Life cycle assessment of sugar and electricity production under different sugarcane cultivation and cogeneration scenarios in India

摘要

Sugarcane is a valuable raw material for bioenergy and bioproduct production. The environmental performance of sugarcane-derived bioenergy and bioproducts vary with sugarcane cultivation practices and energy conversion technologies. A farm to factory gate life cycle assessment (LCA) is conducted to assess the energy and environmental performance of sugar production and bagasse electricity cogeneration in Maharashtra, India under different scenarios. Altogether 20 scenarios were developed taking four sugarcane seasons (adsali, ratoon, preseasonal and sum) and four cogeneration boilers (low pressure, medium pressure, high pressure and very high pressure). The functional units are the production of 1 tonne of sugar and 1 MWh of surplus electricity. The ReCiPe 2016 midpoint (H) method is used for impact assessment. System expansion is applied to assess the alternative uses of sugarcane by-products (trash, press mud and bagasse ash).The global warming potential (GWP) of bagasse cogenerated electricity and sugar range from 90 to 142 kg CO2-eq MWh(-1) and 324-834 kg CO2-eq t(-1) among the scenarios. The water consumption potential (WCP) varies from 209 to 354 m(3) MWh(-1) for electricity and 768-2097 m(3) t(-1) for sugar. The Cumulative Energy Demand (CED) for electricity and sugar ranges from 0.8 to 1.2 MJ kWh(-1) and 3-8 MJ kg(-1). The Energy Return On Investment (EROI) differs from 2.7 to 4.5 for electricity and 2.1 to 5.3 for sugar. The alternative uses of sugarcane by-products contribute to negative emission and lower the overall GWP by 13-15%. Scenarios producing only sugar have a much higher environmental impact than scenarios producing both sugar and surplus electricity. The combination of adsali sugarcane and very high pressure cogeneration boiler provides the highest environmental benefits among all scenarios. The findings can help enhance cleaner production initiatives in the Indian sugarcane sector. (C) 2020 Elsevier Ltd. All rights reserved.