The energy systems in both the UK and China face challenges of unprecedented proportions. In the UK, it is expected that the amount of electricity demand met by renewable generation in 2020 will be increased by an order of magnitude from the present levels. In the context of the targets proposed by the UK Climate Change Committee it is expected that the electricity sector would be almost entirely decarbonised by 2030 with significantly increased levels of electricity production and demand driven by electrification of heat and transport. In China, the government has promised to cut greenhouse gas emission per unit of gross domestic product by 40-45% by 2020 based on the 2005 level. This represents a significant challenge given that over 70% of its electricity is currently generated by coal-fired power plants. Energy storage has the potential to provide a solution towards these challenges. Numerous energy storage technologies exist currently, including electrochemical (batteries, flow batteries and sodium sulphate batteries etc), mechanical (compressed air and pumped hydro etc), thermal (heat and cold), and electrical (supercapacitors). Among these storage technologies, thermal energy storage (TES) provides a unique approach for efficient and effective peak-shaving of electricity and heat demand, efficient use of low grade waste heat and renewable energy, low-cost high efficiency carbon capture, and distributed energy and backup energy systems. Despite the importance and huge potential, little has been done in the UK and China on TES for grid scale applications. This forms the main motivation for the proposed research. This proposed research aims to address, in an integrated manner, key scientific and technological challenges associated with TES for grid scale applications, covering TES materials, TES components, TES devices and integration. The specific objectives are: (i) to develop novel TES materials, components and devices; (ii) to understand relationships between TES material properties and TES component behaviour, and TES component behaviour and TES device performance; (iii) to understand relationship between TES component behaviour and manufacturing process parameters, and (iv) to investigate integration of TES devices with large scale CAES system, decentralized microgrid system, and solar thermal power generation system. We bring together a multidisciplinary team of internationally leading thermal, chemical, electrical and mechanical engineers, and chemical and materials scientists with strong track records and complementary expertise needed for comprehensively addressing the TES challenges. This dynamic team comprises 15 leading academics from 4 universities (Beijing University of Technology, University of Leeds, University of Nottingham and University of Warwick, and 2 Chinese Academy of Sciences Research Institutes (Institute of Engineering Thermophysics and Institute of Process Engineering), and 7 industrial partners.

It is accepted that UK energy networks face a number of unprecedented challenges in the upcoming decades. These challenges include the threat to the security of energy supply due to declining indigenous fossil fuel reserves, increased reliance on imported fossil fuel (78% of coal and 50% of natural gas are imported, it is predicted that gas import will be over 80% in 2020), and planned retirement of ageing generation capacity over the next decade (approximately 20GW or 25% of the existing generation capacity); decarbonising electricity generation to achieve the goal of 80% reduction in CO2 emissions by 2050; and coping with the future increases in electricity demand from electrification of transportation and space heating. To address these great challenges, it is recognized that the UK energy networks, must change, strategically and the existing regulatory arrangements should be examined to check if they are fit for the purpose of future energy network operations. To ensure that power supply closely matches demand, the amount of electricity generated must be well controlled and managed. If the balance between supply and demand is broken and the difference exceeds a critical level, the power system may fail and cause a regional blackout. The UK is especially vulnerable in terms of network stability as it has a relatively isolated small island power network. Currently, 80% of our electricity is generated from fossil fuel (coal or gas) with the load balancing function mainly managed through fossil fuel peaking generation plants that respond to load changes. The mix of electricity generation in the UK will change dramatically with a large reduction in the use of coal and gas and an increase in the clean variable, intermittent renewable energy generators. The inherent energy storage capability that we currently enjoy due to our dependence on fossil fuel power generation will then be greatly reduced by 2030. Solutions are needed to address the network challenges that will occur due to a decrease in the implicit energy storage available with the planned reduction in fossil fuel power generation and the integration of large amounts of unpredictable intermittent renewable sources. Energy storage can provide manifold values in i) help meeting of peaky large scale electrical loads, ii) providing time varying energy charge management, iii) allowing renewable power generation to be stored to alleviate intermittence, iv) improving power quality/reliability, v) meeting remote load needs, vi) storage for management of distributed power generation, etc. This proposed research programme will focus on the challenging technical and economic issues faced by integrating large grid scale energy storage with the energy network.