Explainer: what are biofuels?

● By Daniel Tan, University of Sydney, Australia ● Since the beginning of civilisation, humans have depended on organic materials – or “biomass” – for cooking and heat. Many developing countries in Asia and Africa still do. Biofuel or bioenergy is the chemical energy contained in biomass that can be converted into direct, useful energy sources using biological (including food digestion), mechanical or thermochemical processes. The current liquid biofuels (bioethanol and biodiesel) are mainly produced from first generation feedstocks (such as sugarcane, maize, rapeseed) and constitute only a small fraction (1%) of present transportation energy. Second generation biofuels will come from dedicated perennial energy crops (such as miscanthus, switchgrass, agave, pongamia), and in the near future, hydrogen gas may be produced from algae, bacteria, or artificial photosynthesis to fuel hydrogen-cell powered cars. Liquid biofuels Liquid biofuels are most familiar to us. Bioethanol is a substitute for gasoline and biodisesel is a substitute for diesel. Most cars that are built have internal combustion engines which can only burn liquid fuels. While other types of engines, such as electric and hydrogen fuel cells are being developed, in the meantime, liquid biofuels are the transition renewable alternative to fossil fuels for transport. According to the International Energy Agency, liquid biofuels account for only 2% of total bioenergy, and they are mainly significant in the transportation sector. Transportation accounts for 28% of global energy consumption and 60% of global oil production, and liquid biofuels supplied only 1% of total transport fuel consumption in 2009. Globally, liquid biofuels can be classified into three main production sources; maize ethanol from the United States, sugarcane ethanol from Brazil and rapeseed biodiesel from the European Union. There is also a small quantity of palm oil biodiesel from Indonesia ...Zum vollständigen Artikel

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