IoT Energy Storage – A Forecast

(De Gruyter) – Internet of Things (IoT) devices with only non-chargeable battery cells have a limited lifetime based on the total battery energy provided. By replacing batteries on IoT devices with an energy harvester, the situation changes. Many of the performance limitations disappear or are reduced.

The authors discuss forecasts of IoT energy usage in relation to energy harvesting and storage while also considering aspect such as temperature and cycling degradation.

Energy harvesting technologies have improved over the last couple of decades. In particular, photo-voltaic harvesters have made significant progress. The alternatives for energy storage include rechargeable battery cells, supercapacitors, and capacitors all of which suffer from cycling degradation and temperature effects.

For computational energy consumption and with the current rate of irreversible computing, thermal noise at room temperature will become a hindrance close to the year 2030.

With respect to data sampling due to only a small gap between the state of the art and the theoretical limit indicates that there will not be any significant progress in the future, just a delay until designs have been commercialized.

In most cases, it is not the sampling or computation of data that is the most energy-demanding task for a wireless IoT device; rather, it is the transmission and reception of data over the wireless link. To minimize the energy cost of wireless transmissions, strategies have been developed to reduce the active time during which a sensor needs to listen and synchronize its transmission time slot to match the rest of the network. Time synchronization has dramatically reduced the energy spent on wireless communication; furthermore, transceivers have also become more efficient over time.

The authors also present the current trends for transceivers available on the market, showing how their energy cost to transport data has reduced over time with reference to the theoretical limits. A forecast for IoT is provided by using the combined RF chip trend with data on the energy cost for computation and data sampling and the energy storage efficiency for various storage technologies. The data and trends make it evident that wireless IoT devices will only use energy harvesting and short term storage such as ceramic capacitors in the future. The current development trend indicates that such wireless IoT devices are ready for today’s market.

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Edited for Content and Length by Dr. Matthew A. Hood.

The full article can be found at De Gruyter in the journal of Energy Harvesting and Systems.

DOI: 10.1515/ehs-2018-0010

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