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Solvent-based post-combustion carbon capture (PCC) process is widely viewed as the most viable option for reducing CO2 emission. This technology has been deployed globally and many researches have been conducted in this area. In this paper, current status of dynamic modelling, system identification and control scheme of solvent-based PCC process is reviewed. Different research directions of these areas are discussed to conclude the existing challenges. Based on this, this paper is also trying to provide potential solutions as possible pathways for flexible and economical operation.

Overheating in the residential buildings has been identified as a major challenge in terms of public health especially in an urban context. Increased duration and frequency of heatwaves associated with climate change will increase the severity of overheating. However to date overheating has not been adequately addressed by the building regulations. In a case study retrofit high rise apartment block in Leeds, UK major overheating has been identified through and in-depth building performance evaluation (BPE) study. The study was extended with transient dynamic modelling of top floor apartments to explore the effectiveness of 18 fabric and practices scenarios based on actual BPE findings. The results show 10-30% difference in overheating severity was caused by a performance gap in relation to the building fabric. What's more they indicate that in the given climatic conditions of summer 2013 overheating might have been avoided if shading was introduced and mechanical extract ventilation used as designed. This points towards the need of focusing more attention on overheating prevention at design and handover stages.

Assessment of long-term stability of injected CO 2 for geological storage requires a certain level of dynamic modelling, including geochemical modelling of fluid-rock interactions triggered by the injected CO 2 in geological formations. One of the key outcomes of a geochemical simulation is the predicted porosity changes. Decreasing porosity implies an overall plugging of the pore system and therefore probably a reduction in permeability, while increasing porosity implies the possibility of the opening up of flow paths. Therefore the predicted porosity change is an important indicator for self-healing versus self-accelerating behaviour of potential CO 2 leak paths. Based on project studies and natural analogue comparisons, several easy-to-use metrics and cross-correlations are developed in this paper. This is done by starting from a mass balance analysis, and re-writing it as a volume balance analysis plus correction terms. In this way porosity changes can be rigorously split up in distinct contributions from salinity changes, density changes and (de)mineralisation of CO 2 and H2O. By cross-correlating the porosity changes to these contributions, using 11 CCS case studies and natural analogues examples (covering a wide range of settings such as aquifer/gas field, geographic location, geochemical reaction paths, salinity, temperature), distinct patterns and rules of thumb emerge. The methodology and resulting cross-correlations can be applied as a quick and powerful sanity check on geochemical modelling results. The key conclusions that can be drawn from this work are: • The amount of mineralised CO 2 is a reasonable predictor for the porosity change • The amount of mineralised H2O and the density change can be significant contributors to the porosity change, but (without taking into account mineralised CO 2 ) are poor predictors for the porosity change The salinity change is only a minor contributor to the total porosity change. The main conclusion is that the porosity is likely to be reduced if CO 2 is mineralised. This should be considered a rule of thumb. Exceptions are possible (in the dataset used in this paper, 1 out of 11 cases, and the exception was caused by large density differences between dissolved and precipitated minerals). For new geochemical/Reactive Transport Modelling studies it is advisable to check how the calculated porosity change fits on the general trends presented in this study (especially the correlation to mineralised CO 2 ). It is highly advisable to scrutinise exceptions and to understand their root causes. The root cause might be a physical process (like for the 1 exception out of 11 cases we studied), but it could also point to an error in the geochemical model setup or in the model post-processing.

The BASTOR project identifies and characterizes the potential CO 2 storage sites in the southern Baltic Sea. A regional theoretical storage capacity of 16Gt of CO 2 in the Middle Cambrian sandstone beneath 900 meters of cap rock was estimated. 1.9Gt of this storage potential is estimated in the Dalders Monocline with some 743Mt CO 2 in individual hydrocarbon and saline aquifer structures located mainly offshore Latvia and 128Mt in the Dalders Structure. Although the study has established a relatively large theoretical storage capacity no effective capacity proven within these totals. Dynamic modelling undertaken in the Southern Swedish sector suggests that the relatively poor permeability and porosity characteristics would limit the injection rate to 0.5Mt per well per annum and restrict the reservoir pressure increase to 50% above the hydrostatic pressure for an injection period of 50 years. The dynamic modelling for this area suggests that an injection strategy for this sector would be limited to 5 injection wells giving a total injection capacity of 2.5 Mt per annum. Based on these results, the potential of the Southern Swedish offshore sector to sustain injection rates of CO 2 required for regional industrial capture, even when using horizontal wells, brine extraction and hydraulic fracturing, would appear to be very low. Areas to the north east of the Monocline, such as offshore Latvia have been identified as having better reservoir quality despite limited data being available. These areas could sustain higher rates of injection and prove suitable areas for commercial storage. Furthermore, the regional storage capacity assessment demonstrated that there are sweet spots in the Cambrian reservoir such as onshore Latvia, where there is commercial gas storage, and both onshore and offshore Kaliningrad, where there is ongoing hydrocarbon production. The potential for seal failure was investigated as part of the BASTOR study and three possible modes of seal failure were identified. These include top seal failure, migration up the bounding fault planes and leakage across fault planes. The risk associated with all of these is considered low, based on currently available data. A test injection methodology aimed at assessing the commercial viability of CO 2 injection in the Baltic Sea region has been designed. This includes the characterization of reservoir, caprock and hydraulic properties, pump testing as well as CO 2 migration and trapping using a phased approach methodology. An outline MMV program has been developed based on the results of the dynamic modelling and the development phases of a CO 2 injection site. Since the potential to store significant quantities of CO 2 in the Swedish part of the Dalders Monocline appears to be limited, exploration efforts and the acquisition of new, site specific data through geophysical surveys, drilling and injection testing as well as detailed sampling and laboratory analyses, should be focused on areas of better reservoir qualities than the current study area. New data covering the north eastern portion of the Dalders Monocline, in particular offshore Latvia and onshore as well as offshore Kaliningrad, would allow a detailed characterization of individual potential sites for CO 2 storage. This would also define site-specific seal integrity as well as characterize small-scale fault structures that would ultimately dictate the potential injection and storage conditions.

