Personal and public electric transport

Adoption of EVs for personal and public use is expanding, in particular in urban areas

By Morand Fachot

Public and personal transport vehicles are increasingly dependent on electrical systems for propulsion and countless other functions, even more so in urban environments. Many IEC TCs (Technical Committees) and SCs (Subcommittees) prepare International Standards for these vehicles

Toyota iRoad personal mobility vehicle (Photo: Toyota) Toyota iRoad personal mobility vehicle (Photo: Toyota)

The electric car is already with us

Electrical and electronic systems are wholly responsible for the advances made in many areas of the automotive industry. This is particularly true for electronics, which has made a spectacular contribution to the increase in overall value of cars in recent years. In the mid-2000s, electronics accounted for 10-15% of the total production cost of mid-range cars and 20-30% of the cost of luxury models.

Today they represent some 20-30% of the total cost for all categories of car, and this share is expected to reach 40% or so by 2015. The figure is nearer 50% if all electrical systems are included, and is even higher for electric vehicles.

Main factors for wider adoption of electronics in cars

Improving the driveability of vehicles has been a major contributor to the adoption of electronic components in cars. Power windows, light and rain sensors that automatically switch on lamps and wipers, electric power steering, cruise control that allows drivers to maintain a constant speed and advanced parking support systems that manoeuvre cars automatically into a selected parking space contribute, along with many other aids, to better driveability, increased comfort and reduced driver distraction.

Improved safety is another major factor. Sensors play a crucial role – for example by setting off airbags if accidents occur. Safety looks likely to improve further with the introduction of many other devices, such as pre-crash systems that control the brakes and steering automatically so as to mitigate the seriousness of accidents, and collision-avoidance systems that detect hazards or alert careless or drowsy drivers by issuing sound, vibration or light warnings.

Environmental considerations are also implicit in the introduction of additional electronic systems to cars. These allow better and leaner engine management, which translates into reduced consumption of fuel and levels of noxious emissions.

Significant growth in personal EV numbers

According to US-based analyst firm, Navigant Research, global sales of plug-in hybrid vehicles (PEVs) – containing an internal combustion engine and rechargeable battery – and all-electric cars have grown rapidly in the last two years, reaching 137 950 units in 2012.

By 2020, John Gartner, an analyst with Navigant, predicts annual sales of PEVs and all-electric cars will have raced to 1,75 million, while the hybrid market will have progressed steadily to around 2 million units.

Consumer choice

Some 25 automotive manufacturers presented more than 50 hybrid and electric cars at this year's International Motor Show, Geneva. Mainstream auto-makers showcased concept and production vehicles while niche players displayed their latest models.

It is clear that alternatives to the conventional internal combustion engine are on a roll. But why now?

Gartner believes increases in the price of petrol and diesel are helping drive growth right now. Gartner also points to concerns over climate change and carbon dioxide emissions, as well as countries’ desires to reduce reliance on energy imports.

Crucially for plug-in hybrid and all-electric vehicles, there is a growing infrastructure of charging stations. So-called slow-charging stations used for work-place and overnight charging are becoming more commonplace while fast-charging networks are also emerging.

Recent IEC standards have been instrumental in driving up the numbers of vehicle chargers ensuring safe, efficient and reliable charging of present and future electric vehicles. In November 2011, the IEC removed a major hurdle for charging infrastructures when IEC SC 23H: Plugs, socket-outlets and couplers for industrial and similar applications, and for electric vehicles, published two international electric vehicle standards for plugs and sockets.

Complex standardization landscape

"The standardization landscape has been very complex ", says Professor Peter Van Den Bossche, from the Mobility, Logistics and Automotive Technology Research Centre at Erasmus University College, Brussels, and IEC TC 69 Secretary. "But at least for the charging infrastructure we have detailed a limited number of options that are actually being adopted by industry."

IEC TC 21: Secondary cells and batteries prepared IEC 62660-1 to provide guidance for performance testing of lithium ion battery systems and cells in electric road vehicles. As Van Den Bossche notes, one of the key challenges of electric vehicle standardization work has been to achieve collaboration between the electrotechnical world and automotive manufacturers.

Electric urban transport - A revival after a long decline

More than half the world's population now live in cities, according to United Nations data, and that percentage is forecast to hit 60% by 2030. By 2025 there will be 37 megacities (22 of them in Asia), each home to more than 10 million people. The growing use of electric buses, trams and metropolitan "light railways" offers an environmentally friendly option to reduce local emission of pollutants significantly in the expanding cities of the future.

With transport systems estimated to account for between 20% and 25% of world energy consumption and CO2 (carbon dioxide) emissions, electric vehicles offer greater efficiency than their diesel counterparts. Using their brakes, they can generate kinetic energy to be recycled back into the power network. Electric engines on buses and trams cause less vibration, making journeys more comfortable for passengers and reducing maintenance time and costs.

Several IEC TCs (Technical Committees) prepare International Standards for the electric buses, trams, trolleybuses and metro/light rail vehicles used in public urban transport networks, as well as the batteries, capacitors and fuel cells used in propulsion systems, and many other components.

Buses and trolleybuses

Electric buses, which require neither great range nor speed and can be partially recharged during their journeys as they stop for passengers, are seen as the most promising area for potential growth of green urban public transport. The US-based market research and consulting firm Pike Research forecast in August 2012 that the global market for all electric-drive buses including hybrid, battery electric and fuel cell buses would grow steadily over the next six years, with a CAGR (Compound Annual Growth Rate) of 26,4% from 2012 to 2018.

