Land Use

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New Studies Portray Unbalanced Perspective on Biofuels

DOE Committed to Environmentally Sound Biofuels Development

DOE Response based on contributions from Office of Biomass Program; Argonne National Lab, National Renewable Energy Lab, Oak Ridge National Lab, Pacific Northwest National Lab; USDA

Two studies posted last week on “ScienceExpress” — an advance web version of Science Magazine — and widely reported in the press, raise important issues but often read like conclusions looking for an underlying rationale. These two studies fundamentally misunderstand the local forces behind land use change issues and make no provision for mitigating impacts such as the slowdown in urbanization that a vibrant agricultural economy would bring. Further, these two studies somewhat conflict with one another, with one supporting cellulosic ethanol and the other one opposing it, except if produced from waste.

The Fargione, Hill, Tilman, Polasky and Hawthorne study (“Land Clearing and the Biofuel Carbon Debt” claims that biofuels production on agricultural lands is creating a “carbon debt” by initially releasing 17 to 420 times the amount of greenhouse gas emissions that it will save on an annual basis, through land conversion activities. The study is unsubstantiated by independent modeling work, and relies on many erroneous or extreme assumptions, such as stating that the US will widely use CRP land for biofuels production. In fact, most of CRP land is unsuitable for any kind of agricultural use. Further, a joint DOE/Oak Ridge National Laboratory study demonstrates that no CRP land is required to meet the new Renewable Fuel Standard requirements, as mandated by the Energy Independence and Security Act of 2007 (EISA).

While many of the assumptions are flawed, a few points made by the Fargione study are irrefutable. For example, we strongly agree that clear-cutting of rainforest or other carbon-rich lands makes no sense. In fact, it doesn’t make sense for any purpose, not just in the case of biofuels. An important point to remember is that EISA explicitly protects carbon-rich land by lifecycle greenhouse gas analysis that demonstrates a reduction of at least 50 percent in greenhouse gas emissions for advanced biofuels and at least a 60 percent reduction for cellulosic biofuels.

The Searchinger study (“Use of US Croplands for Biofuels Increases Greenhouse Gases through Emissions from Land Use Change”) claims that biofuels production in the US, whether by corn or switchgrass, will trigger harmful land use changes elsewhere, in response to higher agricultural commodity prices, and thereby lead to huge GHG increases initially. The study claims that no greenhouse gas benefits will occur for the first 167 years of corn ethanol production.

The Searchinger study is plagued by incorrect or unrealistic assumptions, and obsolete data. Here is a short list:

  • The study assumes a corn ethanol production scenario of 30 billion gallons per year by 2015, which is double the amount established by EISA (see Figure 3). To meet the new RFS, after 15 billion gallons, biofuels must come from feedstocks other than grain, and primarily be produced from cellulosic feedstocks, such as agricultural wastes and forest residues.
  • Although the text acknowledges yield increases for corn, these increases are apparently not modeled. Since 1975, average yield has grown by 2 percent per year and biotechnology is expected to enable trends to accelerate. We have also made great progress in reducing soil erosion and nitrogen use over the past decades (see figures 1 and 2). Similarly, the corn ethanol industry has also dramatically improved ethanol yields and energy use since its inception.
  • The study relies on a worst-case scenario land conversion model and does not have the precision required to determine ultimate land use. The study then compounds the problem by assuming that land use and deforestation in 2015 will mirror that which occurred in the 1990s. In fact, deforestation rates have already declined through legislation in Brazil and elsewhere. China has experienced reforestation in the past 15 years because of government policies.
  • The assumption that corn exports will decline by 62 percent is contradicted by historical trends. As Figure 4 shows, U.S. corn exports have remained fairly constant at around 2 billion bushels per year throughout the entire growth phase of the ethanol industry. Specifically, the 2007 exports represent a 14% increase compared to 2006 level, while US corn ethanol production has reached close to six billion gallons that same year.
  • The premise that dramatic land use will result from U.S. corn ethanol use production is flawed. Figure 5 shows the dramatic increase in protein-rich U.S. Distiller Dry Grains (DDGS) exports, which is skyrocketing as U.S. corn ethanol production expands rapidly. DDGS export growth will be a growing contributor to the global food supply.
  • One scenario analyzed in the study incorrectly assumes the conversion of US corn cropland to switchgrass. No farmer would convert corn acreage to switchgrass as the value of corn will always exceed that of a non-food crop. Furthermore, a DOE/Oak Ridge National Laboratory study found that more than 1 billion tons of biomass resources are available in this country (Figure 6) without displacing corn cropland.

DOE Commitment to Environmentally Sound Biofuels Development

DOE is committed to ensuring environmentally responsible growth of the biofuels sector. To that end, we are working with USDA, EPA and other agencies to examine the issue of direct and indirect land use, as well as many other sustainability challenges (water use, fertilizer use). DOE’s research, development, and demonstration efforts focus on hastening the emergence of an advanced cellulosic biofuels industry, which will use primarily agricultural wastes, forest residues and energy crops not competing with food. The Department has announced more than $1 billion of investment over the past year, which include ten major cellulosic biofuels demonstration projects (which mostly use waste materials) and three Bioenergy centers led by our major research universities and national laboratories, which aim to achieve transformational breakthroughs in our nation’s ability to produce sustainable, competitive biofuels.

One must keep in mind that land use is a critical issue that must be addressed as we grow our nation’s biofuels production, but this issue is not unique to biofuels. Our nation needs smart land use policy to govern whatever growth and development occurs, whether we are considering biomass production or something entirely different. DOE and the recently passed EISA are calling for sustainable biofuels, not planting crops on every inch of arable land. In fact, as we move toward cellulosic biomass, these feedstocks can grow on more marginal lands. In terms of land use, we would only need about one-third of the land identified in the Billion Ton Study to produce the entire 36 billion gallons required by 2022. And, this does not even take into account increases in yields expected to become a reality over the next decade.

Just as the US must adopt and enforce land use policies that prohibit development of ecologically sensitive lands, this must be the case worldwide. To that end, DOE and the State Department are working to address global sustainability issues with international partners, including environmental organizations, industry, and others.


1 Searchinger study.
2 Illinois Corn Growers Association.
3 Proceedings from National Academy of Sciences, November 2006.

Figure 1: Projected U.S. Corn Yield Increases

Figure 2: U.S. Corn Nitrogen Consumption Decline

Figure 3: Renewable Fuels Standard Volume Requirements
The law establishes definitions for categories of renewable fuels identified in the RFS.

Figure 4: U.S. Corn Exports Have Recently Increased

Figure 5: U.S. DGS Exports Have Increased Dramatically

Figure 6: U.S. Availability of Biomass Resources