Using Piezoelectricity to Harvest Energy (Part 2/4)
We’re back with the review paper! This time, I’ll be talking about the holdbacks with piezoelectricity and what’s stopping it from becoming mainstream.
Last time, I talked about what exactly piezoelectricity is — the creation of electrical polarization in an object when mechanical energy is applied to it. I went over the popular materials used like quartz and PZT, and the 6 categories of materials used. Check it out here before reading this part!
3. Current Holdbacks of Piezoelectricity
The holdbacks and gaps before piezo can become a main source of energy harvesting can be divided into two categories — technical and logical.
3.1. Technical Gaps
Right now, there is no piezoelectric material that can actually sustain the high amounts of energy needed.
Let’s use biking as an example. The average biker is exerting 100 joules of mechanical advantage per second. This means that in one hour, 100 watts of energy is being generated if the pedals are spinning a motor.
If this 100 joules per second was exerted into a piece of quartz connected to a load, this piece would only be able to generate 8.9 watts of energy in that same time frame. This simply makes piezoelectricity ineffective.
Quartz is one of the materials that has a higher intensity of the effect, even though it’s so low.
3.2. Logical Gaps
One of the major logical gaps comes in the practicality of piezoelectricity. Quartz, among other natural resources, is one of the most used piezoelectric materials. Extracting the raw materials and refining them to be usable is already doing such harm to the environment, to the point where the majority of its lifetime is spent making up for the damage it’s done. This negates the end goal of clean energy. Lab made materials like PZT do avoid this for the most part, but those processes can still harm the environment through production, such as with carbon emissions.
No material in use has a high enough intensity of the piezoelectric effect while still being non-toxic, sustainable and durable.
4. Potential Solutions
Of course, with the faith some people have in this technology there are solutions being found and created!
This is a solution solving the technical issue piezoelectricity brings up, while simultaneously solving the logical issue.
Cellulose or (C6H10O5)n is a fiber that is found in many living organisms, playing the role of holding the structure of them and keeping them sturdy.
Nanocellulose is, as the name states, nano-scale cellulose. It is produced by bacteria. In recent studies, it has been found that certain types of nanocellulose show intense piezoelectric effects. It’s also biodegradable, non-toxic and the production is mostly sustainable. It looks like a perfect solution!
Nanocellulose is made by simply breaking down cellulose. Wood-based nanocellulose polymers are very similar to that of single crystalline materials because they have a patterned, unbroken atom structure. This makes them in many cases the most ideal material because of their consistency.
Nanocellulose is the next big thing that might make piezoelectric energy generation mainstream.
We can boil the reasons for this down to 3 main points.
- It’s the most abundant biomass resource on earth. This means it’s common.
- It’s non-toxic, eco friendly and biodegradable. This means it’s sustainable.
- It’s extremely low-cost to extract and refine. This means it’s cheap.
A cheap, sustainable and common material that has one of the highest recorded intensities of the piezoelectric effect has such a high potential!
This seems like the only promising solution to the problems with piezoelectricity right now.
We’re halfway through the series — but don’t worry, there’s more coming. See you soon!