UN study provides biofuels research overview

By Erin Voegele | October 06, 2009
Report posted Oct. 20, 2009, at 8:46 p.m. CST

The United Nations Environmental Programme's International Panel for Sustainable Resource Management recently released its first report, titled "Towards Sustainable Production and Use of Resources: Assessing Biofuels." The report is designed to provide an overview of some of the key issues associated with the sustainable production and use of biofuels, including ethanol and biodiesel. Rather than showcasing primary research, the report is based on an extensive literature review in which the authors took into account recent major reviews of research and aimed to consider a wide range of views from experts around the world. According to the study's introduction, the research focuses primarily on first-generation biofuels. This is attributed primarily to the availability of current data.

As a literature review, the study touches on a wide variety of issues related to the global biofuels industry, including information on current industry trends, environmental impacts of biofuels and the impacts of increased demand and land use change. According to information cited in the study, more than 17 countries had implemented biofuel blending mandates by 2006. In addition to these national standards, the researchers stated that at least 36 states and provinces have implemented their own standards.

Regarding the lifecycle emissions of biofuels, the study found that net greenhouse gas (GHG) savings are largely dependent on a variety of factors, including feedstock, conversion technology and methodological assumptions. In its review of literature, the research team found that the highest GHG savings were attributed to sugarcane feedstock. This ranged from 70 percent to more than 100 percent GHG savings. In comparison, the GHG emissions of corn ethanol ranged from a savings of 60 percent to a 5 percent increase in emissions over fossil fuels.

In the area of land requirements for biofuels, the researchers found that they varied widely and were dependent on the basic assumptions made by those completing the study. These assumptions included the type of feedstock used, the geographical location of fuel production and the input and yield increase.

One concern cited in the report was the GHG emissions that result when land is cleared to cultivate biofuels feedstocks. The report found that clearing vegetation can release large amounts of carbon and can lead to carbon debt, which could make the GHG mitigation effect of biofuels questionable for decades.

According to the report, the use of degraded or marginal and abandoned land for feedstock production may help avoid land use conflicts. In addition, the researchers state that certain crops, such as switchgrass, may help restore the productivity of degraded lands. However, they also note that there are concerns about yields and the effects the required inputs may have on water and biodiversity.

In addition to exploring many issues related to biofuels, the study also describes several areas in which additional primary research must be conducted. This includes:
  • Comparing the bioenergy pathways in different environments and locations; for example, comparing stationary use versus mobile use.
  • Analysis of the environmental implications of second- and third-generation biofuels; especially in the areas of GHG emissions and land requirements.
  • Assessing the overall implications of using sustainability criteria for biofuels, in particular in certification schemes.
  • Advancing the use of residues and waste; this includes clarifying the role of residues is oil protection, maintaining soil carbon content, and nutrient cycling.
  • Identifying realistic production and potential consequences of using degraded cropland.
  • Working to develop biofuel certification mechanisms, including being able to better consider indirect land use change, GHG emissions and other impacts.
  • Harmonizing rules on how to land change assessments on biofuels, including setting guidelines and assumptions for methodological issues, determining how to deal with the associated uncertainty of key parameters, which includes water consumption and pollution issues.