ABSTRACT
Worldwide energy consumption is projected to expand by 50% between 2005 and 2030, which will cause depletion of known fossil fuel resources (EIA, 2007). Fossil fuels currently account for 85% of the world’s total energy consumption, which has created issues such as global warming, fuel security and the depletion of non-renewable resources. The rapid depletion of fossil fuels has resulted in increased utilization of biomass as a bioenergy resource in future systems. Currently, bioenergy represents one of the most significant available opportunities. The UN’s Food and Agriculture Organization (FAO) defines bioenergy as the energy derived from biomass-based fuels, where biomass is defined as ‘material of biological origin excluding material embedded in geological formations and transformed to fossil’ (FAOViews on Bioenergy, 2012). According to the US Department of Energy, bioenergy is the energy derived from any available renewable organic matter that includes energy crops, wastes and residues from the agriculture industry, waste from the forestry industry, aquatic plants, wastes from animals, and municipal wastes (US Department of Energy, 2012). A number of initiatives are currently being developed that aim to reduce oil dependency
and fossil-based greenhouse gas emissions. There is great promise in using renewable energy resources, including the increased production of bio-based fuels, as a possible way to solve environmental issues. Renewable fuels are likely to play an important role in the future as replacement of fossil fuels, due to increasingly strict regulations for greenhouse gas (GHG) emissions reduction. The European Union (EU) has set a target for biofuel use in the transportation sector of 5.75% by 2010 (EU Directive, 2003). According to a 2009 renewable directive (Fig. 10.1), the share of renewable sources should be 20% of energy supplied by 2020 and a share of 10% biofuels in the transportation sector (Swedish EnergyAgency, 2009). Bioenergy currently provides 69 million tonnes of oil equivalent (Mtoe) in the EU,which is equivalent to approximately 4%of EU’s total primary energy consumption. With the increasing consumption of fossil fuels, developing innovative bioenergy polygeneration technologies will help meet these challenging targets. Bioenergy can help in reducing greenhouse emissions related to fossil-based fuels. Biomass is
considered to be CO2-neutral if it is sustainably managed, while it is also important to improve the efficiency of the current bioenergy systems (Thuijl et al., 2003; Möllersten and Yan, 2001). Theoretically, carbon emissions from the bioenergy production and consumption stages may be counterbalanced by photosynthesis during biomass growth. There are different technologies and various energy alternatives exist for bioenergy production, including biofuels for transport, combined heat and power generation, and upgraded biofuel such as pellets. Figure 10.2 shows various bioenergy polygeneration alternatives. Since biomass is a limited resource, bioenergy production should be as efficient as possible and
the integration with other industrial processes should be energy efficient; that is the production of high-quality products should require as little energy as possible. Biomass energy resources can be used sustainably if they are produced in a sustainable manner. Forest-based biomass plays an important role as a raw material for wood-based bioenergy products and as a renewable fuel.
