These guidelines were developed as one of the outcomes of the European project GEOENVI [Grant agreement n 818242--2018-2020]. These guidelines are a first proposal based on expert judgement from GEOENVI partners and represent a consensus among the authors. They are to be shared among the geothermal community to be revised in order to reach a broader consensus.

Life cycle assessment (LCA) is a structured, comprehensive method of quantifying material and energy flows and their associated environmental impacts caused throughout the life cycle of a good and/or service. The Joint Research Centre and the ISO 14040-14044 standards provide a framework for LCA assessments. However, this framework is general and not tailored to energy pathways and more specifically to geothermal systems. It leaves the user with a large range of choices resulting in a large variability in the LCA results that can affect their understanding by decision makers.