Assessing interactions between multiple geological CO₂ storage sites: generic learning from the CO₂MultiStore project

This report is the technical output from Work Package 4, Knowledge Capture and Reporting, from the CO2MultiStore project. Work Package 1 of the project identified possible issues and potential concerns to the secure containment of CO2 by the interaction between two or more geological storage sites within a deeply buried sandstone of regional extent. Reduction of possible issues and mitigation of perceived concerns were investigated in Work Package 2 by static geological, dynamic flow and geomechanical modelling of two reasonable and realistic sites within a northern North Sea case study of storage in the Captain Sandstone. Work Package 3 developed recommendations for a monitoring plan that specifically addresses the uncertainties and threats arising from storage at multiple sites. The report captures knowledge gained from the process, progress and findings of the research that is applicable to the development of any multi-user storage resource.This report is the technical output from Work Package 4, Knowledge Capture and Reporting, from the CO2MultiStore project. Work Package 1 of the project identified possible issues and potential concerns to the secure containment of CO2 by the interaction between two or more geological storage sites within a deeply buried sandstone of regional extent. Reduction of possible issues and mitigation of perceived concerns were investigated in Work Package 2 by static geological, dynamic flow and geomechanical modelling of two reasonable and realistic sites within a northern North Sea case study of storage in the Captain Sandstone. Work Package 3 developed recommendations for a monitoring plan that specifically addresses the uncertainties and threats arising from storage at multiple sites. The report captures knowledge gained from the process, progress and findings of the research that is applicable to the development of any multi-user storage resource

A novel sub-seabed CO\u3csub\u3e2\u3c/sub\u3e release experiment informing monitoring and impact assessment for geological carbon storage

© 2014 The Authors. Carbon capture and storage is a mitigation strategy that can be used to aid the reduction of anthropogenic CO2 emissions. This process aims to capture CO2 from large point-source emitters and transport it to a long-term storage site. For much of Europe, these deep storage sites are anticipated to be sited below the sea bed on continental shelves. A key operational requirement is an understanding of best practice of monitoring for potential leakage and of the environmental impact that could result from a diffusive leak from a storage complex. Here we describe a controlled CO2 release experiment beneath the seabed, which overcomes the limitations of laboratory simulations and natural analogues. The complex processes involved in setting up the experimental facility and ensuring its successful operation are discussed, including site selection, permissions, communications and facility construction. The experimental design and observational strategy are reviewed with respect to scientific outcomes along with lessons learnt in order to facilitate any similar future

Optimising CO2 storage in geological formations; a case study ofshore Scotland - CO2 MultiStore project

