CCS - What to consider when storing CO2 underground
In CCS projects, the largest source of uncertainty is storage. To manage this uncertainty, there are several factors to consider.
07 July 2022 | 1 min read
Energy transition
Andy Kirchin
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Carbon dioxide (CO2) is widely accepted to be a major contributor to global climate change. Carbon Capture and Storage (CCS) refers to the process of capturing CO2, transporting it to a storage site where it is captured to ensure it will not enter the atmosphere.
The Paris Agreement on climate change, signed in 2015, committed members of the UN to reduce their carbon output "as soon as possible" and to do their best to keep global warming "to well below 2°C” above pre-industrial levels. CCS is one tool in our arsenal to achieve this goal while allowing us to move through the energy transition cycle and continuing to meet demand.
CCS projects require the integration of several highly technical skills within an evolving regulatory and commercial environment. RPS has a unique mix of project management, planning, environmental, engineering, regulatory, metocean and sub-surface specialisms, which combine to assist clients in the effective design and implementation of CCS projects.
Capture
Capture of CO2 currently relies upon either a chemical solvent at the source, such as a flue from a power plant or via an energy intensive, and therefore expensive, direct air capture. Therefore, most current CCS projects propose removing CO2 directly from the processing source to keep costs low.
Transport
CO2 is transported in three states: gas, liquid and solid. Commercial-scale transport using tanks, pipelines and ships for gaseous and liquid carbon dioxide (supercritical state). Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.
After capture, CO2 is then either dried for transportation, which limits the formation of carbonic acid that could detrimentally affect the pipeline system. Or, it’s compressed to liquid state, such as in Norcem’s Long Ship(s) Project, [see case study].
Store
Injection of CO2 into deep geological formations utilises technologies that have been developed by the oil and gas industry over many years. Well drilling and completions technologies have been developed for optimal performance under extreme operating conditions such as high pressure, temperature and complex chemical environments.
Monitor
To ensure safe CO2 storage and containment over long periods of time it is imperative that the storage design and monitoring reflects this and provides assurance to all stakeholders including site regulatory and licencing authorities as well as developers, investors and the general public.
CCS is necessary to meet national and international climate change targets as set in the 2015 Paris Accord on climate change.
RPS is uniquely positioned to support the successful delivery of CCS projects. We routinely support our clients to deliver integrated infrastructure projects internationally - with strategic guidance, feasibility planning and specialised technical, commercial and operational advisory services at each stage of the CCS lifecycle.
We can call on years of general and specific industry experience to support our clients with the visualisation, conceptualisation and implementation of CCS and CO2-EOR (Enhance Oil Recovery) projects.
Our CCS self-paced e-learning solutions immerse learners in a rich variety of content and interactive media to provide a personalised learning experience.
Major infrastructure projects, including CCS developments, require a range of consents, permits and licences. These will only be issued once a coherent assessment of the environmental effects of the project has been undertaken. Active consultation with stakeholders, together with careful public education, is required as part of the public consultation process needed in many jurisdictions.
The need to secure the necessary permissions will apply across all stages and throughout the lifetime of the project, including, but not limited to:
How we help
RPS has deep expertise in securing planning consent,perm its and licences and undertaking environmental assessments for large infrastructure projects across a wide range of industry sectors. In the energy sector, this expertise is applied not only to CCS projects, but also in related areas such as gas storage, onshore and offshore windfarms, and LNG projects.
In all cases, high levels of exposure to planning systems, public and stakeholder consultation, public inquiry, and regulatory compliance are handled by a multi-disciplinary project team delivering the best possible information to inform sound decision making.
Although the concept of CCS projects has been around for sometime, its application has been limited. The UK regulators are still defining aspects of the regulatory requirements for some CCU/S technologies. RPS have assisted developers through this process working with our clients and the regulators to ensure a successful permitting/consenting outcome.
Projects we’ve delivered
Site selection is critical as not all geology formations are suitable for carbon storage, nor are they located in all regions. A deep technical understanding of the world's geology comes from our extensive experience working in the oil and gas sector over the last 40+ years.
