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Chile wants to export solar energy to Asia via 15,000km submarine cable

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Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#121

Post by simion314 »

trixie_ wrote: post #107
simion314 wrote: post #97

Earlier quoted context omitted.

You mean Elon companies that have received a ton of money from various governments? Without the government Elon would make cars for rich kids only.

If only the government had helped Boeing and Ford, they could be as successful as SpaceX and Tesla.

First of all I said "goverments" so I don't meant he USA one n particular, Tesla made a lot of money from other goverments too.

Second, the US government from my understanding is doing an pretty open bidding, so SpaceX benefited from that, the reason no SpaceX appeared before is not something I can speculate , maybe there was a need for a new generation of people , or maybe we needed IT to evolve, I am not sure.

I also have no idea if SpaceX would ahve existed if they could not have benefited until now and from now on on government contracts.

Also let's not pretend to forget that SpaceX internet stuff is based on government research/invention. No government no roads for Tesla to run on, no Internet for Starlink to exist.

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#122

Post by frazbin »

elil17 wrote: post #110
frazbin wrote: post #101

Earlier quoted context omitted.

hmm, 500 gigawatts dissipated over 300k square gigameters of ocean surface gives a forcing effect of 1.6 milliwatts per square meter. Global warming right now is forcing 1w/sqm, so it's not a problem at this scale. But it's not a crazy question either.

It’s not evenly spread, though. It’s concentrated along the cable. It won’t heat up the ocean much as a whole, but it will create “hot spots”, which may change the balance of ecosystems in the regions of the ocean the cable passes through. Worth it to stop carbon emissions? Absolutely, in my opinion. Something that should be considered and minimized if possible? Also yes.

That's a good point. 500 gigawatts over 15 megameters gives 20kw/m of local heat to deal with, which sounds kind of yikes.. but then again a pool heater draws 5kw. Seems clear the biggest effect will be on the seabed-- but that's already true because you gotta drop the cable. I reckon the cable itself, and its underwater infrastructure, might have more impact than the heat it generates. Another consideration is that there have always been heat sources in the deep ocean.

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#123

Post by labawi »

dukeyukey wrote: post #12
souenzzo wrote: post #4

Isn't cheaper turn the electricity into liquid hydrogen?! Hydrogen can be stored for months, delivered by car, tubes, ships, etc Do not have many losses across long distances

> Isn't cheaper turn the electricity into liquid hydrogen?! Creating hydrogen is about 80% efficient, so you do lose a fair bit in the process. > Hydrogen can be stored for months, delivered by car, tubes, ships, That's the thing about hydrogen, it's tricky to store for long periods of time. It leaks real easy. And liquid hydrogen isn't very dense, about 7% of that of water, so it's hard to ship it in bulk. And at th…

> isn't very dense, about 7% of that of water

That's not a good metric. Hydrogen has about 2-3x energy density per mass vs carbon fuels. H₂ is about 120MJ/kg, while carbon fuels are about 35-55 MJ/kg, gasoline/diesel is 45 MJ/kg.

Per volume, gasoline - 34 MJ/l, liquid methane 22 MJ/l, liquid hydrogen 8.5 MJ/l. Much smaller, but not laughable 7% (14x).

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#124

Post by zardo »

rich_sasha wrote: post #98
GDC7 wrote: post #71

They have just overlooked that China has a solar area which is comparable (or just a tad inferior to Chile's). Gobi Desert. It's far easier to harness solar there and then push it onto the coast than building a 15,000km submarine cable

Gobi is famously dusty, is that a factor? Also a lot of Chile is at high altitudes (thing Atacama), are PVs more efficient there?

I don't think altitude affects efficiency, but it does effect the light intensity, particularly in ultra-violet.

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#125

Post by bryanlarsen »

jhawk28 wrote: post #55
bryanlarsen wrote: post #26

Casey Handmer calculated that it was cheaper to produce solar power in Boston for local use than it was to ship solar power from Arizona to Boston.[1] Solar power is 3X as expensive to produce in Boston, but HVDC lines are even more expensive. If it's uneconomical to ship from Arizona to Boston, then Chile to Asia seems even more problematic. Although in this case the submarine HVDC line is competing against batterie…

I think the chile to asia is going to be cheaper than AZ to Boston because there is just ocean between chile and asia. It will be much more expensive over land and dealing with all the things in the way (roads, houses, railroads, tunnels, mountains...).

The articles have the cost at $1000/km for overland and $1500/km for undersea respectively.

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#126

Post by swarupberia »

China had presented its concept of a Global Grid to the UN in 2015. (https://reconasia.csis.org/global-energy-interconnection/). They already have a ~3,200 km line at 1100KV UHVDC (https://www.reuters.com/article/china-power-transmission-idU...) Losses are estimated at 1.5% per 1,000km. 3.5% is for 800KV UHVDC. Implies a 23% loss for 15,000 km, which is very efficient. For perspective, ~20,000 km is the half circumference at the equator. Geopolitics should not be a concern for such a global grid. We are already living with a globally interdependent submarine internet cable, in the same geopolitical environment. This transmission line is a natural step for a much faster adoption into a renewable future, than batteries. In battery tech, research investments have to compete on multiple pathways for the development of battery chemistry which are very divergent from each other. UHVDC components and technology require very few fundamental breakthroughs in science and technology, and massive strides have already been made. A good read from ABB on the state and evolution of UHVDC technology here -> https://library.e.abb.com/public/db368ad7692f4c129637d9a7eff.... Do read the last two paras – “Conclusion” and “State of HVDC system and transformer technology”. TLDR: HVAC/UHVAC and HVDC/UHVDC are now almost fully interoperable to feed into each other at all voltage levels. Dielectrics supposedly the most complicated of the technology challenges also appears solved. With global political coordination, it should be easy to commit investments and policy frameworks to rapidly transform the world into a renewable reality.

