IDTechEx Energy Harvesting & Storage conference kicked off this morning in Cambridge, UK, attended by approximately 150 people interested in the harvesting and storage technologies currently reaching maturity and the applications that need them.
Dr Peter Harrop introduced the scope for energy harvesting as a sustainable energy resource and the range of complementary technologies for storage in cases where there’s a necessity for saving energy for later use.
In 2009 $611 million is the market for energy harvesters, with 67% of it being applications for consumer goods. By 2019 the market is predicted to have grown to over $4 billion, with 75% of it being consumer goods harvesters. The rest of the market will be industrial, military or healthcare applications.
Energy harvesting, in terms of number of organizations involved, is mainly a Europe/north America game but large budgets are appointed to energy harvesting from a few, but large, organizations in east Asia.
Photovoltaics, electrodynamics, piezoelectric and thermoelectric technologies are the main sectors currently gathering momentum with applications such as wireless sensor networks, mature right now, and automotive, building and consumer electronics being targeted future markets.
Infinite Power Solutions (IPS) presented their innovative solid state thin film micro energy cell, in other words a thin film battery. 170 microns thick, 90% of it being the packaging, specifically designed for embedding in different applications. The technology is based on the Oakridge National Laboratory research work on LiCoO2- LiPON batteries with a 40mA current delivered from a square inch. Richard Percival of IPS showed demonstrators of the company’s energy harvesters and storage devices, light weight, flexible and embeddable.
The Passive Power Management Unit (PPMU™)the company integrates with the micro cell leads to a completely autonomous, light-powered (but designed to accept energy from a wide variety of sources, e.g. magnetostrictive, thermoelectric, piezoelectric) device that can run without light for 30 hours. Being a prototype up until now, the Micro Power Module (MPM™) together with the THINERGY™ micro-cell will be announced next week as a product, a “perpetually powered” wireless sensor. Collaborators/users of the IPS technology include Siemens Nuremberg, MicroStrain, EPFL Lausanne and Virginia Tech.
Dr Samiul Haque of Nokia Research Centre focused on the research on enhanced energy and power capacity in mobile devices. The Nokia Morph research concept identified the main areas of interest that the company’s future designs are looking to expand into, ensuring, among other features, flexibility, stretchability and ability to harvest energy from the environment (e.g. solar).
Nanostructured battery technology is one of the routes the company is exploring in order to achieve longer autonomous function for their mobile devices.
Research is being focused on Carbon Nanotubes, with ZnO nanowires grown n them, for dye sensitized solar cells, ensuring solar energy harvesting and transparency at the same time. Flexible electrodes are also being developed for energy storage with Nokia’s research partners.
Roll Royce’s collaboration with Sheffield University is looking into wireless monitoring (of marine gas turbine engines or water-jet monitoring for, thrust monitoring, vibration testing etc) and also bringing electronics power down to lower levels in order to avoid interference, as well as energy harvesting. Sensing challenges for the electronics used in turbine engines include operating temperatures; ranging from -55oC all the way to over 250oC, these are levels of temperature in which most electronics do not survive.
For aerospace applications miniaturization and reduction of weight is always an important driver. Magnetic generators do not scale down as easily so the Sheffield University Technology centre is looking into small sized piezo-electric harvesters, using e.g. the gas turbine’s vibration energy.
Florence Fusalba of CEA Liten (the French atomic energy research council’s innovation arm) focused on storage of harvested energy. Research in the Grenoble facility of Liten is focused on developing materials and prototypes for batteries with high energy and power which are safe and low cost. Application for these would range from electric/hybrid vehicles all the way to the new photovoltaics. Liten focused on Li technologies as they exhibit higher energy density, targeting a flexible thin film battery (often less than 400 microns thickness) that’s fully printed (reduced cost). Work is also underway for integration of manufacturing of PV cells and thin film batteries, depositing one layer on top of the other.
ASTRI of Hong Kong presented their work on energy harvesting applications such as battery-less sensors for tire pressure monitoring systems, avoiding batteries that have limited lifetimes and would not be suitable for positioning a sensor inside the tyre. Potential markets according to ASTRI exist also in wearable electronics applications.
