Sustainable Transport

Transport is the fastest growing source of greenhouse gas emissions, the primary cause of global warming and climate change.

Scientific projections suggest that to stabilise the Earth's climate we need to cut our per capita emissions by 60-80%. This is not achievable with current technology and it will be several decades before the combination of appropriate fuels, lightweight materials and fuel-efficient drivetrains will substantially reduce CO2 emissions from the transport fleet.

Greenfleet continues to develop opportunities to showcase future transport, through the promotion of fuel-efficient technology and low carbon fuels at vehicle demonstrations and events.

Kyoto and all that

At the CoP7 Kyoto negotiations, Australia negotiated limiting the increase of our greenhouse gas emissions to 8% compared to 1990 levels. Australia ratified the Kyoto Protocol in 2007, committing us to achieving this goal.

Now we are awaiting the design of a national carbon emissions trading scheme and the development of a post-Kyoto agreement which will come into effect at the end of the Kyoto period in 2012.

Vehicle technology

The motor car as we know it has changed little in the last hundred years. The basic configuration of an internal combustion engine, with drivetrain attached to the wheels, on a body that provides guaranteed levels of comfort and safety remains. Demands for improved safety and accessories have so inflated the weight of current vehicles that there has been little gain in average fuel-efficiency over the last forty years.

It is extraordinary that in this age of composite and other space-age materials, we still apparently need a vehicle that weighs twenty times more than we do to transport us safely and comfortably! It is also extraordinary that we still use an internal combustion engine and drivetrain that use only a fraction of the energy in the fuel to move the vehicle.

Just how efficient is our current vehicle?

There is 34.2 megajoules of energy contained in every litre of petrol. Here is how we use it in our cars:

  • We lose 62% due to the inefficiency of the engine
  • A further 8% is lost in the drivetrain and running the accessories
  • 17% is wasted at idle

That is 87% of the fuel used up before we even move the car!

Of the 13% (4.5 megajoules) of energy left, let us assume that the car weighs 1600kg and that we weigh 80kg, then it will take over 95% of the available energy to move the car and just under 5% to move us!

So out of our original 34.2 megajoules we use just 0.65%, or 0.22 megajoules to move us!

In the middle of all this is there hope?

For years we have been hearing stories of electric vehicles that promise zero pollution, a car that you can plug in at night that will meet all of our travel needs. It hasn’t happened because batteries that promise long life, light weight and high energy storage have not materialised. If we ever have such a vehicle then we will have to examine the source of electricity, because if is is derived from fossil fuels then we could be even worse off than we are already, and just be shifting the greenhouse pollution to somewhere else!

Now scientists and engineers have turned their attention to Hybrid Electric Vehicles (HEVs) that carry an internal combustion engine as an Auxiliary Power Unit (APU) on board.

There are two configurations of an HEV: Series HEV means that the vehicle is electric only, and is powered by electricity generated by the APU that can be stored for peak loads in batteries and super-capacitors. A Parallel HEV means that the vehicle effectively has two drivetrains, mechanical driven by the engine and electric driven by the stored energy. In both cases regenerative braking is used to recoup the energy usually lost as heat during braking.

What can the environmentally minded Aussie look to?

There are now two technologies available to Australian motorists that offer substantially reduced fuel usage and greenhouse emissions.

Now that Australia has some good fuel-standards, new generation high-pressure diesels and hybrid petrol-electric vehicles are making inroads into the car market.

Both Honda’s Civic Hybrid and Toyota’s Prius offer engine-off-at-idle and electric operation only at low speeds, and can achieve fuel efficiencies in urban usage up to 50% less than the equivalent petrol vehicle.

There are also multiple appearances of new diesels into the marketplace that offer a 30% fuel efficiency gain when compared to the equivalent petrol vehicle. These are quiet, refined and high-performance, and not at all like the historic oil-burner!

With both of these technologies there is a price premium to pay, but with the ever-escalating price of fuel we can achieve big operating cost reductions at the bowser, and can also expect substantially higher residual value when we go to sell these fuel-sipping vehicles.

As a general guide, we should look to diesel for country driving, but the hybrid comes into its own in urban stop-start usage.



