This is the final report of the Natural Analogues for the Geological Storage of CO2 in the Geological Environment (NASCENT) project. The NASCENT project has studied natural accumulations of carbon dioxide as analogues of the geological storage of anthropogenic CO2 emissions. http://www.ieaghg.org/docs/General_Docs/Reports/Report%202005_6%20NASCENT.pdf

This report forms part of the international SACS (Saline Aquifer CO2 Storage) project. The project aims to monitor and predict the behaviour of injected CO2 in the Utsira Sand reservoir at the Sleipner field in the northern North Sea, to assess the regional storage potential of the Utsira reservoir, and to simulate and model likely chemical interactions of CO2 with the host rock. This is the final report of Work Area 1 in SACS, whose aims were to provide a full geological characterisation of the Utsira Sand and its caprock. The report summarises the key findings of the component subtasks of Work Area 1. The report also provides references to the various SACS Technical Reports wherein the full details of the scientific work can be found. The report can be downloaded from http://nora.nerc.ac.uk/511461/.

Carbon capture and storage in sub-seabed geological formations (sub-seabed CCS) is currently being studied as a realistic option to mitigate the accumulation of anthropogenic CO2 in the atmosphere. In implementing sub-seabed CCS, detecting and monitoring the impact of the sequestered CO2 on the ocean environment is highly important. The first controlled CO2 release experiment, Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS), took place in Ardmucknish Bay, Oban, in May–September 2012. We applied the in situ pH/pCO2 sensor to the QICS experiment for detection and monitoring of leaked CO2, and carried out several observations. The cabled real-time sensor was deployed close to the CO2 leakage (bubbling) area, and the fluctuations of in situ pH and pCO2 above the seafloor were monitored in a land-based container. The long-term sensor was placed on seafloor in three different observation zones. The sediment pH sensor was inserted into the sediment at a depth of 50 cm beneath the seafloor near the CO2 leakage area. Wide-area mapping surveys of pH and pCO2 in water column around the CO2 leakage area were carried out by using an autonomous underwater vehicle (AUV) installed with sensors. Atmospheric CO2 above the leakage area was observed by using a CO2 analyzer that was attached to the bow of ship of 50 cm above the sea-surface. The behavior of the leaked CO2 is highly dependent on the tidal periodicity (low tide or high tide) during the CO2 gas release period. At low tide, the pH in sediment and overlying seawater decreased due to strong eruption of CO2 gas bubbles, and the CO2 ascended to sea-surface quickly with a little dissolution to seawater and dispersed into the atmosphere. On the other hand, the CO2 bubbles release was lower at high tide due to higher water pressure, and slight low pH seawater and high atmospheric CO2 were detected. After stopping CO2 gas injection, no remarkable variations of pH in sediment and overlying water column were observed for three months. This is a publication in QICS Special Issue - International Journal of Greenhouse Gas Control, Kiminori Shitashima et. al. Doi: 10.1016/j.ijggc.2014.12.011.

The objective of the EU SiteChar Project was to facilitate the implementation of CO2 geological storage in Europe by developing a methodology for the assessment of potential storage sites and the preparation of storage permit applications. Research was conducted through a strong collaboration of experienced industrial and academic research partners aiming to advance a portfolio of sites to a (near-) completed feasibility stage, ready for detailed front-end engineering and design and produce practical guidelines for site characterisation. SiteChar was a 3 year project supported by the European Commission under the 7th Framework Programme. This report introduces the lay reader to the research and concepts developed in the SiteChar project and can be downloaded from http://www.sitechar-co2.eu/SciPublicationsData.aspx?IdPublication=351&IdType=557.

Membrane processes are a promising alternative to the more classical post-combustion capture technologies due to the reduced maintenance of the process, the absence of dangerous solvents and their smaller footprint. This project aims at supporting the development of new mixed matrix membranes for post-combustion applications. Mixed matrix membranes (MMMs) are composite materials formed by embedding inorganic fillers into a polymeric matrix in order to overcome the upper bound and combine the characteristics of the two solid phases: mechanical properties, economical processing capabilities and permeability of the polymer and selectivity of the filler. Despite several studies on the concept, the interactions between the two phases and their effect on the transport properties are not well understood. Yet, this fundamental knowledge is crucial in order to design the reliable materials needed for real-world-applications. Grant number: UKCCSRC-C1-36.

This poster on the UKCCSRC Call 2 project, The Development and Demonstration of Best Practice Guidelines for the Safe Start-up Injection of CO2 into Depleted Gas Fields, was presented at the Cardiff Biannual, 10.09.14. Grant number: UKCCSRC-C2-183.

