The effectiveness of CCS as a global solution to carbon emission abatement will depend on widespread deployment in both established industrialised and developing economies. One of the key stages for any country is the identification of a national CO2 storage resource. To help understand the challenges faced by different countries that have either conducted, or are planning such a resource assessment, a survey was commissioned by the UK and Korean governments. The responses to this survey have generated a useful foundation that can aid governments and other organisations who are less advanced in planning CO2 storage assessments. IEAGHG has now produced a guide based on the survey’s findings. It is designed to help government bodies and policy makers with limited CCS experience to identify and select information on assessment methodologies. The guide provides information on where to find the material required to undertake initial national scale storage assessments. The guidance also includes definitions of technical terminology, proposed steps to establishing a national storage assessment and recent up to date case studies from a variety of countries focussing on Africa and Asia. A variety of methods for capacity estimation have been used and this guide provides explanations of where to find these studies and sources of information including websites, papers and organisations. Most companies and organisations engaged in CCS development have stated their ambition to share knowledge and experience; and they actively collaborate at an international level to aid future projects. This guide provides a link with current expertise in CO2 storage to help facilitate new CCS projects especially in developing countries.
It should be stressed that many detailed storage assessments have been conducted and published in the past decade. A wide variety of techniques and technologies have been used to complete them given the varying nature of each country and individual sites. Although a standardised method has yet to be established, this guide aims to provide links to the most developed methodologies providing a direction on the most suitable approach to adopt.
At the conclusion of this guide there is a nine point summary of the key stages that are recommended for the establishment of a national CO2 storage assessment.
Review of CO2 storage in basalts – new technical review from IEAGHG on the potential of using basalts and other magnesium rich rocks to store CO2.
Conventional CO2 storage relies on injection into a reservoir in sedimentary rock which has an impermeable caprock. It is also possible to trap CO2 in igneous rock formations with high magnesium, iron and calcium contents. Minerals with these metal cations react with CO2 especially if water is present. New carbonate minerals then form permanently locking the CO2 in the subsurface. Because this process is relatively rapid potential leakage is minimised.
Basalts are volcanic in origin and consequently they form rocks with a fine grained mineral matrix when they solidify often with vesicles that can form layers with high porosity and permeability. CO2 injected into these layers is then trapped by carbonation reactions. Two high profile sites, CarbFix in Iceland and the Wallula project in Washington State have both injected and monitored CO2 storage in basalts since 2012. Evidence from both sites shows that injected CO2 reacts relatively rapidly to form carbonate minerals. One potential limitation of this form of carbon sequestration is the large quantity of water required. Further tests are required to demonstrate the process at larger scale.
Some other igneous rocks with high magnesium (>12% by weight) contents are also known to react with atmospheric CO2. Naturally occurring carbonate minerals can be observed where these ultramafic rocks outcrop, for example in Oman. Such rock formations are comparatively rare compared to basalts and do not form layers with permeable zones which limits their carbon sequestration potential. However, ultramafic rocks are mined where they contain valuable metals particularly platinum and chromium. After extraction the crushed rock tailings are dumped in large quantities. One of the largest producers of platinum from ultramafic rocks is South Africa, a country which has evaluated the potential of using mine tailings for CO2 sequestration.
Further details about CO2 storage in basalts, and the potential that ultramafic rocks could offer, are explain in this latest technical review from IEAGHG.
CO2 storage has now been tested at a number of demonstration sites around the world, including some depleted oil and gas reservoirs. The use of depleted reservoirs can offer some advantages because the geological characteristics that are pertinent to CO2 storage, such as the distribution of porosity and permeability, have been pre-determined. Although depleted hydrocarbon fields can show strong evidence of fluid retention, there are risks associated with existing wellbores and the possibility of caprock deterioration.
In 2016 IEAGHG published a study reviewing key factors that influence CO2 storage in depleted oil and gas fields based on four detailed examples. Comparisons were made between storage operations in depleted fields (with or without enhanced hydrocarbon recovery) and storage in saline aquifers with the approaches required in modelling, monitoring, reporting, economics, and operational strategies. Four main case studies were chosen; The Goldeneye (UK North Sea), Cranfield (Texas, USA), SACROC (Texas, USA) and Otway (Australia).
- The use of depleted reservoirs for CO2 storage can offer advantages because the geological characteristics that are important to CO2 storage have been pre-determined.
- There is strong evidence for secure containment if a rigorous risk assessment and characterisation has been conducted.
- Evidence from these case studies has shown that CO2 storage does not have a detrimental impact on adjacent oil and gas fields.
- AZMI (Above Zone Monitoring Interval i.e. a formation above the reservoir and caprock) pressure monitoring has proved to be an effective tool for tracking CO2 in heterogeneous and complex reservoirs (e.g. Cranfield). AZMI is an active area of research and development.
- Monitoring approaches should take into consideration the background geochemical reactions in aquifers that might be prone to ingress from brine or CO2 above a storage reservoir. Simplistic approaches may not be effective and could lead to flawed inferences without an adequate understanding of natural variation in groundwater geochemistry.
