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A post-fossil fuel transport system

Created 2005/10/10, modified 2015/10/02
Contact; email daveclarkecb@yahoo.com

All the problems of climate change and ocean acidification, together with the increasingly obvious fact that the world is running out of easily extracted petroleum, show us that we cannot go on using a fossil fuel powered transport system. This page discusses alternatives that may be viable, or become viable in the near future.


Contents

Major sections on this page are...
Electric transport system
Matching electrical consumption to generation
Wind energy
Geothermal energy
Solar energy
Electrification of rail
Sailing ships
Electric ships
Electric car
Ultracapacitors
Road freight
Compressed air car
Air transport
Energy sources compared
Wood powered transport
Oil from mallee
Algae powered transport
What is the answer?
Index

Pages on this site that cover similar subjects are Payload ratio and Weight-to-power ratio.
 

Introduction

The greenhouse gasses that are released into the atmosphere by human activities are causing climate change. A major proportion of the greenhouse gas carbon dioxide (CO2) comes from fossil fuel (coal and petroleum) fired power stations, and the other main source is the petroleum fuelled transportation that we use. This page is primarily concerned with transport, but since one of the proposed fuels that I have considered for that transport is electricity, power generation methods must be considered. Another page, Sustainable electricity, discusses that.

There is a steadily increasing amount of evidence that the world's petroleum resources are running low (See Peak Oil). There is little point in me going into detail here, good references are the Wikipedia and the Association for the Study of Peak Oil & Gas, ASPO. Our society will have to work with a dwindling supply starting at some date not far off. In fact difficulties will begin before the top of the peak is reached; they will start when the rate of increase in petroleum consumption exceeds the rate of increase in petroleum extraction; this time may already have passed (April 2011), hence the recent oil price increases. The peak oil problem is another reason that we will have to give up burning fossil fuels.

No level playing field

In Australia and the USA the fossil fuel industry has the backing of government. Both major political parties in both countries receive big money in political donations from big business, and in return they look after big business. The fossil fuel industry is allowed to dump its waste, carbon dioxide, into the atmosphere at no cost to the industry, but at great cost to the Earth. This is discussed more fully in my notes on No level playing field on another page. A sustainable energy based transport system will have a hard time against the entrenched and government supported fossil fuel based transport system. The petroleum fuelled car industry and the coal industry in particular have a lot of weight with government in Australia and the USA.

Australian governments are slow to act on sustainable transport because of the power of the entrenched unsustainable transport industry. Private enterprise might, in the end, be the primary mover toward a sustainable transport system. Those businesses run by people with foresight will see the opportunities presented by sustainability compared with the dead ends implicit in non-sustainable systems.

Hydrogen

What viable alternative fuel is there for powering our transport? A major contender is hydrogen, but there are a number of problems that need to be fixed before the hydrogen powered transport system becomes viable.
  • How will we generate the hydrogen at a reasonable cost and without producing greenhouse gasses?
  • How will we move the hydrogen from where it is produced to where it is needed to refuel our vehicles? (There are technical difficulties with piping hydrogen.)
  • How will we safely store a reasonable amount of hydrogen in our vehicles? (Currently available systems for storing hydrogen are much heavier than is the hydrogen itself.)
  • Hydrogen is notoriously hard to confine, highly flammable, burns with an invisible flame, and makes steel containers brittle.
  • Will fuel cells ever be economically viable?
A hydrogen powered transport system might eventually become viable, but we cannot afford the luxury of the time it seems is going to be needed to iron out all the problems.

Ethanol

Ethanol can be produced and burned without a net increase to atmospheric CO2 by making it from such crops as sugar cane. It is not the answer to land transport because there is not enough crop land on Earth to grow that much sugar. However, it could be viable if it was confined to those uses that demand a high power to weight ratio, such as air transport.

Ethanol and methanol can also be produced from wood.

Cut back on energy use?

