Life Cycle Analysis of lattice and tubular wind turbine towers. A comparative study.

Abstract

Abstract Wind energy is the most promising sustainable energy source as one can conclude from the recent boost of wind farms installed globally. It is rather important to investigate the total environmental impacts of wind energy, not only taking into account the zero CO2 emissions when producing electricity from wind but also assessing the total environmental burdens and resources requirement associated with the entire lifetime of all the processes related with the energy chain. In order to quantify the environmental impacts of wind energy life cycle analysis (LCA) is performed. Life cycle analysis of tall onshore wind turbine towers is not very thoroughly investigated in literature, which is a first class opportunity to perform high-end research. More specifically in this work, studies examining the life cycle performance of two types of onshore wind turbine towers are investigated; lattice and tubular. The definition of life cycle analysis and the steps applied for its implementation are also discussed. For Wind Energy LCA five phases are usually taken into consideration: manufacturing and construction, onsite erection and assembling, transportation, operation and finally dismantling. At the first steps of the present investigation, a typical system boundary is taken into account and a literature review summary describing the main conclusions from LCA studies on onshore wind turbine towers are presented. From recent LCA results on onshore wind turbines, the manufacturing stage is proved to have the greatest environmental impact, while recycling (that is used as a preferred scenario instead of reuse in the dismantling phase) is proved to act in the most favourable way. In the present study, two wind turbine towers of the same size and same energy production capacity are investigated and compared. Both structural systems, the tubular and the lattice one are proved robust enough and the total material used for their production is calculated in previous work of the research group. The two systems have different production methods, different amounts of material used and different mounting procedures which diversifies their lifecycle performance as a total and their performance in all LCA phases examined separately. Open LCA software was used to assess the lifecycle performance of the two different wind turbine tower types and very important conclusions were derived. After having performed the structural analysis of the two tower types, the LCA analysis completes the series of criteria that have to be taken into account when deciding between the two tower configurations towards more robust, more economical and more sustainable wind energy structures.