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On May 21th, 2021 Elif Kaymakci from EnBW Energie Baden-Württemberg AG gave a presentation within the framework of the IGC.events webinar on the topic of: “Lithium for batteries from geothermal waters in Germany – The joint UnLimited project.”

On his Summer Tour 2021 this year, State Secretary for the Environment Andre Baumann is visiting exciting places and companies in the state where climate and flood protection and the energy transition are already being put into practice. On his third day, he stopped off today (04.08.) at EnBW's geothermal power plant in Bruchsal in the Karlsruhe district.

The origin of lithium in deep geothermal waters in Germany is largely unknown to date but is an important variable in the sustainable yield of the resource. To minimize this gap of information, the UnLimited consortium will examine drill cuttings and surface analogs from the study sites in the Upper Rhine Graben (URG) and the North German Basin (NGB) with respect to their lithium content.

The investigation of specific isotope systems represents an important tool in clarifying the origin of lithium in the hot deep waters in Germany. Especially, isotopes of strontium, lithium, and boron play an important role.

A team of modelers at University of Göttingen is currently working on the development of a suitable flow and transport model of a multi-porous and multi-scale fractured reservoir. This kind of hydrogeochemical models is using extensive databases of thermodynamic equilibria and mineral dissolution / precipitation reactions. Reactive transport modeling is to be used to understand mechanisms that release lithium from the rock into the deep geothermal water at the Bruchsal study site. In the light of this information, statements about the exploitable number of resources and forecasts about long-term sustainable release rates of dissolved lithium can be generated.

Resources are deposits that cannot be operated at a given time from an economic and technical point of view. Usually, resources are classified in three groups depending on the geological state of knowledge; inferred, indicated, and measured resources. Identified lithium global resources have increased remarkably in recent years owing to on-going exploration and are currently approximately 86 million tons in total and about 2.7 million tons for Germany (U.S. Geological Survey, 2021).

The lithium market situation and current technological developments - such as developments in the recycling of lithium-ion batteries or technical alternatives in a post-lithium phase are being searched. The focus of the research is on resources/reserves, production quantities and the specific production costs and thus the buildability (cut-off value). Data on the local environmental impact of lithium production and resource use - such as water consumption and energy use - are also collected and analyzed. The key data determined here will be an essential part of the Life Cycle Assessment.

This week’s webinar by IGC.events will present a presentation by Elif Kaymakci of EnBW Energie Baden-Württemberg AG titled: “Lithium for batteries from geothermal waters in Germany – The joint UnLimited project.”

Based on the nominal lithium production rate in the produced geothermal brines in Bruchsal a first set of lithium extraction chambers has been designed for the planned lithium extraction bypass. The first design includes geometrical fluid flow parameters and is based on the results of the first successful performed laboratory tests. Since the produced fluid in Bruchsal is a 2-phase mixture, CO2 is both dissolved and gaseous. Therefore, the pressure in the lithium extraction chambers needs to be controlled and potentially released CO2 needs to be led back to the reinjected brine. Additional laboratory tests are planned to optimize the lithium recovery within the extraction chambers and to modify and adapt the design of the prototype.

In order to quantify the fluid residence times in the reservoir under the production-relevant flow regimes, a tracer test will be conducted at the Bruchsal site. 'Spike' slug injection and 'outflow' sampling design is based on the artificial-tracer signals from the ongoing long-term monitoring campaign, which indicates the fluid turnover volumes in the range of ~1 to ~8 million m³ for the precursor flow regimes (according to the conservative estimations by a team of modelers at University of Goettingen). On-site monitoring and fluid sampling is secured by BESTEC and HYDROSION together with the operator's well-site team (EnBW).