- Risks associated with increasing pressure are predominantly and most commonly mitigated by keeping pressures below pre-production levels.
- Case study evidence suggests oil and CO2 miscibility might improve storage estimates by up to 3% whereas residual gas and CO2 miscibility could reduce capacity by up to 6%.
- At Goldeneye proprietary CO2-resistant cements could be utilised if they can be shown as superior to ‘normal’ Portland cement but have not yet been thoroughly tested in terms of their compatibility.
- An in depth understanding of potential risks is essential to allow for balanced cost-benefit modifications and improved costs analysis.
I like to watch the weather in a morning on BBC news to start the day. These days we regularly get images of the flow of the jet stream and I have been amazed by how much it varies, wobbling around the upper region of the globe. This morning we were told that the jet stream was bringing high winds to the UK and planes coming from the USA will be swept over the Atlantic with its force. Sounds like going the other way might take you a lot longer !!!
Then as I read the newspaper the wobble in the jet stream i understand is due to the Arctic ice melting. The melting ice, which is caused by global warming, exposes dark ocean beneath, which absorbs more sunlight than ice and warms further. This feedback loop is apparently why the Arctic is heating up much faster than the rest of the planet. As a result the temperature difference between the Arctic and lower latitudes is narrowing. This is the crucial bit as it is this temperature gradient between them that drives the jet stream wind. So the good old jet stream forms a boundary between the cold north and the warmer south, and the lower temperature difference means the winds are now weaker (although not today!!). This means the jet stream meanders more, with big loops bringing warm air to the frozen north and cold air into warmer southern climes. Another consequence of the weaker jet stream is that is can get stuck over regions for days and weeks which can bring extreme cold periods to our shores.
Who says global warming isn’t happening !!!
Andy Boston from the Energy Research Partnership in the UK has written a great article that presses on an issue that has concerned me for some time, the use of the levelised costs of electricity (LCOE) to compare low carbon technologies. In his article “the levelised cost of fruit” see http://erpuk.org/levelised-cost-fruit/ he dismisses the use of LCOE and declares it dead as a comparator.
He argues that we need to start talking about the total system cost and the value of technologies in reducing that cost relative to a default option such as building CCGTs to meet demand. This he believes is the way forward and I totally agree with him.
A new report entitled The Arctic Resilience Report (see https://www.sei-international.org/publications?pid=3047) indicates that temperatures in the Arctic are currently about 200C above what would be expected for the time of year and that sea ice is at the lowest extent ever recorded for the time of year.
One concern highlighted by the report is that the developments above make the potential for triggering “tipping points” and “feedback loops” whereby the warming of one area or type of landscape has knock-on effects for whole ecosystems. Climate tipping points occur when a natural system, such as the polar ice cap, undergoes sudden or overwhelming change that has a profound effect on surrounding ecosystems, these changes the report says are often irreversible.
The Artic tipping points they highlight include:
- growth in vegetation on tundra, which replaces reflective snow and ice with darker vegetation, thus absorbing more heat;
- higher releases of methane, from the tundra as it warms;
- shifts in snow distribution that warm the ocean, resulting in altered climate patterns as far away as Asia, where the monsoon could be effected;
- and the collapse of some key Arctic fisheries, with knock-on effects on ocean ecosystems around the globe.
They also warn that that people living in and near the Arctic would be badly affected, and called for communities to be provided with equipment and skills to survive. They took evidence from a variety of settlements in the region, finding many signs of significant changes already under way.
This was a lively well attended panel discussion which certainly sparked a lot of debate. My takeaways from this were:
- CO2 utilisation and conversion to chemicals is a hot topic in many countries, with many Governments funding research programmes
- To meet the below 20C target set at COP22 we need mitigation options that permanently remove CO2 from the atmosphere
- CO2-EOR is the leading form of CO2 utilisation and has the potential to store permanently some CO2
- Manufacturing chemical products like methanol and urea do not permanently store CO2 and therefore are not mitigation options.
- Utilising CO2 to make products like methanol and urea could help with the installation of capture plants on new industry processes, like SABIC’s capture plant on its polyethylene process in Saudi Arabia.
- Utilising CO2 from chemical industry is not likely to help develop a transport infrastructure that could take significant volumes of CO2 to offshore storage sites in Europe.
- Expecting large amounts of free renewable energy to be available to convert industrial CO2 to chemicals is improbable.
- Some CO2 based polymers could conceivably last for 50-100 years but that is still not long enough as a mitigation option.
- Mineralisation is a niche opportunity not a global solution and is at very best CO2 neutral as it only serves to recombine minerals that have been de-carbonated with the CO2 they lost during processing.
In short apart from CO2-EOR, coal utilisation is not a solution to climate change.
As GHGT-13 drew so many from the CCS world together in one place for a week it is not surprising that many take advantage to organise launch events there. Two involved the launch of projects’ datasets for wider use by the CCS community, one deep-focussed, one shallow-focussed.
One was organised by Geoscience Australia and CO2CRC to launch their release of data from their controlled-release site at Ginninderra, near Canberra. Their research site has enabled scientists to simulate release of carbon dioxide (CO2) from the soil into the atmosphere under controlled experiment conditions, and to assess the performance of different monitoring technologies.
