Environmental sustainability of bioethanol production from rice straw in India: A review

Rice is the main staple food in most of the Asian countries and rice crops generate a huge amount of rice straw as crop residue in the fields. Unsustainable use of rice straw and open burning of crop in the field not only produces threat to environment by producing large amount of greenhouse gas (GHG) emission, but also make farmer׳s loose a very viable by-product. Rice straw can be used in bio-ethanol production and bring additional income and sustainable utilization. It will also provide clean energy solution to ever increasing energy demand in India. However, it becomes more important to study the sustainability of bio-ethanol production from rice straw and how it can make sense in today׳s Indian agricultural scenario. Although, the bioethanol obtained from rice straw is a carbon neutral in nature, but the concerns of environmental impacts have been raised for the whole process i.e. from rice cultivation, rice logistics, pretreatment techniques, bioethanol generation and transportation. The present review focuses on the environmental sustainability issues arising from use of rice straw for bioethanol production. The environmental impacts are assessed by studying the emission of greenhouse gases from each stage of life cycle. The paper presents an outlook on current status and future prospects of ethanol blending in the country.