Life cycle analysis of different feedstocks of biodiesel production

Abstract

The scarcity of fossil fuel and its environmental impact have shifted the world focus on green innovations At a time when the use of fossil fuel means increasing energy scarcity and an environmental crisis in the world in which we live, we need green innovations now more than ever. Growing attention has been drawn to the use of biofuels, such as bioethanol and biodiesel, which have gradually come to make up part of the total energy supply. Uncertainties about the environmental and ecological aspects of the production and consumption of biofuel still exist despite its rapid development. A life cycle analysis (LCA) evaluates the two principal functional parameters 1) energy efficiency and 2) Greenhouse Gas (GHG) balance of different feedstocks for biodiesel production from the cradle to the grave. By accounting a life cycle analysis stage by stage, we can ascertain the change in GHG emissions and energy demand that result from the various uses of feedstocks for the production of biodiesel. In this thesis, various life cycle analysis models are reviewed and evaluated with emphasis on specific biofuels. Different LCA models depend on different LCA calculation under different situations, including GREET, LEM, SimaPro, etc. The software SimaPro was used to compare the life cycle GHG emissions and energy demand from conventional petroleum fuels and several hydro-processed renewable green diesels. A consistent methodology was used for selected fuel pathways to facilitate relatively equitable comparisons. The building of life cycle flow tree in SimaPro combined the input and output with an emphasis on the following stages 1) raw material farming and acquisition, 2)liquid fuel production, 3)transport, 4)refueling, 5)liquid fuel conversion to biodiesel and 6) end uses. Consistent impact assessment methods were chosen for simulation, equitable comparisons and comprehensive analysis of selected fuel pathways for the calculation of Global Warming Potential (GWP) and Cumulative Energy Demand (CED). However, the results of the entire lifetime estimates vary dramatically in production chains, which make it difficult to take a holistic view about energy intake and yields, economic costs and values, environmental impacts and their benefits. Apart from the diversity in system boundaries and life cycle inventories, a variance in terminologies and the limitations of interdisciplinary communication are the main factors that affect the quality of the results.