It's also possible that a direct increase in ocean temperature has undesirable knock-on effects that don't take place if you operate on land.
https://assets.nrdc.org/sites/default/files/power-plant-cool...
https://www.sciencedirect.com/science/article/abs/pii/S00253...
https://res.mdpi.com/d_attachment/water/water-11-02577/artic...
I think on a smaller scale test with an artificial pool would provide some solid answers. We could even put solar panels across the surface to limit wind and solar evaporation effects
"I think on a smaller scale test with an artificial pool would provide some solid answers. We could even put solar panels across the surface to limit wind and solar evaporation effects "
If it's artificial pool you'd need evaporation to cool it.
Please correct me if I'm wrong.
Thermodynamics should really be emphasized in schools. You are getting some amazing responses that are completely ignoring the fact that our renewable energy solutions are not increasing the overall heat in our planet. They are just moving energy around.
The only thing that really matters is how are the emissions going to look like when we are manufacturing renewable energy equipment (either new capacity or replacing faulty ones).
They do. And so does every single thing we build that's exposed to the outside - bulding, cars, even you when you are out and about.
The effect is minuscule unless we are turning the planet into Coruscant or this is a gray goo scenario.
Oceans warming up is a big thing, and local effects can be substantial even if global average change is negligible.
The effect of a human on the planet is miniscule, but we're still in the bad state we are.
We're looking at covering the planet in solar panels, worth considering how the albedo changes will effect things on a planetary scale.
More importantly, being "free in terms of CO2" is still an all-else-being-equal perspective. It's focusing on one aspect (CO2 emissions) of one small cog (a CO2 extraction+storage plant). If we look more broadly, each barrel extracted is offsetting less than one barrel being burned elsewhere (since nothing is 100% efficient). CO2 extraction and sequestration is thus a form of power transmission: the work that is required to offset emissions (e.g. from a car) is being performed away from where the emissions are made (although for flue capture this might be quite close!). For example, we can think of these as being roughly equivalent:
- A fossil fuel car with solar-powered carbon capture and storage onboard
- A fossil fuel car with solar-powered carbon capture and storage in some other location
- A solar-charged battery-electric car (+ a little CCS to offset manufacturing emmissions, etc.)
These are all solar powered and carbon-neutral (as long as they offset enough). Let's say they each receive a similar amount of solar energy: the first will not get very far, since offsetting is very energy intensive and it needs more fuel to carry the solar+CCS equipment. The second is more efficient, since the fuel doesn't need to move the solar+CCS equipment; it's as if the offboard CCS is transmitting a little extra power to the car. The third will get much further, since the battery and electric motor make much better use of the solar power than the CCS system.
The first approach is clearly silly. The second is useful in situations where renewables can't be used directly (e.g. jumbo jet fuel), but is incredibly wasteful and expensive compared to the third. The third approach is best, and should be used as much as possible.
If somewhere has an abundance of renewable power (e.g. geothermal in Iceland), then "transmitting" it elsewhere via CCS is much less efficient than, say, laying a high-voltage DC line; or moving high-energy, location-agnostic activities to the region like aluminium smelting or datacenters.
Doesn’t matter is strong. It won’t in the short term. But as we continue increasing our energy use as a species, the simple thermal problem of waste-heat management will certainly surface.
Of course, heating water locally, etc, can cause its own environmental impacts.
Hydro, wind and waves are probably at that ideal except to the extent that they are tidal energy.
Solar panels... are literally in the business of making the planetary albedo higher, to the extent that they do so they are introducing thermal energy.
Geothermal is in the business of increasing the rate at which heat escapes from underneath the surface, which increases surface temperature.
Tidal energy is in the business of extracting energy from the kinetic energy of the moon, which probably increases the temperature of earth (but it's hard to say to what degree).
Fusion (if it ever becomes practical, and you count is as renewable) is in the business of releasing potential energy trapped in hydrogen atoms, increasing the temperature. This is particularly problematic because fusion would also enable us to increase our energy usage to the point that direct heating becomes a problem at the same scale as CO2 release currently is.