To drastically cut back on transport and, at the same time, maintain our life-style is not an option either. While cutting back would help, and should be done, our life-style would collapse if we were to suddenly abandon the abundant transport at reasonable cost that we have come to depend on.
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This section written about 2005
Many changes by 2015

A sustainable electrically powered transport system

Electrically powered transport is looking like the front runner for post fossil fuel road transport. Long distance transport should be by electric train, shorter distance by battery-electric vehicles, recharged from the electricity grid. The electricity supply must be powered by renewable energy.

Shipping is problematical, perhaps wind powered shipping (discussed below) will be at least the medium term answer.

There are currently problems with a battery electric powered road transport system:

  1. Existing electric vehicles have short ranges;
  2. Recharging electric vehicles from the power grid results in CO2 being released into the atmosphere from the power stations;
  3. Renewable energy generation methods such as wind are variable and are not suitable for running an entire electricity grid;
There are techniques available now to overcome the greater part of each of these problems:
  1. A prototype electric vehicle developed by the University of South Australia has been shown to have a range of 150km between charges. It is also feasible to use a system of battery replacement rather than battery recharging for longer journies. As of late 2008 a proposal has been made for such a system in eastern Australia; the company will own the batteries, car owners pay a fee to use them, replacing them as needed from numerous stations.
  2. If the electricity going into the grid is generated by sustainable means then the generation of greenhouse gas is no longer a problem.
  3. The way that the electrical grid is operated can be modified so that consumption matches generation. Indeed, the batteries of the electic cars can become a part of this balancing; this is discussed in Sustainable energy: storing electricity.
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Matching electrical consumption to generation

Variable price electricity - supply happens when buyer and seller agree on a price

Methods of sustainably generating electricity, eg. wind, have the disadvantage of being variable in time. The answer to this problem is to modify the way the electricity grid is operated so that consumption varies to match the variable generation.

Vary the retail price of electricity at any moment according to supply and demand and allow consumers to decide the price that they are willing to pay. Supply would only happen when the instantaneous selling price was below the consumer's agreed buying price. The price would be transmitted over the power lines by an AM or FM signal and appliances would be switched on and off automatically. The variable pricing will cause a close linkage between the variable rate of generation and the rate of consumption.

In periods of high generation and low demand the asking price of power would drop causing more consumption. In periods of lower generation and higher demand the asking price would rise.

The owner of an electric car would set his charger depending on how anxious he was to recharge his car. If he was in a hurry he would have to be prepared to pay a fairly high price for his power. If he was willing to wait, say overnight, he could set his charger to not switch on until the price fell to a low level. The charger would only run when the price dropped below the preset value.

The battery charging systems could also be set up to allow the car owners to profit from selling power from their car battery when power in the grid was at premium prices.

Other systems such as water heaters would use the same principle.

More detail is given on my Internet page devoted to this subject.

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Wind energy

Wind farm
Wattle Point wind farm

Wind farms could make a major contribution to providing the energy needed to run a post fossil fuel transport system.

Wind turbines are presently (2005) the most cost effective form of sustainable electricity generation. Wind generated electricity capacity in Australia has increased by something like 70% per annum in the period 2000 to 2004. In South Australia it could easily grow to the point of supplying all of the electricity needed in low demand periods in a very few years.

The main factor holding back the growth of wind energy in Australia is lack of government support, especially from the federal government, and lack of a level playing field. However, it is true that capital expenditure in the distribution system will be needed, and changes to the way the electrical supply system is run to match electrical consumption to generation will be needed if the wind industry is to grow much more in Australia.

More detail on wind energy is given on my page on that subject.




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Geothermal energy

Geothermal energy from hot dry rocks could provide a 100% reliable base-load electricity supply for a post fossil fuel transport system in Australia.

There are two main types of geothermal energy. The only proven method as of 2005 is that which uses natural steam that is captured and used to run turbines in volcanic areas. See my notes on this method in Pros and Cons of various methods of generating electricity.

A second method that is being trialled now in Australia and elsewhere is 'hot dry rocks'. Here water is pumped through a well to depths of up to 5km into exceptionally hot rocks, up to 250 degrees Celsius, and returned to the surface via another well. The water absorbs the heat from the rocks, changes to steam, and drives turbines to generate electricity. An internet site you could visit to learn more is Geodynamics.

