Are biofuels using too much water?
According to Sunita Narain, the head of the Centre for Science and Environment in India, biofuels are "good as an idea, bad in practice." She insists that instead of making more biofuels, we should be concerning ourselves with how to use less fuel in general. The problem that she cites is one not often heard: water. "If you want to use water for it (biofuel production), you must cut down on the consumption of biofuels," she said. The problem is that to make the biofuels, water is required to irrigate the crops. That water usually goes towards the irrigation of crops that people consume, and both cannot increase without running out of fresh water. It's easy to see that point, considering that in many parts of the world, fresh water for drinking is already in short supply. Indeed, even in some parts of the United States, where fresh drinking water is usually a given, water is diverted from other parts of the country. There are some strains of algae being tested which could be used for biofuels that grow well in the sun-drenched southwestern U.S. This algae can and does grow in saltwater, of which there is plenty. There are also some groups using seaweed for biofuels. This would alleviate the problem of biofuels stealing water away from crops for public consumption.
[Source: Physorg]
Reader Comments (Page 1 of 1)
rgseidl 7:32AM (8/19/2007)
Parts of India really do have a water shortage, because what they pump up from very deep wells is actually laced with arsenic and other heavy metals. However, as this years' monsoons underline once again, the issue is not so much a lack of rain as too much of it all at once in the wrong place.
Catchment basins, canals/pipelines and especially, porous drip irrigation hoses in the fields would solve the problem but the poorest regions in India cannot afford all that. These are areas in which microcredit and the World Bank could make a big difference.
In the US Southwest, the problem isn't so much a lack of water as historical water rights. Farmers continue to use some 80% of the fresh water brought in from Northern California and the Colorado river. Many chose to irrigate their crops with giant sprinklers during the day rather than at night, when evaporation losses would be minimal. Drip irrigation is the exception, not the rule.
Another point that is often forgotten: sewage plant effluent (i.e. already fairly clean water) could be used to irrigate non-food agriculturals such as biofuel feedstocks. In diluted form, this already happens wherever the crops are grown downstream of a city and irrigated using water from the same river the city dumps its effluent into.
Otherwise, the effluent would have to be pumped uphill in order to recycle the water. This is expensive, so minimizing evaporation and run-off losses would be absolutely essential. Without dilution, effluent salinity would be a critical parameter for sustainable agriculture. Solar-powered Stirling engines would require significant capital investment but virtually eliminate operating costs. Designs based on free liquid pistons would be especially suitable.
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