Project SAVE-CAES is all about developing large-scale long-duration energy storage that will enable the UK to be powered largely (and possibly completely) from renewables. That energy storage must be affordable, sustainable and large-scale. Compressed air energy storage (CAES) has the potential to meet all these critically-important criteria. Developing such storage is probably the biggest single challenge standing in the way of "Net-Zero" for the UK by 2050. Offshore wind around the UK is a remarkable resource for a future zero-carbon UK electricity system. If we were to exploit all of the area that could feasibly be imagined, UK offshore wind could produce about 2000TWh of electrical energy every year - more than 5 times greater than the amount of electricity we presently consume in one year. Electricity usage will increase, of course, between now and 2050 - possibly increasing from ~350TWh each year to ~1000TWh annually. However, it is perfectly feasible that we can generate all of this electricity from wind. Solar power will also play a key role in powering the Net Zero UK but there are straightforward reasons why this will provide only about 20% of our power in the future. The strongest of those has to do with seasonality: solar on an average day in mid Summer is 9 times higher than on an average day in mid Winter, however our energy demand in Winter is higher than that in Summer. Happily the wind is also seasonal and it typically delivers 2.3 times more energy on an average mid-Winter day than it does on an average mid-Summer day. Nuclear power will also have some role. Opinions differ on how substantial that role will be but that is not very important for the purposes of understanding or justifying this research proposal. The key problem with having a country powered largely from inflexible low-carbon sources is that demand and supply must be matched and demand is relatively "inelastic". This means that proportionately small changes in the cost of electricity have very small influence on how much electricity that is consumed. Quantitative assessments of how much we will be paying for our electrical energy by 2050 suggest that less than half will be made up of the direct cost of generating the actual units of electrical energy. The larger cost will be connected with providing the flexibility - the ability to match up supply and demand. Different researchers predict different proportions, but the consensus is that flexibility costs will be the dominant ones. CAES is one of the most promising sets of options available in the UK for storing very large quantities of (wind or solar) energy over periods of tens of hours - possibly up to 100 hours. CAES has the potential to combine good performance (upwards of 70% round-trip efficiency) with relatively low costs (<£2/kWh). There are two different grid-scale energy storage plant which store compressed air in the world - one at Huntorf in Germany and the other in McIntosh, Alabama - however, these plants also store fossil fuel. Many commentators make the serious mistake of extrapolating from these to estimate what CAES can possibly do. Project SAVE-CAES sets out to apply fundamental engineering science to determine what a well-designed CAES plant without fossil fuel addition could possibly do. SAVE-CAES is a project filled with novelty. Pressurised air will be stored in salt caverns that are either offshore or at the coast. The project will explore the use of isobaric storage of the pressurised air and the management of concentrated brine (salt-water) for pressure regulation. It will also explore ultra-high-pressure air storage (for best value per cubic metre of cavern). It will also explore the potential for exploiting relatively mild geo-thermal heat during the re-expansion of the air and the possibility that some wind turbines might be deployed directly as last-stage compressors for charging the energy stores.

The UK needs carbon capture and storage (CCS) as part of its energy mix to minimise the cost of decarbonising our economy. CCS will have to fit into an electricity market that is increasingly dominated by inflexible nuclear and uncontrollable wind. It will therefore be vital that the CCS plants we develop are sufficiently flexible to interact with this new system, and balance the rapid start and cycling abilities with the lowest possible capital and operating costs. Flexible CCS will be characterised by the ability to simultaneously interact with the complex electricity system of the future and also the downstream CO2 transport and storage system. Rather than burning fuel purely in response to electricity price, CCS operators will also have to factor in waste storage costs, which will suffer similar complexity due to constraints on CO2 transport and injection rates and gas composition. This project will identify the flexibility bottlenecks in the CCS chain and also promising options for the development of resilient CCS systems. These models will internally calculate CCS plant load factors and electricity wholesale prices, thereby enabling a rigorous, technologically- and temporally-explicit, whole systems analysis. Feedback from CO2 storage operations will exert an as-yet unknown impact on the feasible operating space of the decarbonised power plant. We will explicitly quantify the interactions between the above- and below-ground links in the CCS chain. Sample CCS chains developed will be assessed in more detail concerning their broader role in the UK energy system. The implications of technological improvements in critical technologies such as advanced sorbents, improved air separation technologies and the availability of waste heat will also be considered. On a larger scale, the inter-operation of sample UK-specific CCS networks with intermittent renewable energy generation will be examined from an internally consistent whole-systems perspective. The internalisation of exogenous boundary conditions (e.g., the role of renewable energy and CCS plant load factors) and the development of multi-source-to-sink CCS system models will enable the most accurate assessment to date of how CCS will fit into the UK energy system and would interact with other energy vectors. The linking of CCS and renewable energy generation system models will allow us to examine the opportunities and impacts associated with the co-deployment of renewable energy and CCS in the UK. This will feed into a wider policy analysis that will examine the dynamics of changing system infrastructure at intermediate time periods between now and 2050. Dissemination of research output will be continuous over the duration of the project. We will engage with the academic community via publication in the international peer reviewed scientific literature and presenting at selected conferences. Owing to the topical nature of this research, public engagement is a priority for us. We plan on creating and managing a project webpage will provide real time insight into project progress and intermediate conclusions and results. All research papers and presentations will be available from this site. Similarly, we will conduct a continuous horizon scanning activity as part of this project. Our website will be continuously updated with a view to providing an understanding of where our research fits in the broader UK and international research arena. This work will be carried out via the development and integration of detailed mathematical models of each link in the CCS chain. We have engaged with a leading UK-based software development company with whom we will work to make these models available to the academic and broader stakeholder community. Further, a version of the modelling tools suitable for use by the general public will also be prepared. It is expected that this tool will be analogous in form and functionality to the DECC 2050 Calculator.

