• Energy Research
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• 2019 close

Low-cost atmospheric deposition of semiconductor absorbance layers for application in photovoltaic solar cells that do not require expensive instrumentation continue to attract interest of researchers and engineers alike. This project is based on our recent discovery of combinations of solvents capable of dissolving various inorganic salts, which were successfully applied in the fabrication of CIGS PV devices. However, the nature of solutes remains unclear. Therefore this project is dedicated to fill this gap and to carry out investigation of the solutions of metal chalcogenides relevant to the formation of semiconductor thin films. Apart from chalcogenides, pure metals and metal oxides will be also investigated. We aim to establish exact chemical composition of the dominating species of metal complexes in the solutions that will enable better understanding of the underlying chemical processes and will facilitate development of conditions for thermal decomposition of the complexes to form semiconductor films with given stoichiometry and composition. The main focus will be on, but not limited to, the complexes of Cu, Zn and Sn comprising the CZTS thin films. The results will be used in fabrication of efficient solution processed solar cells.

Screw (or helical) piles are foundations which are screwed into the ground. They are widely used onshore for supporting motorway signs and gantries as they possess good tensile and compressive resistance. This project aims to make screw piles a more attractive foundation (or anchoring) option offshore for wind farms, which are being deployed in deeper water and subject to increasing performance demands. The UK has challenging targets for expansion of energy from renewables with the potential for over 5000 offshore wind turbines by 2020. The necessary move to deeper water will increase cost and put greater demands on subsea structures and foundations. The current foundation solutions being considered for these applications are driven piles, large monopiles or concrete gravity based structures (GBS). Driving of piles in large numbers offshore causes concerns over plant availability and impact on marine mammals. There are also concerns over the limit of practical monopile development and the high material demands of GBS. Screw piles have the potential to overcome these issues and are scalable for future development from current onshore systems which have relatively low noise installation and are efficient in terms of both tensile and compressive capacity. To meet offshore demands, screw piles will require geometry enhancement but it is envisaged that these will initially be modest to allow de-risked transfer of onshore technology offshore. This will lead to the deployment of several smaller piles or pile groups rather than moving straight to very large single screw piles that may prove difficult to install and require significant investment. To allow screw piles to be considered as a foundation solution for offshore wind this project will develop piles with optimised geometries that minimise resistance to installation but are capable of carrying high lateral and moment loads. In order to install screw piles torque devices are used to effectively screw the anchors into the ground. With increased pile size requirements and potential changes in geometry this project will develop improved, less empirical techniques to predict the torque required in a variety of soil conditions. This will allow confidence in pile installation and investment in appropriately sized installation plant. As new pile geometries are being developed these will need to be tested (through model, numerical and field testing in this project) to verify that they can meet the performance demands of the offshore environment. The project will also develop bespoke analysis techniques to allow consulting geotechnical engineers the tools they require to design the foundations and contractors the tools to inform the installation processes. As piles can be deployed as large single units or smaller units in groups the efficiency of group deployment and multiple foundation geometries will be explored, as using several smaller geometry foundations could reduce the risks during offshore installation and actually be more economic due to lower fabrication costs and demands on installation plant. The areas of investigation above will be combined to produce a design and decision making toolkit for use by geotechnical designers to allow deployment of screw piles as offshore foundations in an efficient and cost effective manner. The research has the potential to make it easier to deploy screw pile foundations for offshore renewables. This project will develop foundations able to deal with current water depths and will provide understanding of the behaviour of piles as water depths and the demands on the foundations increase. By harnessing the installation and performance benefits of screw pile/anchor technology, the results of the project will contribute to an overall cost reduction in electricity generated by renewable means and increase the public's confidence in the future viability of this energy source.

One problem when we are trying to field super-big wind turbines is that all components involved become super heavy as well, particularly power generators. Heavier power generators require more robust foundation towers for support, which dramatically increase the cost of the entire system. The project is to investigate approaches of lightening up the next generation of utility scale turbines to generate 10 MW peak power. The major aim of this project is to develop a new compact superconductor-based generator able to work in both onshore and offshore wind turbines. Based on previous research work, it was proven that the weight when compared to conventional power generators could be reduced by at least 30% by applying superconductors. However, further work is required to analyse and improve the existing design; such as in regards to the superconducting windings and the cryogenic cooling system. The final objective is to build a 15kW prototype to prove the feasibility of the new lightweight power generator.