Comprehensive knowledge gained through the application of a unique and multidisciplinary monitoring program at the Ketzin pilot site has been largely integrated into the development of a site-specific static geological model. Although dynamic modelling results have demonstrated good conformity with the field observations thus far, the long-term fate of CO2 remains uncertain. This is due to the lack of sufficient data regarding the geological characteristics of the far-field region in the reservoir. In this paper, the authors describe a methodology to quantify these uncertainties in order to perform a site-specific risk assessment for the post- closure period.

Oxy-fuel combustion is a promising CO2 mitigation technology that will allow the continued utilisation of abundant coal reserves in the power sector in a carbon-constrained world. The CO2 capture and purification unit (CO2CPU) is an important unit that determines the CO2 product quality and energy consumption of the oxy-fired power plants. Several studies have been published on this unit but information on the dynamic behaviour of the CO2CPU is limited. This study developed a dynamic model of the pilot- scale CanmetENERGY's CO2CPU (CanCO2). Dynamic modelling of the CO2CPU is challenging due to the highly-integrated flow sheet structure and the occurrence of two phase flow heat transfer in heat exchangers. This study takes into account the property variation in the two phase region while calculating the heat transfer coefficients in heat exchanger models. Detailed mathematical models are provided and transient analyses were performed to gain insight into the dynamic behaviour of the CO2CPU. Dynamic data obtained from the transient analysis was used to design a suitable control scheme for this process and study the dynamic operability of this process in closed-loop. A decentralized multi-loop control scheme for the CO2CPU is proposed based on the Relative Gain Array (RGA) method. The performance of the proposed control structure was evaluated for both disturbance rejection and set point tracking scenarios. Stable closed loop responses were obtained.

Flexible operation of post-combustion CO 2 capture (PCC) plants can improve efficiency through coordinating the balance between consumer demands for electricity and CO 2 emission reductions. This strategy however, will impose process disturbances and the immediate and long term impact is unclear. There is a justified need for the development of accurate dynamic PCC models, as well as practical experience in dynamic operation of PCC pilot plants. This paper presents CSIRO PCC pilot plant data from the 2012 and 2013 dynamic campaigns using MEA solvent. The step-change approach to dynamic plant operation was implemented and the use of density meters to instantaneously measure CO 2 loading instantaneously was investigated.

In this work, a dynamic model of the Brindisi CO2 capture pilot plant is implemented in K-spice general simulation tool. The model is used to simulate relevant step changes performed during a pilot plant campaign conducted in the EU project Octavius in May and June 2013. Model results are compared to dynamic pilot plant data and it shows good transient agreement to the experimental results. The model is therefore able to capture the main process dynamics. An offset is, however, observed in some cases, especially during the initial simulation time. This is most likely caused by the fact that the model was given a steady state starting point, while the pilot plant was not necessarily completely at steady state when the step change was introduced. It is challenging to ensure steady state conditions prior to dynamic tests in a pilot plant, especially for one that is connected to a real power production unit as this one. Power production variations will act as disturbances to the capture unit, and due to slow transients in the solvent inventory of the capture unit, it will take several hours to ensure steady state conditions with stable inlet flue gas conditions.