 Left: Launched in 2006, the Honda Civic Hybrid.

 Below: The 2005 Toyota Prius

 

 

 

Honda’s first-generation hybrid vehicle, the Insight, was somewhat more radical than the first Toyota Prius. A lightweight two-seater coupe, powered by a one-litre three cylinder engine and the company’s Integrated Motor Assist system. The vehicle was built using a number of technologies developed on the ‘Dream’ solarcar that won the World Solar Challenge, breaking the record, in 1996. At the time the Insight was the most fuel-efficient production car in the world.

Above: Honda's first generation hybrid, The Insight, at the conclusion of SunRace 2003.

For tips on ways to reduce your current fuel usage click here 

A few home-grown solutions

Both Ford Australia and Mitsubishi have recently released dedicated LPG vehicles. This can provide a 10% reduction in greenhouse gas emissions over the equivalent petrol powered vehicle, yet only costs marginally more to purchase. The variation in LPG fuelling costs Vs petrol suggests that for high mileage users this can be a very economic option.

Holden has partnered with CSIRO to develop a prototype hybrid-electric ECOmmodore. Though not intended for production in the near future, this vehicle could offer most commuters the ability to drive to and from work without using the engine at all! Simply plug it into an off-peak power point at night to charge up the batteries and super capacitors. The beauty of this particular vehicle is that it uses fairly unsophisticated all-Australian technology, such as advanced lead-acid batteries and does not fall into the trap of excessive cost. Some very clever engineering solutions mean that this vehicle could be produced for about $5,000 more than a standard Commodore. Unfortunately, indications are that Australian motorists will not pay more for fuel efficiency, and Holden has no current production plans for a hybrid Commodore.

Looking to the future

The next stage beyond hybrids is inevitably the fuel-cell powered electric vehicle. Fuel cells are an electrochemical device that converts hydrogen and oxygen into water, producing electricity in the process. Hence we get a vehicle whose only emission is pure water!

The promise of fuel-cell vehicles

GM's first prototype fuel cell vehicle is the Hy-wire, an electric car which uses hydrogen as its power source.

 

 

GM's Hy-wire:
Radically different inside and out




"New hydrogen-powered fuel cell technology will have the potential to deliver wonderful benefits for the environment," says Greenfleet.  The only emission from these vehicles will be water, offering significant reductions in greenhouse gas emissions that scientists warn is causing global warming and climate change. 

While some argue that hydrogen is not a clean form of power - that really depends on the source. Initially hydrogen will be extracted from natural gas, which is a fossil fuel, so we can expect a greenhouse impact. As the technology matures we would hope that the CO2 can be pumped back into the earth in a geo-sequestration program to reduce this. The great advantage of the fuel cell vehicle will be that we will have the technology in place to take advantage of hydrogen supplies from renewable energy in the future.

This technology isn't too far away. According to Dr Sloane from GM in Detroit, these vehicles will be on the road by 2010 - followed by a build-up towards production targets of a million a year by 2020.

In addition to providing clean motoring, you'll also be able to plug this electric car into your house. This means using the family car as a source of electricity for your home, also reducing stress on the power grid during peak times. 

GM's first concept car, the Hy-wire (pictured above), is an example of the latest hydrogen-powered fuel cell technology.  The electronic 'drive by wire' function is similar to an aeroplane. Traditional foot controls have been moved from the floor to the steering wheel, and this can be slid from one side of the car to the other - just slide it over for your passenger to drive!

Hydrogen vehicles will be noiseless, clean and will provide more power than current vehicles. Dr Sloane says, "The Hy-wire feels exciting to drive. But beyond that, it has lots of neat attributes - one is a very, very open design. It gives a tremendous opportunity for electronic power on the vehicle, lots of safety features, and [because of its skateboard-chassis design] you can take one body off and fit another one without buying a new car."

Challenges ahead for the motor industry will include winning the public's acceptance of hydrogen vehicles in terms of affordability, making them fun to drive, safe, and having fuel readily available at a competitive cost.

So what should we do now?

In the meantime, we must invest in technology to substantially reduce fuel usage, whilst at the same time we should create carbon sinks to ameliorate our current emissions. But let’s create sinks that provide habitat for our endangered species and leave a legacy of investment in rural Australia for the benefit of future generations.

