Propulsion Technologies
There are many technologies for public transit buses that have emerged over the years. We will not go into specific detail on any one particular energy source, but will give a table of pros and cons for each one.
Mature Supply Chain
Least expensive
Parts are readily available
Basic Mechanic training, partially done
Large supply chain of parts
Most reliable for hot and humid climates
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From a production, distribution and implementation stand point there’re almost no additional investment needed for new infrastructure, storage facilities and service stations versus other alternatives, as all fueling, HVAC, and safety equipment’s are already in place and operating.
Bio-Diesel is better than other fossil fuels
Modern engines and exhaust systems reduce pollution and CO2
Existing and inexpensive for fueling.
Longest range of any fuel
Limited life it is a transitional technology
Fuel not readily available outside of certified facilities
Due to low volume parts can be difficult to find and are expensive
Retrain mechanics to support new systems
Engines run hot and burn out quicker especially in hot climates
Short service life of on-board cryogenic fuel pump
Fuel pump dispensing errors leads to buses running outof fuel
Highly volatile fuel. Needs extra facilities to supportsafe fueling
Higher cost of bus due to engine, fuel tanks. Gas detection systems, fire suppression systems
Higher Maintenance costs as parts are more expensive
Maintenance facility needs to be modified for fuelstorage and gas leaks
Brake, suspension and tire costs higher due to increasedvehicle weight
More oil changes due to engine heat
High training costs due to technology not beingmainstream
Still a fossil fuel
New fast fueling stations costs in excess of $2M
Heavier bus weight due to tanks will impact roads
Approximately 30% less range than diesel
New technology in high demand and short supply.
Battery availability can be an issue
Existing mechanics have to start fromscratch, including high voltage training
Not as robust as diesel due to the life spanand progression of diesel reliability
Needs special garage, first responder, driver training for HV
Higher cost of bus due to new tech, batteriesetc. Can be 5x cost
Retrain mechanics to support new systems.
First responders need to be trained.
Chargers need to be installed at a high capital cost
Battery recycling will be an issue
If electricity is generated by fossil fuel less beneficial
Very hard on electric grid
Heavy weight of buses will ruin roads quickly
Very low range
Diesel buses
Learn when it is premature to become overly involved in vehicles utilizing the latest propulsion technologies and energy sources, which may potentially limit the procurement of buses.
- Lack of infrastructure to support a large fleet of vehicles
- Lack of maturity of the technology
- High Training Costs
- Longer time frames required to have a service infrastructure and support network
- A significantly higher price for newer technologies
Continuing with diesel buses, especially those powered by bio-diesel, remains a prudent choice considering both economic and environmental considerations.
Basic criteria when selecting any alternative fuel
- the fuel has to be in abundant supply or, preferably, derived from renewable sources,
- it should have high specific energy content, easy transportation and storage, minimum environmental pollution and resource depletion, and
- it should have good safety and handling properties.