The project included development of world-leading monitoring techniques, including using mobile sensor and remote sensing technology to detect CO2 emissions and impacts. Monitoring results were found to depend on climatic conditions, groundwater levels and the extent of the soil zone above the water table. The results found significant horizontal movement in the near surface, fundamentally changing perceptions of how CO2 migrates and expresses itself at the near surface. Surface leakage was found to be patchy, a result similar to that observed in other controlled release facilities internationally.
A highlight of the work was improved quantification techniques to accurately measure emission rates. Results from a comprehensive assessment of soil flux techniques were presented in a technical session at GHGT-13. Over 20 monitoring techniques were trialled, with the datasets now available for free download via Geoscience Australia's website. The intention of this data release is to make the data available for comparison with measurements taken at other controlled release experiments, CO2 storage projects and natural analogues. This will hopefully facilitate the further development of greenhouse gas monitoring technologies, methods and monitoring strategies and increase our understanding of the migration behaviour and impact of near surface CO2 leakage.
For more information, including on how to access the data, see http://www.ga.gov.au/news-events/news/latest-news/results-released-from-world-leading-CO2-monitoring-project .
IEAGHG’s Environmental Research Network and Monitoring Network had the pleasure of visiting Ginninderra during the Networks’ meeting in Canberra in 2013 (see for the report of the meeting and visit see http://www.ieaghg.org/docs/General_Docs/Reports/2013-15.pdf.
The CO2 Storage Data Consortium (CSDC) also launched at GHGT-13. This is a new international collaboration for sharing reference datasets from CO2 storage projects in deep saline formations.
To increase efficiency of building capacity, confidence and competence in CO2 storage, this international consortium is developing a platform for sharing datasets from pioneering CO2 storage projects. CSDC promotes sharing of datasets on site geology, well data, geophysical monitoring data, and reservoirs data and models. Access to properly curated and well-understood data accelerates new development of site characterization methods, reservoir simulation and monitoring technologies.
IEAGHG are very pleased to assist by being on the Steering Committee for CSDC.
Two great initiatives in sharing data, to facilitate wider learning from projects and so to assist CO2 storage developments around the world, much praise to all involved.
A Discussion Panel was organised to celebrate the 20 years of successful injection by Statoil at Sleipner, and how best to transfer knowledge globally. Statoil have been doing a good job over the years of sharing their seismic data (via IEAGHG) and other monitoring results at IEAGHG and other meetings, with very many papers published also.
So the world has benefited a lot from the experiences and data from Sleipner and from Snovit. The learning continues in new ways! I discovered that the Norwegian government has transposed the EU’s CCS Directive into Norwegian law in 2014, and then went through a permitting exercise for both Sleipner and Snovit in 2016. Both passed and were permitted, with some additional monitoring requirements. We look forward to learning more on the application of the CCS Directive to two more projects (ROAD was the first).
We also learnt about the considerable exercise on storage assessments by geological organisations in East and South East Asia in the CCOP CCS-M initiative, as presented by Sim Caluyong the project coordinator. This involves many countries in the region, showing case studies for Malaysia, Vietnam, Philippines, and the work towards a pilot injection (onshore) in Indonesia at the Gundih gas field.
The growing interest of Nigeria was also noted, arising from the Offshore Workshop held in Austin earlier this year (see IEAGHG report). The value of being able to re-use existing oil and gas infrastructure was emphasised.
Tip Meckel described the global offshore storage potential, some specific regional geological examples, and the scale-up challenges for the scale of global deployment required, hence the need for offshore storage as well as onshore.
Questions were posed to the panel and audience on how best to transfer knowledge, such as by workshops and by capacity building efforts for developing countries which could be funded by the UNFCCC’s CTCN and other such bodies. Questions were also posed from around the world on tectonic settings, and on cost savings from Sleipner and Snovit.
At the end, written comments were collected from the audience on the importance of Sleipner, and included:
“A very good project”
Happy Birthday Sleipner”
“Hopefully it motivates the other 999 projects we need!”
Thank you Sleipner! Named after an eight-legged horse in Norse mythology, it’s benefits continue to gallop around the world.
Statoil have been operating at Sleipner since 1996 marking twenty years of injection monitoring at the site. The monitoring programme has been shown to be a success proving both conformance and containment as well as including contingency plans. Repeated seismic and gravimetric surveys have been conducted throughout the lifetime of the project alongside acoustic imaging of the seabed. Statoil and partners have released all seismic data acquired up to and including 2008. Gravimetric surveying allowed initial estimates of the density of CO2 within the reservoir to be calculated and then later to determine an upper limit on the amount of CO2 dissolved in brine (when combined with other data). Key learnings highlighted from the past 20 years included the importance of controlling the injection in-situ conditions using downhole pressure and temperature gauges; repeated seismic surveys were crucial for ensuring containment monitoring; the combination of seismic and gravimetric data allowed an estimate of the amount of CO2 dissolution in water to be made and future dedicated monitoring plans should take into account higher frequency and resolution technologies now available.