On a global scale it’s estimated that there is capacity to store up to 900 GtCO2 in depleted oil and gas reservoirs, and 10,000 GtCO2 in saline aquifers, offering significant mitigation potential to climate change. Depending on scale and location, various geological sites which may be suitable for long term storage of CO2 include:
Locating and assessing appropriate sites is a critical step in planning any CCS project and involves multiple technical disciplines
Long term security of storage can only be assured through in-depth knowledge of all aspects of the site, including its history. Enhanced Oil Recovery (EOR) projects may also be suitable for long term storage of CO2, albeit that the additional value associated with such projects may be impacted by more complex regulatory and monitoring requirements.
How we help
RPS offers an exceptional range of international subsurface experience, from reservoir screening to field development. We have conducted numerous projects for CCS purposes at asset and regional scales, for both pure and EOR sequestration. RPS geoscientists work closely with our petroleum engineering team to develop comprehensive models of potential storage sites. To better simulate the distinct characteristics of injecting supercritical CO2 and assist accurate forecasts of diffusion through a storage site, RPS has developed proprietary software to complement industry standard tools. Consideration of both the technical and economic feasibility of CCS is central to our studies, with a focus on optimising both CO2 injection for Enhanced Oil or Gas Recovery and long-term CO2 .
Projects we’ve delivered
Safe transportation of captured CO2 is critical and involves careful planning, specialised engineering and risk management. As was the case with the development of natural gas distribution systems, new CO2 pipeline and transportation networks will evolve as the number of CCS projects increases.
Detailed evaluation of potential pipeline routes takes many factors into consideration:
CO2 is already transported via high pressure pipelines, however, as the scale of infrastructure increases more populated areas may be impacted. To secure necessary rights of way, comprehensive HSE and risk mitigation policies will be obligatory. As an alternative to pipelines, shipping of liquefied CO2 via tanker may be an option, comparable to current LNG and LPG transportation. This will require its own risk mitigation policies.
How we help
Due to these sensitivities, RPS integrates state of the art technology, laboratory analysis and specialised engineering with risk assessment capability. We draw on proven international experience to provide a robust evaluation that leads to a pragmatic solution.
Experienced engineers provide field-based assessments of pipeline routes, interfacing with key engineering contractors. Geological Information Systems allow visual recognition of complex spatial situations for route selection. Communication with all interested parties is enabled via web-based systems, so generating a rigorous assessment of potential Health, Safety, Environmental and Social impacts. This helps differentiate between perceived and actual risk related to transportation of CO2.
Projects we’ve delivered
Injection of CO2 into deep geological formations utilises technologies that have been developed by the oil and gas industry over many years. Well drilling and completions technologies have been developed for optimal performance under extreme operating conditions such as high pressure, temperature and complex chemical environments.
Gas storage and transportation infrastructure projects also provide valuable experience when considering facilities designed and engineered to accommodate CCS. As producing fields approach the end of economic life, it is feasible that existing infrastructure could be converted for CCS purposes. However, to make the most of this potential there needs to be an integrated approach from power generation, infrastructure and asset owners.
How we help
RPS provides integrated engineering design across multiple industry sectors, with significant experience of gas storage, gas transportation and associated infrastructure. We play an invaluable role at the interface between structural engineering, civil engineering, building services and geotechnics.
Our range of services encompasses design, procurement, validation and commissioning in complex and highly regulated environments. Our team has years of experience in the provision of well planning, well engineering and design, construction, execution, management and post well project close-out. This experience has been gained on more than 7000 wells world-wide.
Projects we’ve delivered
A comprehensive strategy for Monitoring, Mitigation and Verification (MM&V) is required at all phases of a CCS project to ensure the safe transportation, injection and long-term storage of CO2.
MM&V capability will give surety to regulators and local government who must approve large CCS projects by providing confidence in the volumes of CO2 stored, to ensure safety, environmental and commercial viability.
How we help
Our teams support all phases of an installation from concept design through to decommissioning, providing services to deliver an installation’s Safety Case and ongoing safe operation. Ongoing MM&V draws on several RPS disciplines such as geophysical survey design, support and analysis, stack monitoring, geohazards, meteorological, oceanographic and environmental sampling consultancy services.
RPS has established an excellent reputation for HSE and risk management services to the oil and gas, chemical, power, FMCG, manufacturing, nuclear and defence sectors. We combine sector specific regulatory and operational knowledge with experience of sector-specific best practice.
Projects we’ve delivered
2D/4D seismic monitoring planning and acquisition observation for the CCS Sleipner Field, Norwegian North Sea, Equinor
Director Subsurface Low-Carbon Solutions
Director Energy Operations - AAP