Are biofuels a viable alternative?


Researchers say the numbers do not look promising. James Mitchell Crow reports.


Australia’s entire current wheat crop would produce less than 4% of the nation’s energy needs. – iStock

Biofuels are often touted as a promising low-carbon alternative to fossil fuels, but could they ever be produced on a scale that makes them a viable alternative energy source? Monash climate scientist Graeme Pearman has done the sums.

They don’t stack up well. The trouble is that, although the planet is bathed in solar energy, photosynthesis doesn’t capture it very well. Even the most efficient plants only turn 1% of it into usable energy. To put that into perspective, Australia’s entire current wheat crop would produce less than 4% of the nation’s energy needs.

How much land would we need to replace a typical Australian 1000 MW coal-fired power plant with biofuels? In the case of wheat, thousands of square kilometres. Even the most energy-efficient crops such as sugar cane would have to be grown across hundreds of square kilometres to produce the equivalent amount of energy. Solar panels look a more realistic option, Pearman argues. – Graeme Pearman
Plants are nature’s solar energy cells. Globally, humans use almost 25% of the energy they capture, mainly for food, leaving 75% for natural ecosystems like forests. If plants are to supply our energy needs as well, we’d need to take another 43%, leaving nature with a paltry 34%. – Graeme Pearman

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