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#127

Post by aaron695 »

CoastalCoder wrote: post #50

I'm curious about this from a security perspective. With oil, coal, and natural gas, a cut in the supply network doesn't necessarily have an immediate impact. Buffers exist in some parts of the distribution network: ships holds, rail cars, and storage tanks. With electricity, it doesn't seem like we have much infrastructure for buffering the supply. So cutting those cables might have an immediate and significant impa…

It allows energy independence for a time of war and trouble, since you can install complex locally producing projects relying on a global grid to smooth them out.

Then at war, your local supply will have it's normal ups and downs, but you'll be self sufficient.

> Perhaps this creates a disincentive for any of these powers starting a war.

Or... we can just stick with Golden Arches theory and not move that to critical infrastructure.

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#128

Post by nuccy »

philipkglass wrote: post #14

European Commission Joint Research Center Technical Reports: HVDC Submarine Power Cables in the World https://publications.jrc.ec.europa.eu/repository/bitstream/J... According to table 1, losses for 800 kilovolt HVDC systems can be as low as 3.5% per 1000 km. That comes to 52.5% loss over 15,000 km. Losses should go lower at 1100 kilovolts (the highest voltage HVDC systems running today) but I can't find detailed los…

Total losses in case of 1100 kV line can be found as follows. As correctly commented below 3.5% loss per 1000km yields to 58.6% retained power over 15000km. So I will use 41.4% loss on that distance for my napkin calculation.

P_total = V_in * I_in, and P_loss = (V_in - V_out) * I_out

Since the charge flowing into the cable should exit on the other side I_in = I_out, then:

1 - V_out/V_in = P_loss / P_total = 0.414, and V_out = 0.586 * V_in = 468kV.

Voltage drop in 800kV line: V_in - V_out = 314kV = I * R (since lossses in DC lines are mostly due to heating, unlike AC lines where there is also capacity induced resistance).

Assuming that the same wires are used to transfer 1100kV DC current (i.e. resistance is the same) we can outline two cases:

A) you want to transfer the same inflow power on the Chilean side, then the voltage drop would be a 800/1100 fraction in comparison with 800kV line, i.e. V_in - V_out (1100kV case) = 314 * 800 / 1100 = 228kV. So the total loss is 20.7% (1.54% per 1000 km)

B) you want to transfer the same outflow power on the Asian side (i.e. smaller current due to lower voltage), then the voltage drop would be 162kV (there is a simple quadratic equation, if instead of considering inflow powers, one considers outflows which depend on V_out), so the total loss is 14.8% (1.06% per 1000 km)

Summary: same (as in 800kV line case) inflow power on Chilean side - 20.7% loss, same outflow power on the Asia side - 14.8% loss.

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#129

Post by [deleted] »

elil17 wrote: post #91
disco_nap wrote: post #78

Earlier quoted context omitted.

Are the losses thermal? How significantly could this change the ocean temperature near the cable? 50% of 600 GW is enough to cause a 10C increase in the temperature of 10 million liters of seawater every second?

The short answer is that if 10,000,000 L/s of well mixed water passed over the wire, it’s temperature would increase by 0.75 degrees Celsius. The long answer is that this is not quite the right way to view the question. There will be a temperature gradient around the cable - a zone where water is heated. The question is, how hot is this zone and how large is it. The cable will be buried, which makes the zone larger a…

[deleted]

Re: Chile wants to export solar energy to Asia via 15,000km submarine cable

#130

Post by jdmichal »

_Microft wrote: post #84
sudhirj wrote: post #69

Earlier quoted context omitted.

For one, the power cables seem to be thicker and better shielded than the fiber optic ones. That aside, I don’t think any economy will rely purely on imported power - backups in the form of natural gas plants or grid scale storage will likely need to form part of the mix - there’s already the chance of some cloudy or rainy days over the solar farms, so it’s unlikely there isn’t a contingency.

There was a study recently that used historic weather, solar irradiance data and energy use data and worked out that a certain mix of (over-provisioned) solar, wind and 3 hours of storage would have sufficed to provide energy during almost all hours of the studied decades. https://www.nature.com/articles/s41467-021-26355-z

I'm not sure where you're getting that "almost all hours" from? Here's the relevant figure, which seems to indicate hundreds to thousands of hours under your given scenario:

Please note the logarithmic scale on the hours!

https://www.nature.com/articles/s41467-021-26355-z/figures/4

(Note the green lines are 1.5x generation, with three lines at different saturations for 0 hours, 3 hours, or 12 hours of storage.)

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