New Biofuels Feedstocks Are Water Hogs

Many energy researchers and environmental advocates are excited about the potential for biofuel producers to make the switch from corn to feedstocks based on large grasses like miscanthus or switchgrass. These crops have many benefits over corn, including increased yields, better economics and the fact that they are not also grown for food. However, researchers from the University of Illinois have found one drawback to growing these crops as feedstock for the next generation of biofuels: water.

Praveen Kumar, the Lovell Professor of civil and environmental engineering at the University of Illinois, recently published a study in the Proceedings of the National Academy of Sciences Early Edition, detailing the effects that large-scale land conversion will have on the hydrologic cycle, both now and as conditions change in the future. Kumar and his colleagues found that, because miscanthus and switchgrass have more surface area and a much denser growth pattern than corn, these crops require significantly more water to grow. The result of large-scale adoption would be a reduction in soil moisture and runoff, and an increase in atmospheric humidity.


image via L. Brian Stauffer

Kumar – pictured above, at right, with fellow researcher Phong Le at a miscanthus research plot in Champaign, Ill. – and his group used a sophisticated model to study the crops’ adaptation to changing climate conditions. They found that the combination of rising temperatures and increased carbon dioxide in the atmosphere causes plants to transpire more, and lose significantly more water, compounding the increase in water usage caused by a change in land use.

image via Praveen Kumar

“There are many countries around the world that are looking into biofuel energy, but if they are adopting these (large grasses) into their regular policy, then they need to take into account the considerations for the associated demand for water,” Kumar said. He added that rainfall in the midwest should remain sufficient to meet water demand, but areas that rely on irrigation could find they do not have enough water to meet higher demands.

Lauren Craig is a writer and consultant living in Seattle, WA. She holds an M.S. in International Development from Tulane University, and is co-founder of Sustainable Systems Integrators, LLC., an employee-owned solar energy design and installation firm in New Orleans, LA. She is also certified in PV design and installation by the North American Board of Certified Energy Practitioners (NABCEP).


  • Reply September 10, 2011

    Jay Selthofner

    Missing a four letter word in this article…HEMP!

  • Reply September 10, 2011

    Jenna Colagiacomi

    What is the point of bothering with switchgrass or any other kind of grass as a biofuel?? For months I have been hearing that switchgrass is the new answer, the new solution to our energy crisis. Well, it’s absurd. Why are we going to switch from coal and natural gas to SWITCHGRASS? All of these fuels need to be burned, and the byproducts of combustion are the number one reason we are in this climate mess!!! How can I possibly stress enough that we need to move away from the combustion and focus on CLEAN fuels.u00a0 nnUsing switchgrass and any other type of plant as a fuel is going to drain our planet of the precious freshwater we have left. Haven’t you noticed the deserts that are resulting from not enough water? Haven’t you noticed that people are importing water because their region has run out?u00a0 We need water to survive and we need to reduce the amount of carbon we put into the air. So please, before you get all crazy and excited over a “NEW” fuel, do yourself a favor and think about the long term effects of using that fuel. n

  • Reply September 15, 2011


    Switchgrass does not need to be burned.u00a0 It can be converted to energy sources in 2 other ways.u00a0 As a PhD scientist who has grown switchgrass side by side with corn, I can assure you that given similar inputs (fertilizer, rainwater i.e. no irrigation, and herbicide), switchgrass far outyields corn in many areas of the US (also see Varvel et al, 2008).u00a0 Switchgrass can be grown successfully in large parts of the country without irrigation as well as on marginal land not suitable for growing traditional agronomic crops like corn and soybeans.u00a0 No one has promised that switchgrass is THE answer to our energy problems; no silver bullet for our energy crisis exists.u00a0 It is just one of the many new methods of energy production that can be utilized in specific regions of the US that will help alleviate our dependence on foreign oil.u00a0 To those who criticize the use of switchgrass, I suggest you educate yourself by becoming more familiar with the scientific research currently available in this area.u00a0

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