces passenger capacity of the bus);
• vulnerable to impact and shorting, potentially causing fire (as has been seen in the recent accidents with the Boeing Dreamliner, and the all-electric, US-made Tesla passenger car);
• additional costs – transporting and warming (in the winter-time) the battery pack all day, in itself consumes battery charge in considerable quantities;
• inability to absorb a high charging current makes them unsuitable for recuperating high amounts of energy generated during downhill descent or braking of the bus;
• limited lifespan and limited number of charging cycles which necessitates their multiple replacement in the course of the useful life of the bus.