The most mature technology for CO2 capture is absorption with suitable solvents, be it physical or chemical. However, important issues still need to be addressed. Two of the most prominent are: a) the large energetic costs involved, and b) the need for capture plants to operate flexibly. Recently, considerable research efforts have been devoted to both the identification of optimal solvents, and the development of improved capture plant process configurations and operating conditions. These two aspects are generally regarded as the main drivers that can bring down the costs associated with solvent-based CO2 absorption processes. Additionally, an understanding of the dynamic behavior of capture plants is imperative in order to design CCS chains that will be increasingly subjected to variable electricity demand. This work introduces a predictive dynamic modelling framework for solvent-based CO2 absorption, part of the gCCS system modelling environment for CCS chains. The framework aims to serve as a platform to address the issues abovementioned, among others. Applications to optimization and dynamic studies are presented.

The feasibility of a carbon capture and storage (CCS) project at the Fort Nelson Gas Plant in British Columbia, Canada, has been conducted. The feasibility study included the collection of baseline characterization data, static and dynamic modelling efforts, two rounds of risk assessment, and the development of a draft monitoring, verification, and accounting (MVA) plan. Those activities have been compared to the Canadian Standards Association (CSA) standard for geologic storage of carbon dioxide. Although the remote location, difficult terrain, and extreme climate of the potential injection site make MVA challenging, cost- effective MVA that meets or surpasses the CSA standards is achievable.

Carbon capture and storage (CCS) is a potential means of mitigating the contribution of the green house gas emissions from the fossil fuel usage to the global warming. Post combustion CO2 capture via amine absorption is one of the most matured techniques to comprehend the goals of CCS. A Dynamic model of an amine based post combustion capture plant including the absorption and stripping towers is developed in order to contribute in the journey from the lab scale towards the industrial scale capture plants. The dynamic model is validated against the literature data. The capability of the model to predict the dynamics of a post combustion CO2 capture unit is analyzed via a possible scenario of a real plant.

This paper describes in detail the numerical solution of a dynamic process developed for post-combustion absorption based CO2 capture. The method used in this work is sequential modular integration. This means that each process unit is modeled and integrated individually while co-ordination algorithms are developed to synchronize process units in time and provide input between connecting units. A pressure-flow interaction algorithm (p-f network solver) is also developed to provide estimates of downstream pressures for each unit. This is required in order to calculate the outlet flow from the units. The complete process plant model is developed to enable simulation of the post-combustion CO2 capture process at power plant load variations. Two examples of load variations are presented in this paper. Copyright © 2013 The Authors. Published by Elsevier Ltd. Published under a CC BY-NC-ND 3.0 license.

Oxyfuel combustion technology is one of several Carbon Abatement Technologies (CATs) currently being developed. The technology offers a means of generating carbon dioxide rich flue gas requiring minimal treatment prior to sequestration or beneficial application. The oxyfuel process is based on excluding the inert components (mainly nitrogen) of air from the combustion process. In oxyfuel combustion, nitrogen is largely absent from the flue gas, since the fuel is combusted with a mixture of nearly pure oxygen (∼95% O 2 -separated from air in an air separation unit (ASU)) and CO 2 rich recycled flue gas. It is recognised as a leading Carbon Capture technology for new and retrofit power plant. Previous studies undertaken by Doosan Power Systems, Air Products, University of Edinburgh and others have shown that there is significant scope to optimise overall plant efficiency, both at the design stage and during normal operation. Therefore the current work seeks to realise these benefits through the adoption of optimised designs and the development of appropriate control and dynamic optimisation strategies. Recycling flue gas in the Oxyfuel process gives rise to a number of operational and control features not seen in conventional air-fired power plant systems. Comprehensive dynamic models of the Oxyfuel process systems and associated controls are being developed as part of the TSB collaborative project “Optimisation of Oxyfuel PF Power Plant for Transient Behaviour” to study these aspects. The Oxyfuel specific models are coupled to a whole cycle, non-linear, dynamic model of the boiler and turbine systems allowing development of control schemes, which can meet the full range of operational requirements and capabilities of the Oxyfuel plant. Early results from the model suggest that operation in Oxyfuel mode may provide an opportunity to improve plant flexibility and both primary and secondary response, a capability which is of increasing importance as the mix of conventional, nuclear and renewable generation changes.

NOTICE: this is the author's version of a work that was accepted for publication in Energy Procedia. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in ENERGY PROCEDIA, VOL 4, (2011) DOI http://dx.doi.org/10.1016/j.egypro.2011.02.056 Post combustion CO2 capture via absorption into aqueous alkanolamine systems is considered to be the most mature and potential technique for CO2 removal from the power plants' exhaust gases. Modeling and simulation of such plants have achieved an interesting place in research, and several steady state models already exist. Though steady state models are capable of giving an understanding of the process, dynamic models are most useful for controlling and optimizing the plants. A dynamic model for the absorption column in a CO2 removal plant is been developed. Usability of simple thermodynamics for modeling is checked with the development of this model, instead of using complex thermodynamic models which are very popular in recent research. It is concluded that the steady state simulation results show a good agreement with the trend of the available pilot plant data. Dynamic predictions of the model indicate that the model is capable of handling an excitation of the inputs and reaches steady states. Yet, the whole CO2 absorption plant has to be included into the dynamic model before it is ready to be used for control or optimization applications.

