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Comment by jefflombardjr | Hacker News Reader

I'm all for exploring new approaches, however:

a) Salt water is highly corrosive. Wouldn't maintenance costs be high?

b) Isn't marine biology highly sensitive to heat pollution?

For high latency services like Amazon Glacier, wouldn't it make sense to host in a place like Iceland? Really cheap hydrothermic/clean power. Highly educated local talent pool, and relatively consistent cool temperatures. If you're maintaining 80F (http://www.datacenterknowledge.com/archives/2008/10/14/googl...) the ambient temps outside should provide ample cooling year round.

For lower latency requirements, wouldn't it be worth it to install efficient cooling powered by electricity? (preferably renewable) With cheap solar who really cares about grid power loss and associated inefficiencies?

Essentially, I think it makes sense to get better at solar than to have Steve Zissou as a server admin.

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Essentially, I think it makes sense to get better at solar than to have Steve Zissou as a server admin.

1) In the original article, these server farms would be remote administration only.

2) Such facilities would make the secret construction of one's James Bond Villain underwater base much, much easier. (Wouldn't Elon Musk, Jeff Bezos, and Peter Thiel all make great Bond villains?)

Don't forget Larry Ellison, the original tech CEO-cum-Bond Villain http://www.josephrosenfeld.com/wp-content/uploads/2013/06/La...

Kim DotCom needs a good place that is in international waters so he doesn't get extradited.

Villains are sometimes just victims of their circumstances and trying to survive.

Elon and co are the secret villains.

Villains are sometimes just victims of their circumstances and trying to survive.

Julius Caesar is the quintessential example of someone who becomes something just out of trying to survive. He was a hero to many and a villain to many as well. I wish more villains were written that way.

>Wouldn't Elon Musk, Jeff Bezos, and Peter Thiel all make great Bond villains?

You know if Elon Musk tried to take over the world as a benevolent dictator I'm not entirely sure I'd fight against it...

Lord Acton comes to mind.

> b) Isn't marine biology highly sensitive to heat pollution?

Impact on the marine environment is briefly mentioned in the last couple of paragraphs of the article, although they're a little dismissive and don't provide any evidence supporting their claim of negligible impact.

Nuclear power plants usually dump their tertiary cooling water into the ocean. That's not a great situation for the local sea life (within a few hundred meters, IIRC), but doesn't have much significance beyond that. That is several orders of magnitudes more heat output than could conceivably come off a data centre. So their dismissiveness is likely warranted.

A bit more concerning is the notion of relocating these data centre pods. Long-term "reefs" that are relocated around the world could perhaps be a new and different vector for transmitting invasive organisms. I'm not an expert, but I'd want to hear a few of them opine as to whether this creates any risks that ordinary shipping does not.

A 1 GW reactor puts 2 GW+ heat into the sea, a river, or lake.

A server sub would put 200W * (say) 1000 servers, or 0.0002 GW.

> "A bit more concerning is the notion of relocating these data centre pods"

What are the requirements for cargo ships? I suspect they run into this regularly when in a dock for extended periods or undergoing maintenance that doesn't require a dry-dock.

>Nuclear power plants usually dump their tertiary cooling water into the ocean

The heated water from a power plant can actually provide a refuge for manatees and other wildlife that prefer warm water during cold winter. They're actually known as good fishing spots in Florida!

Nuclear power plants usually dump their tertiary cooling water into the ocean.

Nuclear plants also use cooling towers to lower the temperature before it dumped back into a lake/river/ocean. You can do a Google search, but those towers are hollow on the inside. Water runs down the inside walls and convection currents move up.

Yes, but not always. When the body of water is big enough, they don't need cooling towers.

I don't think the plan is relocations. More than likely, MS see server numbers growing over time, at the very least for the foreseeable future, and they'll be located once, and then decommissioned, not moved.

That may change, but I doubt there are less server farms in 2020 than now.

As a side note, isn't that also Google's plan - the server farm as a single entity, where nothing is really fixed, just turned off and eventually replaced? In such a world, where a server farm exists then dies, underwater seems a great place for them. No regulations, no repairs, locally powered via means that no one can complain about (NIMBYism is a powerful force) just run until decommissioned.

The claim is:

> The water just meters downstream of a Natick vessel would get a few thousandths of a degree warmer at most.

