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.

This project will assess a class of systems that blend electricity generation and storage, to understand the role that they could play in future energy systems. Their ability to deliver low-carbon energy on demand, at low system cost, will be investigated from technical, economic, and policy standpoints. With a growing fraction of electricity consumption being supplied by variable renewable energy sources, the ability to match energy generation and energy consumption is rapidly taking centre stage. Flexible ('dispatchable') coal and gas plants are being displaced to lower carbon emissions. At present, both nuclear and renewable energy technologies are generally configured to generate as much electricity as possible, regardless of the electricity demand at the time. Standalone energy storage, in which surplus electricity is converted to an intermediate energy form and then back again, is emerging as a vital partner to these generation technologies but it is prohibitively expensive for the duties that will be required in the near future. Active management of electricity demand (by shutting down or deferring loads) and electrical interconnections with neighbouring countries will also play important roles but these also have costs and they will not obviate the need for storage. This project will build a deep understanding of a class of system which takes a different and potentially much lower cost approach. These Generation Integrated Energy Storage (GIES) systems, store energy in a convenient form before converting it to electricity on demand. The hypothesis is that the lowest cost and highest performance storage can be achieved by integrating generation and storage within one system. This avoids the expense and inefficiency of transforming primary energy (e.g. wind, solar, nuclear) into electricity, then into an intermediate form, and later back to electricity. For example, the heat produced by a concentrating solar power plant can be stored at far lower cost and with lower losses than producing electricity directly and operating a standalone electricity store. A broad range of opportunities exist for low-carbon GIES systems, in both renewable and nuclear applications. The research team's expertise in wind, nuclear, and liquefied air storage will be applied directly to GIES systems in all three. The project will also establish a framework for the wider significance of GIES to energy systems. Technical and thermodynamic metrics that characterise high performing GIES systems will be developed, and used to compare with standalone generation and storage equivalents. The theoretical groundwork laid by this research will have applications far beyond the current project. Opportunities for current and future technologies will be mapped out and publicised, supporting and accelerating further work in the field. The deployment and operation of such technologies will be modelled by means of a pragmatic real options economic analysis. The unique policy and economic considerations of fusing generation and storage will be reviewed in detail, considering challenges and proposing solutions to regulatory and financial hurdles. Taken in concert, these will determine the value and scope for substantial deployment of GIES systems. In bringing to light the potential of the class of GIES systems, the research team will rectify a gap in energy systems thinking, in time to inform what will be a multi-billion pound expenditure in the coming decade. By providing the tools to analyse and deploy these systems, the research will open up a new avenue for cost-effective flexibility across the energy infrastructure of the UK and other regions worldwide.

The future sustainable production of bulk and fine chemicals is an ever-increasing global challenge that requires a transformative scientific approach. We must develop new ways of efficiently exploiting valuable fossil-fuel resources and tools to exploit renewable resources such as CO2 and lignin. Catalytic methods, the heart of this CDT, are key to these transformations, offering the single most powerful and broadly applied technology for the reduction of energy demand, cost, environmental impact and toxicity. This CDT will drive forward a sustainable and resource-rich culture. This CDT in Critical Resource Catalysis (CRITICAT) combines the catalysis research collective of St. Andrews, Edinburgh, and Heriot-Watt Universities to create a new and unique opportunity in PhD training and research. CRITICAT will allow 80+ bright minds to be challenged in a comprehensive and state-of-the-art PhD training regime in the broad remit of catalytic science, transforming them into future scientific researchers, business leaders, entrepreneurs, and policy makers. These will be people who make a difference in a technologically-led society. Our critical mass in critical resource catalysis will accelerate training, discovery, understanding, and exploitation within catalytic chemistry. We will focus our efforts on the future of catalysis, driving new advances for environmentally sustainable economic growth and underpinning current growth in the UK chemicals sector. The economic impact in this area is huge: in 2010, an EPSRC/RSC jointly commissioned independent report showed that the UK's "upstream" chemicals industry and "downstream" chemistry-using sector contributed a combined total of £258 billion in added value to the economy in 2007, equivalent to 21% of UK GDP, and supported over 6 million UK jobs. Sustained investment in PhD training within this area will provide the highest quality employees for this sector. The CRITICAT PhD students will be exposed to a unique training and research environment. Extensive taught courses (delivered by CRITICAT PIs and industrial collaborators) will offer fundamental insight into homogeneous, heterogeneous, industrial and biocatalysis coupled with engineering concepts and essential techniques to showcase cutting-edge catalysis. The CRITICAT partners will develop these core courses into a foundational textbook for graduate training across catalysis using critical resources as its cornerstone that will serve as a legacy for this programme. We will expand our pedagogical innovation to all PhD graduate students at our three partner universities, providing region-wide enhanced academic provision. Continuous growth and peer-to-peer learning throughout their research efforts will create graduates who are keen to continue learning. They will be equipped with business, management, entrepreneurial and communication skills synergistic with core science knowledge and research undertakings. In this way, we will ensure that our CRITICAT students will be able to innovate, think critically, and adapt to change in any technological career. We will prepare the next generation of scientists, managers and innovators for key roles in our future society. To support this broad developmental approach, industry and business leaders will contribute widely to CRITICAT. Industries will (i) provide scientific ideas and objectives, (ii) deliver new competencies through targeted courses ranging from entrepreneurship to intellectual property rights and (iii) provide laboratory placements to consolidate learning and exploit any scientific advances. Furthermore, our extensive collaboration with leading international academic institutions will engender PhD student mobility, expand impact and allow experiential learning. We will build on our existing public engagement frameworks to enable our students to deliver their research, impact and scientific understanding to a wide audience, exciting others and driving new scientific policy.

