Applying Harmonised Geothermal Life Cycle Assessment Guidelines to the Rittershoffen Geothermal Heat Plant

Mélanie Douziech,Nicola Ferrara,Maria Laura Parisi,Lorenzo Tosti,Guillaume Ravier,Paula Pérez-López

doi:10.3390/en14133820

Abstract

Heat production from a geothermal energy source is gaining increasing attention due to its potential contribution to the decarbonization of the European energy sector. Obtaining representative results of the environmental performances of geothermal systems and comparing them with other renewables is of utmost importance in order to ensure an effective energy transition as targeted by Europe. This work presents the outputs of a Life Cycle Assessment (LCA) performed on the Rittershoffen geothermal heat plant applying guidelines that were developed within the H2020 GEOENVI project. The production of 1 kWhth from the Rittershoffen heat plant was compared to the heat produced from natural gas in Europe. Geothermal heat production performed better than the average heat production in climate change and resource use, fossil categories. The LCA identified the electricity consumption during the operation and maintenance phase as a hot spot for several impact categories. A prospective scenario analysis was therefore performed to assess the evolution of the environmental performances of the Rittershoffen heat plant associated with the future French electricity mixes. The increase of renewable energy shares in the future French electricity mix caused the impact on specific categories (e.g., land use and mineral and metals resource depletion) to grow over the years. However, an overall reduction of the environmental impacts of the Rittershoffen heat plant was observed.

Highlights

Geothermal energy refers to the thermal energy stored in the Earth’s underground
For the ozone depletion (ODP) and ionizing radiation (IR) impact categories, where heat production from geothermal shows larger impacts than natural gas, our analysis showed that the prospective developments of the electricity grid mix can help improve the environmental performances of geothermal heat
The comparison of the results obtained in this study with those available in literature on the same geothermal heat plant clearly underlined the importance of developing dedicated energy-pathway Life Cycle Assessment (LCA) guidelines to ensure that reproducible, transparent, and comparable LCA results are published

Summary

Introduction

Geothermal energy refers to the thermal energy stored in the Earth’s underground. The most common applications remain the production of heat and/or electricity. In Europe, the potential use of geothermal energy for power or heat production is increasingly gaining attention. European geothermal power generation capacity has increased in 2019 to 3.3 GWe, representing a 5% growth compared to 2018. 5.5 GWth geothermal district heating and cooling capacity was installed in Europe in 2019 and the planned projects foresee a rapid growth of this type of geothermal resource exploitation [5]. Technological developments have further increased the deployment potential of geothermal energy. Enhanced Geothermal Systems (EGS) make non-accessible geothermal resources useable by injecting water and/or chemicals into the underground to improve its permeability

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