Sounds negligible to me, but I'm not a marine biologist. Would be interested to hear a specialist weigh in.

I'm not an expert either, but one should keep in mind that this was an experiment with a single vessel. Even the shiny PR images in the articles show clusters of hundreds of vessels for actual operation. So it's more "few thousandths of a degree times X" and that seems less harmless to me.

A single coal power plant is negligible to the environment too. Half the world powered by coal isn't.

It would be interesting to know how the heat from such data centers would compare with active submarine volcanoes and submarine hydrothermal vents.

Some of them apparently are at 500°F [1].

[1] http://geology.gsapubs.org/content/34/6/453.abstract

The sun provides over 1GW/sq km when it's shining. The biology seems to get by fine with that.

> The sun provides over 1GW/sq km when it's shining. The biology seems to get by fine with that.

The issue is the amount of heat relative to the environment in which flora and fauna have evolved to survive, not relative to absolute zero.

It's like saying that a 313 Kelvin body temperature shouldn't bother me because I do fine with 310K (~37C). It's only a 3K difference, after all.

OTOH, that 1GW drops to almost zero at night.

> 1GW drops to almost zero at night

I'm not sure what that means (or if it's really true). The temperature at night doesn't drop to almost (absolute) zero; the oceans don't freeze; so plenty of the Sun's energy must still be present.

The initial statement was power/area, the instantaneous energy input from the sun, given as 1GW/sq km. The energy input from the sun at night really is pretty much zero.

The initial statement argued that because organisms are "fine" with 1GW/sq km, they therefore should be fine with the additional heat of a datacenter. I disagreed with the conclusion, not the number.

The second statement was that "OTOH, that 1GW drops to almost zero at night." It may be a literally true statement on its own, but it's misleading in response to a statement that absolute zero isn't a realistic basis for this discussion.

That's fine if you think it was misleading, my point was that the intended meaning was clear enough in context.

That the ecology is able to handle variations in temperature, even large ones, does not mean it can handle an absolute shift. 10±5 degrees is not the same as 11±5.

For a, you can put a sacrificial anode on the frame. Given that the rate of corrosion should be known, the size of it can be calculated to however long the pod is expected to be in service.

This sounds really interesting, can you explain it further for a layman? (Not being snarky, I genuinely know very little about chemistry)

See this article: https://en.wikipedia.org/wiki/Cathodic_protection

This is probably what OP meant:

"They are made from a metal alloy with a more "active" voltage (more negative reduction potential / more positive electrochemical potential) than the metal of the structure. The difference in potential between the two metals means that the galvanic anode corrodes, so that the anode material is consumed in preference to the structure." https://en.wikipedia.org/wiki/Galvanic_anode

Basically, the reason that things corrode is that there are dissimilar metals, one with more electrons than the other creating a voltage between them. So your part is a battery and the ocean is the "wire". The electrons move from your part (corroding them), to other parts with less electrons. If instead you have a sacrificial piece of zinc, the zinc has more electrons than your part so the electrons will come from the sacrificial piece of zinc instead of your part. Think of it like a lightning rod, but for corrosion instead of lightning. It's more complicated than this, but that's the general idea.

It's fairly common on boats to have exposed zinc whose only purpose is to be sacrificially electrolized (IIRC) to protect your steel or aluminum.

I worked on a 120m old passenger ship for a while. During dry-dock each year we'd put 8 or so 2kg (ish) zinc anodes around the hull, a welded bracket around each one.

The trouble was that they're pretty expensive, and zinc has a great resale value - so we had to do extra watches around the lower decks with rigged firehoses to try and stop local divers stealing them who knew we'd just come out of drydock. (This was in the Philippines). We lost several that way.

I will say that my only experience with sacrificial anodes is that they help but don't prevent corrosion entirely. We had screws starting to turn to dust from a couple hundred hours of pool water exposure even with a sizeable anode. Maybe it wasn't in sufficient contact or whatever. They're unlikely to be curealls anyway.

One thing about sacrificial anodes is that multiple seem to be required. E.g. even though the hull of a ship may be a good conductor, you don't just have one sacrificial anode.

Wikipedia ["Galvanic anode"]: The arrangement of the anodes is then planned so as to provide an even distribution of current over the whole structure. For example, if a particular design shows that a pipeline 10 kilometres (6.2 mi) long needs 10 anodes, then approximately one anode per kilometere would be more effective than putting all 10 anodes at one end or in the centre.

