Electricity drives global move towards greener transport

As populations continue to grow, authorities must find ways to make transport greener and more efficient so that people leave their cars at home

By Antoinette Price

City traffic is increasingly congested and air quality often poor. However, transport systems which rely on full electric power, such as the metro, trams and railway lines, can transport huge numbers of people without causing pollution at the point of use. However, their infrastructure is very costly to build and if a route change is required, this will not be possible outside of the existing rail tracks.

Solaris Urbino electric bus
Solaris Urbino electric bus Photo: (Solaris Bus & Coach/Marcin Gorgolewski)

On the bus!

Buses, on the other hand, complement transport systems. They can service all manner of streets and accommodate route changes in the event of obstructions or road works. However, most are powered by internal combustion engines (ICE), burning predominantly diesel which is polluting and can be noisy.

A number of IEC Technical Committees (TCs) and Subcommittees (SCs) produce International Standards used for all existing solutions adopted for the electrification of urban mass transport systems, for example, IEC TC 9: Electrical equipment and systems for railways, which develops International Standards covering “(…) metropolitan transport networks (including metros, tramways, trolleybuses and fully automated transport systems)”. Components and systems within these systems are covered by IEC TC 20: Electric cables, IEC TC 22: Power electronic systems and equipment, IEC TC 32: Fuses, and IEC SC 48B: Connectors.

Over the year, e-tech has looked at how technology is changing the transport landscape, whether on the ground, in the air or at sea.

Batteries play major role in full electrification of urban buses

Many cities are beginning to green their bus fleets, but this will take years given the number of buses in some of the fleets (over 21 000 in Beijing, 16 000 in Shanghai or 8 700 in London). The gradual process will be linked to the life of existing buses, and for future ones, depend on the development of cleaner, more efficient technologies.

IEC TC 21: Secondary cells and batteries, develops International Standards for all secondary cells and batteries, irrespective of type and chemistries (i.e. lithium-ion, lead-acid, nickel-based) or application (i.e. portable, stationary, traction, electric vehicles or aircraft). They cover all aspects such as safety, performance, dimensions and labelling, a new battery technology. Chemistry for flow batteries – another potential candidate for large-scale electrochemical energy storage – is now part of the TC remit.

Achieving full electrification will also require new infrastructure, which is not yet available. Before reaching this stage, other hybrid vehicles will be used and run on one of the following systems:

  • Hybrid drive with an internal combustion engine (ICE) (diesel, liquid or compressed gas, petrol). Additionally, energy recovered from braking or energy harvesting shock absorbers is stored in energy storage devices, like batteries, ultracapacitors or flywheels. A start and stop function for the ICE allows the bus to run on batteries alone, when required. Advantages: low emissions and low thermal cut-off (TCO), or the temperature at which the electrical safety device interrupts the electric current.
  • Hybrid drive with fuel cell. Energy recovered from braking or energy harvesting shock absorbers is stored in energy storage devices, like batteries, ultracapacitors or flywheels. Advantages: no emission and low TCO.

IEC TC 105 prepares International Standards for all fuel cell technologies, including for transportation. Since fuel cells can ideally be used as the main power source for all-electric systems in ground vehicles, ships and aircraft, this TC works with a number of other TCs which contribute to standardization of component parts and systems for transport.

Additionally, IEC TC 40: Capacitors and resistors for electronic equipment, develops International Standards for electric double layer capacitors, which are better known as super or ultracapacitors.

New ways to stay charged

Except for trolleybuses, which generally take their power from overhead lines, electric buses will need batteries for power. Innovative systems are being trialed, which include charging batteries at end stations and on-road charging, for example through wireless power transfer (WPT).

WPT describes a range of technologies, which enable electric energy to be transmitted to a source of demand without the need for conductive cables or making a physical connection. One of the most developed WPT technologies is magnetic induction. This is being used on some London buses at terminals. Very like the way an electric toothbrush charges without needing direct electrical contact, the bus parks over an induction pad. The induction coil in the ground is matched with one installed on the bottom of the bus and allows the recharging to happen at a rate of 10kW every five minutes.

