Life Cycle Assessment and Energy Systems

Abstract

The environmental impact of energy systems has a diverse origin. The combustion of fuels leads directly to emissions and potential environmental harm, whereas the use of electricity does not lead directly to environmental impacts. However, the production of electricity from fuels leads to emissions of, for example, carbon dioxide and nitrogen oxides, which can lead to climate change and acidification respectively. If wind turbines or photovoltaic cells produce the electricity, these emissions are avoided. However, the material-intensive production of wind turbines and photovoltaic cells is associated with environmental releases. Therefore, assessing the environmental impacts of energy carriers involves not only the process of using the energy carrier but also all related processes: from extracting primary energy from nature, its conversion into secondary energy carriers, its use, and any processing of waste flows at the end. Environmental life cycle assessment is the “cradle-to-grave” approach for assessing the environmental impacts of products such as electricity and petroleum. The cradle-to-grave approach involves all steps between extracting materials and fuels from the environment until the point where all materials are returned to the environment. The methodology of life cycle assessment and its application to energy systems are the subject of this article.