Reducing transport demand

There are two obvious ways to reduce transport emissions: Increase fuel-efficiency of the fleet and reduce transport demand.

  • Urban renewal

    Our cities and towns have been designed and developed based on the use of the motor car. We must address this and instead of designing our habitat around the motor car as our primary mode of personal transport, we need to plan to have access to facilities and services by walking, bike riding, and by access to a viable public transport system.

  • Intra-modal systems

    Because of the level of urban sprawl it may never be viable to provide adequate public transport to many urban regions. We must consider how best to promote intra-modal travel, so that we can leave our cars securely parked at interchanges and use trains, trams or buses for the balance of our trips. Time, cost and convenience are all issues here. It is currently easier to stay in the car for the entire trip than to transfer to public transport and many feel that once they have the car they might as well use it for the marginal cost of the fuel.

  • Carrot and stick

    There are a number of initiatives that we need to examine, bearing in mind cost, convenience and equity issues. Consider:

    Making 'Express' Lanes available to vehicles with more than two passengers, and/or nominated 'Fuel Efficient' vehicles

    Providing 'Priority' parking concessions to vehicles with two or more passengers, or to nominated fuel-efficient vehicles

    Charging a 'Public Transport' levy on all-day parking in the city, the revenue to assist with public transport infrastructure

    Provide Public Transport vouchers instead of free parking as part of salary packages

    Longer term it is likely that we may have to move to ‘congestion’ charges such as have recently been introduced in London. This has radically reduced traffic loads, and consequently has improved air quality and reduced greenhouse emissions substantially

  • The future

    We must aspire to a future where our normal day-to-day activities, like getting to and from work and doing the shopping, do not require the use of a full sized motor car just carrying the driver.

    This is going to require quite a substantial cultural change.

    The evolution of internet shopping and tele-commuting should bring reductions in personal transport demand, but will provide other problems associated with the delivery of goods and services to the home.

    We cannot expect major improvements until all levels of government and industry take on the issue of reducing transport demand.

Improving the efficiency:

Engine technology

  • There are a number of technologies currently being introduced that can substantially improve fuel efficiency of the internal combustion engine including: Variable valve timing; Cylinder deactivation (~15); Engine off at idle (~10%); Common-rail direct injection; high pressure turbo diesel engines (~30%). Most of these technologies are now available off the shelf but necessarily incur a price premium. Hence the proliferation of diesels in Europe where fuel is very much more expensive than in Australia.

Drivetrain

  • Traditional vehicles with mechanical drivetrains require an engine that can provide the maximum power on demand and that must idle for a lot of the time that the vehicle is at rest. All engines have a 'Sweet Spot' within their cycle, where they operate at their most efficient. Unfortunately, this is at the point of their maximum torque delivery, meaning that during their normal usage they are seldom near it, and therefore tend to run very inefficiently.
  • A hybrid-electric vehicle uses either a mechanical and electric (parallel) or an electric only (series) drivetrain.
  • Each of these configurations can allow the vehicle to run on electric power that is stored in batteries and perhaps supercapacitors in the city, and where peak power demand is not required.
  • Hybrid-electric vehicles do not have the engine running when at rest, and (in a series hybrid) the Auxiliary Power Unit (APU) that generates electricity can be mapped to operate at its sweet spot. Fuel savings of approximately 50% can be achieved with this configuration.

aXcessaustralia hybrid electric prototype showcases Australia's low emission technology.

The ECOmmodore is a prototype full-sized family car that dramatically reduces fuel consumption and exhaust emissions by using a parallet hybrid-electric drivetrain developed in a partnership between CSIRO and Holden.

At the present time there are no plans for production of a Holden hybrid, but with fuel-efficiency becoming a major issue for all manufacturers we can hope that such a vehicle may reach the market soon. 