Project SAVE-CAES is all about developing large-scale long-duration energy storage that will enable the UK to be powered largely (and possibly completely) from renewables. That energy storage must be affordable, sustainable and large-scale. Compressed air energy storage (CAES) has the potential to meet all these critically-important criteria. Developing such storage is probably the biggest single challenge standing in the way of "Net-Zero" for the UK by 2050. Offshore wind around the UK is a remarkable resource for a future zero-carbon UK electricity system. If we were to exploit all of the area that could feasibly be imagined, UK offshore wind could produce about 2000TWh of electrical energy every year - more than 5 times greater than the amount of electricity we presently consume in one year. Electricity usage will increase, of course, between now and 2050 - possibly increasing from ~350TWh each year to ~1000TWh annually. However, it is perfectly feasible that we can generate all of this electricity from wind. Solar power will also play a key role in powering the Net Zero UK but there are straightforward reasons why this will provide only about 20% of our power in the future. The strongest of those has to do with seasonality: solar on an average day in mid Summer is 9 times higher than on an average day in mid Winter, however our energy demand in Winter is higher than that in Summer. Happily the wind is also seasonal and it typically delivers 2.3 times more energy on an average mid-Winter day than it does on an average mid-Summer day. Nuclear power will also have some role. Opinions differ on how substantial that role will be but that is not very important for the purposes of understanding or justifying this research proposal. The key problem with having a country powered largely from inflexible low-carbon sources is that demand and supply must be matched and demand is relatively "inelastic". This means that proportionately small changes in the cost of electricity have very small influence on how much electricity that is consumed. Quantitative assessments of how much we will be paying for our electrical energy by 2050 suggest that less than half will be made up of the direct cost of generating the actual units of electrical energy. The larger cost will be connected with providing the flexibility - the ability to match up supply and demand. Different researchers predict different proportions, but the consensus is that flexibility costs will be the dominant ones. CAES is one of the most promising sets of options available in the UK for storing very large quantities of (wind or solar) energy over periods of tens of hours - possibly up to 100 hours. CAES has the potential to combine good performance (upwards of 70% round-trip efficiency) with relatively low costs (<£2/kWh). There are two different grid-scale energy storage plant which store compressed air in the world - one at Huntorf in Germany and the other in McIntosh, Alabama - however, these plants also store fossil fuel. Many commentators make the serious mistake of extrapolating from these to estimate what CAES can possibly do. Project SAVE-CAES sets out to apply fundamental engineering science to determine what a well-designed CAES plant without fossil fuel addition could possibly do. SAVE-CAES is a project filled with novelty. Pressurised air will be stored in salt caverns that are either offshore or at the coast. The project will explore the use of isobaric storage of the pressurised air and the management of concentrated brine (salt-water) for pressure regulation. It will also explore ultra-high-pressure air storage (for best value per cubic metre of cavern). It will also explore the potential for exploiting relatively mild geo-thermal heat during the re-expansion of the air and the possibility that some wind turbines might be deployed directly as last-stage compressors for charging the energy stores.

