Intermediate biofuels to support a flexible application of biomass

Abstract

As the previous book chapters concluded, the future bioenergy provision concepts for power, heat and transport fuels are characterised by more complex demands. A future energy market is characterised by the need for a sustainable flexible energy carrier with homogeneous properties for application in the fields of CHP, heat and fuel. To some extent these energy carriers are already available today (see Chaps. 4, 5, 6, 7) in many cases untreated biomass cannot fulfil the requirements of existing and future conversion processes or demands respectively. As far as solid biofuels are concerned, the high moisture content of untreated biofuels coupled with a low energy density and high biological activity require the development of often costly storage, transport and conversion techniques. Various research activities are still ongoing to improve the utilisation of biofuels in existing and future technologies, available infrastructure and therefore also in logistic and storage issues. A similar development can be observed regarding the biogenic substitutes for natural gas (biomethane, bio–SNG). Such upgraded ‘new’or rather ‘advanced’ solid and gaseous biofuels are high energy value products for gasification and combustion in industrial conversion plants as well as for domestic applications with excellent advantages in flexible energy provision. The amount of advanced solid biofuels in the markets of heating and power or combined heat and power systems will increase, as will the share of the biogenic substitutes for natural gas with further development and process optimisation.This chapter reviews the current developments in selected biomass pretreatment processes and their intermediate biofuel products that have the potential to increase flexible bioenergy production in the short and mid-term. On the one hand, these include biomass densification without thermal treatment as well as torrefaction and hydrothermal treatment for producing intermediate solid biomass. On the other hand, technologies for biogenic substitutes for natural gas are evaluated. The focus lies on the surplus value of the technologies in terms of flexibility during energy production or use of the advanced solid biofuels or biogenic substitutes for natural gas as intermediate bioenergy carriers.