Enocean Alliance presented their work with sensors in the building environment, sensing humidity, temperature, the presence or not of someone in the room etc. The company’s applications include products harvesting solar energy, mechanical energy as well as thermal energy. Individual room temperature control lead to energy savings of up to 30%, installed in hotel buildings, hospitals, etc. using occupancy sensors. Enocean is now moving towards the private home market, not just industrial, public or office buildings. Studies are also on-going with partners like Boeing who are looking to incorporate this type of technology in aircrafts.
Facility: Innovate is an architect and design firm trying to lead sustainable projects, reducing energy bills by up to two thirds. The Innovation factory is the sister R&D company. Addressing energy costs, which have been hugely affected by increasingly higher costs of fossil fuels, can be pushed forward by enabling new, sustainable, technologies but also by affecting consumption of energy, in houses, offices, etc. Energy harvesting devices and sensors can lead to better energy efficiency and are promoted by the Innovation factory. The company has a patent to prototype floor vibration harvesting, but also building or transport vibration, in order to power electric devices.
During the 2012 Olympics an energy harvesting staircase at one of the three main transport gateways which will be dealing with 22,000 passersby per day, will be used to power 400m of EL tubing, or EL displays and the power generated will be adequate to run the electrics throughout the duration of the Olympics.
In the last session, Lauriane Thorner gave an over view of the MOBESENS European project for marine wireless sensor networks and work performed in the framework of the project from Imperial College London. According to Miss Thorner, one of the main future challenges includes the resonant frequency tuning with the frequency of waves.
Savi Technology presented on their needs for energy harvesting in RFID, one of the company’s main focuses is to be able to predict where RFID is going to be in 3-5 years, making sure that it stays ahead with the solutions it can provide to its customers. Being a company that provides integrated solutions, Savi is looking into end-to-end supply chain innovation. Battery dependence of active RFID tags is one of the main challenges that Savi faces and work on Energy harvesting techniques is of great interest to the company. For that reason the company is identifying strategic partners who can supply solutions on their challenges.
Finally, Dennis Hohlfield from the Holst Centre/IMEC, presented on their use of micro-systems technology for their energy harvesters, their progress and challenges. Their wireless autonomous transducer solution (WATS) is working with a micropower module of 100µW powered by 4 sources primarily: vibration, light, RF or thermal. These are the main sources of energy that are being researched for applications such as predictive maintenance, body monitoring, tyre pressure monitoring, or building sensing. The main aim of their work is reduction in size and weight and of course reductions in cost. Micro-machining is the suggested way to achieve the necessary reductions in the manufacturing part of the chain.
The second day of the IDTechEx conference on Energy Harvesting and Storage in Cambridge UK was dedicated to the technology roadmap. There was agreement that photovoltaics PV is and will remain the preferred form of energy harvesting EH overall and electrodynamics ED is number two. However, from harvesting floors to mini wind turbines and vibration harvesters, there were many devices described for very similar applications where one developer favoured electrodynamic and another favoured piezoelectric PZ versions so perhaps it will emerge later that only one was right.
The most frequently expressed need for energy harvesting was Wireless Sensor Networks WSN, however. Professor Neil White of the University of Southampton in the UK noted that energy harvesters are a reality including for WSN, where he advised that sensor nodes should incorporate several sources of energy. This theme of multiple harvesting was taken up by several speakers. Another recurrent theme was using the new Intel ultra low power chips.
Professor White felt that PZ is worse than ED for vibration harvesting because bandwidth, size and integration are important. He saw cost and size as ongoing challenges for EH and thermoelectric TE needs higher efficiency. He is looking at BiSbTe based TE and printed piezoelectrics using nano particles but his department is not equipped for materials development.
