• Energy Research
• 2016 close

The future energy system is challenged by the intermittent nature of renewables and requires therefore several flexibility options. Still, the interaction between different options, the optimal portfolio and the impact on environment and society are unknown. It is thus the core objective of REFLEX to analyse and evaluate the development towards a low-carbon energy system with focus on flexibility options in the EU to support the implementation of the SET-Plan. The analysis are based on a modelling environment that considers the full extent to which current and future energy technologies and policies interfere and how they affect the environment and society while considering technological learning of low-carbon and flexibility technologies. For this purpose, REFLEX brings together the comprehensive expertise and competences of known European experts from six different countries. Each partner focusses on one of the research fields techno-economic learning, fundamental energy system modelling or environmental and social life cycle assessment. To link and apply these three research fields in a compatible way, an innovative and comprehensive energy models system (EMS) is developed, which couples the models and tools from all REFLEX-Partners. It is based on a common database and scenario framework. The results from the EMS will help to understand the complex links, interactions and interdependencies between different actors, available technologies and impact of the different interventions on all levels from the individual to the whole energy system. In this way, the knowledge base for decision-making concerning feasibility, effectiveness, costs and impacts of different policy measures will be strengthened, which will assist policy makers and support the implementation of the SET-Plan. Stakeholders will be actively involved during the entire project from definition of scenarios to dissemination and exploitation of results via workshops, publications and a project website.

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.

Energy provision is a big challenge for our Society, being the present production/consumption paradigm not sustainable. To change current trends, a large increase in the share of Renewable Energy Sources (RESs) is crucial. The effectiveness of Thermal Energy Storage (TES) poses Concentrated Solar Power (CSP) systems at the forefront, as the first dispatchable option among all intermittent RESs. In order to realize the CSP potential, the efficiency of the adopted Power Conversion Units (PCUs) must grow over 50%, entailing temperature levels of the order of 1000 °C: promising solutions are based on Brayton thermodynamic cycles. This project stems from the observation that no existing TES option can be coupled to such PCUs and/or work at these temperatures, and aims at filling this gap. Three interrelated research objectives are proposed, to prove the feasibility and assess the potential of 1. an innovative CSP concept whereby (i) the receiver is co-located with the TES vessel, (ii) the solar radiation is directly absorbed by the liquid storage medium, and (iii) the thermal power is withdrawn from the TES by bubbling a gas through it, which can thus be used as working fluid in a Brayton cycle. An efficient and simple system results, without irradiated metal tubes, secondary fluid loops, heat exchangers, valves, nor pumps; 2. the adoption of common glass-forming compounds as novel TES materials. These are nontoxic and inexpensive (mainly sand), and the related know-how is already available from the glass manufacturing field, whose deep synergies with the CSP sector will be explored in a multi-disciplinary perspective; 3. the CSP systems resulting from the integration between receiver–TES and PCUs. The envisaged approach combines advanced theoretical and experimental research activities to achieve these goals. The final scope is to inaugurate a new branch in the field of solar systems, with the potential of enabling the CSP plants we need to ensure a bright Future.

As railways are increasingly electrified, service levels depend on an increase in life and reliability of overhead electric power supplies beyond the performance of current materials and technology. Overhead power lines are highly stressed structures without redundancy. Their failure in service is caused by a combination of wear, fatigue cracking, and corrosion, and can be strongly influenced by geometry (e.g. gradient at approach to tunnels). Current collection quality is determined by material behaviour under combined cable tension, the frequency of cable supports, dynamic load from current collection pantographs, and environmental loading (e.g. side winds). Completion of the project will lend itself to the ongoing commitment by Network Rail to improve the reliability and lowering of the cost in maintaining the existing overhead line equipment. Integration of the research with Network Rail's aims provides a route through which results can be implemented. Aims and objectives: To establish how novel line materials, components and geometries may offer improved dynamics at reduced cost relative to current systems. This will be achieved through developing an existing finite element model to incorporate the existence of limited clearance cases such as overbridges and level crossings. The research will identify areas of high force on the overhead line equipment through the use of the developed model, enabling investigation of how forces can be reduced or managed, and be used to predict areas that would be prone to failure in the future over an range of conditions. Novelty of the research methodology: The research will consider materials, components and installation geometries which have not yet been applied in overhead line installations. Research will focus on developing current model of overhead lines to incorporate gradients to predict dynamic loads in areas of the rail network such as over/underbridges and level crossings. Fluid models will also be developed to work with the overhead line model to determine the loads and effects of side winds (e.g. the effect known as galloping wires). Alignment to EPSRC's strategies and research areas: The research is aligned with the sustainability agenda in producing longer life infrastructure. Environmental change is considered through the effect of increased wind forces on structures. Materials engineering (metals and alloys) is a key factor in selecting novel materials for use in this industrial application. Moreover, the research is aligned well with EPSRC's areas of engineering design, in the sense that we will seek to optimise the design of future overhead lines. With side winds included in the model, this will also align with EPSRC's research areas of fluid dynamics and aerodynamics. Any companies or collaborators involved: Network Rail - access to data, field test/measurement sites, and key engineering expertise Furrer+Frey - co-financing the research, access to data, and key engineering expertise

The MPC-: GT project brought together a transdisciplinary team of SMEs, large industry and research institutes, experienced in research and application of design and control systems in the combined building and energy world. Based on prior research, supported by (joint) EU and national projects, and practical experience the bottlenecks where identified that prevent at this moment a real breakthrough of geothermal heat pumps (GEO-HP) combined with thermally activated building systems (TABS) - GEOTABS. Solutions, which need to be implemented in an integrated way, were identified and sufficient proof of concept was gathered to join forces in a RIA. The innovative concepts aim at increasing the share of low valued (low-grade) energy sources by means of using low exergy systems on the one hand and aim at upgrading low/moderate temperature resources on the other hand. The overall solution consists of an optimal integration of GEOTABS and secondary supply and emission systems. To allow for an optimal use of both the GEOTABS and the secondary system, a split will be made between a so-called “base load” that will be provided by the GEOTABS and the remaining energy needs that should be supplied by the secondary system. A generic rule, eliminating case-by-case simulation work, will be developed. The second part of the proposed solution aims at a white box approach for Model Predictive Control (MPC) to generate a controller model with precomputed model inputs such as disturbances and HVAC thermal power to avoid case by case development. Research is needed to assess the overall performance and robustness of such an approach towards uncertainties. As such, the MPC-: GT consortium believes to have identified an integrated solution that will provide a near optimal design strategy for the MPC GEOTABS concept using optimal control integrated design. The solution will support the industry, especially the SME members, to expand their activities and strengthen their competitiveness.

This project will develop a novel wind turbine blade structural health monitoring system based on digital cameras and image processing using an array of optical markers installed inside the blade. An optical system will be designed, and a digital image correlation technique will be used to track the markers which will characterise the dynamics of the blade during operation for both onshore and offshore wind turbines. The output data will be used to characterise the blade structural condition by monitoring changes in properties in real time in all weather and all operational conditions. For the feasibility study the layout of camera, illumination and markers will be optimised for a real blade using the design geometry and structural properties and proven in a state-of-the-art 7MW wind turbine