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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

#141

Post by AnimalMuppet »

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…

10,000,000 L/s over 15,000 km. That's 15,000,000 meters. That seems quite likely to happen, and then some.

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

#142

Post by 5F7bGnd6fWJ66xN »

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…

Is it possible to lay fiber optic cables alongside and use the wasted energy to power up the cables for transmission?

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

#143

Post by dreamcompiler »

popinman322 wrote: post #93
mschuster91 wrote: post #53

Earlier quoted context omitted.

It's hard to build an actual network out of DC power, which is partially why AC power took over.

Looks like DC power is more efficient for long haul cables. https://engineering.stackexchange.com/a/19759

That's a good link.

Summary: DC is always a bit more efficient than AC. The reason our grid is AC is because high voltage transmission is much more efficient than low voltage transmission.* But you don't want multi-thousand volt feeds coming into your house, so voltage conversion is necessary. If you don't have power electronics, you have to use magnetic transformers to convert between voltages, and magnetic transformers only work on AC. Thus our electric grid is mostly AC.

Now that we have power electronics we can convert voltages without magnetic transformers, and AC is no longer a requirement except for backward compatibility.

*unless you have superconducting cables

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

#144

Post by adrianN »

mataug wrote: post #82
Negitivefrags wrote: post #80

Earlier quoted context omitted.

The whole point is that you can generate the power at different times. The deserts of the middle east get sunlight at a different time then South America. If we had a worldwide spanning power grid we wouldn't need to have a grid storage solution at all.

That's a good point, I can see how this could be better than battery based storage for night time. But I wonder if wind power coupled with some limited battery storage, geo thermal, and newer generation nuclear peaker power plants can solve this problem instead of laying a mega cable under the ocean.

A mix of power sources and some storage can of course solve this problem. The question is whether it is cheaper (or more desirable for other reasons). An infrastructure of a couple of HVDC lines that are vital for countries on different continents has very interesting geopolitical consequences for example. Imagine the bargaining power a country has if it can literally turn off the lights during the night in another country.

With fossil fuels it is at least easy to store months worth of energy, but still OPEC is quite powerful.

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

#145

Post by onecommentman »

sudhirj wrote: post #69
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…

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.

They would need to be thicker and better shielded. Sharks might very well be attracted to any EM generated and attempt to bite the cables.

https://www.oafrica.com/broadband/sharks/

Still sounds fairly fragile, but no more vulnerable I suppose than undersea fiber optic cables. But there is no alternative routing or satellite backup in this power transmission case.

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

#146

Post by elil17 »

AnimalMuppet wrote: post #141
elil17 wrote: post #91

Earlier quoted context omitted.

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…

10,000,000 L/s over 15,000 km . That's 15,000,000 meters. That seems quite likely to happen, and then some.

What seems quite likely to happen?

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

#147

Post by AnimalMuppet »

elil17 wrote: post #146
AnimalMuppet wrote: post #141

Earlier quoted context omitted.

10,000,000 L/s over 15,000 km . That's 15,000,000 meters. That seems quite likely to happen, and then some.

What seems quite likely to happen?

10,000,000 liters per second flowing past the cable.

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

#148

Post by CyberDildonics »

baybal2 wrote: post #137
lxe wrote: post #46

Earlier quoted context omitted.

It's a power cable, not a communications cable.

There is nothing preventing them to put more DC-DC up conversion mid-way.

Why would you use DC at all, and why would you put something in the middle? I don't think that makes any sense.

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

#149

Post by _Microft »

jdmichal wrote: post #130
_Microft wrote: post #84

Earlier quoted context omitted.

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.)

Thanks, I'll have another look!

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

#150

Post by baybal2 »

CyberDildonics wrote: post #148
baybal2 wrote: post #137

Earlier quoted context omitted.

There is nothing preventing them to put more DC-DC up conversion mid-way.

Why would you use DC at all, and why would you put something in the middle? I don't think that makes any sense.

To up the voltage
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