Linking geological and infrastructural requirements for large-scale underground hydrogen storage in Germany

Hydrogen storage might be key to the success of the hydrogen economy, and hence the energy transition in Germany. One option for cost-effective storage of large quantities of hydrogen is the geological subsurface. However, previous experience with underground hydrogen storage is restricted to salt caverns, which are limited in size and space. In contrast, pore storage facilities in aquifers -and/or depleted hydrocarbon reservoirs- could play a vital role in meeting base load needs due to their wide availability and large storage capacity, but experiences are limited to past operations with hydrogen-bearing town gas. To overcome this barrier, here we investigate hydrogen storage in porous storage systems in a two-step process: 1) First, we investigate positive and cautionary indicators for safe operations of hydrogen storage in pore storage systems. 2) Second, we estimate hydrogen storage capacities of pore storage systems in (current and decommissioned) underground natural gas storage systems and saline aquifers. Our systematic review highlights that optimal storage conditions in terms of energy content and hydrogen quality are found in sandstone reservoirs in absence of carbonate and iron bearing accessory minerals at a depth of approx. 1,100 m and a temperature of at least 40°C. Porosity and permeability of the reservoir formation should be at least 20% and 5 × 10−13 m2 (∼500 mD), respectively. In addition, the pH of the brine should fall below 6 and the salinity should exceed 100 mg/L. Based on these estimates, the total hydrogen storage capacity in underground natural gas storages is estimated to be up to 8 billion cubic meters or (0.72 Mt at STP) corresponding to 29 TWh of energy equivalent of hydrogen. Saline aquifers may offer additional storage capacities of 81.6–691.8 Mt of hydrogen, which amounts to 3.2 to 27.3 PWh of energy equivalent of hydrogen, the majority of which is located in the North German basin. Pore storage systems could therefore become a crucial element of the future German hydrogen infrastructure, especially in regions with large industrial hydrogen (storage) demand and likely hydrogen imports via pipelines and ships

An analytical algorithm of porosity–permeability for porous and fractured media: extension to reactive transport conditions and fitting via flow-through experiments within limestone and dolomite

Accurate prediction of permeability evolution is essential for forecasting the long-term performance and lifetime of hydrothermal reservoirs, an important goal in the geothermal, ore, and petroleum industries. Erol et al. (Transp Porous Media 120(2):327–358, 2017. https://doi.org/10.1007/s11242-017-0923-z) introduced a general (non-empirical) analytical Kozeny–Carman type equation for predicting matrix and fracture permeability during single-phase, non-reactive flow. Here we incorporate the equation into an algorithm for addressing the influence on porous and fractured media permeability of the transient reactive processes of mineral dissolution and precipitation. Analytical algorithm predictions are identical to permeability values measured during fluid circulation through limestone and dolomite core samples from the Campine Basin deep geothermal system in Belgium. Benchmarking used identical values for initial hydraulic aperture dimension and porosity, measured during fluid circulation based on nondestructive micro-CT imaging. Analytical algorithm predictions of reactive surface area and fracture porosity are similar to results based on the TOUGHREACT reactive transport code. TOUGHREACT implements several well- established power-law models for predicting permeability, notably Civan (AIChE J 47(2):1167–1197, 2001. https://doi.org/10.1002/aic.690470206) and Verma and Pruess (J Geophys Res Solid Earth 93:1159–1173, 1988. https://doi.org/10.1029/jb093ib02p01159). However, these models rely on specification of empirical exponents, which are not straightforward to measure. Our results suggest that a more general, computationally inexpensive analytical method can lead to accurate permeability calculation

Regulatory Preconditions for the Deployment of Bioenergy With Carbon Capture and Storage in Europe

Paris-compatible climate scenarios often consider bioenergy with carbon capture and storage (BECCS) as an important technology for carbon dioxide removal (CDR). Although the main barrier to BECCS deployment is often associated with lack of economic policy incentives, unfavorable regulations can also impede investments. Over the past decade, the regulatory conditions at the UN and on the EU level have developed to be more permissive toward BECCS. For instance, CDR accounting guidelines have been developed by the UN, and the EU CCS Directive regulates responsibilities regarding storage of CO2. However, several existing regulations still cause deployment hurdles. Taking a European viewpoint, this perspectives article takes stock of recent regulatory developments and provides a discussion on legal acts that need to be reformed in order to facilitate BECCS deployment. Although the European trend is characterized by developing a regulatory regime that is more supportive of BECCS, we identify three areas for further improvement: (1) allowing EU Member States to use negative emissions from BECCS to comply with their obligations under the legislative pillars that underpin the EU’s climate objectives: (2) amending the CCS Directive to exempt physical leakage of biogenic CO2, attributable to sustainably sourced biomass, from the requirement to surrender emission allowances in the EU ETS or, if BECCS has been economically rewarded, the penalty for leakage should correspond to the level of the reward; and (3) pushing to erase the last few barriers due to multilateral regimes, such as clarifying whether BECCS is covered by the geoengineering moratorium maintained by the UN Convention on Biological Diversity. These proposed reforms would further improve the regulatory preconditions for BECCS deployment in the EU

