The production of biofuel is considered a bandwagon today due to its many benefits to machines as well as to the environment. However, two scientists are challenging the popular belief that biofuels are clean sources of energy. A recent commentary found in GCB Bioenergy, pulls the conclusion that the benefits of using them are overrated compared to the use of non-renewable sources of energy because the calculation of greenhouse gas emissions from biofuels production is neglected.
The critics used the Life Cycle Analysis model, which is a technique used to measure as well as compile all information related to production, use and disposal of biofuel and its byproducts. According to the two authors, the LCA overestimated the benefits of biofuels, as the emission of carbon dioxide by vehicles using biofuel was not measured.
The proponents of biofuel and other bioenergy sources argued that while plants serve as a carbon pool, the amount of carbon that biofuels release due to combustion is equivalent to the amount present in plants, which is negligible. However, the critics argued that converting plants into biofuel doubles the count of carbon absorbed by plants because the crops are grown on highly productive lands.
Moreover, biofuels can only reduce greenhouse gas emission if the areas where they are planted have additional biomass or other plants to capture the released carbon from decomposing plants and other byproducts that are not used in biofuel production.
The overestimation of the LCA model of bioenergy is magnified when carbon dioxide emissions are combined with the underestimation of nitrogen emissions due to the application of fertilizers in areas where the biofuel crops are grown. According to Dr. Keith Smith from the University of Edinburgh and one of the proponents criticizing biofuel, the emission of nitrogen monoxide (N2O) pooled from the soil contribute to global warming and with large areas of highly productive lands converted for biofuel production, the production of nitrogen monoxide can also be doubled. Moreover, he added that a kilogram of nitrogen monoxide released to the environment has the same effects of 300 kilograms of carbon dioxide.
According to the critics of biofuels, there are also other industries where the LCAs undervalue nitrogen emission due to fertilizer application. The proponents of the commentary claimed that the value of nitrogen monoxide present in the atmosphere is double compared with the values in the LCAs.
The authors, Smith and Searchinger, concluded that with the dependence of bioenergy proponents on the LCA when it comes to measuring the greenhouse gas emission of biofuels, the development of this technology is heading in the wrong direction. According to Dr. Smith, their study aims to challenge the industry to find opportunities and use the waste materials produced in biofuel production or to focus on using unarable or degraded lands such as peat and marshes used in growing biofuel crops. Using degraded lands produces less greenhouse gases as the moisture in the land serves as efficient carbon pools.