The chatter about the “internet of things” makes it sound like the solution to all our problems. “Smart” devices in a 5G world do have the potential to indirectly improve efficiency without requiring any particular effort or sacrifice on users’ part. But the internet of things has drawbacks as well – particularly regarding cybersecurity. Whether it turns out to be a good thing or a bad thing will depend on how mindfully we develop it. Fortunately, one emerging aspect of the internet of things could have a direct environmental benefit. Some companies are dreaming of a future that is not only connected, but also battery-free.
The Internet of Things
Most simply, the term “internet of things,” often shortened to IoT, refers to objects that are connected to the internet. By now everyone is used to internet-connected computers and electronic devices like tablets and cell phones. The internet of things expands that connection to include all kinds of household items from televisions to toasters. Many of these products seem like solutions in search of a problem or even a cynical grab for your personal information. (Is it really helpful to start your clothes dryer using a phone app when you still have to manually switch over the clothes?) But smart devices can make your life easier and even greener. Smart thermostats and smart window shades can reduce heating and cooling costs, even when you aren’t home. Smart gardening products can help you save hundreds of gallons of water in your garden.
The Problem With Batteries
But all of these items have potential environmental downsides, too. They have all of the recycling challenges of stealth electronics. And they do draw power, often even when they are not in use. All those new sensors and portable devices also means a proliferation of batteries. Rechargeable batteries are better than disposable ones, but both rechargeable and single-use batteries can be hard to dispose of responsibly. Disposal is only one of the serious drawbacks to batteries. Batteries of all kinds contain toxic and corrosive materials that are dangerous at every stage of life. Mining and processing these materials requires huge quantities of water and pollutes water, soil, and air.
Research in energy harvesting has led to a new development in the internet of things – sensors and devices that bypass the need for batteries completely. The concept is familiar thanks to kinetic watches that “harvest” energy from the wearer’s movement using a pendulum to wind the gears. (But they often include a small battery that ensures the watch won’t stop if it is removed for a few minutes.)
Now electronics designers are using more sophisticated methods to power a host of sensors and other devices. Ultra-low-power integrated circuits that harvest energy from sources like indoor light and vibrations to generate data are already being used in industrial applications. These circuits never turn off, require basically no maintenance, and can last over 20 years. Data collection is a major focus of the internet of things. Consumer devices that incorporate these circuits could draw less power and last longer (because the sensors don’t wear out).
A Battery-Free Internet of Things
The circuits currently in use require minuscule amounts of energy, but many innovators are working to develop energy-harvesting devices that — either alone or in combination with such circuits — can power more than just sensors. Various projects are exploring energy sources such as radio waves, temperature differentials, vibrations, ambient light, and even Wi-Fi backscatter.
Researchers at Northwestern designed a Nintendo Game Boy powered by game-play and sunlight. It uses energy generated by tiny magnets and tightly wound coils every time a user presses a button. Researchers at the University of Washington are working to develop battery-free cell phones. The environmental benefit of cell phones whose useful life is limited by materials rather than the lifespan of rechargeable batteries is immediately obvious.
As radio and backscatter-harvesting devices become more common, regulatory concerns will develop. Questions over who holds the data will need to be addressed. But currently, the biggest barrier to a battery-free future is the amount of energy these technologies can harvest. So far, they can only power very small devices. Even for small devices, most industrial designers struggle to imagine systems without batteries. A bio-inspired design paradigm may enable more robust energy harvesting, but as yet, scaling up to more significant devices still requires batteries for the storage of harvested energy.