Environmental benefits of energy harvesting
Energy harvesting has emerged as a leading alternative to conventional means of powering sensors and node devices. There are a number of reasons why they are increasingly being chosen over battery-powered systems - One of these advantages is that they can potentially make for a much smaller environmental footprint. In fact, this is one of the least spoken about among the many advantages that they bring to the table. In this post, we take a look at why energy harvesting based solutions are much more environmentally friendly than their traditional, battery-based counterparts.
IoT technology is dramatically changing the very way we conduct business and go about our daily lives. Over the past decade or so, IoT has entered practically every single aspect of human life and is only continuing to increase its impact with each passing day. As we’ve mentioned in earlier posts, there are a number of reasons why we are being pushed to look past batteries as a viable solution to power this IoT explosion.
Batteries vs energy harvesting
Before we get any further, let’s get a broad bird’s-eye view on how these two kinds of power solutions for IoT devices compare to one another.
Batteries present a host of logistical, financial and environmental challenges which have threatened to stifle the growth of IoT technology and nip the IoT revolution right in the bud. The who’s who of the IoT world have had to contend with this problem for quite some time now. A number of possible workarounds were explored, with energy harvesting technologies emerging as the closest thing we had to a viable, real-world solution.
Energy harvesting enables sensors to circumvent the need for an external power source such as batteries and be self-powered instead. These energy harvesting based self-powered sensors are able to draw the tiny amounts of energy they need from their surroundings, including radio waves (rf energy harvesting), heat energy (thermoelectric energy harvesting), vibrations (piezoelectric energy harvesting) among several others.
In previous posts, we have examined the several advantages that self-powered sensors have over their battery powered counterparts. In this post, we are going to focus on the environmental benefits of energy harvesting.
Impending ecological catastrophe?
There’s not a whole lot of energy going around in the world. This much, it’s fair to assume, we all know already. But not many of us regular folks going about our regular workaday lives know that sourcing a lot of this already-scanty energy is extremely expensive in terms of resources and ecological footprint.
Take a second, look around your room and count the number of electronic and electrical devices that you can spot. Most of us would all but run out of fingers just counting the devices inside our bedrooms, competing with each other for socket space - and that doesn’t even include the other rooms of our houses.
Whether we like it or not, this is the truth of the world as it is today. In this article, we thought we would bring your attention to some of these painful truths and having done so, move on to why we think energy harvesting technologies promise to be an ameliorating influence, to whatever small extent.
To start with, we need to understand that there are no fairytale solutions to any of this. On the other hand, it’s beyond childish to just deride big corporations, governments and policymakers for this state of affairs. This is simply the price we have paid, consciously or not, for the many comforts and conveniences that we have come to take for granted.
The very fact that we wake up each morning with the certainty that we won’t end up as some creature’s food that day, believe it or not, is a massive luxury in the natural world. And here’s the thing - we didn’t get to this stage overnight - the cushy and secure life that we have come to take for granted took centuries upon centuries to establish.
Long story short, the point we’re trying to make here is that the scary ecological and climatic crises that are staring us in the face, truth be told, are just the bill that’s being handed to us for the cushiness of our lives.
This is not to make some perverse case against everything modern and industrial - it is simply to acknowledge that every time we use a personal computer, air conditioner or actually, even a tubelight, we are complicit in the enterprise of industrial civilization and all its dubious effects on the ecosystem.
Adopting this kind of a viewpoint forces us to grapple with the problem at hand and look for equitable and realistic solutions instead of resorting to pointless name calling and fear mongering.
Energy harvesting is one such solution that aims to make a small, but nevertheless, concrete contribution to our efforts against the sort of large scale ecological catastrophe that many claim we are inevitably heading towards.
Batteries - an ecological nightmare
It is a matter of sad irony that in just a couple of decades, batteries have gone from being the promised saviour of our ecological situation to a major culprit in land and water pollution, resource depletion and large-scale habitat loss.
In 2019, the Nobel prize for chemistry was awarded to John B. Goodenough, M. Stanley Whittingham and Akira Yoshino the inventors of the Lithium-ion battery.
And fair enough really.
Back when it was invented, the lithium-ion battery represented a move away from fossil fuel dependence. For decades, fossil fuel dependence was touted by environmentalists as the single most dangerous risk factor to our environment.
Batteries were supposed to guide us through to an era where we would be more conscientious and environmentally sustainable. And to some extent, this was founded on sound reasoning.
No one foresaw the massive boom in mobile devices and personal computers back then. The 2000s witnessed a global explosion in the proliferation of hand-held telephonic devices and personal computers. These devices, for the most part, were powered by Lithium-ion batteries which were rechargeable and so, were perfect for consumer electronics.
Add to this the parallel developments in the electrical automobile industry and what we got was a global bottleneck in lithium supply.
As such, lithium isn’t a very widely distributed mineral to begin with. An overwhelming majority of the world’s lithium resources are concentrated in a very small belt of South America, where water sources have essentially already been recklessly depleted on account of lithium operations.
