Novel micro-scale combined feedstock biomass generation plant for grid-independent power supply

Why it matters

According to the researchers, biomass-based power generation and supply could provide a significant share of electricity to most regions in the world and be a milestone in achieving energy self-sufficiency. Recent activity in biomass-related system design and operation focuses on optimising large-scale plants for a base and flat power supply; a grid connection is expected to be available for exporting excessive and importing shortfall amounts of power to meet domestic demands. Although this approach may be suitable in developed countries with well-operated transmission and distribution grid systems, a stable grid connection is not available everywhere. As remote locations normally provide high regional availability of biomass, a continuously operated biomass plant with flexible power output would provide significant benefits and improvements in areas where otherwise only intermittent and fossil-fuel-dependent power can be provided. In order to gain understanding of the processes and operation of such a system, the authors provided a detailed model of a micro-scale biomass-based generation plant. The underlying design principles were specifically developed in a way that the plant can be operated in remote regions and does not depend on a grid connection.

Reference

The article appears in the March 2010 issue of the International Journal of Energy Research (volume 34, issue 4, pages 303-320). Authors: M. Loeser & M. A. Redfern.

Abstract

Remotely located and sparsely populated areas often do not have access to an efficient grid connection for electricity supply. However, plenty of biomass is normally available in such areas. Instead of employing island solutions such as diesel generators or large battery stacks with severe impacts on both the environment and economics of rural electrification, a micro-scale biomass plant using locally available feedstock to produce electricity and/or heat is an efficient way of not only providing those areas with competitive and reliable electricity, but also a step towards energy self-sufficiency for a large share of areas worldwide. Both wet and dry feedstock are usually available in remote areas, therefore a novel plant design combining thermochemical and biochemical treatment has been developed. The system consists of a small-scale downdraft gasifier and an anaerobic digester unit, both coupled to a gas storage system and a microturbine as the generation unit. This combined feedstock design is suitable to provide electricity down to a level of around 50 kWe, which suits a remote village or a large farm. This paper covers the modelling of the plant design in chemical engineering simulation software. Additionally, feasibility studies and results obtained from operation simulations are described and show that such a system is a feasible and an economic solution for remote power supply.