In Korea the online electric vehicle (OLEV) system being developed for electric transit buses is a cutting-edge WPT. The wireless-charging infrastructure installed under the road charges the batteries of electric buses as they operate over the road.

Where do EVs fit in?

Many of us go into a panic when our phones and other devices run low on battery power. We have become so used to the convenience of being connected all the time, which means having access to power sources and time for recharging. It is one thing to run out of phone battery, but what if it happens to your car and you’re in the middle of nowhere?

While electric vehicles (EVs) have the potential to greatly reduce cost in terms of the environment, consumers must first trust their range and battery life if they are to be broadly adopted. In other words, recharging infrastructure must be easily accessible everywhere and the process must not be too lengthy.

WPT, through magnetic induction, is seen as the most promising approach to resolving these issues. Capable of delivering significant power and increasingly rapid charging, it has already been rolled out in the first market-ready EV WPT system from Plugless and is the choice of a number of major auto manufacturers looking to do the same in the coming years. According to a research report, sales for wireless charging equipment for light duty vehicles will grow by a CAGR of 91% from 2013 to 2020. As wireless systems become an integrated part of new EVs, 283 000 units are expected to sell annually by 2020.

IEC TC 69 develops International Standards for road vehicles and industrial trucks that are totally or partly electrically propelled from self-contained power sources, including WPT. All of these are addressed by an IEC TC 69 Joint Project Team, JPT 61980: Electric vehicle wireless power transfer systems, established by IEC TC 69 and ISO/TC 22: Road vehicles. JPT 61980 develops International Standards for WPT and deals with issues such as interoperability, specific requirements for communication between EVs and infrastructure and magnetic and electric field power transfer systems.

In addition, for standardization work for batteries used in EVs and electric industrial trucks, IEC TC 21 and SC 21A as well as IEC TC 69 have created the following Joint Working Groups (JWGs):

  • IEC JWG 69 Li: TC 21/SC 21A/TC 69 – Lithium for automobile/automotive applications
  • IEC JWG 69 Pb-Ni: TC 21/SC 21A/TC 69 – Lead acid and nickel based systems for automobile/automotive applications

Playing with cars

Remember the excitement as a child of riding your first electric go-kart or car at a fair? Over the years EVs for children have expanded to cover cars, various motorcycles, all-terrain vehicles, quad bikes, trucks, tractors and more.

Many car companies licence their designs to toy companies and manufacturers, making toy vehicle features similar to real vehicles. They can contain sound systems, touch screens, electric motors, safety devices, lights, batteries as well as light and touch sensors. IEC TCs and SCs produce International Standards which cover these and other components.

Safety aspects concern the batteries and motors, operation and braking, remote control functions, or possible electrical fires if the wrong charger is used but also seat belts, speed limiters and smart pedals. All of these are guided by International Standards developed by IEC TC 61: Safety of household and similar electrical appliances. IEC 62115, Electric Toys – Safety, is intended for use by children under age 14 and also applies to toys containing lasers or light-emitting diodes (LEDs).

Looking beyond electric vehicles

It may be hard to imagine, but the next generation of energy independent vehicles (EIVs), which rely on the on-board conversion of harvested energy already exists and works, however, they are still too expensive to be introduced on a large scale.

In China, small bus-like EVs powered by solar panels can be bought with or without batteries. They can transport up to eight people and are ideal for tourist resorts. The Swiss Solar Impulse plane recently completed its flight around the world powered by solar panels, and the Nuon Solar, a solar powered car, recently won the World Solar Challenge in Australia.

Just as Formula 1 racing gave the world disc brake and flywheel recovery systems, research into the different ways to harvest energy will most likely benefit future transport and possibly other technology.

Electric car WPT WPT is used to charge an EV at the Tokyo Motor Show Photo: (NJo)
Solaris Urbino electric bus Solaris Urbino electric bus Photo: (Solaris Bus & Coach/Marcin Gorgolewski)
Johnson 48V micro hybrid battery This lithium-ion battery enables optimization of energy generation and consumption (Photo: Thomas Content, Milwaukee Wisconsin Journal Sentinel)