MEETing the transport materials challenges - reducing cost and energy consumption
Dr Valeska Ting and Chris Bowen from the University of Bath, UK, discuss MEET – a European-funded project aiming to identify and develop materials for energy-efficient transport.
One of the greatest drivers for improving energy efficiency is the increasing cost of fossil fuels and a need to reduce emissions of harmful pollutants and greenhouse gases. According to the International Energy Agency, transporting people and freight accounts for a quarter of the world’s energy demand and more than 60% of all the oil used each year. The optimisation of advanced materials for the manufacture of functional and structural components of road vehicles, aircraft and marinecraft will lead to important improvements in structural weight reduction, reduced energy consumption, lower waste and reduced emissions associated with transportation. New materials can also enable alternative power sources to be employed more efficiently to enable a mobile society beyond the lifetime of fossil fuels.
The provision of energy-efficient transport is a complicated and multi-faceted problem. It requires not only improvements in the fuel efficiency of existing vehicles, but also development of infrastructure and supply chains to allow greater penetration of new alternative energy sources. To address the issues associated with the development of new materials for improved transport efficiency, the EU, through the Interreg IV Programme funded by the European Regional Development Fund (ERDF), has initiated a three-year, research based UK–French network on Materials for Energy Efficient Transport (MEET). The MEET Network, which is funded until June 2015, involves a geographical grouping of universities and research centres interested in a wide range of aspects of efficiency in transport. In view of the multidisciplinary themes of the transport sector, including lightweight materials and structures, smart systems, supply chains and new energy sources, the MEET network includes a diverse range of chemists, engineers, social scientists and scientific communicators. The French project partners are CNRS, ENSICAEN and the University of Caen, Institut de Plasturgie d’Alencon (ISPA) and Universite de Bretagne Sud, while the Universities of Exeter, Bath and Southampton represent the UK.
The project facilitates greater collaboration and the sharing of expertise, with the support of several market research studies led by innovation development companies such as MIRADE and Mov’eo in France, and TWI in the UK, which aim to define the technical and skills requirements in specific transport-related industries. The research themes of the consortium include lightweight composites and bio-derived composites for use as structural materials in aerospace and automotive industries.
Developing new materials
The use of fibre-based composites is an established technology in the development of materials for aircraft, as the combination of high strength and stiffness with a low density can reduce weight. In addition to mechanical properties, researchers are considering imparting functional properties into the composites. For example, consortium members from ISPA are developing composite materials based on glass fibres that not only enhance the strength and reduce the weight of structural components in vehicles, but can also be used to diagnose failure points of materials used under stress. The use of bioderived composites also provides opportunities for sustainable supply and reduced energy consumption in materials manufacture.
On-board storage of the energy generated from intermittent renewable sources is vital for the practical implementation of renewable energies in transportation, be it for road vehicles, aircraft or marinecraft. One method of converting renewable energy into a transport fuel is via the electrolytic generation of hydrogen from water. This hydrogen can then be stored, for example via physical adsorption onto porous materials such as zeolites, high-surface area activated carbons or metal-organic framework (MOF) materials. These materials act as molecular sponges, adsorbing the hydrogen and storing it at high densities. Comprehensive screening of promising new porous materials for hydrogen storage is being carried out using a combination of experimental hydrogen capacity measurements, modelling and simulation. Models for the comparison of the storage capacities of existing materials with conventional methods of storing fuels (for example, in compressed gas tanks) allow the cost and safety of new systems to be compared to existing methods. In addition, atomistic simulations of the interactions of gas molecules including hydrogen and CO2 with porous materials aids in determining the appropriate structural and chemical qualities for high performance gas storage materials. This new information results in steady improvements in the design and evaluation of porous storage materials.
A second option for onboard use of renewable energy is to store it electrochemically, for example using Li-ion batteries, which have recently attracted media interest due to their use in electric vehicles such as the Nissan Leaf. These batteries are already in common use in consumer electronics and thus could be integrated into existing vehicles. However, the need to improve power-to-weight ratios, cyclability, safety and recharging times require the development of new lithium cathode and anode materials. Such materials, including LiFePO4, Li2FeSiO4 and LiVO2 are being designed and tested with the aid of computational modeling and simulation. Energy harvesting materials such as thermoelectrics and piezoelectrics can be incorporated into the structures of vehicles for harvesting temperature gradients or vibrational energy, respectively. These materials have the potential to recycle and regenerate energy that would otherwise be wasted. For example, new materials are being examined for their thermoelectric properties, for harnessing electrical energy from hot regions of vehicles by researchers at CNRS in France and car manufacturers across Europe. For these materials there is a need to maximise the performance at the application temperature and consider the cost implications.
Piezoelectric fibres with high activity approaching bulk materials are now commercially available. These have the potential to be incorporated into structural composites, although appropriate methods of integration into host structures need to be developed. In addition to harvesting mechanical vibrations, these piezoelectric materials can also offer the opportunity for vibration damping. Researchers at the University of Bath and Exeter are investigating the optimisation of vibration damping structures for reduction of the energy loss through extraneous vibrations. Porous materials such as zeolites and metal-organic frameworks are currently used in commercial vehicles in catalytic converters, but they could find additional use as highly selective sensors for monitoring the composition of exhaust gases and thus providing information to the onboard computer for optimisation of fuel consumption. Modification of the atomic structures of these materials can also improve their ability to absorb greenhouse gases such as CO2, removing them from exhaust streams. These materials therefore have opportunities for multifunctional structures in transport applications. OLED/LED materials and devices will also be examined, as they require less energy to operate than traditional incandescent lighting and can be used to lower the weight of instrumentation, personal lighting on aircraft, as well as in motor vehicles.
There are growing demands for improved and multifunctional materials in transport. The MEET network will explore new materials by building partnerships between key players and fostering crossborder research between centres of excellence and encouraging synergies of skills. It also aims to raise interest in materials sciences for energy efficiency in transport and form new collaborations and service supply between laboratories and industries.
The Materials in Energy and Efficiency in Transport project has been selected in the context of the INTERREG IV A France (Channel) – England European crossborder co-operation programme, which is co-financed by the ERDF.