ELECTRIC BUS

Currently, a large portion of the transport demand is met by private vehicles. Unless a greater share of this transportation need is met by public transport, the demand for crude oil as well as CO2 emissions will reach untenable levels. A greater emphasis on public transport will certainly have a positive impact, but this will be of limited scope unless public transport vehicles shift their source of power from diesel to electricity. Current energy emissions as well as different scenarios based on the mode of interventions have been analyzed in this sub-section

EVs are powered by electricity and propelled by traction motors. In conventional vehicles, Internal Combustion Engines (ICEs) and fossil fuels are used instead of traction motors and an electricity source. EVs can use electric energy from on-board sources such as a battery or an electricity generator connected to the ICE, or off-vehicle energy sources such as overhead lines. EVs have applications in road and rail transportation, surface and underwater transport, and electric aircrafts.

China is currently operating 36,500 electric buses as compared with a negligible number of electric buses in India (Electric Vehicles Initiative and International Energy Agency 2015).

What Is an Electric Bus?

An electric bus is a type of electric vehicle (EV), meaning it is fueled by electricity rather than other fuel types like diesel fuel or gasoline. Unlike a hybrid vehicle, which combines battery power with an internal combustion engine, an electric bus relies solely on electricity for power.

How Does an Electric School Bus Work?

An electric bus draws electricity from the power grid and stores it in a battery that can be recharged once the electricity has been used up. This basically mirrors the way our electronics work. We plug them in and let the battery charge and then use them wirelessly until it’s time to charge again.

The main difference between an electric bus and our cell phones and laptops is that the electrically charged battery powers an electric motor in the bus. “The wheels on the bus go round and round,” thanks to this electric motor. More precisely, when the bus driver’s foot presses on the accelerator, the battery powers the motor, which powers the gears that rotate the bus’s tires.

In a traditional bus, a motor works along with an alternator, but an electric motor in an EV has the double function of acting as an alternator and motor. This is possible because the voltage of an AC signal can easily be increased or decreased.

From the driver’s perspective, an electric bus functions essentially like any other type of bus. There is no special way of operating it. Of course, when it’s time to refuel, this is when the difference becomes obvious, but it’s a process that EV driver quickly become use Electric Bus Benefits.

If you’re considering an electric bus for your school, you’ll want to know about the benefits of electric buses. Why should you consider an electric bus over more traditional options? There are advantages and disadvantages to consider with any type of bus — diesel, propane, gasoline, electric or otherwise — so it’s always smart to compare these options and see which is the best fit for your needs. When it comes to electric buses, there are some valuable benefits to consider. Electric buses are eco-friendly, quiet, low-maintenance and affordable.

1. Eco-Friendliness

One of the main reasons to consider an electric bus over other options is how eco-friendly they are. Compared to combustion engines that run on fuel like diesel, an electric vehicle will have a minimal impact on the environment.

Environmental friendliness is also a benefit of hybrid electric buses, but hybrid buses still burn fuel and, therefore, don’t have zero emissions like an all-electric bus does. When your priority is choosing a bus that will contribute to a healthier environment, an electric bus is the clear choice.

2. Quiet Operation

One thing you might notice the first time you drive or ride on an electric bus is how quiet it is. Electric buses operate far more quietly than other types of buses with internal combustion engines. This is always a nice feature of electric vehicles, but it can be a major benefit when it comes to school buses.

School bus drivers in an electric bus are better able to hear what is going on in the seats behind them. This can help drivers feel more of a sense of control and can increase the level of accountability among students on board. A quieter operation can also help drivers maintain better focus on the road.

3. Minimal Maintenance

Another major advantage of electric buses is how little maintenance they require. Many of the maintenance tasks needed with a diesel or gas-powered bus are unnecessary with an electric bus. When performing maintenance on an electric bus, you can eliminate:

• Engine oil changes
• Engine air filter changes
• Smog testing
• Replacing coils or spark plugs
• Transmission maintenance

Additionally, you won’t have to change the coolant as often, and you can get a longer lifespan out of the brake pads. Overall, electric vehicles are extremely low-maintenance compared to other vehicles. Fewer maintenance needs can translate directly into cost savings. It also means buses in your fleet can stay on the road and don’t have to be out of commission at the auto shop as often.