Energy aware sensor nodes are an interest. Prioritising message packets through a WSN makes it possible to limit the signalling and therefore power load on those nodes that are harvesting poorly at that time. In WSNs, energy harvesting wins by permitting a lot of processing in the nodes and permitting upgrade to higher power consumption as required. By contrast, primary batteries lock you into the designed duty cycles. Nevertheless, he felt that, one day, fuel cells will compete with harvesting in small electronic devices.
Professor Shashank Priya of VirginiaTech described work at his superbly equipped Center for Energy Harvesting Materials and Systems. It included multimodal harvesting and harvesting in environments rich in vibration, magnetic field or wind with piezoelectrics being a frequent feature of the designed solutions. A challenge is to reach 1 mW/cm3 from 0.8 microwatts today. TE and ED are also developed with combined PE, TE and photovoltaics PV appearing to be attractive. Many different devices have been made, the applications varying from aerospace to medical.
Dr Simon Alliwell of the UK Sensors and Instrumentation KTN reported on their survey on harvesting needs for sensor networks. For example, impedance matching is an issue and inability to compare devices is a concern. At least 200 microwatts is needed for most applications. Standards need to take harvesting into account. The cost of batteries is not the main issue because the cost of changing batteries usually dwarfs this.
Roy Freeland of Perpetuum, which sells ED vibration harvesters “in volume”, took up some of these themes, noting that there is a 3% fatality rate when people are cut open to replace heart pacemakers with flat batteries. He argued the need for interchangeable harvesting options so wireless nodes, as an example, could have the appropriate form of harvesting fitted in situ. He bemoaned the many announcements of energy harvesters designed for frequencies of vibration seldom encountered in the real world.
Thomas Rodig of Fraunhofer IKTS in Germany described his work on PZ generators for low power applications. Dr Harry Zervos of IDTechEx summarised the global situation with PV, observing that CdTe is rapidly taking market share from silicon on price but other options, notably DSSC, CIGS and organic PV, probably all have a market because of the diversity of needs. He was optimistic that work to extend PV to harvesting infrared and even ultraviolet will bear fruit but he did not thing that the very expensive multilayer constructions used in space would be competing on price for terrestrial applications any time soon.
This was followed by two talks on nano antenna harvesting as a complementary IR technology to visible light PV and maybe a more efficient, lower cost alternative to it in due course. These nantennas have dimensions near the wavelength of the radiation converted. With appropriate rectification, arrays of thousands of the printed devices can provide ac current. Dr Steven Novack of Idaho National Laboratory in the USA handed round a sheet of his flexible printed terahertz nantenna arrays and explained how it will be straightforward to print them reel to reel. Indeed, several layers could harvest different wavelengths and it is angle tolerant. Different frequencies and bandwidths can be designed in. He noted that there are IR frequencies that hit the earth unaffected by clouds and at useful power levels. Professor Aimin Song of Manchester University in the UK then described how he may have the necessary diodes in the form of zero threshold, ultra fast printed ballistic nano diodes. Indeed these devices which do not have a pn junction can be useful in TE as well. He described a thin film superlattice thermoelectric device.
Leo Poll of Philips Research presented ultra low power radio technology and Ciaran Connell of Decawave, a fables chip designer in Ireland described its new 802.15.4a and proprietary designs suitable for Real Time Locating Systems and WSN – two types of system which, he feels, will merge in the years to come. Peter Spies of Fraunhofer Institute for Integrated Circuits described many relevant projects. Yen Kheng Tan of the National University of Singapore also looked at WSN but focussed on a variety of harvesting options including a mini wind turbine he demonstrated. He explained the design considerations for WSN harvesting in practical situations.
There was a general consensus that this event had enabled interested parties to network for the first time, from those in activities as disparate as military, ophthalmology, security printing, consumer goods and retailing to those in universities, research centers, venture capital and other sectors. Wireless Sensor Networks is the most recurrent potential application, so IDTechEx is right to combine conferences on energy harvesting and WSN at its forthcoming event Energy Harvesting and Storage/ Wireless Sensor Networks, RTLS & Active RFID in Denver, Colorado on November 3-4, see www.IDTechEX.com/ehUSA for more details.