A U.N. panel said today that biofuels' effects on air and water have not been sufficiently explored despite growing global production.
The U.N. Environment Programme's report concludes that so-called lifecycle assessments must go beyond calculating greenhouse gas emissions and consider how agricultural production of feedstocks affects the acidification and nutrient loading of waterways.
"The available knowledge from life-cycle-assessments ... seems limited, despite the fact that for those issues many biofuels cause higher environmental pressures than fossil fuels," the report says.
"From a representative sample of [lifecycle] studies on biofuels, less than one third presented results for acidification and eutrophication, and only a few for toxicity potential (either human toxicity or eco-toxicity, or both), summer smog, ozone depletion or abiotic resource depletion potential, and none on biodiversity," it adds.
The study is the second major report this month calling for greater research on the environmental effects of producing ethanol and other renewable transportation fuels.
A Government Accountability Office report released Oct. 2 said Congress should require U.S. EPA to consider a wider range of environmental effects when deciding which fuels are eligible under the federal biofuels use mandate (E&ENews PM, Oct. 2).
The topic is one of many covered in the broad UNEP survey of issues surrounding "sustainable" production and use of biofuels and notes wide variation in greenhouse gas emissions reductions and increases that biofuels can spur.
It warns that some biofuels production methods can cause large increases in greenhouse gas emissions, such as clearing Indonesian rainforest to grow palm plantations for biodiesel.
The study examines options for lessening the effects of expanding agricultural production prompted by fuels, such as using currently marginal or degraded land for fuels feedstock production.
The report is the product of UNEP's International Panel for Sustainable Resource Management.
"Biofuels are neither a panacea nor a pariah but like all technologies they represent both opportunities and challenges," Achim Steiner, U.N. undersecretary-general and UNEP executive director, said in a statement.
"Therefore a more sophisticated debate is urgently needed which is what this first report by the Panel is intended to provide," he added. "On one level, it is a debate about which energy crops to grow and where, and also about the way different countries and biofuel companies promote and manage the production and conversion of plant materials for energy purposes -- some clearly are climate friendly while others are highly questionable."
Biofuels use in the United States and elsewhere has grown considerably in recent years. Global ethanol production tripled between 2000 and 2007 from 17 billion to more than 52 billion liters. Biofuels still provide 1.8 percent of transportation fuels globally.
Growth in biofuels production and use is driven by mandates in many countries. The United States expanded its federal biofuels mandate in a 2007 law to reach 36 billion gallons by 2022, with up to 15 billion gallons coming from corn ethanol and the balance from so-called advanced biofuels like cellulosic ethanol.
However, these next-wave fuels have not yet reached commercial-scale production, although a number of projects are under development.
Click here to read the report.