Comment by LoveMortuus | Hacker News Reader

Comment by LoveMortuus | Hacker News Reader

> The computer ran in cycles of 45 minutes of calculating sums of consecutive integers to simulate a computational workload, which required 0.3 microwatts of power, and 15 minutes of standby, which required 0.24 microwatts. The computer itself measured the current output from the device and this data was stored in the cloud for researchers to analyse.

> Christopher Howe at the University of Cambridge and his colleagues built a small enclosure about the size of an AA battery out of aluminium and clear plastic.

That's REALLY not a lot of power, which of course is reasonable, but I do wonder how far can it scale, can it reach any generally usable.

Let's take a very conservative estimate of watt-hours of an AA battery of 2 Wh. The computer used in the paper could run for 2,000,000 µWh / 0.3 µW = ~6,666,666h.

Let's convert to a more human friendly numbers: 6,666,666h / 24h = ~277,777 days. 277,777 days / 365 days = ~761 years.

I probably calculated all of this incorrectly, but I still have a feeling that blue-green algae might not be very scalable... :/

Thank you for the accurate and concise summary of what I wanted to know, but I think that this has larger implications that has nothing to do with computers or algae. As you observed, that is really not a lot of power. And off I go... it is incredible that that is not a lot of power, iow, what can be achieved optimizing for low-power is nothing short of miraculous, and we as a global society... we should suck it up, optimize for low power, and immediately ban everything contributing to Global Warming, and stop it by force if necessary, you know, optimized for zero casualties using psyops and harmless hallucinogenic bombs. We should get with our allies, get China on board, and take over the world, and stop Global Warming with a quickness. Power hogs can read books and sleep at night instead of insisting on more and more power.

I keep looking for, and failing to find, any metrics that suggest that GPUs or CPUs have gotten more efficient and less energy intensive over time. Simple intuition would suggest "yes, obviously, of course", but I would love to see a simple line graph indicating so. Toms Hardware seems like a good place to look, but their comparisons dont overlap backwards very far

I think they have gotten more efficient. Just by the fact that pretty much every laptop today has a much better battery life then any had many years ago. Of course the difference is also in the battery tech, but the change and improvement is still visible.

Devices probably became more energy efficient in that they can do more with 1 watt-hour, but I doubt if they suck up less watt-hours: probably more.

"blue-green algae might not be very scalable..."

Actually, the idea is, that they are very scalable, because to make more solar panels you have to manufacture more panels.

To make more algae(and get more power), you just let it grow.

So you still have to build more sun exposed tanks but this is very low tech, compared to cleanroom solar panel manufacturing. What is missing is probably a breakthrough in genetic modified improved efficeny, which is currently indeed very low (way lower than solar panels per area)

That's only scalable if the material & labor costs to build and maintain the tanks is within a certain margin.

How many m^2 of algae is required to equal a m^2 of solar? From there you could calculate relative costs, given reasonable assumptions of lowered tank/algae costs as the tech matured.

"How many m^2 of algae is required to equal a m^2 of solar?"

Some years ago, the efficency was at around 1 % vs. 20% with solar panels, meaning you would need 20× the space, meaning only dessert areas and big scale production worth it. And since no one did it big scale yet, means it is economically not worth it yet.

But the cost of further algae itself are zero, which makes the idea attractive in theory. Like I said, there is a breakthrough required in efficency, or some cheap big scale production/deployment system.

Or it might just need an applications where panels aren't viable but algae is. Not sure what that would be, but I also don't consider myself a visionary. Maybe a high dust area where maintenance isn't practical for panels?

Hum... A large share of the solar costs are on support and installation. Those are proportional to the area, and are even higher (by area) for algae, because algae requires some water, and water is heavy.

So, if they need 20x the area, just their support and installation will already cost some 5x more than a full solar plant.

Also these algae need an open system so that they don't kul themselves. And I think they might be much more sensitive to heat and especially cold then solar panels.

