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Comment by Retric | Hacker News Reader

You don’t need to do anything to keep panels with a significant angle clear of dust in deserts. The Sahara is near the equator but you can stow panels at night and let the wind do its thing.

The lack of launch costs more than offset the need for extra panels and batteries.

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What’s your source for that claim? Soiling is a massive problem for desert solar, causing as high as 50% efficiency loss in the Middle East.[1]

[1] https://www.nlr.gov/news/detail/features/2021/scientists-stu...

A relevant quote from that article.

“The reason I concentrate my research on these urban environments is because the composition of soiling is completely different,” said Toth, a Ph.D. candidate in environmental engineering at the University of Colorado who has worked at NREL since 2017. “We have more fine particles that are these stickier particles that could contribute to much different surface chemistry on the module and different soiling. In the desert, you don’t have as much of the surface chemistry come into play.”

You’re not summarizing the article fairly. She is saying the soiling mechanisms are environmentally dependent, not that there is no soiling in the desert. Again, it cites an efficiency hit of 50% in the ME. The article later notes that they’ve experimented with autonomous robots for daily panel cleaning, but it’s not a generally solved problem and it’s not true that “the wind takes care of it.”

And you still haven’t provided a source for your claim.

Shouldn't swarms of quadcopter drones zipping around the panels be able to handle that?

Wouldn't even need to be that 'autonomous', since the installation is fixed.

More like the things simulating fireworks with their LEDs in preprogrammed formation flight over a designated area.

You don't need quadrocopters. Solar panels arranged in rows have rails that cleaning robots can drive on.

Indeed, that seems unnecessarily complex for what is actually needed. I don't understand why the great grandparent comment seems to suggest it's an "unsolved" problem - as if grid-scale solar buildouts don't already have examples of things like motorized brushes on rails for exactly this already.

And it's always a numbers game - sure they're not /perfect/, but a few % efficiency loss is fine when it's competing against strapping every kilo of weight to tons of liquid hydrogen and oxygen and firing it into space. How much "extra" headroom to buffer those losses would that equivalent cost pay for?

And solar panels in space degrade over time too - between 1-5% per year depending on coatings/protections.

I’m saying the same thing she is, that soiling isn’t as severe in the desert not that it doesn’t exist.

The article itself said the maximum was 50% and it was significantly less of a problem in the desert. Even 50% still beats space by miles, that only increases per kWh cost by ~2c the need for batteries is still far more expensive.

So sure I could bring up other sources but I don’t want to get into a debate about the relative validity of sources etc because it just isn’t needed when the comparison point is solar on satellites.

You are again misquoting the article. She did not say soiling was "significantly less of a problem" in the desert. She in fact said it "requires you to clean them off every day or every other day or so" to prevent cement formation.

You claimed it was already a solved problem thanks to wind, which is false. You are unable to provide any source at all, not even a controversial one.

And that's just generation. Desert solar, energy storage and data center cooling at scale all remain massive engineering challenges that have not yet been generally solved. This is crucial to understand properly when comparing it to the engineering challenges of orbital computing.

Now you make me want to come up with a controversial source. The Martian rovers continued to operate at useful power level for decades without cleaning.

But but lack of water…

Anyway here’s some actual science on why going vertical makes a big difference.

https://link.springer.com/article/10.1007/s11356-022-19171-5

Thank you for providing a source. That’s an early stage research paper, not the proven solution you originally implied. There are tons of early stage research papers on all these problems on earth and in space. Often we encounter a bunch of complications in applying them at scale such as dew-related cementation[1], which is a key reason why they haven’t been deployed at sufficient scale.

That you point to the Mars rover, a mission with extremely budgeted power requirements, as proof of how soiling doesn’t pose an impediment to mega scale desert solar farms, only underscores the flaw in your reasoning.

[1] https://www.sciencedirect.com/science/article/abs/pii/S22131...

“I don’t want to get into a debate about the relative validity of sources etc”

> Not the proven solution

Yet you quote a paper saying it can work. “This impact can have a positive or negative effect depending on the climatic conditions and the surface properties.”

I have no interest in debating with you because I don’t believe you are capable of a honest debate here. The physics doesn’t change and the physics is what matters.

> doesn’t pose an impediment

Nope. I said it beats “space” not that soiling doesn’t exist. That’s what you have to demonstrate here and you have provided zero evidence whatsoever supporting that viewpoint. Hell they could replace the entire array every 5 years and it would still beat space.. Even if what you said was completely true, you still lose the argument.

The argument here is simply over your false claim that "You don’t need to do anything to keep panels with a significant angle clear of dust in deserts." Your only source does not, in fact, establish that, and cementation is in fact a challenge with desert solar -- something that happens much faster than every five years.

Repeating unsupported claims and declaring yourself the winner does not, it turns out, actually help you win an argument.

The same panel produces much more electricity in space than at the bottom of the atmosphere, because the atmosphere already reflects most of the light. Additionally, the panel needs less glass or no glass in space, which makes it lighter and cheaper.

Launch costs have shrunk significantly thanks to SpaceX, and they are projected to shrink further with the Super Heavy Booster and Starship.

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