How the scum of the earth could help save the planet

Australian
Tuesday 9/12/2008 Page: 10

The use of algae in producing fuels has the potential to transform energy the way aeroplanes transformed transport, so why aren't governments paying more attention, asks Mark Tester

HERE are many reasons for wanting to reduce our dependence on oil: the increasing cost, reliability of supply, finite resources, the contribution of fossil fuels to global warming. Yet when people talk about alternative sources of fuel they mostly discuss the conversion of food, such as corn, into ethanol, which puts enormous pressure on food supplies. During the past year, demands for food and fuel have combined to drive up food prices sharply, which has particularly important ramifications in developing countries.

When one adds to the mix growing populations and global environmental change, with the pressures these impose on our ability to maintain high crop yields, the prospects for providing sufficient food for all are not good. So, the idea of converting a significant proportion of our food into fuel for vehicles or diverting agricultural land to grow biomass seems misguided. Although the growth of biomass on marginal lands has some prospect, the impact on nature conservation must be considered. Furthermore, the contribution that such areas can make to global liquid fuel needs will always be modest.

Marginal lands provide only low density cropping potential and biomass from plants or crop residues generally has a low energy density, while a significant proportion of the energy gained from the biomass will be consumed in the process of moving the biomass to the processing centres. Yet one group of plants could make a sustainable, significant contribution to world energy supply. They do not require agricultural land and need only minimal processing.

Single-celled algae can grow very rapidly in low quality water, producing biomass at 10 to 30 times the rate of terrestrial plants. They can do this mainly because the cells are immersed in a medium providing all their needs, including physical support, and so the cells have no need to build infrastructure to move materials and to support themselves.

A pond 60km by 60km (less than 500,000ha) well stocked with a vigorous microalga would go close to producing sufficient biomass to meet most of Australia's liquid fuel needs. Furthermore, algae have remarkable biochemical abilities: some strains produce oils that could be used unmodified in diesel engines. Indeed, there is good evidence that many of the world's vast reserves of fossil liquid fuels are the products of ancient algal activity.

The demands of algae are simple: sunlight, warmth, water, nutrients and, most significantly, carbon dioxide, the much maligned gas that is a major contributor to global warming. Australia has more sunshine and warmth than any other developed country, and seawater is common, thanks to our extended coastline. Augmentation of seawater with waste water from sewage treatment plants could completely satisfy algal nutrient demands and would have the side benefit of treating the waste water.

Significantly, carbon dioxide can be delivered to the algal cells either direct from the atmosphere or in a concentrated form from cement factories and electricity stations. The algae can also be engineered to convert waste carbon dioxide to produce valuable products, such as liquid fuels. Consequently, this process has much greater economic potential to be an economic option than, for example, carbon capture and storage, which, other than the carbon credits produces no useful product.

In addition to the production of liquid fuels, the algae can be used in other ways: there is potential for the cells to be pyrolysed to char for burial, which effectively removes carbon dioxide from the atmosphere, or they could be used as animal food. Across the world, including in Australia, pilot programs are pioneering this new biotechnology. The main engineering challenge is efficiently harvesting the algae. The biological challenges would not surprise anyone who has attempted to keep an aquarium clean.

The algae must be resistant to pests and pathogens and must be able to outcompete other algae that are likely to contaminate the ponds. Reliable containment methods, such as those used for bacteria and fungi in research laboratories for decades, are also necessary to prevent the escape of the microalgae into our waterways. The use of algae that have evolved in natural ecosystems will not be adequate. To optimise productivity, alteration of the algae will be necessary, including their genetic modification. Globally, most of the research on algal biofuels is in private hands.

Recently, Bill Gates invested in a US company developing algae as a fuel. But if industry is to bridge the gap between theory and reality, large companies will need to dig deep in order to develop long-term research programs. Perhaps some government-sponsored research is also necessary. Support for the integration of algal production systems with existing infrastructure power stations and waste treatment works will also require government intervention.

But, on the whole, this new and exciting area of research and development is likely to be driven by the private sector. Meanwhile, the Government is grappling with solutions to climate change without factoring in new technology. The international community is meeting this week in Poznan, Poland, to try to negotiate a global agreement on reductions in greenhouse gas emissions. These negotiations are bound to be diabolically difficult, to use Ross Garnaut's phrase. There will be heated discussions about what the level of greenhouse gas emissions should be in 25 years and in 50 years.

It is as if a conference were being held in 1908 on global transport for the 20th century without taking into account the work of Wilbur and Orville Wright. Nobody imagined that their rickety plane would transform the world. But it did. In the 21st century we need to build on this understanding of the power of technology to transform the way we live. As Rupert Murdoch observed when he delivered his first Boyer Lecture last month, there will be great rewards for Australians who discover new ways of reducing emissions or cleaning the environment.

With some hard economic analyses, some cutting-edge plant biotechnology and engineering that balances economic and biological demands, algal liquid fuel production could provide us with the most sustainable and economically viable biofuels option and a contribution to greenhouse gas reductions.

Mark Tester is director and research professor at the Australian Plant Phenomics Facility at the University of Adelaide.