Ten years ago, IBM predicted the world will have one trillion connected devices by 2015. However, as 2015 rolled by, the world had yet to reach even 100 billion connected devices. The major problem—a trillion sensors mean at least a trillion batteries.
Although a significant problem, it did not make economic sense. Everyone was expecting the IoT technology to bring on a large value-addition, that of range. They expected IoT to bring the Internet to remote corners of the world, thereby interconnecting vast areas with IoT sensors and their information-gathering powers. Therefore, the internet and its incredible power would be visible in various places like large farms, factories, lumbering operations, construction sites, and mining operations, with enormous coverage and decentralized operations.
Typically, sensors collect data for IoT networks, which distribute it for processing and analysis. If sensors require batteries for operation, it places a severe restriction on the number of sensors that a network can use. This, in turn, goes on to defeat the entire point of having IoT in the first place.
For instance, consider a large-scale agricultural operation. IoT can bring major value addition to such a business through its coverage. By deploying multiple sensors across the entire operation, it is possible to access valuable information capable of generating highly actionable insights. Now consider the recurring cost of replacing or maintaining the huge number of batteries every year—making the proposition less compelling very quickly.
Not only would the resources, cost, and manpower, for replacing or maintaining the batteries on all the sensors be astronomical, but they would also easily surpass any possible savings that the system would likely bring.
According to an estimate, a trillion sensors would need 275 million battery replacements every day. This, assuming every battery deployed in the IoT network reached its claimed life of ten years. The next hurdle is even worse—discarded batteries poisoning the environment.
The above problem has resulted in sensors and microcontrollers getting more efficient and cheap. Modern sensors are now extremely reliable, consuming minuscule amounts of energy. Batteries have also improved, with the industry exhibiting robust batteries with higher energy density and longer life. However, the future of microcontrollers and IoT sensors needed to be batteryless. This led scientists and engineers to develop energy harvesting technologies that could eliminate the battery from IoT altogether.
Energy harvesting is the technique of scavenging power from the surroundings, which has many forms of it—heat energy, electromagnetic energy, vibrational energy, and so on.
Considering that modern microcontrollers for IoT need only a few millivolts to operate, many are developing energy harvesting technologies as a potential power solution that can replace batteries.
This has given rise to self-powered microcontrollers in the market. For these MCUs, batteries impose no restrictions, as they harness their own energy from the environment. They use a number of harvesting technologies based on various power sources and kinds of materials—piezoelectricity, triboelectricity, and RF energy harvesting being the leading contenders in the category. Therefore, with energy harvesting powering microcontrollers, IoT can once again begin to chase the magic figure of one trillion interconnected devices.
