Algae still lagging in the race

Algae are seen as the ideal biofuel source. They feed on CO2 from the surrounding air and grow using the photosynthesis route. They can be stored and processed as biofuel.

One of the benefits to harnessing algae is that it can use waste-water and ocean water, and it is relatively harmless to the local environment should it spill or leak. Algae also have a much higher production rate per acre than soy or corn.

Some studies have shown that up to 99% of the CO2 introduced to the solution can be converted or sequestered. However, algae populations can bloom and grow so quickly that they outrun the supply of nutrients or sunlight, leading to a collapse of the population. The cost of production in terms of water and energy input is also high. Carbon emissions have also been shown to be high.

New techniques have been working around these problem areas, but more is to be done. A new study in Energy and Fuels shows that when you grow that algae in bioreactors made up of clear tubes, so much energy is required that the carbon footprint of the biofuel is over three times greater than the fossil fuel it would replace.

According to Anna Stephenson from the University of Cambridge, when algae is grown in clear-tubed bioreactors the energy required to move the algae around so that it gets enough sunlight means that per megajoule equivalent of fuel, the algae fuel has a carbon footprint of 320 grams while petro-diesel takes 86 grams. Stephenson notes that when in grown in open ponds, however, the carbon footprint drops markedly, becoming 4.5 times lower than petro-diesel. However open ponds utilise more water! And the yield of biofuel from open ponds is much low than from reactors.

Just when algae seemed to be the intelligent way to use sunlight, absorb carbon dioxide and make fuel! Not to be discouraged, some way will be worked out. That's what technology and research is all about.