Seaweed could help meet energy needs: Study

June 9th, 2008 - 1:52 pm ICT by IANS  

Washington, June 9 (IANS) The humble seaweed holds the potential of not only countering climate change but also providing bio-fuels to tackle the growing energy crisis, according to a new study. The large-scale cultivation of biofuels on land has serious environmental costs, including deforestation, water use and greenhouse gases - these are costs avoided by seaweed cultivation, reports Scidev.Net.

And the potential for sea cultivation, or mariculture, has now been recognised and statistics show it is strongest in Asia and the Pacific, according to Ricardo Radulovich, director of the World Bank funded Sea Gardens Project at the University of Costa Rica.

Aquaculture production has risen 60-fold since the early 1950s (to 59.4 million tonnes in 2004) and is worth around $70 billion, with 91.5 percent of the production in Asia and the Pacific.

Similarly, 99.8 percent of the eight million or so tonnes of seaweed produced each year, with a market of nearly $6 billion, come primarily China, Japan and Korea.

In Costa Rica and Japan, seaweed farming has been re-established to produce energy. It can quickly yield large amounts of carbon-neutral biomass, which can be burnt to generate electricity. High-value compounds - including some for other biofuels - can be extracted beforehand.

Less than three per cent of the world’s oceans or about 20 percent of land used in agriculture would be needed to fully substitute for fossil fuel cultivation.

Until now, seaweed has been valued mainly as food, but it is also used as fertiliser and animal feed. It doesn’t require soil and has all the water it needs - a limiting factor for most agricultural expansion.

One concern is that harvesting naturally occurring seaweed could have comparable effects on atmospheric carbon dioxide and habitat loss or fragmentation as large-scale deforestation. But cultivation is a different matter.

But there is a grossly misused nutritional source on hand: domestic wastewater, post-treatment. Growing large seaweed fields for energy using wastewater nutrients could be economically sound, for millions of tonnes of untreated wastewater are dumped daily into the seas and seaweed helps clean it up.

This idea has been tested successfully using human wastewater in experiments at US institutions, including the Woods Hole Oceanographic Institution and the Harbour Branch Oceanographic Institution.

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