Carbon capture, transport and storage (CCS) is considered a key technology to provide a secure, low-carbon energy supply and reduce the greenhouse gas emissions (DECC, 2014) that contribute to the adverse effects of climatic change (IPCC, 2014). Commercialisation projects for the permanent storage of carbon dioxide (CO2) captured at power plants are currently in the design stage for the Peterhead, White Rose, Caledonia Clean Energy (DECC, 2013, 2015) and Don Valley projects. Storage of the CO2 captured by these projects is planned in strata deep beneath the North Sea in depleted hydrocarbon fields or regionally extensive sandstones containing brine (saline aquifer sandstones). The vast majority of the UK and Scotland's potential storage resource, which is of European significance (SCCS, 2009), is within brine-saturated sandstone formations. The sandstone formations are each hundreds to thousands of square kilometres in extent and underlie all sectors of the North Sea. The immense potential to store CO2 in these rocks can only be fully achieved by the operation of more than one injection site within each formation. Government, university and research institutes, industry, and stakeholder organisations have anticipated the need to inform a second phase of CCS developments following on from a commercialisation project in Scotland. The CO2MultiStore study, led by Scottish Carbon Capture and Storage (SCCS), investigates the operation of more than one injection site within a storage formation using a North Sea case study. The Captain Sandstone, within the mature oil and gas province offshore Scotland, contains the Goldeneye Field, which is the planned storage site for the Peterhead CCS project. Previous research (SCCS, 2011) was augmented by data from offshore hydrocarbon exploration and detailed investigation of the Goldeneye Field for CO2 storage (Shell, 2011a-i). The research was targeted to increase understanding and confidence in the operation of two or more sites within the Captain Sandstone. Methods were implemented to reduce the effort and resources needed to characterise the sandstone, and increase understanding of its stability and performance during operation of more than one injection site. Generic learning was captured throughout the CO2MultiStore project relevant to the characterisation of the extensive storage sandstones, management of the planned injection operations and monitoring of CO2 injection at two (or more) sites within any sandstone formation. The storage of CO2 can be optimised by the operation of more than one injection site in a geological formation by taking a regional-scale approach to site assessment. The study concludes that at least 360 million tonnes of CO2 captured over the coming 35 years could be permanently stored using two injection sites in the Captain Sandstone. Confidence in the planned operation of two or more injection sites in a storage formation is greatly increased by the use of existing information, knowledge and data acquired during hydrocarbon exploitation. Widespread pressure changes should be expected by the injection of CO2 at more than one site. Assessment, management and monitoring of pressure changes on a regional scale will optimise the storage capacity, ensure security of storage and prevent adverse effects to existing storage and hydrocarbon operations. The vast offshore potential across all sectors of the North Sea could be made accessible and practical for storage of CO2 captured from European sources by the operation of two or more sites in a storage formation by following the approach taken in CO2MultiStore.Carbon capture, transport and storage (CCS) is considered a key technology to provide a secure, low-carbon energy supply and reduce the greenhouse gas emissions (DECC, 2014) that contribute to the adverse effects of climatic change (IPCC, 2014). Commercialisation projects for the permanent storage of carbon dioxide (CO2) captured at power plants are currently in the design stage for the Peterhead, White Rose, Caledonia Clean Energy (DECC, 2013, 2015) and Don Valley projects. Storage of the CO2 captured by these projects is planned in strata deep beneath the North Sea in depleted hydrocarbon fields or regionally extensive sandstones containing brine (saline aquifer sandstones). The vast majority of the UK and Scotland's potential storage resource, which is of European significance (SCCS, 2009), is within brine-saturated sandstone formations. The sandstone formations are each hundreds to thousands of square kilometres in extent and underlie all sectors of the North Sea. The immense potential to store CO2 in these rocks can only be fully achieved by the operation of more than one injection site within each formation. Government, university and research institutes, industry, and stakeholder organisations have anticipated the need to inform a second phase of CCS developments following on from a commercialisation project in Scotland. The CO2MultiStore study, led by Scottish Carbon Capture and Storage (SCCS), investigates the operation of more than one injection site within a storage formation using a North Sea case study. The Captain Sandstone, within the mature oil and gas province offshore Scotland, contains the Goldeneye Field, which is the planned storage site for the Peterhead CCS project. Previous research (SCCS, 2011) was augmented by data from offshore hydrocarbon exploration and detailed investigation of the Goldeneye Field for CO2 storage (Shell, 2011a-i). The research was targeted to increase understanding and confidence in the operation of two or more sites within the Captain Sandstone. Methods were implemented to reduce the effort and resources needed to characterise the sandstone, and increase understanding of its stability and performance during operation of more than one injection site. Generic learning was captured throughout the CO2MultiStore project relevant to the characterisation of the extensive storage sandstones, management of the planned injection operations and monitoring of CO2 injection at two (or more) sites within any sandstone formation. The storage of CO2 can be optimised by the operation of more than one injection site in a geological formation by taking a regional-scale approach to site assessment. The study concludes that at least 360 million tonnes of CO2 captured over the coming 35 years could be permanently stored using two injection sites in the Captain Sandstone. Confidence in the planned operation of two or more injection sites in a storage formation is greatly increased by the use of existing information, knowledge and data acquired during hydrocarbon exploitation. Widespread pressure changes should be expected by the injection of CO2 at more than one site. Assessment, management and monitoring of pressure changes on a regional scale will optimise the storage capacity, ensure security of storage and prevent adverse effects to existing storage and hydrocarbon operations. The vast offshore potential across all sectors of the North Sea could be made accessible and practical for storage of CO2 captured from European sources by the operation of two or more sites in a storage formation by following the approach taken in CO2MultiStore

A novel sub-seabed CO₂ release experiment informing monitoring and impact assessment for geological carbon storage

