Estimation of global bioenergy potentials and their contribution to the world's future energy demand - A short review

The global energy question is currently dominated by three concerns that strongly affect decisions on energy development priorities, i.e. the security of the energy supply, the security of the food supply and climate change. A very challenging question in this context is the estimation of global bioenergy potentials and their possible contribution to the world’s future energy demand. The sustainability potential of global biomass for energy is widely recognised and thus a primary concern of the book. The annual global primary production (GPP) of biomass is equivalent to the 4,500 EJ (EJ = 1 Exajoule = 1018 J = 1,000 Petajoule; 14.0 EJ = Germany’s primary energy consumption in 2008, while 508 EJ = the primary energy consumption of mankind in 2009) of solar energy captured each year. Around 5 % of that energy (225 EJ) could deliver 50 % of the world’s total energy use today. This approximation is in accordance with other estimates that show a sustainable annual bioenergy production of around 270 EJ. The 50 EJ that biomass contributed to the global energy supply in 2006 (the approximate energy demand was 490 EJ) was mainly used in the form of traditional non-commercial biomass fuels and contributed only 10 % to global energy use. This chapter provides a synthesis of analyses of the longer term potential of biomass resource availability on a global scale. Various studies have assessed global biomass potentials and have arrived at widely varying results. These studies highlight the reasons for these uncertainties and explain the factors that can affect biomass availability. Estimates, for instance, are sensitive to assumptions about crop yields and the amount of land that could be made available for the production of biomass for energy usage. The sustainable use of biomass as an energy source requires comprehensive management of specific landscapes and their natural resources, which are subject to restrictions (e.g., nature protection, contaminated land, priority for food production, etc.). Knowledge of the regional landscape’s potential to provide biomass and hence bioenergy, is urgently needed and best provided by bottom-up approaches, because unsustainable biomass production would diminish the climate-related environmental advantage of bioenergy. Therefore, based on a review of currently available studies on the subject, this chapter discusses the role of sustainable biomass in the future global energy supply.