A systemic approach for dimensioning and designing anaerobic bio-digestion/energy generation biomass supply networks

Anaerobic bio-digestion/energy generation complexes using animal waste raw materials represent an important component of renewable energy initiatives and policies worldwide, and are significant contributors to broaden sustainability efforts. In such projects bio-power feasibility depends heavily on generation complex access to biomass which is of costly transportation. As a result, an important component of renewable energy planning is the optimization of a logistics system to guarantee low-cost access to animal waste. This access is a function of local characteristics including number and geographic location of organic waste sources, operating and maintenance costs of the generation facility, energy prices, and marginal contribution of biomass collected and delivered to the anaerobic bio-digestion unit. Because biomass exhibits high transportation costs per unit of energy ultimately generated, and because different types of biomass have different biogas-generating properties, design of the supply logistics system can be the determinant factor towards economic viability of energy generation from an anaerobic bio-digestion plant. Indeed, to address this problem it is helpful to consider the farms, the logistics system, the anaerobic bio-digestion plant, and the generation plant as subsystems in an integrated system. Additionally, the existence of an outlet for manure may allow farmers to significantly raise boundaries of one constraint they face, namely disposing of animal waste, therefore permitting increases in farm production capacity. This paper suggests and outlines a systematic methodology to address the design of such systems.