4. Affordability

Some schools may shy away from purchasing electric buses because they cost more than other bus models. These buses do require a larger upfront investment, but they can also save you money over time. Electric buses save money by minimizing maintenance costs and eliminating fuel costs.

Battery electric buses (BEBs) store electricity on-board, and are charged either overnight, or intermittently throughout the route

ADVANTAGES

• Emissions, less GHG and local pollutant emissions.

• Reduced vibration, increasing passenger comfort and reducing damage to surrounding infrastructure.

• Noise, electric motors produce less noise than ICEs and do not keep running when a bus is stationary.

• Fuel efficiency, all types of electric buses usually demonstrate increased energy efficiency.

DISADVANTAGES

• Cost, electric bus options are currently more expensive to purchase than their diesel alternatives.

• Infrastructure, electric bus options require different types of additional infrastructure.

Full battery electric buses (BEBs) store all required energy in an on-board battery. Energy is transferred to the vehicle via electric charging systems, while regenerative braking is used to recover kinetic energy during operation

Outlined below are some advantages and disadvantages specific to BEBs, beyond the general advantages and disadvantages of all types of electric buses

ADVANTAGES

• No tailpipe emissions and very low overall emissions if renewable energy sources are used.

• Efficient, very high vehicle energy efficiency of the electric motor.

• Reduced operating cost, based on current electricity prices, the cost of operating BEBs would be much cheaper than DBs. This is true even if the current fuel tax was added to the electricity price.

DISADVANTAGES

• Low distance range, current BEBs are limited to a reasonably small distance range. The effects of this can be reduced by rapid-charging on-route.

• Heavy, current batteries are heavy, adding to the weight of the bus, potentially limiting what roads they would be able to operate on.

• Capacity, the increased weight means the vehicle capacity is reduced to stay below maximum axle weight limits.

• Infrastructure, BEBs require charging infrastructure (either at depots, bus stops, or both).

Battery Electric Bus Categories

BEBs can be divided into two categories based on their range and charging routine. The first category is the opportunity BEB, which has a shorter range and can be rapidly charged throughout the day, at convenient ‘opportunities’. The second category is the overnight BEB, which has a longer range to complete a day’s service, and is slowly charged overnight.

Opportunity BEBs have a shorter range than overnight BEBs, usually 30-70 km, and can often recharge 80-100% in five to ten minutes.

Overnight BEBs are charged slowly overnight, and might also make use of some opportunity charging throughout the day. Proterra7, a U.S. BEB manufacturer, claims that its longest range BEB, the E2 max, has a nominal range of 560km and a charge time of five hours. This Proterra BEB range is not independently verified and BEB ranges can vary greatly under different operating conditions; air conditioning load, average passenger volume, stopping frequency, driver behaviour, and route gradient are just a few examples of factors that can greatly affect a bus’s energy consumption and potentially significantly reduce its overall range.

In practice, the range of a BEB is governed by the design choices of the manufacturer. A BEB can be designed to have any reasonable range by installing different batteries. The two main consequences of increased range (by increasing battery size) are increased vehicle purchase price and increased vehicle mass. The latter is of particular concern as it reduces both vehicle passenger capacity and vehicle energy efficiency

A shift to an electric bus fleet necessitates an understanding of the technology. The design of an electric bus and the necessary infrastructure depend on the application scenarios. The battery size depends on the drive cycle, terrain features and other operating conditions. The battery system preference depends on the operating conditions of the vehicle. The cost is determined by the bus and the battery size, battery type and carrying capacity. Thus, having a fundamental understanding of the technology landscape and application scenarios is important. Understanding future developments and industry expectations will give a sense of the direction in which the electric bus sector is heading.