Fuel cells

  • Electric fuel-cell powered vehicles are expected to begin to appear on our roads by the end of this decade. These run on hydrogen, that in an electrochemical process combines with oxygen from the air and produces electricity to run the vehicle, leaving water or steam as the only emission.
  • Though fuel cell powered electric vehicles look like the most promising system of the future, there are still technical problems to be overcome with the supply and storage of hydrogen.
  • One option is to 'reformulate' a fuel on board the vehicle, extracting the hydrogen from it. This appears to be a very practical solution but using petrol, which has a relatively low hydrogen content, suggests no greenhouse gain. Compressed natural gas (CNG) has a higher hydrogen content but the infrastructure for refuelling is not in place.
  • Another option is to store hydrogen on board the vehicle and refuel at depots. This has its problems, as compressed hydrogen and storage in hydrides both have technical and weight implications. A promising option here is to store the hydrogen in liquefied form at -253°C in cryogenic tanks. Again, this poses difficult technical problems - How do you store it and offer refuelling, and what happens if your car is standing for a prolonged time?
  • The problem remains to provide the infrastructure to deliver hydrogen through conventional service stations. Energy (oil) companies are working with the car industry to overcome this.


General Motors' fuel-cell Zafira runs on hydrogen. The only emission is water!

Lightweight materials

  • Weight is the real bugbear when it comes to designing for fuel-efficiency. Theoretically we could build full family size cars today that weighed a lot less than the 1,500 - 1,700kg we are used to. Herein lies a difficult safety aspect.
  • With the development of advanced composite materials (such as carbon/fibre) and light metals (such as aluminium and magnesium) for vehicle use, the technology to drastically reduce weight is readily available, though still largely prohibitively expensive. Even though the strength of these materials may be greater than those traditionally used in motor vehicles, lack of mass in an accident can subject occupants to excessive G forces.


'Spirit of Canberra', a solar car built and raced by students at Lake Tuggeranong College was outright winner of the 1999 Sydney to Melbourne Sunrace.

The future

Fuel cells are likely to be the stepping stone to truly sustainable transport vehicles. While the move to new-generation turbo diesels and hybrids is an interim solution that can reduce fuel consumption dramatically, fuel cells, depending on the source of hydrogen, can offer much more. We have not yet seen the final step in this evolution - a technology that promises to produce hydrogen using renewable energy, and a mechanism to store it on board the vehicle.

Fuels

Petrol, Liquefied Petroleum Gas (LPG), Diesel and Compressed Natural Gas are all hydrocarbon based fossil fuels, and therefore burning them releases CO2 greenhouse gas emissions that contribute to global warming and climate change.

While CO2 emissions are directly related to the amount of fuel burnt, toxic emissions that lead to urban air pollution are largely a function of the quality of the fuel, the combustion process and the effectiveness of the catalytic converter.

Lead was traditionally used as an octane booster in petrol and is currently being phased out around the World due to environmental concerns.

The next essential change from an environmental point of view is to reduce the sulphur content in both petrol and diesel. Low sulphur diesel will allow catalytic converters to be fitted to heavy trucks and buses, which will greatly reduce toxic emissions. The development of 'New Generation' common rail direct injection diesels has revolutionised the luxury car market in Europe. This technology can offer up to 30% fuel saving when compared to petrol and the latest engines are both quiet and refined.

One of the perennial problems with diesels has been the emissions of fine particles of soot that are known to contribute to cancer and respiratory problems. With zero sulphur diesel fuels the manufacturers have been able to develop particulate traps that will largely remove this problem.

Australia has taken the first step towards cleaning up its fuel with national standards introduced in 2003. More stringent standards came into effect in 2006/2007 and promise the opportunity of enjoying some of the best technology from around the world.

CO2 EMISSION FACTORS & LIQUID FUEL ENERGY DENSITIES BY FUEL TYPE

Fuel Type

k

Proportion of

CO2 Emissions
(full fuel cycle)

Energy Density

 

 

Fuel Oxidised
Pk

Factor Fk
(g/MJ)

Dk
(MJ/L)

Automotive Gasoline

1

0.99

72.4

34.2

Automotive Diesel Oil

2

0.99

74.8

38.6

Liquefied Petroleum Gas

3

0.99

65.3

25.5

Aviation Gasoline

4

0.99

72.0

33.1

Aviation Turbine Fuel

5

0.99

74.5

36.8

Industrial Diesel Fuel

6

0.99

69.7