Carbon capture and storage is a mitigation strategy that can be used to aid the reduction of anthropogenic CO2 emissions. This process aims to capture CO2 from large point-source emitters and transport it to a long-term storage site. For much of Europe, these deep storage sites are anticipated to be sited below the sea bed on continental shelves. A key operational requirement is an understanding of best practice of monitoring for potential leakage and of the environmental impact that could result from a diffusive leak from a storage complex. Here we describe a controlled CO2 release experiment beneath the seabed, which overcomes the limitations of laboratory simulations and natural analogues. The complex processes involved in setting up the experimental facility and ensuring its successful operation are discussed, including site selection, permissions, communications and facility construction. The experimental design and observational strategy are reviewed with respect to scientific outcomes along with lessons learnt in order to facilitate any similar future

Does the United Kingdom have sufficient geological storage capacity to support a hydrogen economy? Estimating the salt cavern storage potential of bedded halite formations

Hydrogen can be used to enable decarbonisation of challenging applications such as provision of heat, and as a fuel for heavy transport. The UK has set out a strategy for developing a new low carbon hydrogen sector by 2030. Underground storage will be a key component of any regional or national hydrogen network because of the variability of both supply and demand across different end-use applications. For storage of pure hydrogen, salt caverns currently remain the only commercially proven subsurface storage technology implemented at scale. A new network of hydrogen storage caverns will therefore be required to service a low carbon hydrogen network. To facilitate planning for such systems, this study presents a modelling approach used to evaluate the UK's theoretical hydrogen storage capacity in new salt caverns in bedded rock salt. The findings suggest an upper bound potential for hydrogen storage exceeding 64 million tonnes, providing 2150 TWh of storage capacity, distributed in three discrete salt basins in the UK. The modelled cavern capacity has been interrogated to identify the practical inter-seasonal storage capacity suitable for integration in a hydrogen transmission system. Depending on cavern spacing, a peak load deliverability of between 957 and 1876 GW is technically possible with over 70% of the potential found in the East Yorkshire and Humber region. The range of geologic uncertainty affecting the estimates is approximately ±36%. In principle, the peak domestic heating demand of approximately 170 GW across the UK can be met using the hydrogen withdrawn from caverns alone, albeit in practice the storage potential is unevenly distributed. The analysis indicates that the availability of salt cavern storage potential does not present a limiting constraint for the development of a low-carbon hydrogen network in the UK. The general framework presented in this paper can be applied to other regions to estimate region-specific hydrogen storage potential in salt caverns

The Late Pleistocene Afton Lodge Clay Formation, Ayrshire, Scotland: evidence for Early to Middle Devensian climatic changes and Late Devensian onshore ice flow and rafting from the Firth of Clyde

An investigation into the late Pleistocene sediments exposed at Afton Lodge has helped to clarify the glacial history of western central Scotland. The sequence includes several allochthonous bodies of ‘shelly clay’ (Afton Lodge Clay Formation) associated with Late Devensian (Weichselian) age diamict. The shelly clay contains abundant marine macro- and microfauna, as well as palynomorphs consistent with its deposition within a shallow marine to estuarine environment. Faunal changes within the main body of marine clay record at least one, millennial-scale cycle of Arctic-Boreal, to Boreal, and back to Arctic-Boreal climatic conditions. A radiocarbon date of over 41 ka 14C BP obtained from the foraminifera indicates that the marine clays are older than the surrounding till. Afton Lodge is thus one of a suite of ‘high-level’ shelly clay occurrences around the Scottish coasts that are now considered to be glacially transported. Together with closely associated ‘shelly tills’, the rafts were emplaced during an early phase of the last glaciation by ice flowing from the western Grampian Highlands of Scotland through the topographically-confined Firth of Clyde basin. The blocks of marine sediment were detached subglacially, unfrozen, and carried at least 10 km by ice that splayed out onshore against reversed slopes favouring raft emplacement and the creation of closely associated ribbed moraine. Transport of the rafts was facilitated by water-lubricated de´ collement surfaces and their accretion was accompanied by dewatering. The shelly tills were formed mainly by the attenuation and crushing of rafts of shelly clay during their transport within the subglacial deforming bed