Seaweed being harvested in China.

Slime power: bioenergy from the sea

14 December 2012

As global oil supplies decline and greenhouse gas emissions continue to rise, the search for renewable energy sources is more urgent than ever. Joanne MacDonald and Michele Stanley explain how marine algae could be part of the answer.

All plants turn sunlight energy and CO2 into organic molecules such as sugars and lipids (oils), which we can extract and use to produce biofuels like bioethanol, biobutanol and biodiesel. This bioenergy is likely to be a big help in reducing our dependence on fossil fuels.

But the biomass – the raw materials – have to be both sustainable and economically viable, and that’s proving to be a bit of a problem.

The most common biofuel – bioethanol – is made from sugar cane and maize. It currently accounts for 90 per cent of the world’s biofuel supply, with biodiesel from plant oil such as rape seed and palm accounting for the rest. But these ‘first generation’ biofuels are still far from meeting even existing demand for bio-based alternatives to petroleum. And we can’t simply increase production, because these energy crops compete with food crops for land and water.

So attention has turned to the other 70 per cent of the Earth’s surface – the oceans – and the potential for aquatic plants to provide a sustainable fuel source.

Read more: Slime power: bioenergy from the sea — Planet Earth Online.

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