Tackling climate change, providing energy security and delivering sustainable energy solutions are major challenges faced by civil society. The social, environmental and economic cost of these challenges means that it is vital that there is a research focus on improving the conversion and use of thermal energy. A great deal of research and development is continuing to take place to reduce energy consumption and deliver cost-effective solutions aimed at helping the UK achieve its target of reducing greenhouse gas emissions by 80 per cent by 2050. Improved thermal energy performance impacts on industry through reduced energy costs, reduced emissions, and enhanced energy security. Improving efficiency and reducing emissions is necessary to increase productivity, support growth in the economy and maintain a globally competitive manufacturing sector. In the UK, residential and commercial buildings are responsible for approximately 40% of the UK's total non-transport energy use, with space heating and hot water accounting for almost 80% of residential and 60% of commercial energy use. Thermal energy demand has continued to increase over the past 40 years, even though home thermal energy efficiency has been improving. Improved thermal energy conversion and utilisation results in reduced emissions, reduced costs for industrial and domestic consumers and supports a more stable energy security position. In the UK, thermal energy (heating and cooling) is the largest use of energy in our society and cooling demand set to increase as a result of climate change. The need to address the thermal energy challenge at a multi-disciplinary level is essential and consequently this newly established network will support the technical, social, economic and environmental challenges, and the potential solutions. It is crucial to take account of the current and future economic, social, environmental and legislative barriers and incentives associated with thermal energy. The Thermal Energy Challenge Network will support synergistic approaches which offer opportunities for improved sustainable use of thermal energy which has previously been largely neglected. This approach can result in substantial energy demand reductions but collaboration and networking is essential if this is to be achieved. A combination of technological solutions working in a multi-disciplinary manner with engineers, physical scientists, and social scientists is essential and this will be encouraged and supported by the Thermal Energy Challenge Network.

In recent years, the cost of energy produced by renewable supplies has steadily decreased. This factor, together with socio-economical reasons, has made renewable energies increasingly competitive, as confirmed by industry growth figures. Considering wind turbines (WTs), there are some interesting technical challenges associated with the drive to build larger, more durable rotors that produce more energy, in a cheaper, more cost efficient way. The rationale for moving towards larger rotors is that, with current designs, the power generated by WTs is theoretically proportional to the square of the blade length. Furthermore, taller WTs operate at higher altitudes and, on average, at greater wind speeds. Hence, in general, a single rotor can produce more energy than two rotors with half the area. However, larger blades are heavier, more expensive and increasingly prone to greater aerodynamic and inertial forces. In fact, it has been shown that they exhibit a cubic relationship between length and mass, meaning that material costs, inertial and self-weight effects grow faster than the energy output as the blade size increases. In addition, larger blades also have knock-on implications for the design of nacelle components. The wind-field through which the rotor sweeps varies both in time and space. Consequently, the force and torque distributions for the blades exhibit strong peaks at frequencies which are integer multiples of the rotor speed. Additional peaks are induced by lightly damped structural modes. The loads on the blades combine to produce unbalanced loads on the rotor which are transmitted to the hub, main bearing and other drive-train components. These unbalanced loads are a major contribution to the lifetime equivalent fatigue loads for some components which could cause premature structural failure. As the size of the blades increase, the unbalanced loads increase and the frequency of the spectral peaks decrease. Hence, they have an increasing impact as the size of the turbines become bigger. In this scenario, the demand for improvements in blade design is evident. The notion of increasingly mass efficient turbines, which are also able to harvest more energy, is immediately attractive. The viability of a novel adaptive blade concept for use with horizontal axis WTs is studied in this project. By suitably tailoring the elastic response of a blade to the aerodynamic pressure it could be possible to improve a turbine's annual energy production, whilst simultaneously alleviating structural loads. These improvements are obtained in a passive adaptive manner, by exploiting the capabilities that structural anisotropy and geometrically induced couplings provide. In particular, induced elastic twist could be used to vary the angle of attack of the blade sections according to power requirements, i.e. the elastic twist is tailored to change with wind speed proportionally to the bending load. The adaptive behaviour allows the blade geometry to follow the theoretically optimum shape for power generation closely (which varies as a function of the far field wind speed). This concept retains the load alleviation capability of previously proposed designs, whilst simultaneously enhancing energy production. Structurally, the adaptive behaviour is achieved by merging the bend-twist coupling capabilities of off-axis composite plies and of a swept blade planform. Potentially, an adaptive blade, controlled only by generator torque, could perform to power standards comparable to that of the current state-of-the-art-while greatly reducing complexity, cost and maintenance of wind turbines, by challenging the need for active pitch control systems.