Below are the abstracts of some of the talk at the imec symposium “The future of energy harvesting”

“Laboratory Toy or Practical Power”- The Route to Commercial Success.

Roy Freeland, Perpetuum

There continue to be many announcements about energy harvesting: some are gimmicks, some defy the laws of physics and a few have practical applications. The focus is on those that can actually deliver a practical solution to providing sufficient energy with case studies which explain the commercial success of Vibration Energy Harvesting.

Micro Energy Harvesting beyond the first phase- from basic to application-oriented R&D

Peter Woias, IMTEK Freiburg

From today’s perspective, micro energy harvesting has seen a tremendous start in the last decade, concerning basic re-search, fabrication technologies and the outcome of first products and applications. The main driver of this success is the on-going application of distributed and embedded microsystems in almost every area of our daily living. More and more wireless sensors are used in logistics, environmental and building technologies or automotive applications, with their need of a reliable power supply without batteries or power cords. Also, the “internet of things” is considered as the main future – and ubiquitous – network for signal processing, data transmission and control. Finally, our ever growing infrastructure networks claims for widely distributed sensor and actuator networks, e.g. for the structural integrity monitoring of bridges and tunnels or for a reliable control of our waste water management system.

As a consequence, the phase of early “high-flying” research in energy harvesting is settling down towards a more technically and application-oriented approach. Also, it is more and more recognized by potential customers that micro energy harvesting cannot be considered as an isolated technology whose only distinction is the replacement of batteries or wire cords in a modular fashion. In contrary, the embedded system together with its energy harvesting capabilities has to be re-designed in a “full system approach” as an energy-autonomous embedded system that embraces energy conversion, energy storage, energy management and the system hardware and functionality. Finally, it turns out that conventional and familiar technologies, e.g. for energy storage or power management, do not show an optimal performance when used in an energy-autonomous embedded system. This presentation gives an outlook for the actual and future research in micro energy harvesting, having these directives in mind.

Challenges of Micro Power Management in Energy Harvesting Systems

Peter Spies, Fraunhofer IIS

Energy Harvesting makes use of minimum amounts of ambient energy like thermal gradients, vibrations or light. Collecting these amounts of energy a long time to power short actions like sensor measurements or data transmission is the key of energy harvesting. Aside from the efficiency of energy transducers like solar cells, inductive or thermo-generators, the power consumption of the power management and the energy storage devices are of paramount significance. Micro power management must handle smallest amounts of energy while providing an acceptable efficiency at these low power levels. To collect the maximum of the available energy, the micro power management should have a high dynamic range and provide a good efficiency all over that range. While the different transducer types like solar cells, piezo materials or inductive generators have different electrical properties, the power management has to match these properties pretty well to maximise the gathered energy. Present down-sides of energy harvesting are the device costs, related to the power output while competing with primary batteries. Asides from a high efficiency of the power management, implementing all power management building blocks on one semiconductor chip will enable cost-effective power supplies in the future.

PASTEUR: Perishable goods monitoring by RFID

Romano Hoofman, NXP

PASTEUR is a European project, labelled by CATRENE (Cluster for Application and Technology Research in Europe on Nano Electronics) and funded by the national funding authorities of Austria, Belgium, Netherlands and Spain. The goal of PASTEUR is the development of a battery and sensor assisted UHF transponder platform which enables a low cost solution for monitoring a broad pallet of perishable goods during the supply chain and storage.  At the end of the project, a fully working and integrated prototype will be evaluated in a field test.  The targeted device covers a UHF-RFID chip, an antenna, sensors and a battery.  Sensors for temperature, humidity, ethylene, O2, CO2, and pH are targeted within the PASTEUR project. Thanks to the integrated sensors, the obtained RFID solution could provide retailers, distribution centres/ wholesalers and food services with a verifiable proof of the product quality and safety. In fact, with the proper security measures included in the RFID platform gathering, proccessing and storing the data recorded from embedded sensor, the RFID platform can generate certificates proving that for example the cold chain was never interrupted or that there were no unauthorised modifications. This could thus solve some problems regarding breaks in cold chain, leaks in meat packages and others that might affect meat safety.  Moreover, it will allow controlling products’ quality and predicting shelf-life, reducing product losses, which is an important problem in perishable products, and avoiding this way related costs.

Trends in Energy Consumption within Energy Autonomous Sensor Systems

Eugenio Cantatore, Eindhoven University of Technology

Energy efficiency of electronic systems has emerged as one of the most important trends in integrated circuits research in recent years. The results of this continued effort are visible in all kinds of electronic functions: DSPs (reaching the 10 µW/MMAC according Gene’s law), data converters (the FOM of recent ADCs is approaching 15 fJ/conversion step [1] (Liu et al., 2010)), power converters (reaching unprecedented efficiencies in ultra-low-power regime) and radios (achieving an energy budget lower than 1 nJ per received-transmitted bit [2,3] (Daly et al., 2010; Mercier et al., 2008)). Exploiting this continuously improving energy efficiency, the progressing battery technology and advances in energy harvesting, miniaturized electronic sensors that do not need to be recharged for their whole operational life and can communicate among them to build up an energy-autonomous system are possible nowadays. A working group has been set up by CATRENE to study the state and the development of these ‘‘energy autonomous systems’’. The presentation summarizes the trends sketched by the working group in terms of energy use in autonomous sensor systems.