What is the energy future of the IoT?
The IoT is a vast ecosystem currently developing in a large number of sectors, including smart homes, smart buildings, transport, agriculture and manufacturing, and also in mobile systems such as wearable devices. At a time when the major operators are attempting to standardize the sector (such as Amazon, Apple and Google, who are forming an alliance with the objective of developing a communication standard for all connected objects dedicated to the smart home sector), other issues are emerging with the implementation of sensor networks, notably problems relating to energy. Despite the lauded installation simplicity of IoT sensors, including the associated WiFi, network and energy connectivity, it is frequently ignored that this requires the use of batteries that must be replaced more or less frequently depending on the data collection frequency. And with over 50 billion objects connected at the present moment in time, growing at some 15% per annum, there are significant environmental and economic issues!
Intelligent energy management thanks to the IoT, yes…
In the construction sector (residential and tertiary), which accounts for 45% of total energy expenditure and produces 25% of greenhouse gas emissions in France, the expectations are high and every bit of progress counts.
In addition to energy-related renovation, the emergence of new systems able to better regulate energy expenditure inside buildings is certainly of real benefit. This notably applies to certain IoT solutions designed to monitor consumption (electricity, gas, water, etc.) by networking an ever-increasing number of appliances and sensors. Such solutions offer significant savings and combine building management with actual utilization. It is therefore possible to gather information relating to utilization (electrical load profiles, occupancy and activity indicators…), consumption (temperature control and settings of heating / AC…) and the environment (air quality, weather…), leading to the definition of habits and the creation of specific scenarios. Connection to building management systems (BMS) also enables the variables of the various systems to be adapted in order to optimize energy consumption in real time.
Yet the possibilities of the IoT do not stop there! By incorporating users’ peripherals (wearables, smartphones, badges, connected bracelets, etc.), our buildings and living spaces can adapt to individual utilization: customization of the environment in line with occupancy and individual preferences and/or authorizations, added to exposure to a whole range of complementary services (access control, geolocation, room reservations, etc.). From this point of view, the arrival of the IoT is a clear success, enabling implementation of numerous inspirational ideas to help many sectors successfully enter the digital era.
… but what about sensor energy management?
The possibilities of the IoT are vast and offer significant potential, but the growing mass of sensors has a non-negligible environmental and economic impact. Although battery and sensor manufacturers pay particular attention to optimizing the operational durability of their products, the growing trend for more data to be fed back more frequently creates a major issue in terms of sensor autonomy, which is significantly constrained by their level of energy consumption.
First of all, there is the environmental aspect: What can be done with the millions, and even billions, of batteries at the end of their useful life? How can this be successfully integrated within an ecological and sustainable development approach? The question is complex, given that the number of end-of-life batteries will only continue to rise in the coming years. And even though the battery recycling sector is making progress, notably in relation to the automotive sector, the absence of equivalent sectors for sensor and wearable device batteries is a matter of fact.
We are then faced with the economic aspect: as IoT solutions operators are holding ever greater volumes of sensors and/or which are more geographically dispersed (at the level of the city, region or national property portfolio), the human and financial costs of maintaining the batteries can rapidly become prohibitive.
And finally, there is no simple answer to these issues: the data collection networks and technologies of the IoT (Lora, Sigfox, NB-IoT, 3G/4G, etc.) remain highly diverse with significant disparities in terms of sensor electricity consumption. This does not mitigate in favor of the adoption of simple and easily reproducible technological solutions.
This is not a conclusion…
But merely a beginning!! Technologies exist, however, that can offer solutions for some of the issues stated above, mainly thanks to the boom in renewable energy and technological advances with the sensors themselves. Sensors are becoming increasingly energy efficient, thereby reducing their consumption of electricity. Furthermore, embedded intelligence is becoming sufficiently effective such that data can be fed back in accordance with the available energy. The recovery of energy from the environment (energy harvesting) is now becoming possible thanks to the emergence of new generations of components. Whether thermoelectrical, piezoelectrical, radio or photovoltaic, the energy can be collected, stored and then reused in order to extend the operating duration of the equipment without it having to be manually recharged.
Solutions such as organic photovoltaics (OPV) are therefore becoming increasingly relevant, enabling sensors to make gains in terms of both functionality and autonomy. Due to its ability to operate at low luminous intensity (even indoors), or by playing the role of sensor, it is easy to imagine the possibilities offered by this solution:
- Utilization of the film as an additional sensor (luminosity, LiFi reception);
- Recharging of batteries in virtually all environments (indoors and outdoors, low light);
- Sensors able to operate with complete energy autonomy;
- Low maintenance costs.
If we also add that OPV solar modules offer the advantage of being lightweight, flexible and semi-transparent, the field of possibilities is vast. The future of the IoT perhaps lies here, in combining the technological progress of the equipment with recovery of energy from the environment via photovoltaics. Perhaps a first solution able to tackle the growing volume of end-of-life batteries and the challenge of recycling!