A method to calculate the cumulative energy demand (CED) of lignite extraction

For the utilisation of an energy carrier such as lignite, the whole life cycle including necessary energy supply processes have to be considered. Therefore using the ‘Cumulative Energy Demand’ (CED) is especially suited to determine and compare the energy intensity of processes. The goal of the CED is to calculate the total primary energy input for the generation of a product, taking into account the pertinent front-end process chains. So the CED is in many steps similar to the LCA, especially in the ‘inventory analysis step’. The statements of the CED for energy supply-systems are concerned with the (primary) energy-efficiency of the energy supply and pointing out the life cycle steps with high energy-resources demand. Due to the great environmental impacts of energy supply and use which have to be laboriously assessed in LCA, the CED provides a useful, additional, energy-related ‘screening-indicator’ to LCA. This case study analyses the extraction of lignite in an opencast mine in West-Germany as the first step of energy carrier provision. Our data for the inventory analysis arise from a measuring campaign about the period of one year. The results underline the great energy demand of lignite extraction in West-Germany. With reference to the energy contents of lignite, the fraction of primary energy demands for its’ mining amounts to about 6.2%. This accounts to 93.8 % of the lignite energy content being available as usable energy for further processes, which is obviously worse than other studies have shown.