What is meant by energy harvesting?
It is the ability of electronic devices, especially lower energy consuming sensors – to exploit the omnipresent, ambient energy that is present in the environment all around in various forms: kinetic energy (movement, vibrations), thermal energy, electromagnetic wave energy and solar energy.
Some of this energy is natural such as solar, wind or the movement and heat of the human body. Other forms derive from modern but still inefficient technology invented by humans like RF waves, machine vibrations and waste heat from vehicle exhaust pipes, machines and industry.
This energy isn’t enough to power larger devices let alone huge industrial machines – but is sufficient to keep sensor networks, wearable tech and smaller consumer electronic devices working for years on end.
The technology and materials science still has a long way to go because we all still use cables to charge our phones, laptops and tablets. Our TV remotes still use batteries.
Energy harvesting will not solve the current energy crisis or heat our homes, currently only fossil fuels and nuclear power can do that on a large scale, with the future pinned on huge solar towers, wind farms and the holy grail of fusion energy.
But it can eliminate the need for constant battery replacements in up to a trillion sensors in the very near future. That is a lot of batteries no longer in olympic pool sized landfills, seeping poisons into the earth. But this extends even further: all the energy and resources needed to manufacture those batteries in the first place will no longer be needed, putting even less stress on the environment. There is a knock on effect.
Look closer to home, and namely to what we are holding in our hands for much of the day, every day. Yes, the mobile phone. Currently around 15 billion of them and only growing in number. Each phone is discarded every few years, along with the exhausted battery inside. Research is ongoing on how to harness the energy around us to power these devices, especially from high frequency electromagnetic radiation. This is one of the biggest challenges of energy harvesting as our phones also grow in complexity and power each year and so are hungry for ever greater electricity.