Driving Solutions: The case for electric vehicles

by Phillip Calais

Reprinted from energy Matters # 11

November 1999

Faced with global concern over greenhouse gas emissions and diminishing fossil fuel reserves, some car manufacturers are making impressive progress with electric vehicle technology

TRAVELLING AT an amazing 105.8 km/h, the Jamais Contente (Never Content), the first ever purpose-built racing car, smashed the world speed record in April 1899 by 13 km/h. Driven by Monsieur Camille Jenatzy, the torpedo-shaped car was powered by electric motors and a battery bank. Now, a century later, electric vehicles are breaking new records in efficiency and environmental performance.

Monsieur Jenatzy aboard his electric racing car, the Jamais Contente

At the turn of the 19th century, only 22% of cars had petrol engines while 40% were steam powered and 38% were electric and each technology had its limitations. Steam cars took a long time to warm up and electric cars had limited range. Petrol-powered cars had two problems - fuel was not readily available and starting the engine with a crank handle was often difficult and dangerous.

When new oilfields were discovered, the problem of fuel availability and cost were overcome and in 1911 a new, more compact and powerful electric motor was invented. Just the thing for increasing the performance of electric cars - and for starting petrol-powered cars. The golden age of the petrol-powered car had begun and with it the golden-brown haze now so common above many of our cities.

Driving costs

Most people consider that the cost of car ownership is only the initial purchase, fuel and maintenance. But the costs to society that arise from the environmental, health and social problems caused by fossil fuel use must also be considered.

Pollution from fossil fuel is slowly changing the Earth's climate, affecting human health, and damaging buildings, structures and vegetation.

Costs also arise from the need to 'protect' oil resources in politically unstable regions. The US Government estimates it spent an average of $87 billion (1999 Aust. dollars) per year since 1949 safeguarding oil supplies from the Persian Gulf. But this figure pales to insignificance when compared to the $410 billion the US spends each year dealing with pollution from petroleum use such as cleaning up oil spills and the effects on crops, forestry and health.

At about 40 (Australian) cents per litre, the US has the cheapest petrol in the western world. But another 50 cents per litre is paid indirectly to cover these costs through taxes.

Running on empty

W.A. has plenty of oil and gas reserves for the immediate future and is a net exporter of fuel, but this may not always be the case. Petroleum resources in W.A. can sustain 19 years of consumption at current production levels. If, in the future, we will need to import fuel, billions of dollars would be drained from the economy.

Fossil fuel emissions are also a major contributor to the greenhouse effect and the emissions are thought to be resulting in an increase in the average temperature of the Earth and causing more severe weather patterns. Of the 41 million tonnes of carbon dioxide emitted last year from fossil fuel use in W.A., 20%, came from car use.

One potential solution to the problems of resource depletion and emissions is to decrease the amount of fuel used. The Union of Concerned Scientists found that the biggest source of emissions that can be easily controlled is from car. This can be achieved by changing behaviour - driving less - or by changing to a more efficient car. Either way, less resources are used and less pollution and greenhouse gases are produced.

Change is occurring in the US, Japan and Europe, where environmental damage, health issues, the costs of maintaining influence in foreign oilfields and other problems are starting to be taken into account. Once again, electric vehicles and other so-called Zero Emission Vehicles (ZEVs) are being seen as the radical change of tack that could help solve the dilemma.

Sunny and often smog-bound California is playing a leading role in bringing about the change needed. Stirred by the 1990 Californian laws that required at least 2% of all new vehicles sold to be emission-free by 1998, increasing to 5% by 2001 and 10% by 2003, the major car manufacturers developed new ZEVs for California. Lobby groups pressured successfully for the rules to be relaxed, but other States have since followed the Californian lead and passed similar regulations.

Efficiency matters

While a normal car needs only about 20 kW (27 HP) to cruise at 110 km/h, it may need four or five times more power to accelerate and overtake or when climbing a hill. Consequently car engines are usually sized for the maximum needs - usually 100 - 150 kW (130 - 200 BHP) - while running most of the time at only about 20 - 30% capacity. At such low engine loadings, fuel efficiency suffers. A typical internal combustion engine (ICE) car uses only about 20 - 25% of the energy in the fuel, the rest wasted as heat.

An electric car's motor need only be sized for the average load. During the short periods when more power is needed, the motor can safely be run 'over-rated' so a small 20 to 30 kW (27 - 40 HP), light and highly efficient electric motor can replace a big, heavy and inefficient ICE engine.

Because the electric motor is so much smaller, a purpose-built electric car's bonnet can be made lower, reducing drag and improving the vehicle's aerodynamics. Together with the possible reduction in weight and the high efficiency of electric motors, electric cars may use less than a quarter the energy of an ICE-powered car.

Car designers are now experimenting with composite materials and light-weight alloys to reduce vehicle weight which contributes to both energy efficiency and safety.

Light-weight composite cars stop more quickly than heavy cars, and being stronger and much more elastic than steel, composite materials absorb impact with significantly less damage to vehicle and passengers.

General Motors EV1 is available in the United States

Ready, steady, charge!

Like ICE-powered cars which store energy in the fuel tank, electric vehicles also need some form of energy storage system. Batteries are usually the preferred option, but other methods have also been tried.