The energy harvesting difference
“And more than a few watts saved here or a coin-cell that doesn’t need to be thrown away there, this makes all the difference in the world.”The first law of thermodynamics states that the total energy of a closed system always remains constant i.e if we imagine our universe as one big closed system, then the total energy within this system always remains constant - no new energy can be created and as a corollary, energy can not be destroyed.
Hey wait a minute! If energy can never be destroyed, then what’s the problem? What’s with all this scary talk about an energy crisis then?
It’s not that simple. While it is true that the net energy in our universe is always going to be the same - which theoretically does mean that there’s practically endless reserves of energy for all our needs - there’s a caveat. Not all forms of energy are useful to us. We are limited by the fact that we can only harness and employ certain forms of energy.
Some forms of energy are highly valuable to us because they are easier to harness and exploit. For instance, let’s take the example of hydroelectric power plants - we use the potential energy in a reservoir to drive turbines, which in turn converts the energy into electricity, which is a desirable form of energy that can be used for several purposes.
This is the first thing we need to understand - not all forms of energy are made equal.
Whenever we use energy to do anything, there are invariably losses along the way. Consider the example of a car - a typical car that runs a petrol engine usually has an efficiency of about 25% - i.e 25% of the energy produced by the combustion of the petrol goes towards moving the car. The rest is dissipated into the atmosphere as waste heat. In fact, our muscles help us move with a more or less similar rate of efficiency.
The value proposition made by energy harvesting technologies is this - what if we find a way to harness and utilise this “wasted energy”? Like we said earlier, there are energy losses in every step of the process - every link of the chain if you will. The more energy we salvage from these losses, the more our environment will benefit from it.
Ideally of course, we would cut out the middleman and just find cleaner ways to generate energy in the first place. But that’s easier said than done. In the meantime, energy harvesting technologies are incredibly promising in that they enable us to take advantage of the tremendous amounts of ambient energy that we have available all around us, all the time!
Granted, we are not talking about astronomical amounts of energy here but the environmental impact is far from negligible - it is substantial.
Now that we’ve got the basics out of the way, let’s get to the ways in which energy harvesting is better for our environment.
- Small electronics don’t need a lot of power. And today, all manner of highly complex industrial operations are carried out through IoT networks which consist of hundreds of thousands of tiny “node” devices that collect, process and transmit data. These devices need microscopic amounts of electricity to do their jobs. Nevertheless, if each of these tiny devices was to be powered by a coin cell, that would add up to a ginormous number of batteries that need to be disposed of safely. This presents an environmental challenge of herculean proportions, what with the number of such IoT edge devices only set to keep growing in the future.
- Sourcing batteries is very resource-heavy. Like we mentioned earlier, entire regions of South America have become bone dry thanks to lithium extraction operations which require exorbitant amounts of water.
- In addition to being expensive in terms of resources, battery-production is also highly toxic. The humanitarian expense of lithium-ion battery production is seriously macabre. Energy harvesting, to whatever extent, reduces our dependence on lithium-ion cells, which in turn helps alleviate some of the untold amounts of misery that communities in Africa go through on account of the developed world’s insatiable appetite for consumer electronics.
- There are a number of species which irreversibly lose their habitats when ecosystems and water bodies are polluted by toxic wastes. And the truly horrible thing about any loss in biodiversity is that it ripples out and causes further waves of ecological destruction. When one species dies out, it’s not just one species that dies out - it’s a dent in the tightly linked web of all species, which results in long-term consequences that can be incredibly serious and very hard to predict.
“And more than a few watts saved here or a coin-cell that doesn’t need to be thrown away there, this makes all the difference in the world.”
The Big Picture
All of this is incredibly pertinent to the ecological situation at hand. From an environmental perspective, the issue of energy is super important. The present situation is this - no matter how small the changes are, they matter.
Every drop counts.
There is probably never going to be one cataclysmic event that saves us all from the clutches of planetary ruin and climate change for ever and ever.
It doesn’t work like that. Whatever harms befell our environment as a part of our industrial developments, they didn’t happen overnight. However scary and gargantuan our energy crisis and environmental woes may seem at the moment, they are the result of centuries of tiny actions and tiny decisions, all adding up to this cumulative end.
If there is going to be a lasting solution, it is going to work in the same way. It is going to be a result of a million tiny changes, woven together to make sizable differences. It is in this light that energy harvesting technologies are super important.
If not in terms of magnitude, they are definitely a step in the right direction in terms of thinking.
Parsimoniousness. Abstemiousness. Frugality
If these words sound old-fashioned to you, here’s the sad part - it’s not just the words but the very meanings they encapsulate that have gone out of vogue in the world we inhabit today.
If it’s broken, just buy a new one
That’s how we go about in today’s world. It is in this context that energy harvesting has so much to offer to our environmental agenda. It signifies a willingness among our intellectual and technological elite to look for old fashioned solutions to our modern woes.
And more than a few watts saved here or a coin-cell that doesn’t need to be thrown away there, this makes all the difference in the world.