Sammanställning av kunskapsläget kring gällande regelverk för bio-CCS i Sverige

Avskiljning och geologisk lagring av biogen koldioxid (bio-CCS) utgör en potentiellt viktig kompletterande åtgärd i att nå Sveriges mål om noll nettoutsläpp av växthusgaser år 2045 och därefter negativa utsläpp. Potentialen för att skapa negativa utsläpp via bio-CCS i Sverige bedöms som god, men i gällande lagar och regelverk finns fortfarande utmaningar att ta hänsyn till och lösa för att verksamhetsutövare ska kunna tillämpa tekniken. Denna rapport belyser och ger ett nuläge av de områden i regelverket som behöver behandlas för att möjliggöra investeringar och drift av bio-CCS anläggningar för verksamhetsutövare inom massa- och pappersindustrin och el- och fjärrvärmeproduktion inklusive avfallsförbränning. Rapporten sammanfattar även gällande regelverk på internationell nivå, EU-nivå och nationell nivå. Områden som kräver behandling inför en framtida implementering av bio-CCS är bland annat hur negativa utsläpp ska beräknas och redovisas genom kedjan för bio-CCS, hur moratoriet kring biologisk mångfald kopplar till bio-CCS och bilaterala avtal mellan Sverige och lagringsstat.Granskning:Granskat av andra forskare och verksamma inom området inom ramen för det projekt i vilket rapporten tagits fram Färdplan för BECCS i fjärrvärmesektorn i Sverig

Evaluation of porositiy and permeability estimates for rock samples based on X-ray micro-tomography

Von besonderem Interesse für die Langzeitentwicklung von Reservoiren und die Effizienz von geothermischen Anlagen sind die Gesteinseigenschaften Porosität und Permeabilität, welche in experimentellen Untersuchungen mittels verschiedener Laborexperimente bestimmt worden sind. Die experimentell bestimmten hydraulischen Gesteinseigenschaften wurden mir Resultaten aus dem bildgebenden Verfahren der Röntgen-Computertomographie (CT) verglichen, um dieses zu evaluieren. Dazu wurden Sand- und Kalksteine mit Porositäten von weniger als 1 % bis zu 25 %, sowie Reticulit, eine pyroklastische Gesteinsprobe mit einer Porosität von ca. 95 %, untersucht. Die Grauwertbilder wurden mit verschiedenen Segmentierungsmethoden ausgewertet und die Ergebnisse hinsichtlich a.) Auflösung der Grauwertbilder, b.) Rauschunterdrückungsverfahren (Filter) und c.) Segmentierungsverfahren interpretiert. Die Auflösung ist dabei der limitierende Faktor für eine zutreffende Quantifizierung von Gesteinskennwerten

The evolution of the Dominga Fe-Cu deposit (northern Chile): Insights from mineral textures and micro-CT analysis

The Fe-Cu Dominga deposit (2082 Mt at 23% Fe, 0.07% Cu), located in the Coastal Cordillera of northern Chile, is hosted by volcanic rocks of the Punta del Cobre Formation (131.5 +/- 1.5 Ma zircon U-Pb) and into subvolcanic units (Dioritic Complex, 131.6 +/- 1.0 Ma zircon U-Pb). The Fe-Cu mineralization is controlled by three structural systems which developed from a transtensional to a transpressional tectonic regime and can be divided into three groups: Early iron, Late iron and Early copper ores. Early iron ores are comprised of magnetite + pyrite + biotite breccia (1A ore), veins (1B ores), layers (1C ores) and disseminated ores (1D ores). Late iron ores are characterized by two groups of magnetite-apatite-actinolite hydrothermal breccias (2A, 2C ores) and syntaxial/antitaxial veins (2B, 2D, 2E ores). Early copper ores occur as syntaxial K-feldspar and quartz + epidote + chalcopyrite veins (3A ores), and as anhydrite + chalcopyrite-rich matrix breccia and veins (3B ores). This work presents a detailed mineral texture study of veins, hydrothermal breccias and disseminated iron-rich layers of the Dominga deposit which aims to determine fluid flow mechanisms associated with both iron and copper ores. The description of vein and breccia textural and internal structures was conducted in thin/ polished sections perpendicular and parallel to the wall using optical and Scanning Electron Microscope techniques. In addition, two oriented surface samples were analyzed by computerized X-ray microtomography and numerical fluid flow simulations through the Lattice-Boltzmann method to obtain (3D) permeability anisotropy associated with early iron ores. Microtextures associated with Dominga iron and copper ores suggest that the main mass transfer fluid flow mechanism corresponds to advection (channelized and pervasive fluid flow), regardless of the tectonic regime. However, early copper ores have more complex mineral textures and internal structure due to the recurrence of crack-seal episodes. We propose that the various mineral textures and structures indicate changes in fluid flow direction over time, controlled by the permeability anisotropy of each tectonic regime. Results from numerical fluid flow simulations of early iron ore (1B) veins show a higher value of structural permeability in the vertical direction (kVz), which is consistent with a transtensional tectonic regime and the formation of vertical veins. Moreover, permeability related to 1C layered ore is higher in horizontal directions (kHx, kHy) rather than vertical (kVz) because of the natural permeability anisotropy of volcaniclastic rocks parallel to bedding. However, the kVz value suggests that the development of such layered ores also exhibits a degree of structural control at several length scales consistent with a transtensional regime. These results indicate that the occurrence of early iron ores as veins and layers may be controlled by both primary permeability anisotropy related to each lithology present at the Dominga Fe-Cu deposit and to the tectonic regime at the time. Finally, the Dominga Fe-Cu deposit attests to long lived hydrothermal activity with a transition from early fluids capable of precipitating iron ores under a transtensional system to later-stage fluids which precipitated copper ores under a transpressional regime that generated multiple crack and seal episodes.Fondequip project: EQM 130028. Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT): 21171021