Geothermal energy would be advantaged by the introduction of a level playing field in the electrical generation industry.

More can be found in Wikipedia.






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Solar energy

Solar energy has a part to play in a post fossil fuel transport system

There are two main types of solar energy. Thermal and photovoltaic.

Solar thermal

Various methods collect the heat of sun light and put it to use. Unfortunately no solar thermal method has found wide use as of 2005. See my notes on this method in Pros and Cons of various methods of generating electricity.

Solar photovoltaic

Here sunlight shining of panels is directly converted into electricity. The major disadvantage is the capital cost of the panels.

Solar photovoltaics are used on the solar cars in races such as the Darwin to Adelaide World Solar Challenge. They may prove to be viable as a way of supplementing the power from the batteries of electric cars, or for recharging electric cars.

Solar photovoltaics are certainly viable in places remote from the electricity grid. However, their economical viability in competition to other forms of sustainable energy is questionable.

See my notes on this method in Pros and Cons of various methods of generating electricity.

Solar energy would be advantaged by the introduction of a level playing field in the electrical generation industry.

More can be found in Wikipedia.






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Electrification of rail

Electric rail could provide the long-distance land transport for a post fossil fuel transport system

Diesel powered rail transport has a sustainability advantage over road transport in that it is more energy efficient. More tonnes can be moved over a given distance on a litre of diesel by rail than by road transport. This is mainly due to the smaller rolling friction of a steel wheel on a steel rail compared to a rubber tyre on a bitumen road. The greater size and weight of a typical train also gives an advantage in reduced air resistance, per tonne, compared to road.

However, diesel powered rail is not sustainable, it uses fossil fuel. The way to make rail transport sustainable is to electrify the railways and produce the electricity by sustainable means. You could see my notes on sustainable electrical generating methods in Pros and Cons of various methods of generating electricity.

More can be found in Wikipedia.






Sailing ships?

 
Solar & wind-powered shipping
Skysail
Skysails - credit GmbH
Windship
Windship - credit Knud E. Hansen

Innovative modern sailing ships might be able to provide sea transport in a post fossil fuel transport system

What fuel can we use to replace bunkering oil for ships? There do not seem to be any obvious contenders on the horizon.

Going 'back' to sail is an obvious possibility, but how practical is it? There have been proposals for modern sailing ships; some using retractable metal aerofoils instead of the traditional cloth sails which require so much manual labour to raise and lower.

Engineers from the Hamburg company SkySails have tested the potential of high-tech kites for pulling a ship. (Top picture on right. See SkySails)

And a team of naval architects in Copenhagen has been working on a 50 000-tonne cargo ship with aerofoil sails on six masts. (Bottom picture on right. See New Scientist)

Both these proposals would keep the conventional ship's engines, the sails would only be a supplementary source of power. With the rising cost of fuel these proposals are suggested to be viable from an economic point of view at present.
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Electric ships?

Orcel
Proposed solar/wind/wave powered cargo ship, Orcel - Credit Solar Navigator
A Scandinavian company, Wallenius Wilhelmson, reportedly plans to build the ship pictured on the right. It combines solar photovoltaic, wind, and wave powered propulsion. See Solar Navigator.

Small boats powered by solar photovoltaic panels have been used successfully. I'm not sure of my ground here, but I believe that this scales-up favourably for large ships because the resistance to movement through the water increases at a lower rate than the length of a ship increases. Ie. At a given speed the wave making resistance is less than directly proportional to the length. Also, the mass of a ship, and therefore its profitable load, is proportional to the cube of its length while the wetted surface is proportional to only the square of the length. In a few words this means that larger ships, tonne for tonne, require less power than smaller ships and large solar powered ships, I believe, should be able to travel at higher speeds than small solar powered boats.




A practical electric car?

 
Trev
Trev - credit Uni. SA
A team from The University of South Australia have shown that a practical electric car is possible.

In the past electric cars have had quite short ranges. Peter Pudney and his teem have developed Trev (Two-seat Renewable Energy Vehicle), a light-weight (about 250kg) ultra-compact car with a range of 150km. Other features of Trev are a top speed of 120km/hr, two comfortable seats and enough luggage space for at least two overnight bags.

