Biofuels and water
3 Apr, 2009 09:29 pm
The oil company Shell has announced that it will end its investments in wind energy. It intends to focus on biofuels. This remarkably comes at a time that there is increasing concern about the effects of transport biofuel production on fresh water availability.
requirements for achieving the Chinese biofuel production target of 2020. By then, the Chinese government envisages the production of 12 million metric tons of biofuel. Yang and coworkers assume the biofuel to be bioethanol from the relatively water-efficient starch crop maize (corn). They calculate that for producing 12 million metric tons of bioethanol from corn the equivalent of the annual discharge of the Yellow River would be required. This is a very heavy burden for China. Of Chinese arable land about 64% is in the northern part of China where water tables are falling as water consumption
exceeds the addition to water stocks (2). Thus, Yang and coworkers have a stern warning about the impact on food prices and the environmental impacts following from meeting the Chinese biofuel target by producing biofuels.
China is not the only country where large negative impacts linked to massive water demand are to be expected from expanding biofuel production. In much of the starch crop producing areas of India and in the West of the United States water tables are also falling. Another traditional major producer of starch crops that may serve biofuel production, Australia, suffers from a heavy multiyear drought. And it has been argued that, due to climate change, such a heavy drought may in the future also hit the American West.
When one looks at biofuel production worldwide, there is no reason for complacency.
When worldwide all current transport fuel were to be replaced by bioethanol from maize, roughly 5-6000 km3 of fresh water would be needed. For comparison, the total current yearly supply of fresh water available to mankind has been estimated at 13500 km3.
Making biofuel from wheat, soybeans or rapeseed would require an even larger amount of water than bioethanol production from corn.
So, it would seem necessary that governments of countries with a relatively limited supply of fresh water, and major fuel producers such as Shell, with ambitious plans for the expansion of biofuel production re-evaluate such plans in view of the impact thereof on future fresh water availability.
(1)H. Yang, Y. Zhou, J. Liu. Land and water requirements of biofuel and implications for food supply and the environment in China. Energy Policy (in press)
(2)S. Khan, M.A. Hanjra, J. Mu Water management and crop production for food security in China: a review. Agricultural Water Management 2009; 96: 349-360