BIO-CCS I FJ\uc4RRV\uc4RMESEKTORN – SYNTES

Den svenska fj\ue4rrv\ue4rmesektorn har stor potential att bidra med negativa koldioxidutsl\ue4pp genom bio-CCS, minst 10 Mton per \ue5r. Den st\uf6rsta os\ue4kerheten betr\ue4ffande m\uf6jligheterna f\uf6r bio-CCS g\ue4ller marknads f\uf6ruts\ue4ttningarna.Uppv\ue4rmningsbranschen har en vision om att \ue5r 2045 utg\uf6ra en kols\ue4nka. Ett s\ue4tt att \ue5stadkomma detta \ue4r genom att avskilja och lagra koldioxidutsl\ue4pp med biogent ursprung. Ett antal fj\ue4rrv\ue4rmef\uf6retag har redan olika l\ue5ngt g\ue5ngna planer p\ue5 att satsa p\ue5 bio-CCS. De har sett ett v\ue4rde i att samarbeta kring hur detta kan \ue5stadkommas. Ett led i detta \ue4r projektet Bio-CCS i fj\ue4rrv\ue4rmesektorn som best\ue5r av ett gediget underlag baserat p\ue5 forskning kring olika aspekter av fr\ue5gan samt en strategi baserad p\ue5 det underlaget. I denna rapport redovisas en syntes av detta forskningsarbete.Projektet visar att fj\ue4rrv\ue4rmesektorn har stor teoretisk potential att bidra med negativa koldioxidutsl\ue4pp, minst 10 Mton per \ue5r. I huvudsak \ue4r avskiljning, transport och lagring av koldioxid bepr\uf6vad teknik \ue4ven om till\ue4mpningen i detta fall \ue4r ny. \uc4ven om bio-CCS \ue4r f\uf6rknippad med energianv\ue4ndning s\ue5 bidrar tekniken sett ur ett systemperspektiv med stor nytta f\uf6r att minska koldioxid[1]utsl\ue4ppen. Bio-CCS \ue4r en relativt dyr teknik och det \ue4r angel\ue4get att utnyttja samverkan och kluster f\uf6r att exempelvis skapa \uf6kad kostnadseffektivitet i transport och mellanlagring. Tillg\ue5ng till lagringsplatser \ue4r en f\uf6ruts\ue4ttning f\uf6r framg\ue5ng och flera alternativ bed\uf6ms bli tillg\ue4ngliga. Det kan dock uppst\ue5 konkurrens om tillg\ue5ngen till lagringsplatserna. De regelm\ue4ssiga f\uf6ruts\ue4ttningarna f\uf6r bio-CCS i Sverige har f\uf6rb\ue4ttrats avsev\ue4rt de senaste dryga decenniet. Flera regelm\ue4ssiga hinder kvarst\ue5r dock. En del utg\uf6r mindre barri\ue4rer, andra \ue4r av mer betydande karakt\ue4r.Den st\uf6rsta os\ue4kerheten betr\ue4ffande m\uf6jligheterna f\uf6r bio-CCS g\ue4ller ekonomin. Flera potentiella finansieringsmetoder har studerats, b\ue5de st\uf6d, regleringar och frivilligmarknader. Det finns fortfarande oklarheter kring syftet med planerade st\uf6d och det framtida \ue4gandet av de negativa utsl\ue4ppen. Det genomf\uf6rda projektet har skapat ett forum f\uf6r kunskapsuppbyggnad, erfarenhetsutbyte och n\ue4tverkande, vilket de deltagande f\uf6retagen bed\uf6mt vara mycket v\ue4rdefullt