Lorenzo Talluri

University of Florence | UNIFI · Dipartimento di Ingegneria Industriale

Dear colleagues, We are acting as Guest editors for a Special Issue entitled "Sustainable Geothermal Energy" in the open-access journal Sustainability (Impact Factor: 2.576). We are inviting you and your team to contribute with your valuable works to this special issue. The submission deadline is 30 November 2021. This Special Issue will focus on sustainable geothermal technologies, including different features, from reservoir modelling, to solutions for energy storage integration, non-conventional power plant solutions, innovative drilling techniques & fluids, and multi-product systems (electricity, heat, cold, and material streams). The general objective is to pave the way for the development of environmental-friendly geothermal systems. For more information on the Special Issue, please visit: https://www.mdpi.com/journal/sustainability/special_issues/Sustainable_Geothermal_Energy A limited number of discount-price Open Access vouchers are available to the Editors and you may consider applying for them by contacting us directly. Please be aware that these conditions will depend on the issue of the reviewing process. Thanks for considering it, and hoping you are well in these difficult times. We look forward to hearing from you soon. Best regards, Special Issue Editors Fausto Batini and Lorenzo Talluri

The GECO project is industry driven. It is coordinated by Reykjavík Energy (OR), one of the most experienced, largest and oldest geothermal energy providers in the world. OR has been at the frontier of the geothermal development in Iceland for heat and power since OR leads a diverse and expert international consortium from throughout Europe. Zorlu Energy Group was founded with the establishment of Zorlu Enerji Elektrik Üretim Inc. (ZOREN) in 1993. It is a group of companies serving at a global scale in different fields of the energy. Graziella Green Power S.p.A (GGP) operates in the field of electricity production from renewable sources. The company is born in 2010 to produce clean and sustainable energy. From industry, GECO’s consortium partners are Zorlu Energy Group, Graziella Green Power S.p.A (GGP), STORENGY (Storengy), Green Minerals (GM). These industrial partners are joined by 13 Research and Technology Development (RTD) partners located in France, Italy, Spain, Norway, Turkey, Germany, UK and Iceland. These academic partners provide state-of-the-art analytical techniques and expertise and provide a link for GECO to help train the next generation of scientists to move EGS technology into the future.

METU and a group of 17 partners across Europe have received a EUR 16 Million grant from the Horizon 2020 Research and Innovation programme. The funding contributes to the GECO project, GECO standing for “Geothermal Emission COntrol”. The project will advance the provision of cleaner and cost-effective geothermal energy across Europe and the World with reduced emissions of carbon and sulphur. The core of this project is the application of an innovative technology, recently developed and successfully demonstrated at a pilot-scale in Iceland, which can limit the emissions from geothermal plants by condensing and re-injecting gases in the subsurface, or turning them into commercial products. GECO aims to increase public acceptance and generalise this novel approach. To that end, the re-injection method will be applied in four distinct geothermal systems in four European countries: 1) a high temperature basaltic reservoir in Iceland; 2) a high temperature gneiss reservoir in Italy; 3) a high temperature metamorphic reservoir in Turkey; and 4) a low temperature sedimentary reservoir in Germany. Within GECO, gas capture and purification methods will be advanced by lowering consumption of resources (electricity, water and chemicals) to deliver cheaper usable CO2 streams as commodity to third parties. GECO’s unique approach consists of capturing the waste gases, dissolving them in the exhaust geothermal water stream, and re-injecting the aqueous solution. The re-injected acidic gas-charged fluid provokes the dissolution of subsurface rocks, which increases the reservoir permeability, and promotes the fixation of the dissolved gases by mineralization. The waste gases are therefore stored in the long term, in an environmentally friendly manner, while geothermal emissions are cost-effectively cleaned compared to standard industry solutions. A detailed and consistent monitoring program, geochemical analysis, and comprehensive modelling will characterise the reactivity and consequences of fluid-flow in the geologically diverse field sites of GECO. This will create new and more accurate modelling tools to predict the reactions that occur in the subsurface in response to induced fluid-flow, and favour the scalability of gas capture and purification. Finally, gas capture for reuse will be demonstrated by producing a CO2 stream with only trace H2S levels. This prerequisite for most utilisation pathways will be demonstrated as part of the GECO project. At a glance GECO aims to develop near Zero Emission Geothermal power plants. Project Co-ordinator: Reykjavik Energy, Iceland Project Office: GEORG, Iceland 18 Partners: Power companies, Universities and Research Institutes 9 Countries: France, Germany, Iceland, Italy, Norway, Spain, The Netherlands, Turkey, United Kingdom. Project duration: 4 years, 95 annual work units. Total Horizon 2020 funding 16 €M Funding for METU 825K €