Batteries can be recharged anywhere there is a power point and this usually takes a few hours. Since most cars spend 90% of their life parked, this is usually no problem. Electricity can come from any source such as from the sun, wind, water or from fossil fuel power stations. Drivers could literally be running on sunshine!

Until recently the only batteries that gave reasonable performance were heavy lead-acid cells. Relatively cheap and reliable, they only store a small amount of energy for their size and weight. If the number - and hence weight - of the batteries is minimised, the energy stored is also minimised, a factor that limits vehicle range.

On the other hand, if more batteries are added, their increased weight requires so much energy to drag them around that range is also limited, giving the name of 'lead-sleds' to the early electric vehicles.

New battery types offer more range with less weight. Nickel-metal hydride, zinc-bromine, and sodium-sulphur batteries are some of the options being developed for vehicle use.

While charging with solar or wind power produces no greenhouse gases, it is usually cheaper and easier to charge batteries from a fossil-fuel derived source. This will not lead to a 'true' ZEV, but emissions can be controlled more easily at a few big power-stations than in thousands of individual vehicles. Due to electric vehicles' very high efficiency, total emissions - including those generated at power stations - are still typically a half of those from petrol-powered ICE vehicles.

New batteries may not be the only solution - or even the best. Perhaps the most promising solution to the energy storage question is to carry around the power station with the vehicle and recharge batteries when needed. This concept, first raised in 1905, led to development of the Hybrid Electric Vehicle (HEV).

Configurations differ, but the principle of an HEV is quite simple. For short trips, the car might use only battery power and the electric motor. For longer trips or when more power is needed for overtaking or hill climbing, the ICE motor starts and supplements the electric motor.

One possible configuration of a Hybrid Electric Vehicle. (click here for full size image)

Modern cars powered by internal combustion engines typically use between 5 and 15 litres per 100 km on the Standard City Test Cycle. In comparison, the hybrid Toyota Prius, a medium-sized sedan, uses about 3.5 L/100 km.

To optimise energy efficiency, it is vital to use all the available energy. When a car brakes, a great deal of energy is dissipated as heat in the brakes. But by using the electric motor as a 'regenerative' electric brake, the kinetic energy of the car can be captured and reused the next time the car accelerates.

One main difference between driving an electric car and an ICE-powered car is due to the different power and torque characteristics of the motors. An ICE typically has maximum power and torque at relatively high engine speeds, making it necessary to keep the engine RPM fairly high by changing down a gear to overtake or to climb a steep incline. With a electric car however, maximum torque is often obtained at very low RPM. This means that when overtaking or climbing an incline it may be necessary to change into a higher gear.

End of the ICE age

Many car manufacturers are exploring new directions in the search for high-efficiency cars. While some simply replace the conventional engines in standard models with electric motors and batteries, others are designing new vehicles from the ground up.

Highly efficient, light-weight vehicles made from composite materials and alloys hold the promise of better performance, enhanced safety and fuel consumption of less than 0.5 litre per 100 km.

Many major car manufacturers sell or lease electric or hybrid cars in the US, Japan and Europe, but no commercially-made vehicles are available in Australia. In Japan, Toyota alone sells or leases five models, including an all-electric RAV4 EV, a fuel-cell hybrid RAV4 and the hybrid Prius family sedan.

Available in Japan since 1997, the 160 km/h Prius sells for $A29,000 and has a range of about 1400 km. In the US, the two models of the ZEV RAV4s have been available since 1997 and the Prius is planned for release this year at a price of about $A25,000.

Not to be left behind, General Motors, Ford, Nissan, Honda, Chrysler, Peugeot, Renault and Volkswagen also sell or lease electric and hybrid vehicles. The VW CityStromer electric Golf, for example, has been available since 1982.

Of all the many ultra-efficient vehicles available overseas, none are available in Australia as most do not comply with the Australian Design Rules (ADRs).

Designed for the Japanese market, the Prius, for example, fails on a number of points: the windscreen wipers are not quite long enough; the rear vision mirror is curved, not flat; the automatic trans-mission indicator is not visible when the car is turned off; and the fuel tank inlet is larger than the rules allow.

While seemingly minor failures, the cost of modifying vehicles to meet ADR requirements, combined with the expected small market in Australia, has meant that it is not profitable to sell them in Australia - at least for now.

All is not lost however. The Commonwealth Department of Transport and Road Safety has commenced a program to harmonisation the ADRs with the UN Economic Commission for Europe and the European Union Directives for motor vehicles. As Toyota is planning on releasing the Prius in Europe next year, the right-hand drive European models should also comply with the harmonised ADRs, making them road-legal in Australia.

The past few years have seen rapid advances in electric and hybrid vehicle technology. Available at prices comparable to conventional vehicles and with lower running costs and greatly reduced emissions, these vehicles are set to challenge the dominance of conventional engined vehicle. Our cars may one day be clean, green and electric.

Note: The Toyota Prius is now available in Australia. The cost is about $40,000. Another hybrid car now available is the Honda Insight.

Electric vehicles come in a wide range of size, price and form. Pictured from top left is the Swiss EB electric trike, then the Aston Birdie, an electric trike, the Toyota Prius, Toyota RAV4EV, the electric 'slant' bike, a Ford Ranger EV and a Zap electric trike (click here for full size image)