Exploring the improvement of CO2 storage and CCS representation in Integrated Assessment Models


Undertaking climate mitigation is a hugely complex task requiring choices to be made on which technologies and resources to apply and when and where to apply them, all under changing conditions of amongst others population, energy demand, food production need and social perspectives. Key instruments to explore and advise these choices are Integrated Assessment Models. These combine socio-economic, resource, energy, technology availability and deployment, and climate change modelling to develop, assess and understand decarbonisation scenarios and strategies consistent with achieving climate policy objectives such as those negotiated at the UNFCCC conference in Paris in December 2015.

Founded in 1992 following the Rio Earth Summit the Potsdam Institute for Climate Impact Research (PIK) is a leading centre of Integrated Assessment Model research with their models extensively used in the development and analysis of global and regional decarbonisation scenarios. These analyses contribute to climate mitigation policy advice and formulation e.g. through Intergovernmental Panel on Climate Change (IPCC) Working Group 3 assessments of climate mitigation.

Integrated Assessment Models assessments have very strong consensus on the critical role of deploying substantial quantities of Carbon Capture and Storage (CCS) in achieving climate mitigation objectives, both to decarbonise on-going usage of fossil fuel resources and potentially to enable net CO2 removal ‘negative emissions’ through the deployment of Bio-Energy with CCS. Much of this CCS deployment is suggested to occur in developing world regions where energy demand and industrial development is increasing.

As with all models, the results are to some extent sensitive to the quality and uncertainty of the underlying information used. With respect to CCS, this includes knowledge on the energy system, the costs of fuels, the efficiencies and costs of CO2 capture, and the availability of geological CO2 storage capacity and the capabilities and infrastructures to enable access to this CO2 storage.

Following discussion at several conferences we decided it would be useful to try and bring together expertise from the Integrated Assessment Models and CO2 storage to explore how the representation of CO2 storage capacities, capabilities and infrastructures might be improved, and what the results of the models suggest for future CO2 storage and CCS research and development. We applied for funding to the UKCCSRC International Research Collaboration fund (Call 4) and were successful – thanks UKCCSRC!

Our visit:

In early September 2016, Vivian Scott, Gareth Johnson and Niklas Heinmann from the University of Edinburgh and SCCS headed for a weeks visit to PIK. Our hosts - Nico Bauer and Jessica Strefler in PIK’s Integrated Assessment Modelling team welcomed us to PIK’s fantastic new research building – a clover-footprint design set amongst woods on Potsdam’s famous Telegrafenberg research institute campus.

Following introductions we started the week sharing and discussing our perspectives on CCS development and deployment, its expected role in energy system decarbonisation, and the factors and conditions influencing the scale and timing of its potential applications. Nico and Jessica introduced us to the PIK Integrated Assessment Model and some of its scenarios and results. Gareth presented how CO2 storage capacities are assessed and defined and reflected on his different experiences working on CO2 storage assessment in Canada and South Africa. The former is a compelling example of a very well explored region with very robust potential for huge amounts of CO2 storage, with its development well-facilitated by existing infrastructures, experienced sub-surface industries and regulators. By contrast, South Africa has had little detailed geological exploration applicable to CO2 storage, and has very little existing experience in relevant sub-surface industry and regulation. We discussed how these contrasting levels of preparedness might perhaps be better reflected in model inputs.

We then examined the Integrated Assessment Model inputs in detail, working through regions one at a time discussing the quality of the data, whether or not and how it might be improved, and what effect any alterations might have on the model results. Would the optimal locations for CCS and BECCS change? What might be the effect on the calculated choice of energy systems or trade of energy resources? How would any delays in CO2 storage availability due to the time taken to undertake detailed geological exploration and development alter the expected scale and locations of (BE)CCS?

Next, we explored the concept of geological storage constraints further. Following presentation by Niklas we considered if approaches to basin-scale pressure models could be adapted to develop a constraint on regional-scale injection rates. This could provide a method to set improved conditions on ‘how fast’ (injection) the ‘how much’ (capacity) CO2 storage might be utilised.

We then moved on to thinking about factors influencing ‘when’ (how soon) CCS deployment might be possible. Here we considered both economic and policy factors but also the important role of CO2 transport and storage infrastructures to facilitate faster and less commercially risky CCS deployment. For instance the CO2 pipeline and injection site enhanced oil recovery network in the South-West US has been a significant enabler in CCS project development as it removes the ‘chicken and egg’ problem of needing captured CO2 to justify investment in storage infrastructure and vice-versa. We also discussed the changing context for CCS application. As renewable electricity generation technologies continue to fall in cost and their rapid expansion continues CCS might play a lesser role in electricity production decarbonisation than previously envisaged. However, to meet climate targets the rapid application of CCS on industrial emissions and on liquid biofuels (e.g. to replace aviation fuels) remains critical.

In Integrated Assessment Models, investment in e.g. industrial CCS R&D and CO2 transport and storage infrastructures are endogenous actions (ones in which the model determines the timing and optimal resource invested versus other investments).  Conversely, effective CO2 storage capacity is exogeneous (a constraint that the model has to operate within). While generally treated as exogenous, rates of injection lie somewhere in between – with physical limitations but also potential to improve with different injection strategies and investment. On our last day we workedon ideas for how this might be reflected in a simple enough way to be implementable in the model. These will be taken forwards and their parameterisation and implementation tested.

Overall, the visit was very productive, both in the modellers gaining improved understanding of CO2 storage and CCS processes and how capacity data is developed, and from the CCS research side, learning how data is selected and used and reflecting on how this might influence methods and approaches used in CO2 storage assessments. We will continue our collaboration on improving CCS representation in decarbonisation scenarios and models and explore future research opportunities combining our respective perspectives and expertise.

Exploring Potsdam:

In the evenings we explored Potsdam, a city a short distance from Berlin, embedded with history including the royal palaces and parks of the Prussian emperors, the site of the 1945 Potsdam conference and the famous Glienicke ‘bridge of spies’. Potsdam also has superb lakes for swimming, which provided welcome relief from the 30+ degree late summer heatwave.

Huge thanks to Nico and Jessica and PIK for hosting and working with us and we look forwards to continuing our collaboration.

Vivian, Gareth, Niklas   

V. Scott