Second-generation biorefineries use agro-residues like straw as feedstock to produce green fuels like bioethanol. While offering immense potential to meet our future energy needs, these refineries also help efficiently manage agro-residues and simultaneously prevent the food vs energy conflict. By aiding the removal of considerable quantities of straw from the field, they also contribute to mitigating the severe environmental issue of straw burning. The uncertainties associated with straw availability, the short collection times and the high costs of collection, transportation and storage make the biorefinery's feedstock procurement planning a challenging task. While an appreciable amount of research has been conducted to make efficient feedstock procurement plans that minimize procurement costs, some crucial aspects of the procurement process are still overlooked. This work attempts to include the neglected factors like baler contracting under uncertain baling time availability and choice of storage under a possibility of storage disruption in the feedstock procurement model. Additionally, we introduce a novel idea of distributed procurement that ensures an environmentally and socially sustainable procurement process. Carefully designed incentive schemes are utilized for this purpose. The proposed distributed procurement plan controls the extent of straw burning across the entire straw collection region, thereby preventing high pollutant emissions and their adverse health and environmental impacts.
Due to its proven capabilities in dealing with uncertainties, a multi-stage stochastic programming approach is our preferred decision-making tool. We conduct a case study for feedstock procurement for a second-generation biorefinery located in the Bargarh District of Odisha, India. The results highlight the importance of including baling time uncertainties and storage disruption possibilities during procurement planning. The influence of warehouse costs on the choice of storage decisions is also discussed in detail. A comparison of PM10 emission intensities under different procurement plans was carried out to understand the effectiveness of the proposed distributed procurement scheme. It is found that the distributed procurement approach can mitigate the harmful effects of burning the unprocured straw by significantly reducing the high localized concentration of uncollected straw across the collection region. The incentive schemes employed to promote distributed procurement also help the biorefineries slash their feedstock procurement costs substantially.
This study is highly significant in the present Indian scenario, where twelve commercial second-generation bioethanol plants are being constructed under the government's Pradhan Mantri Jaiv Indhan-Vatavaran Anukool fasal awashesh Nivaran (JI-VAN) Yojana. The feedstock procurement model developed by us can assist these new biorefineries in making important decisions related to the procurement and storage of their feedstock.