Hydrogen power (1984)
What are the long term prospects of hydrogen replacing petrol as the fuel which powers the family car?
In Australia, one research team has modified an ordinary car to run on hydrogen. The car performs well in traffic, even under freeway conditions, and produces very few pollutants. Storing the hydrogen gas is a problem, since even under pressure, it takes up a lot of space.
Another group is looking at various metallic alloys which, under slight pressure, will combine with hydrogen, thus storing it conveniently for later release.
Producing the hydrogen cheaply and efficiently is another problem. One group is looking at a photo-chemical process which uses light to break down water molecules, thus releasing hydrogen. Another is using a method which is rather like a cross between a photo-voltaic cell and a solar water heater. The objective, in both cases, is to produce hydrogen from sunlight and water.
[Music plays and two students appear on screen conducting an experiment]
Narrator: For high school students simple laboratory experiments bring science to life. This particular experiment is also of great interest to professional scientists looking for solutions to the world’s energy crisis.
[The camera zooms in on the jar labelled ‘Hydrogen’]
The jar is collecting bubbles of hydrogen. It comes from ordinary water through which a small electric current is being passed. The collected hydrogen can be combined again with oxygen to produce water and a vast amount of energy.
[The jar the hydrogen was collected in is removed from the other part of the experiment and a match is light over the jar, a loud pop is heard]
The same reaction is used to power the American space shuttle.
[Image changes to show a space shuttle being launched]
Faced by the threat of dwindling oil resources research teams all over the world have been trying to harness this unruly energy to the more mundane task of powering the family car.
[Image changes to show a car driving along a road]
This car developed at Melbourne University’s Department of Mechanical Engineering is encouraging evidence that it can be done. It runs on hydrogen instead of petrol in a modified version of an ordinary internal combustion engine. These modifications have taken 15 years to develop in a long-term research program led by Dr Harry Watson and Eric Milkins. Dr Harry Watson.
[Camera zooms in on Dr Harry Watson who is driving the car]
Dr Harry Watson: This car running as it is now on gas cylinders has a range only of about 40 kilometres but with a hydride tank installed we will expect a range of about 200 kilometres. Loaded as we are now to the same weight as though we had the hydride tank we have made three significant discoveries. The car will keep up with the traffic even under freeway conditions. The pollution levels from the car are very low compliant with the most stringent standards existing in the United States or Japan and lastly and most significantly, the energy consumption of the car is such that it will go 70% further on the same amount of energy as though it were running on petrol.
[Image changes to show Dr Watson reversing the car into a garage]
Narrator: Although the car can be driven around the streets like any other vehicle, at least on short journeys, it spends most of its life anchored to a dynamometer subject to rigorous scientific scrutiny.
[Image changes to show a man preparing the dynamometer]
The researchers are particularly interested in testing the car’s exhaust emission under various loads and comparing the results with those of a conventional petrol engine.
[Image changes to show two men viewing data on a monitor]
Eric Milkins: Righto Chris, could you pull up the results please? Oh, Harry these are some results of the petrol car and the hydrogen one. Lots of emissions of hydrocarbons, CO, NOx with petrol and only a little bit of oxides of nitrogen with the hydrogen.
[Camera zooms in on the graphs that are being showed to Dr Watson]
[Image changes back to someone performing tests on the car]
Narrator: Each design modification is carefully tested. So far the results have revealed that the car actually performs better in some ways on hydrogen. It’s more efficient by about 40% and produces fewer pollutants. There are no carbon gases, some oxides of nitrogen and hydrogen dioxide, otherwise known as water, pure enough to drink. Using a bench rig Eric Milkins demonstrates the most serious problem they’ve had to face.
[Image changes to show Eric using the bench rig a few seconds later there’s a loud bang and sparks fly. It is demonstrating the way the research engines backfires]
Eric Milkins: Well that’s the backfire problem in a research engine and we can’t have that in a motor car.
[Image changes to show Eric with the cut away section of the cylinder head and zooms in on the valve]
This is a cut away section of a cylinder head and this is the special valve we’ve developed to control that backfire problem. The valve allows air in before the hydrogen and so cools the charge. Also we have to have special coatings inside the cylinder. We have to have special lubricants. Finally under some high load conditions we have to resort to water injection.
[Image changes to show under the hood of the research car]
Narrator: Eventually the modifications will be controlled electronically but for the moment the systems are mechanical. The inlet system has been modified to replace the carburettor. The distributor now rotates as the vehicle accelerates while controlling the gas flow sets the engine speed. In these experiments hydrogen is stored under pressure in large cylinders.