Of course there is no advantage of changing to electric cars from petroleum power so long as the electricity is generated by burning coal. The advantage would come by replacing coal-fired power stations with renewables such as wind, geothermal (including hot dry rock) and solar power.

The operators of TREV (as I write this, 2010/08/23) are buying power from the Snowtown Wind Farm to power TREV on a 'Race around the World'. TREV is expected to use 2.1MWh of electricity in total; that is one hour's generation from one of the Snowtown turbines at full power.

A plug in electric car could provide backup power for your home

Since the batteries of an electric car must have a large capacity, it would be possible for them to provide, through a suitable inverter and switching system, backup power for your house if the mains supply failed for a short period. I have no data on how expensive this would be to set up.

 
Reva
Reva - credit Reva Electric Car Co.

Indian electric car, the Reva

The Reva is a production electric car in India. It is claimed to have a range of 80km on a full battery charge, 65km following a 2½ hour battery top-up. It is a very small car, a two-door hatchback, designed for city driving, having a maximum speed of 65km/hr.

The Australian Alternative Technology Association, (ATA) published an article about the Reva in Issue 95, April-June 2006. It seems that the Reva cannot be registered for use on public roads in Australia because of bureaucratic red-tape; another demonstration that Australian governments are not serious about reducing the country's greenhouse gas emissions.

More information on About Reva.

Why are electric cars so rare?

The electric cars mentioned above seem to indicate that battery powered electric vehicles are viable for at least suburban travel. If their batteries were charged using renewably generated electricity, eg. wind power, then these vehicles would not add to atmospheric CO2. The fact that there are so few of them demonstrates, to me at least, the political power of the fossil fuel and conventional motor car industries. Surely these industries must be lobbying governments to not put money into development of non-conventional sustainable vehicles?

Ultracapacitors in electric vehicles

It has been suggested that ultracapacitors, as a way of supplying large currents for short periods, would be a way of providing peak power in an electric vehicle while smoothing the drain on the battery.
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Road freight

Land freight transport could be sustainably handled by a scaling up of the electric car concept for short-haul combined with the handing over of long-haul transport to electrified rail.




Compressed air car

Compressed air powered car
MiniCat
A car powered by compressed air is said to have a top speed of 110km/h and a range of 80km at top speed, further if run at lower speeds.

The car is fitted with its own air compressor, so you can fill it anywhere that you can plug in to electricity; it takes about four hours. The company has developed a method for 'refuelling' that takes only three minutes, but no doubt it will be a long time before facilities are widespread. The air tank is built to stand a working pressure of up to 300 bars.

Moteur Development International, based in Luxembourg is said to expect to produce the car in 2005. It will initially go on sale in France. It comes in two versions, the three-seater compact MiniCats (pictured, right) will cost US$9850 and the six-seater sedan CitiCats will retail for US$16 000. MDI claims that at French electricity prices filling the air tank will cost about US$2.50.

If the electricity used to 'refuel' the car is sustainably generated this car will have no greenhouse gas impact. However, if the electricity is produced by a coal burning power station the vehicle could be effectively more polluting than a petroleum fuelled car.

One advantage that this concept has over battery-electric cars is that there are no expensive batteries to periodically replace.

A hybrid petrol/compressed air version is also to be marketed.

Energy savings by integration?

Unfortunately, compressing air is not an energy-efficient process, a lot of energy is lost in 'useless' heating of the air. However, if this heat could be put to good use for purposes such as heating water for later use within the home, or heating homes in the cooler part of the year, this would make the compressed air car concept more environmentally friendly.

Just as air is heated by compressing it, so it gets cold when it runs through the motor of the car and is returned to ambient pressure. It would be quite possible to use this cold air 'exhaust' to cool the operating car in warm weather.

Links

More can be read at MSNBC.

