Influential parameters for estimating the environmental impacts of geothermal power: A global sensitivity analysis study

Abstract

The life-cycle environmental impacts of geothermal power generation are highly variable and depend on many site-specific conditions. The objective of this work is the identification of the most influential parameters for estimating the environmental impacts of geothermal electricity production. First, we developed a general model for computing the impacts of both conventional and enhanced geothermal technologies. The model is validated against selected literature studies for the climate change category. We then use Global Sensitivity Analysis (GSA) to evaluate the contribution of each parameter to the overall variance of the model's output. The results of the GSA suggest that i) the uncertainty of environmental impact estimates can be significantly reduced by obtaining more accurate values for a small number of key parameters, such as the installed capacity of the plant, operational emissions of CO2 and the depth and capacity of wells; and ii) the majority of parameters do not affect significantly the environmental impact estimates and therefore can be fixed anywhere within their range of variability. Finally, we discuss some of the limitations of the present study and propose approaches that could be implemented to overcome such limitations.

Keywords

• Geothermal energy
• Life cycle assessment
• Carbon footprint
• Sobol’ indices
• Renewable energy