Published Papers: 1) Brown, W.J., Mound, J.E. \& Livermore, P.W., (2013) Physics of the Earth and Planetary Interiors, Vol 223, pp 62-76 Jerks abound: an analysis of geomagnetic observatory data from 1957 to 2008 doi:10.1016/j.pepi.2013.06.001 2) Cox, G.A., Livermore, P.W. & Mound, J.E., (2014) Geophysical Journal International. Vol 196, pp 1311--1329. Forward models of torsional waves: dispersion and geometric effects doi:10.1093/gji/ggt414 3) Hori, K., Jones, C.A. & Teed, R.J. (2015) Geophysical Research Letters, vol 42, pp 6622--6629. Slow magnetic Rossby waves in the Earth's Core. doi:10.1002/2015GL064733 4) Teed, R.J., Jones, C.A. & Tobias, S.M., (2014) Geophysical Journal International, vol 196, pp 724--735. The dynamics and excitation of torsional waves in geodynamo simulations. doi:10.1093/gji/ggt432 5) Teed, R.J., Jones, C.A. & Tobias, S.M., (2015) Earth and Planetary Science Letters, Vol 419, pp 22-31. The transition to earth-like torsional oscillations in magnetoconvection simulations. Doi:10.1016/j.epsl.2015.02.045

This project aims to build on and strengthen joint industry research programmes between Edinburgh, Doosan Power Systems in the UK and Sulzer ChemTech, a world leading manufacturer of separation processes equipment, with the objectives to move beyond current concepts for designing CO2 absorption columns for base-load operation, and towards new columns capable of meeting the requirements for flexible and highly dynamic operation of CCS power plants. It is an important research for the UK to ensure that conventional power plants fitted with CCS can become a source of dispatchable and low carbon energy to complement non-dispatchable renewable technologies such as wind or solar power. We propose to demonstrate the capabilities of novel ways to use solvent property instrumentation to significantly enhance the dynamic flexibility of the amine pilot plant at the UK CCS Research Centre Pilot Advanced Capture Testing facilities and to develop an underpinning understanding of the capabilities of state-of-the-art hardware, such as structured packing,liquid distributors, used in and around packed columns. Grant number: UKCCSRC-C2-214.

Flexibility in power plants with amine based carbon dioxide (CO2) capture is identified in the literature as a way of improving power plant revenues. Despite the prior art, the value of flexibility in power plants with CO2 capture as a way to improve power plant revenues is still unclear. Most studies are based on simplifying assumptions about the capabilities of power plants to operate at part load and to regenerate additional solvent after interim storage of solvent. This work addresses this gap by examining the operational flexibility of coal power plants with amine based CO2 capture, using a rigorous fully integrated model. The part-load performance, with capture and compression bypass, and with interim solvent storage with delayed regeneration, of two coal power plant configurations designed for base load operation with capture, and with the ability to fully bypass capture, is reported. With advanced integration options, including boiler sliding pressure control, uncontrolled steam extraction with a floating crossover pressure, constant stripper pressure operation and compressor inlet guide vanes, a significant reduction of the electricity output penalty at 50% fuel input is observed, from 458 kWh/tCO2 to 345 kWh/tCO2, compared to a reduction from 361 to 342 kWh/tCO2 at 100% fuel input. Advanced integration options for improved part-load allow for maximum additional solvent regeneration, although to a lower magnitude than conventional integration options. The latter can maintain CO2 flow export within 10% of maximum flow across 30% to 78% of MCR (Maximum continuous rating). One hour of interim solvent storage at 100% MCR is evaluated to be optimally regenerated in 4 hrs at 55%MCR, and 3 hours at 30% MCR, providing rigorously validated useful guidelines for the increasing number of techno-economic studies on power plant flexibility, and CO2 flow profiles for further studies on integrated CO2 networks. The paper is available at http://www.sciencedirect.com/science/article/pii/S1750583616300275, DOI: doi:10.1016/j.ijggc.2016.01.027.

A three dimensional hydrodynamic model with a coupled carbonate speciation sub-model is used to simulate large additions of CO2 into the North Sea, representing leakages at potential carbon sequestration sites. A range of leakage scenarios are conducted at two distinct release sites, allowing an analysis of the seasonal, inter-annual and spatial variability of impacts to the marine ecosystem. Seasonally stratified regions are shown to be more vulnerable to CO2 release during the summer as the added CO2 remains trapped beneath the thermocline, preventing outgasing to the atmosphere. On average, CO2 injected into the northern North Sea is shown to reside within the water column twice as long as an equivalent addition in the southern North Sea before reaching the atmosphere. Short-term leakages of 5000 tonnes CO2 over a single day result in substantial acidification at the release sites (up to -1.92 pH units), with significant perturbations (greater than 0.1 pH units) generally confined to a 10 km radius. Long-term CO2 leakages sustained for a year may result in extensive plumes of acidified seawater, carried by major advective pathways. Whilst such scenarios could be harmful to marine biota over confined spatial scales, continued unmitigated CO2 emissions from fossil fuels are predicted to result in greater and more long-lived perturbations to the carbonate system over the next few decades. This is a publication in QICS Special Issue - International Journal of Greenhouse Gas Control, Jack J.C. Phelps et. al. Doi:10.1016/j.ijggc.2014.10.013.