Studies have been carried out to show that there could be benefits in employing a hybrid of the post combustion capture and oxyfuel processes. The former is suited for retrofit purposes but involves an energy intensive solvent regeneration process. The oxyfuel process would result in high partial pressures of CO 2 in the flue gas making separation easier. However, the Air Separation Unit is also energy intensive and significant modifications would have to be made on the power generation process. An enhanced- O 2 coal power plant with post combustion CO 2 capture would produce flue gas with reduced mass flow and higher CO 2 partial pressures. The dynamic response of the downstream CO 2 capture plant was studied in this paper.

This paper outlines the development of a methodology which can be used to produce key performance indicators for operability and efficiency of a CO2 storage site. The methodology is based on the premise that individual geological formations and their characteristics can be assessed on the basis of their depositional and tectonic setting and more recent reservoir/site history using hydrocarbon exploration and development data. The methodology is illustrated for a candidate storage reservoir in the Rotliegend Leman Sandstone Formation of the UK Southern North Sea.

CCGT power is well-positioned for flexible operation due to its favorable dynamic character and is likely to play a significant role in the future intermittent power generation mix, specifically with an increasing penetration of intermittent renewable power capacity. However, concerns exist around the impact of adding Carbon Capture & Storage on the flexibility of low-CO 2 fossil fuel power plants. This paper presents the results of a study on the dynamics of a carbon capture plant in order to address the impact on flexibility. This will enable the development of the learning curve to improve flexibility of future commercial scale CCGT-CCS plants. A dynamic model was set-up for a CCS retrofit on an existing typical commercial CCGT plant. Various load-following, shutdown and start-up scenarios were studied. It was concluded that flexibility of gas-fired power plants for mid-merit cycling or base-load operation does not have to be limited by the addition of post-combustion CO 2 capture. It was concluded that only start- up scenarios may lead to additional CO 2 losses, which can be limited by appropriate design. Various options to enhance start-up response have been identified and require further study and development to explore their value. The dynamic modelling capability built for this study provides an excellent tool to do this. It is noted that, starting from early FOAK CCGT-CCS power plants, a learning curve will be required to further develop flexible operation. Reference is made to the learning curve that delivered the current flexibility of CCGT power plants, where the steam cycle follows load variations on the gas turbine.

The stability of output performance plays a very important role in the thermoelectric generation (TEG) system, but the fluctuation problem of heat source widely exists in the industry which releases the waste heat, and the fluctuating process will cause the instability and low efficiency of the TEG system. In this article, a novel TEG system with thermal switch was proposed to solve this serious problem. In order to get the detailed characteristics of the TEG system with thermal switch, experimental and dynamic modelling methods were used. The experimental and modelling results show that the thermal switch can efficiently reduce the temperature fluctuation and increase the output power and efficiency of the TEG system, and there is an optimal turning on temperature and turning off temperature to maximally increase the output power and electricity efficiency of the TEG system. The comparison between the numerical data and the experimental results has approved the reasonability of the dynamic model.

A Phase Change Material (PCM) thermal energy storage module has been built and tested successfully at CEA on the LHASSA experimental facility. The test campaign aimed at validating the thermo-hydraulic behavior of the storage module under operating conditions similar to those of commercial Direct Steam Generation CSP plants. The measured performances have been compared to the simulation results given by a dynamic model developed at CEA. Tests gave very satisfactory results, with a measured storage capacity meeting the specifications and a very small degradation of temperature and pressure levels in discharge mode. The storage module tests allowed to validate the modeling approach chosen to assess system performances and dynamics. The simulation model developed within the Dymola platform was proven to accurately reproduce the tests results and therefore can be effectively used for performance predictions and for the definition of operating strategies of commercial CSP plants.

International audience; Photovoltaic-Thermal (PV-T) hybrid collectors are a promising technology, representing an efficient exploitation of solar energy with which to fully optimize the surfaces of integration within the building envelope. In spite of sustained interest since the mid 70s, there are only few studies providing a statement on the actual utility of this technology for real usage scenarios. In 2012, the project PHOTOTHERM was initiated with the aim of evaluating the real potential of covered water based PV-T collector coupled to a Solar Domestic Hot Water System (SDHWS). In this paper, first results obtained in the frame of this project are presented. First the design and indoor performance of the selected PV-T prototypes are presented, and the full scale PV-T plus DHWS system installed at EDF R&D outdoor test facilities is described. The results of monitoring this test system are presented and discussed. Finally, an overview on the ongoing work regarding PV-T collector and system simulation is presented as well as the next steps of the project.