Box 1.2 Key terms
Biomass is plant and animal matter, including micro-organisms (such as algae).
Life - Cycle Assessment (LCA) is a tool, which allows comparison of various biofuel pathways. It shows that not all biofuels are created equal, with impacts depending on many variables. It is critical that LCAs cover a broad range of impact categories to allow for a holistic assessment, rather than comparison of a single element, such as greenhouse gas emissions (GHG).
need for safeguards...
One biofuel end-product, for example, might have a positive GHG balance but a serious impact on water, or it might have environmental benefits but cause social impacts. Yet again it might have very detrimental, possibly irreversible impacts.
Box 1.1 Life-Cycle Assessment
Life-Cycle Assessment (LCA) is a tool devised for evaluating the environmental impact of a product, process or service through its life cycle, also referred to as its ‘environmental footprint’. All inputs and outputs of material, energy, water and waste over the entire product life cycle and their relative impacts are accounted for, including the extraction of raw materials, processing, manufacturing, transport, use and disposal. The main objective of an LCA is to compare the impacts of several alternative processes in order to choose the least damaging one.
Source: UNEP (2011) Towards a Green Economy. Pathways to Sustainable Development and Poverty Eradication. A Synthesis for Policy Makers
In three main chapters Biofuels Vital Graphics first explores the potential of biofuels to become a component of the green economy, following on with a discussion on safeguards, with special emphasis on mitigating risks related to land and water-use as key natural resources for biofuel production. The publication concludes with a set of options for facilitating the development of a sustainable bioenergy sector.
Definitions Figure 1.2 illustrates the various feedstocks, which can be converted to biofuels for transport. However, this represents only part of the larger bioenergy family, which covers liquid, solid and gaseous biofuels for different uses, including electricity production, and the traditional biomass for energy use.
not all biofuels are created equal...
For the purposes of this publication, some definitions are outlined below. Biofuels
Graphics recognises the commonly used distinctions between first, second and third- generation biofuels based on the type of feedstock, conversion technology and end-product. But the authors advocate distinctions based on sustainability, better suited to policy-making and planning.
Biofuels are combustible materials directly or indirectly derived from biomass. Liquid biofuels, such as bioethanol and biodiesel, are generally used for transport; biogases are used for stationary applications such as electricity generation; and solid biofuels for electricity generation and heating.
Bioelectricity refers to electricity generated from a biofuel or directly from a biomass feedstock.
Bioenergy is defined as energy produced from organic matter or biomass.
Traditional bioenergy refers to unprocessed biomass which does not go through a conversion process, but is directly combusted; including agricultural residues, wood and charcoal.
Modern bioenergy refers to biomass that may be burned directly, further processed into densified and dried solid fuels, or converted into liquids or gaseous fuels. It includes biofuels for transport, and processed biomass for heat and electricity production.
Feedstocks are crops and other materials used to make modern forms of bioenergy.
First-generation biofuels refer to biofuels made from sugar, starch, vegetable oil, or animal fats using conventional technology. The most common first-generation biofuels are bioethanol and biomethanol, followed by biodiesel, vegetable oil and biogas.
Advanced biofuels comprised so-called second and third- generation biofuels, as well as hybrids with first-generation biofuels.
These are produced primarily from cellulose,
hemicellulose or lignin, found in residues from forestry, corn stover (the dried stalks and leaves of maize after harvest), bagasse, wheat straw, and algae. Lignocellusoic technology converts the cellulose stored in the cell walls of the plant into products that can be processed in the same way as first-generation biofuels.
Source: UNEP (2009) Assessing Biofuels, UN-Energy (2007) Sustainable Bioenergy: A Framework for Decision Makers, http://esa.un.org/un-energy/pdf/susdev.Biofuels.FAO.pdf