The geopolitical and geo-economic shifts we are experiencing have stress-tested the national security and resilience of the United Kingdom. The consequences of EU Exit, COVID-19, Russia's invasion of Ukraine and other events of national importance, have coalesced around three global challenges that will shape the future direction of our economy and society; energy security, climate change and cyber security. Our world is characterised by high degrees of volatility, uncertainty, complexity and ambiguity (VUCA); this context means that emergencies will be much greater in frequency and are likely to have far reaching consequences for our national economy. It is therefore essential for the UK to ensure adopt a sophisticated and nuanced approach to our understanding and communication of risk. If we are to enhance resilience and security through improved risk management, it follows that the doctrine of 'prevention rather than cure' should guide policy wherever possible. However, the intractable problem of recognising and quantifying the value of good risk management is omnipresent. We believe that risk management is the antecedent to a robust resilience system; it is the glue which connects central government, the devolved administrations, local authorities, and the private and third sectors. Risk intelligence is crucial to effective decision-making, this is particularly important in the context of emergency and crisis situations that require government to adopt a radically different 'operating rhythm' and where decisions and actions occur at pace. In response, the 'Government Risk Profession' was launched in 2021 to advance professionalism, effectiveness and efficiency in the way risk is managed. It is clear that a socio-technical systems approach that recognises resilience as an interacting set of sub-systems at both social and technical levels is crucial to adopting a human-centred approach that aligns will the Integrated Reviews' recognition of the 'professionalism and commitment of the people who contribute to our resilience' Our proposal for a new coordination hub (SALIENT) to support the UK's contribution to building a secure and resilient world will focus the UK's research effort on national resilience through the lens of human centred systems-thinking. Our five-year programme of research will deliver a portfolio of evidence and insight to support central and local governmental actions and ultimately strengthen the UK's resilience to civil contingencies and threats. Our human-centred approach, informed by a distinctly anthropological perspective, will enable SALIENT to identify and articulate the systemic changes that are needed to strengthen resilience. We know that resilience requires a 'whole of society' mindset; this means organising our social order and government in ways that enhances transparency, leadership and promotes greater accountability. The mere notion of a resilience-focused outlook requires consideration of how we use 'futures' to engage citizens in ways that empower their communities. It follows that the research to underpin this effort must be of the highest quality in terms of originality, methodological richness and impact. SALIENT will provide the means to coordinate research actions across a broad spectrum of disciplines and sectors and deliver evidence that will shape the UK's response to the increasingly complex threat landscape.

Energy models provide essential quantitative insights into the 21st Century challenges of decarbonisation, energy security and cost-effectiveness. Models provide the integrating language that assists energy policy makers to make improved decisions under conditions of pervasive uncertainty. Whole systems energy modelling also has a central role in helping industrial and wider stakeholders assess future energy technologies and infrastructures, and the potential role of societal and behavioural change. Despite this fundamental underpinning role, the UK has not had a national strategic energy modelling activity. Models have been developed on a fragmented, reactive and ad-hoc basis, with a critical shortfall in the continuity of funding to develop new models, retain human capacity, and link modelling frameworks in innovative ways to answer new research questions. The whole systems energy modelling (wholeSEM www.wholesem.ac.uk) consortium is explicitly designed to enable the UK to make an internationally leading research impact in this critical area, and hence to provide cutting-edge transparent quantitative analysis to underpin public and private energy systems decision making. Following a rigorous selection process, the wholeSEM consortium encapsulates leading and interdisciplinary UK capacity in quantitative whole systems energy research. The key aims of the interdisciplinary wholeSEM consortium are: 1. Undertake internationally cutting edge research on prioritised energy system topics; 2. Integrate whole energy systems modelling approaches across disciplinary boundaries; 3. Build bilateral engagement mechanisms with the wider UK energy systems community in academia, government and industry. The wholeSEM consortium will prioritise on key modelling areas of high relevance to interdisciplinary energy systems. Internationally leading research will focus on: 1. How does energy demand co-evolve with changes in practice, supply, and policy? 2. How will the endogenous, uncertain, and path dependent process of technological change impact future energy systems? 3. How can the energy supply-demand system be optimised over multiple energy vectors and infrastructures? 4. What are the major future physical and economic interactions and stresses between the energy system and the broader environment? The consortium, will employ extensive integration mechanisms to link and apply interdisciplinary models to key energy policy problems. This will take place across the conceptualisation and development of innovative modelling approaches, model construction, and through an integrated set of use-cases. A key element of the wholeSEM is substantive bilateral engagement with stakeholders in academia, government and industry. Multi-layered integration mechanisms will include: - A high-profile advisory board, with key policy/industry representation plus wider academic experts; - An innovative fellowship programme to enable bi-directional UK academic, policy and industrial and international experts to work with wholeSEM research teams; - A range of workshops including four internationally high profile annual UK energy modelling conferences, technical workshops focused on key modelling issues, and non-technical stakeholder workshops on model conceptualisation, development and use-cases; - Detailed and transparent documentation for all of the consortium's new energy models; - Model access, based on collaborative agreements with an expert model user group. This will ensure best-use of models, accountability and two-way flows of information from/to model developers, users and critics; - Collation and curation of energy modelling data sources (building off and working with the UKERC Energy Data Centre); - Provision of training in modelling techniques and software platforms, to train and develop the next generation of energy systems modellers, including interactions with centres for doctoral training (CDTs); - Interactive web-based information dissemination