[Image changes to show the last of four red hydrogen cylinders being placed into the tailgate of the car]
This is where, compared with petrol, hydrogen performs very badly. Despite their size and weight these cylinders contain only enough gas to drive the car for 40 kilometres.
This problem is being tackled by Dr Douglas Bradhurst and his team at CSIRO’s Division of Energy Chemistry in Sydney.
[Image changes to show the metal hydride storage system]
They are experimenting with a metal hydride storage system, a radiator sized arrangement of pipes filled with as much gas as a conventional cylinder but at lower pressure. Using a test rig based on a small rotary engine without a carburettor they’re able to compare the two storage systems. They have to make sure it’s possible to extract the gas from the new system smoothly and fast enough to supply the engine. The storage pipes are actually solid.
[Image changes to show the powdered iron and titanium being tipped into a metal cylinder]
They are packed with a powdered metallic alloy of iron and titanium. Under slight pressure the hydrogen will bond chemically to the alloy structure forming a metallic hydride. A whole family of alloys has been developed with this useful trick. Each one performs best at a unique combination of temperature and pressure. Their absorption characteristics are tested in collaboration with Dr Watson’s project at Melbourne University as part of a program to develop new alloys with greater storage capacity.
[Image changes to show a printer, plotting out results]
In searching for ways to produce hydrogen from water efficiently and economically a number of new approaches are being tried.
[Image changes to show amber coloured liquid being poured into a narrow square glass container]
At CSIRO’s Division of Applied Organic Chemistry in Melbourne Dr Wolf Sassi and his team have been investigating how a special ruthenium dye responds to light. [Image changes to Dr Wolf Sassi with the container of amber liquid inserting it into a light box]
The dye reacts photochemically to break down the water molecules and produce hydrogen using light rather than electricity. The idea behind Dr Sassi’s work is to use the energy of sunlight to power this hydrogen producing reaction.
[Image changes to show Dr Wolf Sassi behind the light box]
Dr Wolf Sassi: The experiment you just saw is in a sense very efficient. In fact it’s ten times more efficient than what most of our competitors overseas can do. On the other hand, we still have to solve the problem of stability. We have to produce components which last longer so that these compounds don’t have to be renewed too often. The ultimate picture that we have in our minds is that of a shallow lake or pond which will be sitting in the sun slowly producing hydrogen day in day out whether the sun is shining or not and this picture is something which is in the mind of many people in this country and overseas. Whether it can be realised will depend of course on the success of our work and the work of other people.
[Image changes to show Dr Bradhurst pouring water into a glass reactor attached to a large curved reflector]
Narrator: This intriguing machine is a cross between a photovoltaic cell and a solar water heater. It’s a completely different approach being tried by Dr Bradhurst in Sydney. He’s interested in adapting these existing technologies in order to generate hydrogen.
[Camera pans over the reflector]
The curved reflector focuses sunlight onto a central tube containing a pair of electrodes. One is made of titanium with a coating of titanium oxide. This functions as a semiconducting layer to absorb light and generate bubbles of gas. The economics of the approach are very promising. The problem is to scale it up and increase the efficiency.
[Image changes to Dr Douglas Bradhurst standing in front of the reflector]
Dr Douglas Bradhurst: This collector demonstrates that hydrogen fuel can be produced from solar energy either for domestic use or as a vehicle fuel. We have designed a flat plate collector rather like a domestic solar water heater but the amount of hydrogen you could get from something like that would only fuel your car for half a kilometre. So our laboratory research is aimed primarily at improving this efficiency up to the point where useful amounts of hydrogen are produced. The whole beauty of hydrogen is that it has three times the energy per unit weight of gasoline.
[Image changes to bubbles of gas flowing through a glass tube]
Narrator: This technology could have a spectacular effect, not only on the car but the home of the future.
[Image changes to show domestic solar collectors on a house]
It’s possible that domestic solar collectors containing semiconductor electrodes could heat the domestic water supply as well as providing enough hydrogen to power the family car. These preliminary experiments point towards a whole family of new technologies. They’re part of the motorist’s secret dream to run a car on nature’s unmetered gifts, sunlight, air and water.
[Image changes to a wireframe computer animated model of a car driving on a blue grid and then credits roll: a CSIRO film Commonwealth Scientific and Industrial Research Organization, Australia Copyright © 1984]