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Comment by cwmoore | Hacker News Reader

> Salt water destroys everything

This is the statement I hear relating to all kinds of ocean-based renewable energy ideas. Sources are never provided.

The problem must have to do with economic viability and the replacement/maintenance costs exceeding savings.

Could you supply sources to elaborate on where the break even point of solar tail (or any two other ocean renewable energy) systems would be as relates to costs and benefits?

Edit: I don't really want to argue whether or not steel rusts in saltwater. My argument was that the break-even point of a "solar tail" is dismissed out of hand without sources because of land-based technologies being considered as the only ones.

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> Sources are never provided.

We also do not need to provide sources for statements such as 'water is wet'.

Anything on a boat, or even shoreside near to the ocean is subject to corrosion and corrosion protection is a serious maintenance issue. I've lived 2 km from the sea and even there the nails would rust right out of the building due to the salt that the wind would carry in.

My request was not intended to be asking for sources about corrosion, but for sources as to why corrosion should be the limiting factor. I would edit it to lead with the question it asks in the third line, if it weren't now too late.

There’s a reason why pictures of “beautiful” beach front houses are usually from a long distance away: they are usually in pretty rough shape.

Yes, salt water is corrosive. And yet, there are metal ships with viable lifetimes. This sub-thread is a bit less helpful than I am asking for.

Edit: Come on. It's not impossible to engineer for ocean use.

Wave power generation: https://www.bbc.co.uk/news/uk-scotland-scotland-business-250...

Longer term: https://en.wikipedia.org/wiki/Submarine_power_cable

Salt water is so corrosive that there is a whole branch of materials science dedicated to coatings and all kinds of other anti-corrosion measures such as galvanic protection using sacrificial material. The evidence is overwhelmingly on the side of statements such as 'simple systems that work well on the shore need extensive rework for ocean deployment assuming they can work at all'.

Even a simple scratch is enough to lay all your carefully produced work to waste.

Agreed that the environment is vastly different than on land, that a scratch through a coating is akin to no coating at all, that anti-corrosion measures are a constant vigil in oceans.

But I asked for sources treating the proposal in the original comment, and got told that "water is wet".

It’s obviously not impossible, it’s just expensive, which is a problem in the given context.

How big is the check and why? That's what's so hard to get an answer for when people are determined already to not to try. I mean, I guess I have Google and a long-weekend. I was hoping for someone to drop an URL that can explain this and provide key terms.

Throw out a speculative idea, get a speculative answer.

Dunno why you’re expecting me to go all civil engineer on you, nor do I understand why you’re acting like I’m the barrier to the idea being tried.

Go do the math yourself, it’s your idea.

It wasn't my idea. My idea was that it shouldn't be dismissed for the reason you presented without a citation.

What can be asserted without evidence can also be dismissed without evidence.

As there's a well known consensus that some factor (e.g. saltwater caused maintenance issues in this particular case) tends to be a game-breaker, then it's perfectly reasonable to dismiss 'without a citation' ideas that encounter this factor if the idea has no mention/citation of how they're going to fix, avoid or tolerate this.

If there's a plausible-seeming way that the idea can work despite the obstacle, then by all means we can discuss if that way will be sufficient or not; but if the idea simply ignores major problems, then there's nothing to discuss.

Point taken regarding your first line, though that sword would cut both ways I think. See https://news.ycombinator.com/reply?id=17886400 regarding the second and third.

Here's a source for you that mentions that even some typical formulations of stainless steel are susceptible to corrosion in saltwater:

https://www.clintonaluminum.com/304-stainless-steel-in-seawa...

White bread is bad in saltwater too, that doesn't mean there aren't better materials for the application.

https://www.quora.com/Does-aluminium-react-with-salt-water

https://en.wikipedia.org/wiki/Organic_solar_cell

That's the point of the source you requested and I provided: there are some formulations of stainless steel that are actually kind of ok in salt water despite most being poor.

No one is arguing that it's impossible to build a bear with solar panels. The point is that you can't slap a cheap panel from Alibaba on a float and have any assurance that it will work reliably. Thus costs go up and the whole idea may become infeasible.

Salt water destroys everything so don't build boats guys

I don't have a source, but as an engineer working for the US Navy, we are frequently told that the Navy spends an enormous amount of money on corrosion control. Like, in the billions to tens of billions of dollars per year. As a consequence, corrosion control is a significant fraction of the Navy's R&D budget.

https://www.gao.gov/assets/650/647926.txt

https://www.onr.navy.mil/en/Science-Technology/Departments/C...

Thank you.

How would you keep them clean enough to produce optimal output? Every drop of salt water would quickly dry and leave a salty residue. How do you clean that while at sea?

I am not the author of the original comment, but I really like the concept. From what I understood this would be floating at surface level and would be continuously washed over by surface water.

There are many good objections. It may be that the original comment does not illustrate the promise of this energy platform very thoroughly.

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