In an earlier post I mentioned briefly that I am concerned plans to grow crops for producing domestic biofuels do not adequately consider how much water this project will require. I am all for domestic production of biofuels, and have a small project going to examine the possibilities. But in my experience the people who have already launched businesses to this end, and the venture capitalists who funded them, all evince surprise at the notion water should be part of the engineering model for fuel production.
It seems I'm not the only one thinking along these lines, as Reuters today is reporting that, "biofuels could worsen water shortages". The International Water Management Institute has just release a report that claims, "Conquering hunger and coping with an estimated 3 billion extra people by 2050 will result in an 80 percent increase in water use for agriculture on rainfed and irrigated lands."
The Western US is already stretched for water supplies; we mine aquifers for water faster that it can be replaced and declining yearly snow packs are producing drought conditions in cities accustomed to profligate summer water usage. Some improvement could be made in the way we transport and use water, by switching to drip irrigation and lining canals and irrigation ditches to prevent leakage, for example. But, given the yields from soy or canola, producing sufficient plant matter to replace any significant fraction of petroleum fuels with biofuels could easily require as much water as we already use to grow food crops. I'm not nearly as bullish on algae for biodiesel now, although we might still figure out how to make it work.
I don't see any sign of the IWMI report online yet, and I quail at reading something compiled by 700 people. But I will probably have a look when it is available. This is exactly the sort of thing we have to figure out if we are to produce carbon neutral biofuels at scale.