Green cells for a greener Australia?

(January 1997)

Australia is one of the worst offenders when it comes to carbon dioxide emissions. It has a first world demand for energy, no nuclear power, limited hydroelectric power, and places little reliance on oil as a fuel for its electricity generation, using the country's abundant coal supplies instead. Successive Australian federal governments have so far done very little beyond the level of rhetoric about the problem.

Coal produces more CO2 per joule when it is burnt than hydrocarbons such as oil and natural gas. These fuels produce some of their energy from the oxidation of the hydrogen in the hydrocarbons, yielding harmless water vapour, while coal yields almost nothing but CO2. So as countries around the world start doing their bit to reduce greenhouse gases, Australia's poor record and lack of action is looked at more and more harshly.

Alternative energy sources have long been used in small amounts in Australia, but the areas of high tidal range are far from the main cities, and so are the most windy areas. Rainfall is generally too low for any increase in hydroelectric power, and Australia's old mountains are too low in any case to provide the sorts of levels needed. And while Australia has abundant uranium deposits, there is a general public reaction against nuclear power. That leaves just one major resource that Australia has in abundance: sunlight.

The problem has been a lack of efficient solar cells, but now that task is coming under control. Situated partly in the tropics, any Australian developments are likely also to be of immediate use across much of the third world, so some of the recent breakthroughs from the international team at the University of New South Wales look very exciting.

The need is for a large, efficient, cheap, cell which has a low maintenance demand. It has to use cheap materials in small amounts, it needs to be made in large units so connection costs are reduced, and it has to be efficient so that a good energy yield is delivered.

The University of New South Wales in Sydney has drawn together interested researchers from all around the world, working on a number of promising directions at the same time, under the leadership of Professor Martin Green, who developed the first "Green cells" some years ago. The workers are trying to improve the performance of photovoltaic cells to get them closer to the limits of performance, put thin films of silicon on cheap materials while maintaining performance, and also develop the hardware that is needed to use the cells in practical environments.