What is an electric bus?

• Community and social benefits: an efficient and sustainable public transport system makes a city much more liveable by reducing the noise pollution created by loud and clunky diesel buses. Looking at the big picture, electric buses invite city managers to rethink their infrastructure needs. Electric buses silently glide through urban avenues, maintaining lower noise levels both inside and out, making it a wise transit choice for heavily populated streets and neighborhoods. Passengers enjoy a comfortable ride, thanks to pneumatic suspension technology and the positive experience on board has seemingly translated into greater civil respect for the vehicles. Studies have shown a reduction in fare evasion and graffiti markings with the introduction of electric buses in cities.

The advantages go beyond cleaner cities and lower operating costs. There are also important performance differences between electric bus vs diesel bus. An e-Bus offers better performance both in terms of drivability, maintenance and consumption. In particular, maintenance costs are about half of what they are for diesel vehicles, and management costs are just 35% compared to diesel.

According to a 2021 study carried out by Bocconi University and Enel in several Italian cities, an 8 meter diesel bus cost 0.21 euros per km to maintain, while the same size electric bus cost 0.12 euros per km. 

Electric buses work just like electric cars do. An electric bus plugs into the electricity grid to get charged, and stores the electricity in batteries (often located on the roof). The batteries power an electric engine. Since an electric engine has fewer parts than an internal combustion engine, it requires less maintenance. When the batteries are depleted, the bus is recharged at charging stations (which takes an average of 4 hours with a 150 kW charger). Since buses run on regular routes, scheduling a timetable for batteries to be recharged is a fairly straightforward planning exercise. Depending on the size of the bus and on such factors as traffic conditions, a bus can travel an average of 200 km (124 miles) on a single charge during its first year in service.

The electrification of public transport through electric buses requires a wide range of capabilities and installing a new infrastructure of EV fleet charging stations. Charging an e-Bus varies depending on the type of charger and the vehicle’s capability to absorb a charge. With a 150 kW charger, for example, it takes an average of 4 hours to charge a 450 kW battery.

A fleet of electrical buses is charged respecting the available power at the charging site. Furthermore, if one bus requires less power, the remaining power is allocated to other electric buses. Thanks to smart charging platforms and softwares like the one designed by Enel X, a public transport company can analyze its needs and create schedules, scheduling suite integration.

Charge prioritization offers the possibility to identify and set different priorities and criteria to charge the electric buses. This priority can be defined based on the order of arrival, for example: the first electric bus to arrive is the one that charges faster, or on station-based priority, or departure-based priority. What happens to these enormous batteries when they reach the end of their useful life cycle after 7-8 years?  When batteries reach the end of their useful life, they can be reused, becoming a so-called “second life” battery. This can happen in two ways. Repurposing, wherein several suitable packs are selected and combined based on residual state, capacity, et cetera, is one option. Refurbishment of packs is a second viable option. In this case, packs are disassembled and then single cells are reconditioned and repacked in new modules.