High-Temperature Geothermal Utilization in the Context of European Energy Policy—Implications and Limitations

Abstract

The European Union (EU) has made climate change mitigation a high priority though a policy framework called “Clean Energy for all Europeans “. The concept of primary energy for energy resources plays a critical role in how different energy technologies appear in the context of this policy. This study shows how the calculation methodologies of primary energy content and primary energy factors pose a possible negative implication on the future development of geothermal energy when comparing against EU’s key energy policy targets for 2030. Following the current definitions of primary energy, geothermal utilization becomes the most inefficient resource in terms of primary energy use, thus contradicting key targets of increased energy efficiency in buildings and in the overall energy use of member states. We use a case study of Hellisheidi, an existing geothermal power plant in Iceland, to demonstrate how the standard primary energy factor for geothermal in EU energy policy is highly overestimated for efficient geothermal power plants. Moreover, we combine life cycle assessment and the commonly utilized combined heat and power production allocation methods to extract the non-renewable primary energy factor for geothermal and show how it is only a minimal fraction of the total primary energy factor for geothermal. The findings of the study apply to other geothermal plants within the coverage of the European Union’s energy policy, whether from high- or low-temperature geothermal resources. Geothermal has substantial potential to aid in achieving the key energy and climate targets. Still, with the current definition of the primary energy of geothermal resources, it may not reach the potential.

Geothermal energy extraction using abandoned oil and gas wells:Techno‐economicand policy review

“…In 2015, updated targets from the 2020 package were released in the new 2030 climate and energy framework, “Clean energy for all Europeans.” Revision on the target, increased efficiency and renewable energy share, was made in 2018. In December 2019, a long term strategy to achieve “climate‐neutral” by 2050 was formulated in “The European Green deal” growth strategy for the EU 153 . This supportive legal framework has help in the encouraging growth of geothermal energy utilization across Europe and can be used as benchmark for other region 154 …”

Environmental Assessment of Hellisheidi Geothermal Power Plant based on Exergy Allocation Factors for Heat and Electricity Production

“…For the Hellisheidi CHP plant, the majority of the LCA studies reported in the literature have focused on a cradle-to-grave approach and the inventory (LCI) provided by Karlsdòttir et al [16,17]. In these works, secondary data based on an ecoinvent v3.4 database were considered, and the CML-IA baseline and the cumulative energy demand (CED) were selected as the evaluation methods.…”

A Comparison of Different Approaches for Assessing Energy Outputs of Combined Heat and Power Geothermal Plants

“…Karlsdottir et al [11] discussed the possibility of using different methods to calculate partitioning and allocation factors, to be later applied for evaluating the products generated in the geothermal CHP plant. Specifically, they applied the following approaches: no allocation, energy, exergy, economic, and alternative generation method, to divide the primary energy factor (PEF) and greenhouse gas (GHG) emissions between power and heat produced at the Hellisheidi geothermal power plant.…”