Quantifying the Impact of Feedstock Quality on the Design of Bioenergy Supply Chain Networks

Krystel Castillo-Villar,Hertwin Minor-Popocatl,Erin Webb

doi:10.3390/en9030203

Abstract

Logging residues, which refer to the unused portions of trees cut during logging, are important sources of biomass for the emerging biofuel industry and are critical feedstocks for the first-type biofuel facilities (e.g., corn-ethanol facilities). Logging residues are under-utilized sources of biomass for energetic purposes. To support the scaling-up of the bioenergy industry, it is essential to design cost-effective biofuel supply chains that not only minimize costs, but also consider the biomass quality characteristics. The biomass quality is heavily dependent upon the moisture and the ash contents. Ignoring the biomass quality characteristics and its intrinsic costs may yield substantial economic losses that will only be discovered after operations at a biorefinery have begun. This paper proposes a novel bioenergy supply chain network design model that minimizes operational costs and includes the biomass quality-related costs. The proposed model is unique in the sense that it supports decisions where quality is not unrealistically assumed to be perfect. The effectiveness of the proposed methodology is proven by assessing a case study in the state of Tennessee, USA. The results demonstrate that the ash and moisture contents of logging residues affect the performance of the supply chain (in monetary terms). Higher-than-target moisture and ash contents incur in additional quality-related costs. The quality-related costs in the optimal solution (with final ash content of 1% and final moisture of 50%) account for 27% of overall supply chain cost. Based on the numeral experimentation, the total supply chain cost increased 7%, on average, for each additional percent in the final ash content.

Highlights

Bioenergy has been regarded as an important alternative energy source that has the potential to help nations alleviate their reliance on petroleum energy, thereby, producing positive impacts on the economy, the environment, and the society [1]
The second finding is that the optimized final ash content is 1%, which indicates that investing in preventive activities to reduce the ash content before reaching the throat of the reactor is more cost-effective than allowing the biomass to have an ash content higher than the specification at the conversion phase and, applying remedial activities such as the ash disposal and penalization for reduced yield
A cost classification for quality-related costs in bioenergy supply chains using logging residues and a method to quantitatively incorporate the Cost of Quality (COQ) into a holistic supply chain and a method to quantitatively incorporate the Cost of Quality (COQ) into a holistic supply chain model are presented in this paper

Summary

Introduction

Bioenergy has been regarded as an important alternative energy source that has the potential to help nations alleviate their reliance on petroleum energy, thereby, producing positive impacts on the economy, the environment, and the society [1]. “Feedstock logistics” include the necessary operations to harvest the biomass and transport it from the reference site to the pertinent biorefinery. These operations must ensure that the delivered feedstocks meet a set of physical and chemical quality specifications [1]. Most assessments of the biofuel feedstocks availability have focused on Energies 2016, 9, 203; doi:10.3390/en9030203 www.mdpi.com/journal/energies

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