Fission (if you count it) is like fusion.
Space based solar (if it ever becomes practical), is increasing the area of the sun captured instead of the albedo, and is directly introducing energy.
Etc
If you think that's silly (and rightfully so), then perhaps that can sharpen your intuition on how insignificant is the total amount of heat produced by our devices (even if cumulatively they are a big looking number); the total amount of radiation that comes from the sun down to earth is staggering.
IR might be reflected or absorbed.
The visible component is absorbed. Whether it would have turned into heat or reflected back in to space is about a 1 in two chance.
Growing a 100 trees and chopping them into lumber is less hot than growing 100 trees and burning them.
If all the sun's energy were converted to heat (and not radiated away), we'd be in big trouble. That's what "carbon" pollution is all about -- Carbon dioxide is a greenhouse gas that traps heat. Reducing albedo is one way to increase tempterature, but directly burning stuff is another way.
The point was, coarsely: using e.g. solar panels only changes the Earth's surface temperature to the extent it changes albedo. (Ignoring second-order effects of concentrating heat and associated effects on radiation, etc.)
The 84,000 ppm for 60 minutes is roughly the lethal CO2 concentration. Local CO2 concentration is often several times atmospheric CO2 levels. That’s clearly addressable but I suspect around 8,000 ppm atmospheric we would start to see deaths from this which is achievable from coal deposits. Reaching a fully lethal atmosphere is of course much harder.
So, I think you’re right temperature pollution at extreme levels is worse.
I don't know how this would compare between underwater datacenter, solar panels, wind.
Where do you get that idea? A typical EER 12 air conditioner will move 3.5x the heat energy that it consumes (COP = 3.5) [0].
At the location of the hvac it puts 130% of the source heat into the environment.
But 30% of that heat put into the environment came from electricity generated in a power plant. Power plants are typically less than 50% efficient, so it put's out as much heat into the environment at the source of the electricity. Bumping the value to 160% (130% + 30%).
However waste heat is a small fraction of the heating that electricity generation produces. Very roughly 10 times as much heat is trapped via the CO2 released than heat is released by the power plant. Bumping that value up to 460% (160% + 30% * 10).
I.e. 4.6 units of heat are put into the environment for every unit of heat removed from a closed system.
(Obviously the details of this depend dramatically on the environment. Heat pump efficiency depends on the degree of temperature gradient, CO2 release and power plant efficiency depends dramatically on where the power is coming from, which changes with where you are located.)
Also I think you're a bit pessimistic about modern power plant efficiency-- combined cycle plants do better than 50%, and that's before we're considering any benefit from renewables.
Fair point, I guess my argument makes more sense if we were discussing moving naturally occurring heat out (i.e. household ac) than with respect to cooling a datacenter.
Nitpicking the numbers used in the estimate... is probably not worth it. Every bit of it is a very rough order of magnitude number. If you're somewhere with 95% renewable energy it should be an order of magnitude better, if you're somewhere where energy production is dominated by an inefficient coal plant it should be an order of magnitude worse.
Wouldnt solar / Wind have a smaller CO2 foot print and hydro electric be more efficient ?
But without scientific sources, these are only wild speculations.
Consider, if you can achieve a fully passive cooling solution by dropping a datacenter into a lake, you've reduced the energy consumption in service of cooling by 100%.
(In reality, water cooling isn't "free," but I'm willing to bet the amount of energy required to dump heat into surrounding water is a whole lot less than the amount of energy spent for the compression cycles and forced air of above-ground HVAC systems. Water cooling using direct application of chilled water is already a thing, using lakes or retention ponds as places to dump heat; what being at the bottom of a lake gives you is a more consistent and proximate source of cool water than you might expect from a current chilled water distribution system)
Obviously this can be mitigated if you are able to get renewable power from a nearby source like a geothermal plant, hydroelectric, or solar. But if you are using fossil fuel power from a long distance away, that means any unit of heat moved by an HVAC involved many units of heat production to ultimately move that unit of heat.
P.S. am not HVAC wizard.
Overall an underwater data center should generate far less heat overall than an aboveground one.