Decarbonisation of the UK's energy system will require substantial action at a regional and local level. Therefore, the UK's energy system is growing rapidly to a more decentralised model by 2050 with a great level of small-scale electricity and heat generation at the distribution level, where wind and solar renewable energies will play a large role. However, the intermittent nature of these renewable sources presents a great challenge in energy generation and load balance maintenance to ensure stability and reliability of the power network. This highlights the need for electricity storage technologies as they provide flexibility to store excess electricity for times when it is in demand. The majority of recent installations deploy fast response electricity storage systems (e.g. batteries) with short-duration electricity storage (minutes-days) and short-discharge duration of up to 4 hours. However, technologies with long-duration electricity storage (days-weeks) and medium-duration discharge of over 4 hours, with negligible capacity and efficiency degradation are required to ensure power supply security in all weather conditions (e.g. wind or solar energies are not available for several days). There are several possible technologies for long-duration energy storage, e.g., pumped-hydro storage, liquid air energy storage and compressed air energy storage (CAES). Among them, adiabatic CAES systems (ACAES) has the lowest installed energy capital costs (2-50$/kWh) for a wide range of storage applications from micro scale (few kW) to large scale (few MW). In conventional ACAES systems, the electricity is used to compress air in compressors, generating high levels of heat during the process. The heat of the compressed air is removed at the outlets of the compressors and stored in a thermal energy storage (TES) unit, while the cool compressed air is stored in a cavern at depths of hundreds of metres. To discharge the energy on demand, the cool compressed air heats up in the TES before expansion in turbines to generate electricity. Despite its promising features for decarbonising the electricity power system, there are major challenges which hinder further development of ACAES systems, including (1) limitations on the underground geology, (2) low roundtrip efficiency and (3) thermal and structural challenges on the TES unit because of high-temperature air at the outlets of the compressors. This proposal aims to address these major challenges through development of an affordable micro-scale co-generation near-isothermal and adiabatic CAES system with overground air storage vessels (micro-Ni-ACAES). The system utilizes near-isothermal and high-efficiency compressor/expander devices, TES and heat exchanger units based on an innovative composite phase change material and air storage vessels. The project will perform a fundamental experimental and modelling analyses to gain deep insight into the flow and thermal fields in the near-isothermal compressors/expanders as well as charging and discharging kinetics of the TES unit. Both isochoric and isobaric storage processes will be analysed. These fundamental studies will lead to efficient designs of the micro-Ni-ACAES system components and further support the development of a thermodynamics-based design tool. The design tool will be used to identify the system's optimum operating condition and control strategy for steady-state and dynamic operations of the system. Additionally, the project will include a techno-economic and environmental impact assessment in order to evaluate the economic viability of the system, as well as CO2 abatement and fossil fuel savings over the system's lifetime. The proposed high efficiency co-generation micro-Ni-ACAES systems are believed to be the future of the CAES technology, eventually culminating in decentralised microgrid power network in application to district energy network or commercial sectors (e.g. business parks).

The U.K. population is projected to reach 80 million by 2050 and it is anticipated that the overwhelming majority will continue to live in cities. Besides becoming more densely populated, future cities will be surrounded with expanding urban areas. Interactions within cities; across urban areas and with surrounding cities, towns and 'rural' areas with the rest of the UK will place new and different demands on infrastructure, whether housing, energy, transport, freight distribution and disposal of waste. Decisions that are made now will have profound implications for the resultant pressures on transport, living space, energy use, and ecosystem services (the benefits humans receive from ecosystems). These decisions will play out at two fundamentally different spatial scales. First, and by far the better understood, are those decisions that concern individual households and their neighbourhoods. These include issues of how their members move around, what kinds of housing they occupy, how their energy demands and waste production are reduced, and how their negative influences on the wider environment generally will be limited. Second, broad scale strategic decisions regarding regional planning will determine where in the U.K. population growth is primarily accommodated. This will determine, and be shaped by, the kinds of transport and energy infrastructure required, and the environmental impacts. Obviously these two sets of decisions are not independent. The demands for and impacts of broad scale development (whether this be the creation of new urban areas or the intensification of existing ones) - and thus how this is best achieved to deliver sustainability- will be influenced not by the typical demands and impacts exhibited now by households, but by the way in which these have been changed in response to the modification to the associated infrastructure. This makes for a challenging problem in predicting and evaluating the possible consequences of different potential scenarios of regional development. The proposed study SElf Conserving URban Environments (SECURE) will address this grand challenge of integration across scales (the global aim) by developing a range of future regional urbanization scenarios, and exploring their consequences for selected high profile issues of resource demand and provision (transport, dwellings, energy, and ecosystem services) alongside sustainable waste utilisations. In doing so, it will build on findings of research outputs of several previous SUE projects and harness its relationship in the context of policy and economic growth. The study includes specific research objectives under five broad cross-cutting themes - Urbanisation, Ecosystems Services, Building and Energy, Stakeholder Engagement and Policy Integration across themes. SECURE is designed to assemble novel deliverables to bring about step change in current knowledge and practice. The North East Region will be used as a test bed and evaluation of transitional scenarios leading up to 2050 will quantify the benefits of integration across the scales through conservation across the themes. SECURE will deliver policy formulation and planning decisions for 2030 and 2050 with a focus on creating Sustainable Urban Environment.The contributors to this project are researchers of international standings who have collaborated extensively on several EPSRC funded projects, including the SUE research since its inception. The SECURE team builds on their current collaboration on the SUE2 4M project. The Project consortium is led by Newcastle - Prof Margaret Bell as PI and Dr Anil Namdeo as co-ordinator alongside Dr Jenny Brake with academic partners: Prof David Graham (Environmental Engineering), Prof David Manning (Geosciences); from Loughborough: Prof Kevin Lomas, Prof Jonathan Wright and Dr Steven Firth (Civil and Building Engineering); from Sheffield: Prof Kevin Gaston and Dr Jonathan Leake (Animal and Plant Sciences).