Geneva, 10 March 2008 - As demand for biofuels increases, industry will face additional questions: How can the water be equitably shared? Is biofuel a practical energy solution? What are the options? These questions and others at the water and energy nexus will be the focus of a new WBCSD water and energy workstream of the Council’s Water Project.
Geneva, 10 March 2008 - As demand for biofuels increases, industry will face additional questions: How can the water be equitably shared? Is biofuel a practical energy solution? What are the options? These questions and others at the water and energy nexus will be the focus of a new WBCSD water and energy workstream of the Council’s Water Project.
In developed countries, agriculture accounts for about 30% of total water use, but this share rises dramatically to 82% in developing countries. Current biofuel crops need a lot of water to grow, and as the focus shifts to biofuels water demand will rise, placing additional stress on an already limited resource.
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This year the United States set a target for domestic ethanol production to reach 130 billion liters annually by 2017, equivalent to 15% of US liquid transportation fuels. How this will be attained is a topic of much discussion in industry and government.
The US is no anomaly. The EU directive on biofuel use calls for the substitution of 5.75% (energy equivalent) of overall fossil fuel demand by 2010, and proposes a 10% substitution by 2020. China is planning to blend 2 million tonnes of ethanol into gasoline each year by 2010. These targets, and others, will demand substantial amounts of water for ethanol and biodiesel production.
Water use in biofuel production can be discussed from two angles: quantity and quality. First, the amount of water needed depends on crop type and location. For instance, corn in the US Pacific and Mountain regions needs less water than soybeans, on average. In the Northern and Southern Plains, however, the opposite is true, according to the National Research Council of the US National Academies of Science.
Although growing the feedstock is the most water-intensive aspect of biofuel production, it is certainly not the only aspect requiring water. Bio-refineries also use water to convert feedstock to fuel. The amount of water needed for processing varies with the type of feedstock.
Second, various stages of biofuel production can affect water quality, beginning with chemical applications to agriculture. When fertilizers and pesticides containing phosphorus and nitrogen enter bodies of water, they deplete it of oxygen, thus creating a more difficult environment for aquatic species to survive in. Soil erosion can also threaten water quality as soil and chemicals are washed into local streams and lakes. Bio-refineries also release wastewater, potentially high in biochemical oxygen demand, into local water sources.
Current production of biofuels is almost entirely limited to crops, such as corn and soy, which have a high value as a foodstuff or ingredient. This adds to the economic and social pressures to look for alternatives such as cellulosic ethanol, which has issues of its own. The topic is complex, the potential solutions myriad, and the opportunities unbounded.