Trolleybuses are electric buses that use spring-loaded trolley poles to draw their electricity from overhead lines, generally suspended from roadside posts, as distinct from other electric buses that rely on batteries. Because they do not require tracks or rails, they are more flexible than trams and drivers can cross the bus lane, making the installation of a trolleybus system much cheaper. Trolleybuses operate in some 370 cities or metropolitan areas worldwide, according to the Trolley Project.

Trams, metro and light rail

In the 1960s the tram saw a decline in favour of diesel driven buses, but the backlash in recent years against pollution and dependence on fossil fuels has seen a resurgence of interest in electric trams as another urban transport system that can carry large numbers of passengers efficiently and generates no emissions at the point of use. In a December 2012 study SCI Verkehr GmbH, an international management consultancy based in Germany, forecast the global growth in railway electrification at a CAGR of 3,4% up to 2016.

Market growth is mainly driven by new metro and electric light rail urban transport projects under way on most continents.

A metro rapid transit system is an electric passenger railway in an urban area with a high capacity and frequency, typically located either in underground tunnels or on elevated rails above street level. It allows higher capacity with less land use, less environmental impact and a lower cost than typical light rail systems.

Light rail systems use small electric-powered trains or trams that generally have a lower capacity and lower speed than normal trains to serve large metropolitan areas. They usually operate at ground level, but can include underground or overhead zones.

All urban rail systems rely on International Standards developed by IEC TC 9: Electrical equipment and systems for railways. Areas covered include rolling stock, fixed installations, management systems (including communication, signalling and processing systems) for railway operation, their interfaces and their ecological environment. These standards deal with electromechanical and electronic aspects of power components as well as electronic hardware and software components.

Batteries and fuel cells

Buses, which have defined, short routes and daily travel distances of less than 200 km, are well suited to battery-only electric technology. Li-ion (Lithium-ion) technology is the most commonly used. Pure electric buses divide into those using high power density Li-ion batteries alone and those with large banks of supercapacitors in the roof to manage fast charge and discharge and increase battery life. Hydrogen powered fuel-cell vehicles provide longer range than battery electric vehicles. Refuelling times are short and comparable with present internal combustion engine vehicles. Currently, the main drawbacks of hydrogen powered vehicles are the high cost, mainly due to expensive fuel cells, and the lack of refuelling infrastructure. IEC TCs prepare International Standards for batteries and fuel cells used in urban transport systems.

IEC TC 21: Secondary cells and batteries, has prepared standards covering requirements and tests for batteries for road vehicles, locomotives, industrial trucks and mechanical handling equipment. Its work includes standards for performance, reliability, abuse testing and dimensions for hybrid and plug-in hybrid Li-ion batteries, which are seen as one of the most promising types of secondary batteries.

IEC TC 105: Fuel cell technologies, is responsible for standards for fuel cell commercialization and adoption. It focuses on safety, installation and performance of both stationary fuel cell systems and for transportation, both for propulsion and as auxiliary power units.

Almost all fuel cell buses incorporate a battery for energy storage and there is also a balance to be struck in the hybridization of the fuel cell power plant and the supporting battery pack. While fuel cell costs remain high and hydrogen infrastructure sparse, it may be more economical to use battery-dominant buses with fuel cell range extenders.

Conductive charging

Wireless or induction/conductive charging technology to charge electric vehicles, including buses and light rail trains, is in use or undergoing testing in many countries, including South Korea, the USA, Canada, the United Kingdom, Germany, Belgium and Italy.

Wireless charging plates built into the road at bus stops and terminals enable electric buses to be charged wirelessly through a brief connection while passengers get on or off the bus at a stop. This resolves the current battery limitations that prevent an all-electric bus from operating all day off an overnight charge.

There are concerns, however, about different competing wireless or conductive charging technologies, the costs of installing the infrastructure and its capacity to stand up to extreme weather. Meanwhile companies, notably in China and the USA, have developed ultra-fast charging technology capable of charging an electric bus battery in five to ten minutes.

Other features likely to be become standard in the electric buses of the future include regenerative charge braking, energy harvesting shock absorbers, solar panels and quickly replaceable battery packs.

IEC TC 69 and SC 23H prepare International Standards for electric vehicle conductive charging systems.

More IEC standardization activities for electric urban transport

Electric urban transport systems depend also on standardization work from many other IEC TCs and their SCs, such as, TC  22: Power electronic systems and equipment, TC 36: Insulators; TC 40: Capacitors and resistors for electronic equipment; TC 47: Semiconductor devices, and obviously TC 69: Electric road vehicles and electric industrial trucks, to name only a few. Other TCs may be less obvious, such as TC 56: Dependability, which is involved in rolling stock-related standardization work. It maintains liaison activities with TC 9 and stresses that "without dependable products and services (…) transport [would be] non-functioning (…) there would be numerous car, train (…) accidents".

The impressive expansion in the number of personal and public electric vehicles in recent years has been relying to a great extent on IEC standardization work and the healthy prospects for the industry point to a steady workload for all IEC TCs and SCs involved.

Toyota iRoad personal mobility vehicle (Photo: Toyota) Toyota iRoad personal mobility vehicle (Photo: Toyota)
Fuel cell unit for Daimler fuel cell bus (Photo: Daimler AG) Fuel cell unit for Daimler fuel cell bus (Photo: Daimler AG)
Light rail system in Nottingham, England (Photo: Bombardier) Light rail system in Nottingham, England (Photo: Bombardier)