It looks like the company's own Internet site is overloaded, try it - TheAirCar.
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Air transport

The weight of the fuel and power system in aircraft is critical. Electric, hydrogen powered, or compressed air powered aeroplanes are not viable: the energy per unit weight of all these is much too low to power aircraft over long, or even medium, distances. Ethanol (alcohol) powered aircraft would be viable, although ethanol does yield only about 64% as much available energy as the same weight of petroleum. See Energy units, definitions and conversions on an additional page.

Ethanol can be produced and burned without a net increase to atmospheric CO2 by making it from such crops as sugar cane. It is not the answer to land transport because there is not enough crop land on Earth to grow that much sugar. However, if ethanol use was confined to only those cases where the weight to power ratio was critical, production should be viable.






Energy sources compared

The table below shows that much less energy can currently be stored in a battery than in a tank of petrol. Hydrogen has a very high energy content per unit mass, but unfortunately all current storage systems weigh much more than the hydrogen that they store. Even so, in terms of the amount of available energy per kilogram, hydrogen is considerably ahead of all batteries.

Strictly speaking, the energy amounts given below are not 'stored' in the fuels. They are released when the fuels are burned in air.

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Energy sourceMJ/kgComments
Propane50-
Petrol (gasoline)46-
Hydrogen142Excluding storage device
Hydrogen3-4Including the weight of the storage device
Wood16-
Nickel-cadmium0.16-0.29About 1500 charge-discharge cycles
NiMH0.22-0.43~400 cycles
Lithium-ion0.40-0.58~400 cycles

More details, more fuels, and more battery types are on my page, Energy units, definitions and conversions.

Wood is included in the above table because it is a renewable energy source.

The battery capacities are taken from Battery University, What is the best battery?

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Wood powered transport

 

Wood-fired steam trains?

Railway trains used to be coal fired. With electric trains the coal was burned in a power station, about 30% of the energy released was converted to electricity and sent along wires to the train.

It would be quite possible to build wood-fired steam trains where electric trains are not feasible, for example, in the long-distance Australian lines. I'm sure that a steam train using modern technology could be considerably more efficient than those of sixty years ago. (Or a liquid or gaseous fuel could be produced and this used to fuel the train – discussed elsewhere on this page.)

We are approaching 'peak oil' and petroleum prices are likely to more or less continually rise from now on. There is no longer any doubt that climate change is largely man-made and will have dire consequences. What, then, should we consider to fuel our transport system in the future? I suggest that firewood is a partial answer. So long as trees are planted to replace those cut down it leads to no net increase in carbon dioxide in the atmosphere and it is a cheap $160 per tonne (in Adelaide, 2005).

How do you run a car on firewood? A flammable gas can be produced from wood and fed straight into a car engine; it was done during the petrol shortages of WW2 and has recently run at least one car around Australia (there was a page on the Net about it, no longer there). This method has the disadvantage of requiring quite a bit of hardware that you must carry around with you, perhaps on a trailer, although if the process was optimised for a fuel such as wood pellets and made as compact as possible it might become a practicality.

An alternative is to produce a liquid fuel from the wood and then burn that in a car. The Fins are researching a process called fast pyrolysis to produce a substitute for diesel from wood. Another alternative is to produce alcohol from the wood and use that as the vehicle fuel.

South Australian trials have shown that five to six tonnes of firewood can be grown on each hectare of land in a 500mm rainfall area per year; much more can be grown with higher rainfall. Some arithmetic will show that there is not enough land in Australia to replace all our transport fuel with wood, but shouldn't our governments be funding research in this direction?

Advantages of wood as a transport fuel:

  • If as many trees are grown as are cut down, it leads to no net increase in greenhouse gasses;
  • Liquid and gaseous fuels can be obtained from wood (See pyrolysis, oil from mallee trees, oil from algae and ethanol and methanol);
  • High energy storage per kilogram (compared to hydrogen or batteries, either in solid wood or liquid fuels extracted from wood);
Disadvantages of wood as a transport fuel:
  • Solid wood is an inconvenient fuel and energy is lost in producing liquid or gaseous fuels from wood;
  • There is not enough space on the Earth's surface to grow the amount of wood needed to fuel the current world transport system, and land used to grow wood cannot also grow food for the world's increasing population;
  • Irresponsible use of wood could lead to more deforestation;
Note that all the disadvantages can be overcome, except the lack of space, and there are partial answers for that. The practice of producing grain which is then fed to animals that are later used for human consumption is wasteful. If the humans ate the grain directly much less land would be required to feed the same number of people. The land thus saved could be used to grow trees for fuel.

