Michael B. Charles and Suman Sen

Abstract Although biofuels have the potential to supplement conventional petroleum fuels in a variety of energy applications, and as transport fuels in particular, their use also poses some problems from an environmental perspective. Concerns exist relating to whether positive net energy (and therefore effective greenhouse gas mitigation) can be derived from biofuels, whether the cultivation of biofuel feedstocks leads to significant environmental degradation and whether their use could hamper the imple­mentation of a more long-term transport energy paradigm. Yet a clear understanding of these issues, together with the more important technical aspects relating to biomass cultivation and biofuel production, has the potential to ensure that biofuels can play a successful role in weaning the planet off its current carbon dependency. In particular, the ability to assess the total life cycle of biofuels from cradle to grave emerges as a particularly important consideration in ensuring that cultivation and production pro­cesses are optimized.

1 Introduction

The environmental impacts of liquid biofuels remain highly controversial. Biofuels, such as bioethanol and biodiesel, are often touted by their proponents as an envi­ronmentally friendly means to address issues relating to energy security and carbon dependency. This is especially the case given that they can largely be distributed via existing networks and distribution channels, such as those used to distribute conven­tional petroleum-based gasoline (also known as petrol) and diesel. They can also be blended relatively easily with petroleum-based fuels in their anhydrous forms. Biofuels therefore fit comfortably within the existing transport energy paradigm and result in fewer adaptation costs in comparison with those associated with other

M. B. Charles (*) • S. Sen

Southern Cross University, Gold Coast, Australia

e-mail: michael. charles@scu. edu. au

A. Domingos Padula et al. (eds.), Liquid Biofuels: Emergence, Development and Prospects, Lecture Notes in Energy 27, DOI: 10.1007/978-1-4471-6482-1_8, © Springer-Verlag London 2014

mobile transportation energy sources, such as electricity or hydrogen. They have also proved popular among a variety of stakeholders on account of their ability to (1) provide new outlets for increasingly uncompetitive agricultural producers in the developed world and (2) open up new revenue-generating opportunities for farmers in the developing world.

Furthermore, perhaps the very fact that biofuels are produced from natural organic material, usually referred to as biomass, has contributed to the popular perception among politicians, interest groups and the broader public that they are more sustainable than conventional petroleum-based liquid energy products. This is compounded by the fact that combustion of biofuels per unit of volume demon­strably produces less greenhouse gas (GHG) emissions in comparison with con­ventional liquid fuels (EPA 2002). A greater reliance on biofuels in the transport industry is thus regarded as a positive step with respect to reducing overall GHG emissions from a sector that is widely criticized on account of its overall environ­mental impacts. Indeed, according to the IPCC (2007), transport is the fourth high­est emitter of GHGs and contributes 13 % of total emissions globally.[14]

Although biofuels have a clear place within the broader array of renewable fuels poised to overcome global carbon dependency, their use nevertheless has significant environmental implications at a global, national, regional and even local level. These problems result not only from the growing of the organic material required for their production, but also in the manufacturing, distribution and use of the resulting fuel. Issues of real concern include (1) whether the overall life cycle of biofuels results in negative net energy and thus the production of more GHGs than it saves; (2) whether the growing of agricultural inputs into the biofuel production process results in a loss of biodiversity and similar environmental impacts through changed land-use and the overzealous application of fertilizers, pesticides and herbicides; and (3) whether an increase in the use of biofuels will hamper the adoption of more truly efficient tech­nology that will have greater potential to reduce the global carbon footprint. Indeed, the unregulated production and use of biofuels, together with a rapidly expanding demand for the crops on which their production relies, could have significantly detri­mental impacts on the environment that could, in time, outweigh the benefits poten­tially available through a more considered exploitation of this energy source. This chapter looks closely at the environmental impact of biofuels and aims to present the current scientific understanding of issues associated with their use in a way that will be accessible to policymakers, industry and other stakeholders.