I came here to say the exact same thing. The resistance of the metal surface will mean you want to cover the metal needing protection all around. I think dependant on the salinity of the water different metals should be tested to best suit you environment.

Hmm, my experience is with pretty small objects: light enough to be carried by two people.

>Isn't marine biology highly sensitive to heat pollution?

The ocean is really, really big.

Consider that there are many underwater volcanos. A data center would be negligible.

> I think it makes sense to get better at solar

Then why don't you "get better at solar" and become rich in the process? What did you say, it's too hard, practically impossible? Yeah, life's a bitch, isn't it?

> Salt water is highly corrosive.

To metals. Not so much to plastics.

> Isn't marine biology highly sensitive to heat pollution?

Isn't land-based biology highly sensitive to heat pollution?

> Isn't land-based biology highly sensitive to heat pollution?

No, land-based organisms comparatively have a much, much higher tolerance to temperature swings.

Water's high heat capacity and conductivity means that most marine environments have extremely stable temperature ranges (a few degrees one way or other), so most marine species are adapted to live in only that range, and quickly die otherwise. Tropical fish are hard to keep alive precisely for this reason.

Air temperature varies much more widely depending on time of day, season, and weather, so terrestrial organisms have all developed extensive strategies for thermoregulation (e.g. mammals, birds). For example, dogs can survive in both arctic and tropical environments.

Plus, while heat is naturally dissipated upward, underwater thermal plumes are more likely to affect fish than above-ground plumes would affect birds.

FYI, Cornell uses lake water to cool several campus buildings, and they needed to carefully review that the warmer return water wouldn't negatively affect fish [1].

[1] https://energyandsustainability.fs.cornell.edu/util/cooling/...

Sunlight imparts about a kilowatt per square meter to the surface of the ocean at noon, I'm not exactly sure how to use that information, but it does seem relevant for bounding the problem.

The specific heat of water is much higher than that of air.

Right, but the data center heat output will also be measured in (mega)watts.

This gets a lot lower with differing latitudes and seasonal and daily cloud cover/evening time - closer to 100 W/m2 [1]. So over a day you'd get 2.4 kWh. In comparison an electric space heater uses about 1 kWh of energy in an hour.

So how much will 2.4 kWh change the temperature of a cubic meter of water at the ocean surface?

Density of water = 1000kg/1m3 so mass = 1000 kg

2.4 kWh = 8640 kJ

Heat_Energy = Conductance * Mass * change_in_temp

8640kJ = 4.186 kJ/(kg⋅K) * 1000kg * xC

x = 2C

So solar heat will change the first meter of water by about 2C over the course of a day. That's a small number b/c solar radiation is not a huge contributer to temperature swings. Instead what will effect the temperature difference is the seasonal change. If we can calculate the heat energy gained or lost due to seasonal extremes and water temp, then we can figure out what the range of acceptable heat energy is for surface water.

[1] https://www.withouthotair.com/c6/page_38.shtml

ETA: logic.

> To metals. Not so much to plastics.

I'm guessing you've never experienced the joys of owning a 30 to 40 ft sized, completely non metal (fiberglass hull) sailboat kept in salt water, with all of the great fun of paying to haul it and have the marine growth scaped off, pressure washed, double or triple coat bottom paint re-applied, etc. Just because it's not metal doesn't mean it doesn't attract the category of what the maritime industry lumps together as "marine fouling".

Though marine fouling is primarily of concern for fiberglass boats because it massively increases drag which admittedly is less of an issue for a datacenter. It's still an issue for the pods as mentioned in the article, but I'd expect it to be less grave than on a boat.

Marine fouling of the heat exchangers is probably the biggest technical hurdle.

Yes, as well as keeping all kinds of marine life out of there.

But I require a datacenter with a hull speed of at least 7.5 knots.

let me double check the hull speed formula for datacenters.

GP was quite specifically taking about chemical corrosion, not bio-fouling. Even if the marine industry conflates these (I can't tell if that's what you're implying in the last sentence), we don't have to.

Plastics are good, but you need to have tubes going into the thing, as well as some means of accessing the inside even if you only access it on a ship/land. That means rubber and metal will have to be on the exterior somewhere.

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