However, while this would provide a partial answer, in the end there seems no alternative but to use energy more frugally and efficiently than we do at present.

See also my page on Firewood: an environmentally responsible fuel.

Oil from mallee trees

The Oil Mallee Information website tells of a proposed commercial operation that "aims to develop an industry that will produce eucalyptus oil, charcoal, activated carbon and 'green electricity' as bulk industrial products from selected eucalypt species across a range of (Western Australian) Wheatbelt conditions". The stated aim of the project is to plant 500 million mallees over 1 million hectares. The Website provides useful documents on potential carbon sequestration by mallee trees.

Links relating to wood powered transport

Energy sources compared shows that the amount of energy that can be released by burning a kilogram of wood, while not being as great as that contained in a kilogram of liquid fuel, is much greater than currently available in a hydrogen storage system or in a battery.

A page giving a number of links on this subject is at Wood Gas Producers, highforest.tripod.com.

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Algae powered transport

An article posted on OnLineOpinion on 2005/11/30 by Roger Kalla discussed the possibility of producing oil from algae grown in saline water.

Mr Kalla mentioned research done in the USA by The National Renewable Energy Laboratory showing that 28.3 million tonnes of bio-diesel could be produced from 200 000 hectares of desert land. He said that Australia would be ideally placed to develop this industry.

In South Australia or Western Australia, for example, there are many places where a saline water table is close to the surface. Small algae growing ponds could be established in such areas. It would also be necessary to move hypersaline water into salt harvesting ponds. This industry would have the advantage of lowering the water table and reducing the soil salinisation problems in the surrounding land.

On a grander scale, sea water might be pumped from northern Spencer Gulf through about 50 kilometres of channels into the 4000 square kilometre (400 000ha) Lake Torrens where an enormous oil algae industry could be based, and very little existing ecology would need be altered. I believe that Lake Torrens is around 30m above sea level. As an alternative to harvesting the salt from the water as it becomes too saline for algal growth, it could be feasible to run it the remaining 60km or so into Lake Eyre. Most of this distance would be down hill, Lake Eyre is about 12m below sea level.

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What is the answer?

What, then, can we use to power our transport system when petroleum becomes too expensive?
  • Hydrogen has many problems;
  • Electrical batteries recharged by sustainably generated electricity cannot contain enough power to provide as big a range to a car or truck as we would like;
  • Wood, being solid, is not as easily handled as a liquid fuel, and producing a flammable gas from it requires quite a bit of equipment which must be carried around if we are to power our vehicles directly by wood;
  • Even if we produce a liquid fuel from wood (by pyrolysis, oil from mallee trees, or from ethanol or methanol) there is not enough space to grow all the trees we would need to produce the amount of fuel required;
  • Oil can be obtained from algae grown in ponds, but again it is hard to see that there is enough space on our planet to produce as much as we would like;
  • We can cut back on our use of motorised transport - use public transport more, shift most freight to electrified rail rather than road, walk more, use bicycles more - but it seems impossible to do without all liquid fuelled transport;
So what is the answer? I would suggest all of the above. We will not find one sustainable fuel that will fill all our needs, but by behaving more responsibly (using energy more carefully and efficiently) and by using a combination of different transport power options, we should be able to live a lifestyle not too different from that of the early twenty-first century and also look after the Earth.
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Index

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On this page...
Air transport
Algae powered transport
Compressed air car
Contents
Electric car
Electric ships
Electric transport system
Electrification of rail
Energy sources compared
Ethanol
Geothermal energy
Hydrogen
Introduction
Level playing field
Matching electrical consumption to generation
Oil from mallee
Related pages
Indian electric car, the Reva
Road freight
Sailing ships
Solar energy
Top
Ultracapacitors
What is the answer?
Wind energy
Wood powered transport
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