The ability to detect very low light level in the infrared (IR) wavelengths, down to a single photon has numerous applications ranging from enabling highly secured communication that relies on detection of a single photon, measurement of very weak fluorescence in biomolecule identification to high resolution 3 dimensional imaging based on laser ranging. Conventional semiconductor photodiodes do not have the sensitivity required for these photon-starved applications. Therefore it is necessary to use photodiodes designed with internal amplification or gain, called avalanche photodiodes (APDs), to convert the signal from a few photons to a large current that can be detected by an external electronics. In most semiconductors this amplification process also introduces excess noise. However Silicon APDs were able to produce high gain with low excess noise and therefore have been used in many applications to provide detection down to a single photon in the visible wavelengths. This is because, in Silicon the gain is provided predominantly by the electron multiplication process which reduces the excess noise. Unfortunately no commercial IR APD with performance similar to, or better than, Silicon is available despite various proposals to achieve Silicon-like APDs over the last 20 years. This exciting proposal will address this void by developing a new class of APDs based on InAs, a semiconductor with unique band structure features, to achieve high gain with negligible excess noise that is lower than that of Silicon. This proposal aims to provide IR APDs with extremely high performance, capable of detecting a single photon in the wavelength range of 1100 nm to 3000 nm. For instance they can provide low cost high performance large format imaging arrays for IR applications such as LIDAR, a technique that can provide excellent images and range measurements, non-invasive blood glucose sensing, atmospheric CO2 concentration monitoring as well as eye-safe free space optical communication. We therefore expect our APDs to generate new applications and provide highly competitive IR APDs. Based on the understanding of the InAs bandstructure, our APDs will be designed such that only electron will undergo impact ionisation to produce high avalanche gain with negligible excess noise. In addition to excellent gain, our devices can be operated at low voltage, making them compatible with off-the-shelf readout circuits. This could pave the way to a highly sensitive and affordable IR camera. To enhance the exploitation and the gain characteristics we will grow a novel InAsSb APDs on GaAs substrate which is significantly larger and cheaper than InAs substrate. This, if successful, will enable integration with commercial GaAs electronics. To propel our InAs APDs towards exploitation in the applications mentioned above we will;I) Optimise the crystal growth method to achieve high quality InAs materials with low level of impurities.II) Develop fabrication and surface passivation techniques to yield devices with low leakage current, leading to higher sensitivity.III) Pioneer techniques to implant ion species and to perform dopant diffusion to control the electric field in the InAs devices leading to high reliability.IV) Control growth conditions such as temperature and atomic pressure to achieve low crystal defect formation during the growth of InAsSb APDs on GaAs.This exciting project will be carried out by a highly skilled research team, comprising UK universities (Sheffield, Heriot-Watt and Surrey), American university (Virginia) and UK companies (Selex-Galileo and Thales Optronics) with years of experience in research and development of sensing applications. Thus, one of the outputs of the project is to provide a leading IR sensor technology to the research communities to facilitate new research and to the industry to maintain a lead in the IR sensor market.

North temperate regions hold much of the planet's freshwater, an essential ingredient for all life. But anthropogenic activities, such as land-use change, are dramatically altering these landscapes and threatening the delivery of key services provided by aquatic ecosystems, such as productive fish populations. Contemporary paradigms of aquatic conservation have emphasized inputs of pollutants and water resource development as causes of declining water security and biodiversity, but are failing when these two factors alone are improved. Increasingly, local watersheds are seen as critical controls of aquatic ecosystems. This is spurred by the recent discovery that pathways of energy mobilization upwards through aquatic food webs from microbes to fish rely on organic matter originating from terrestrial vegetation. In other words, new research is proving the adage that fish are in fact a "forest product". Any factor that changes the quality and quantity of organic matter exported from land into water will influence the delivery of aquatic ecosystem services. For example, human land use practices and emerging disturbances, such as fire and forest pathogens, will change the cycling of nutrients from terrestrial vegetation into aquatic ecosystems. But which of these factors are most important and consistently operating across different geographic regions is unknown. Identifying these drivers is critical for developing new watershed-level approaches for conserving freshwater that link actions on land to processes in water. Our research will test how different watershed characteristics control the use of terrestrial resources in aquatic food webs across lake-rich regions of the world. We will use our findings to forecast future changes in lake food webs associated with global change and recommend better practices for conserving freshwater resources. Our approach will be to bring together the leading international researchers studying terrestrial-aquatic linkages and synthesize available food web measurements from over 175 lakes. Using bioclimatic, vegetation, biogeochemistry, and land-use data extracted for each study lake, alongside cutting-edge statistical modelling techniques, we will predict the terrestrial drivers of lake food webs and link them to biomass accumulation by aquatic organisms. Outcomes of this research will be highly relevant to the UK and international policy around managing freshwater supplies by demonstrating strong linkages between terrestrial and aquatic ecosystems. A particular focus of our research is improving the Water Framework Directive (WFD), a piece of pan-European legislation designed to protect freshwater. We hope to use our research to impact policy associated with the WFD by engaging with the European Commission in a knowledge exchange symposium that we are organizing at the conclusion of our project. This project will also have many applications for improving regional land use planning and management, as well as restoring environmentally damaged landscapes. We are working closely with partners in the mining industry and government in associated NERC-funded projects and will use the results of this project to better inform these partners of the best practices for re-vegetating degraded watersheds.