This is really cool news!
The article title focuses on the two different types of energy input, but as everybody’s noticed, the rain provides such a tiny amount of output that it doesn’t contribute more than a watt or two over a whole panel. Put that on hold for a minute and let’s look at some other exciting parts of this:
- Long-term solar panel durability has been a hurdle we’ve struggled to overcome. Part of this is due to the sensitivity of the materials to both water and the physical impacts of raindrops hitting them.
- Protecting sensitive materials that collect light can be a challenge because most things you coat them with will decrease the amount of light they’ll gather, and most of what’s left is really expensive (in money, materials, or energy) to effectively and uniformly apply while maintaining its light collecting ability.
So this research group in Spain comes along and says, “Hey everybody, check this out! We got a twofer: we can make solar panels more durable and just as efficient by putting them in a box and spraying them with hot gas! Pretty great, right? Oh, but wait! There’s more! The stuff we’re coating the panels with can also give you a trickle of energy just when it rains! The raindrops bouncing off the panels, I’m serious. That’s enough kinetic energy to drive a tiny potential. It’s not a lot, but it’s still better than two for one!”
Now let’s go back to the tiny bit of electricity produced by rain. These panels might be able to generate enough power to trickle charge a small battery (like on a weather station that tracks data) when it rains. With the way we’ve been engineering things like LEDs and sensors to be smaller and more energy efficient, we’d be able to use these solar panels to keep them running without needing any other energy source. It’s totally fucking free, doesn’t take anything at all from the panel or its efficiency to drive something like a sensor on a train track that can immediately send a localized signal when there’s a track failure or maintenance needs to be done. If you spread those sensors out over an entire rail system, you could offload an incredible amount of work without doing anything more than installing the new panels and getting it going. Improving rail safety (especially in a place like America where the rails are so bad and so inadequately maintained due to capitalist pressures that the trains are a gamble every time they run) with something as clean, simple, automated, and inexpensive as this is incredibly solarpunk stuff. I’m not a person of vision, so really I’m excited to see where they go next. Most of what I’m thinking about right now is municipal/government and industrial stuff, things that would give repair crews more information on the problems they’re being sent out to fix instead of just “sensor offline” messages. Beyond improving industrial safety through greater automation of simple functions, disaster response/recovery times could also see some seismic changes. I’m fuzzier on the consumer side of things, but small things like solar roofing providing power to automated garden switches or illuminated house numbers and doorbells that don’t need to be wired into the house are all steps towards us consuming less energy. I just think that’s neat!
it’s in the low single-digit milliwatts per square centimeter of panel
So low-tens of watts per 2m^2 panel. So like 1/20-1/25 output compared to solar.
The theoretical maximum would be whatever kinetic energy actually hits the panel.
If a 2mm diameter raindrop has a mass of 0.034 g and has a terminal velocity of 9 m/s, the total kinetic energy is 0.00275 joules per raindrop.
The threshold for what is considered heavy rain is about .75 cm of rain per hour, so for our square centimeter panel we’d be talking about .75ml of rain per hour, or 22 of those average sized rain drops per hour. That’s only .06 joules per square cm, over an hour. That’s 0.000016 watts.
2 square meters is 20,000 square cm, so that’s .33 watts on the 2 square meter panel. Not significant enough, even on heavy rain.
This is correct, although it should be noted that the power generation side of this is just a kind of cool incidental thing. The main purpose of the coating is to protect the solar cells
Where did solars output start?
First Gen Hydrogenated amorphous silicon had a similarly low output, but around the same time cadmium telluride was at 160w/2m^2 and gallium arsenide was at 450w/2m^2 (in outer space).
Also idk if it’s fair to compare this Gen of piezoelectric generation to first Gen PV, since piezo has been around for a while
That was going to be my next question.
Do we have anyone that’s looked at energy production lifecycles like that?
And thank you for the response.
Not sure if anyone has studied it across different energy sources, but you might have better luck searching “generational improvements” or “efficiency over time” instead of energy production lifecycle. That sounds more like how much energy would be expected to be produced over the lifetime of the product.
Cool idea but I wonder if there are actually any practical applications where you couldn’t just use a regular solar panel instead.
What happens when you flip it around? Instead of needing a solar panel to power something, what could you do if you had a solar panel that had sensors, lights, or transmitters attached to it? None of those attachments cost anything additional to run and they don’t decrease the panel’s output. You just hook all the panels you want together into an array, and the damn thing could basically monitor itself and send error notifications to you when a problem needs fixing. That’s a lot better than what we’ve had so far, either isolating, identifying, and solving problems without any guidance at all, or needing a monitoring system (computer) that soaks energy in order to keep tabs on your hardware. Some of the solar/battery systems you can buy now even rely on the extra power consumption of an AI agent to make sense of your error codes for you. It’s crazy how many points of improvement this team made. I really hope it’s practical on a large scale!