Algae are living creatures just like humans and stuff, so keeping them alive is probably harder then with solar which is basically just nicely arranged rocks and crystals.

Seems like floating applications might works as well, a large raft of connected plastic bladders on a reservoir might work. Reduce water loss due to evaporation by decreasing light hitting the reservoir at the same time as generating power.

I had a dream that some super-algae leaked out of a lab and colonized the oceans killing nearly all marine life.

The super algea we are looking for here, would likely have no chance in the wild anymore, because to optimize some desired traits (thriving in a protected, stable environment) usually means giving up on other traits, which will force them down when they have competition. (same argument applies to GMO plants)

Are you sure your memory isn't just a bit hazy from last time that happened? I think there are credible reasons to believe the lab leak never happened, but anyone could be forgiven for losing some details in two and a half billion years.

The energy embodied in the metal used to make their housing is more than the entire possible energy they could make in any reasonable timeframe.

So no, this isn't scalable.

On top of that despite them saying the anode was not corrected, it's almost certain the algae aren't making any electricity at all, it's all coming from the cathode and anode oxidizing.

It's easy enough to tell - just let them die and let's see if there is a different in energy output. I can almost guarantee there will not be any difference.

To be fair, I was unable to find the original document, so we don't actually know how many watts the algae generator can provide, we only know how much the computer that they used consumed, also they did note that after 6 months the algae was dead.

That being said, I'm sceptical about the scalability of the algae generator because it's efficiency would have to increase by about 1000x (if we assume that right now it can generate what the computer used while calculating).

Today an average AA battery has t the capacity of 3Wh some even 4Wh. And at 3Wh you could, theoretically, charge your phone at 5V 1A for like half an hour or there about.

Our in other words, what I'm talking about when I question the scalability is energy density. That's the reason why you can do more then 700km with a car that runs on fossil fuels and maybe 350km if it's not too hot and not to cool with an electric car.

Could we engineer there algae to be 1000x times more efficient or even just 500x more efficient, since as long as the algae is alive you don't really need to charge anything. You do need the sun though, these are, from what I understand photosynthetic algae.

I remember running a calculator via a potato battery when I was much younger.

Just in case you don't know: The energy to power your calculator did not come from the potato. It came from the metals you used in the potato. The metals are slowly oxidizing and that reaction (a kind of burning) produces the energy.

The same thing is happening here - it's not the algae producing energy, it's the metal anode and cathode.

Did you read the article?

> "Because the experiment ran without any significant degrading of the anode the researchers believe that the cyanobacteria are producing the bulk of the current."

How was this quantified? How much degradation would be expected if the amount of power were to be drawn from the equivalent battery without algae?

I read the article. I saw what they said and I do not believe them for the following reasons:

1: Looking at an anode and saying "yup not corroded" is not how you check such things.

2: If they actually wanted to check it, there are several methods, they did none of them. They include: Weighing it, killing the algae and seeing if the power output changes, trying other metals for the anodes, trying other plants instead of algae in the water.

3: If you put salt water between two anodes you will get electricity. Period. If they claim this didn't happen, and "the algae did it", you're going to have to posit some method for the algae to prevent this, while substituting their own electricity. This will require new chemistry.

4: Algae are non-polar, so I don't see how they can direct the positive and negative current toward the proper anode to make electricity.

I have read the paper. They showed photosensitivity by both autoclaving the sample and adding DMCU to prevent photosynthesis. Both reduced power production. They do suggest a component of power production is related to electrolytic activity because they observe a dark setting power production; under a light setting the power production nearly doubles.

They also discuss the possibility that the algae are just promoting the oxidation of the aluminum, but do a series of assays I don't fully understand and conclude that some of the current produced is most likely from the algae themselves.

Link to paper: https://pubs.rsc.org/en/content/articlehtml/2022/ee/d2ee0023...

Agreed that it's not a lot, but it was also very small.

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