Life cycle assessment of geothermal power generation technologies: An updated review

The market of energy production coming from geothermal energy is growing around the world. However, in some countries little attention is given to the life cycle environmental impacts of this industrial sector. In addition to the available work presented in previous reviews about this matter, this paper provides an updated review of life cycle environmental studies for the geothermal power generation. For the first time, these results have been compiled by energy conversion technology: dry steam, binary cycle, single flash, and double flash, including the generation pilot projects of enhanced geothermal systems. The analysis of the review shows that the environmental impacts are evaluated by considering from 1 to 18 impact categories commonly used in life cycle assessment (LCA). These impacts are mainly affected by: (i) reservoir characteristics; (ii) geothermal fluid chemistry; (iii) power generation technology; (iv) type of emissions of the life cycle inventory; and (v) data availability. Most of the LCA studies reported global warming, which is mostly caused by the fuel consumption in the construction and operation stages. A deeper analysis of the life cycle environmental impacts to promote an environmental sustainable management of geothermal power generation is proposed, which still represents a challenge for this industrial sector.