What's the voltage drop?

[EatenByLimestone]

over 15,000 km?

(broken link removed to https://www.yahoo.com/finance/news/building-2-billion-subsea-solar-210000939.html)


Just for giggles...

 

[semipro]

Superconductor? Carbon nanotubes?
One day the seafloor is going to be just as dangerous to navigate as near space what with all the anthropogenic crap floating around.

 

[stoveliker]

you'll get a nice ocean warming, dissipating all those megawatts on the (cold) bottom of the pacific....

 

[EatenByLimestone]

I've seen articles stating that it isn't feasible to power the northeast US from a PV array in the southwest desert. I can't imagine that its feasible to lay that long of a cable from Chile to China.

An interesting thought is how much buoyancy a ship would have to have in order to lay the cable across the middle of the ocean. Its holding up a lot of weight before that cable gets supported from the bottom.

 

[peakbagger]

There are some interesting concepts using superconducting cables to transmit large amounts of power long distances. The trick is keeping the super conductor cool. Superconducting cables are already in specialized use. MRI machines use them. It not a supportable technology just moving power one way (rural area to dense city but add in using liquid carbon dioxide that is being transported in the other direction (dense city to rural area) for gas field reinjection and it makes bit more sense. So in this mode there would east to west energy corridors that could be aligned on existing Interstate highway right of ways doing transcontinental load shifting. Off shore wind on both coasts along with desert solar and midwest wind along with real load planning to encourage power demand when there is availability can make a dispatchable system. Plug in some of the new SMR nuclear reactors into the grid and its a carbon free grid. Ideally some sort of large scale storage capacity would complement the system. The only candidate in North America would be an expanded Hydro Quebec system (which has social and environment costs that would need to be weighed). It currently has 176 terra watt hours (1million MW hours) of storage in place ready to go today and the potential for a lot more.

On the CO2 side, carbon dioxide producers like cement producers would need to deal with their carbon emissions so they would either sequester on site or pay to have it shipped via the liquid carbon dioxide pipelines. Due to the 100 years of gas and oil production in the US, there is an incredible amount of potential carbon reinjection volume in known but depleted fields usually in rural areas some which coincide with areas of high wind resource.

To roll back to the Chinese concept, adding in an underwater concept using liquid CO2 and superconducting cables would add a few more levels of difficulty.

 

[stoveliker]

I'm sorry, but the longest superconducting cable (to transport power rather than create a magnetic field) in use is about a mile or so, currently. This is because they"cold losses" (heat input) are such that new cold liquid injection needs to happen at regular distances. A superconducting cable based on liquid refrigeration (rather than e.g. a Peltier based system - don't think this technology is ready either) is utterly unfeasible for this distance, and on the sea floor.

 

[semipro]

DC would probably make more sense than AC for this application.
The power conversion hardware required on each end of a DC transmission line at those power levels would something to see.

 

[EbS-P]

DC would probably make more sense than AC for this application.
The power conversion hardware required on each end of a DC transmission line at those power levels would something to see.

High-voltage direct current - Wikipedia

en.m.wikipedia.org

They are out there.

 

[EatenByLimestone]

That's a really interesting article!

"Depending on voltage level and construction details, HVDC transmission losses are quoted at 3.5% per 1,000 km, about 50% less than AC (6.5%) lines at the same voltage.[24] This is because direct current transfers only active power and thus causes lower losses than alternating current, which transfers both active and reactive power."

So, for a 15k km undersea cable, you'd be looking at a loss of about 50%. It must be worth it or they wouldn't consider it.

LA to NYC IS 2800 miles or 4500km. 15.75% loss. I suppose a western power supply would also have the benefit of producing a good amount of electricity 3 hours after the sun set on the east coast. Conversely, power generated on the east coast would arrive to the west coast 3 hours before their sunrise.

An interesting thing to ponder that I'd never contemplated.

 

[EbS-P]

We have the tech to install and maintain undersea cables. I feel like the cost Chile to China cost could easily be put towards domestic production. I think it probably has a lot to do with international policy and China trying to expand and buy influence.

 

[EatenByLimestone]

Undoubtedly that is part of it, but it is a unique solution to the solar battery issue. At least its one that I'd never considered.

 

[EbS-P]

Stepped hydro reservoirs is an appealing solution to me. Pump it up during the day with the turbines let it out at night generating electricity. At the end of the day transcontinental power transmission just has too many losses for the cost of the infrastructure. I honestly think its a pipe errr wire dream to have an under sea cable that distance.

Look at a map if they were serious they would be looking at closer Southern Hemisphere locations (Australia??) as anywhere (generally speaking) north of say 35 degrees has a larger heating demand than cooling and to be clean we need to heat with electricity. Cooling with solar is relatively easy. Lots of sun makes it hot and makes lots of power.

 

[EatenByLimestone]

I don't think China likes Australia much, lol. They are beholden to their coal, but only grudgingly.

 

[ABMax24]

Something sounds really fishy. The $2 billion price tag alone seems very light. The technological and physical limitations of such a cable seem unsurmountable.

Unless the Chinese had some technological breakthrough for power transmission we don't know about.

 

[EbS-P]

Something sounds really fishy. The $2 billion price tag alone seems very light. The technological and physical limitations of such a cable seem unsurmountable.

Unless the Chinese had some technological breakthrough for power transmission we don't know about.

Agreed.

 

[peakbagger]

Do folks remember the proposed second canal to compete against the Panama canal proposed by the Chinese?

Attempts to build a canal across Nicaragua - Wikipedia

en.wikipedia.org

 

[EatenByLimestone]

I do, it wasn't their orininal idea. It was an option they looked at from the beginning.

 

[begreen]

Something sounds really fishy. The $2 billion price tag alone seems very light.

They are stockpiling for the future!

 

[woodgeek]

Alternatively, we could shut the panama canal, build some seawalls across the Bering strait and near antarctica, and use Pacific seawater as a conductor (and return the current through the Indian and Atlantic oceans). The conductivity is low, but the cross section is a LOT bigger than 1AWG.

Hardest part is probably keeping people from stealing your power.

Did a design project for launching things to orbit using magnetic levitation... turns out the field didn't need to be that strong, it just needed to be large. And a racetrack coil of brine the size/volume of Lake Erie seemed to work better than all the superconductors in the world.

 

[stoveliker]

Stepped hydro reservoirs is an appealing solution to me. Pump it up during the day with the turbines let it out at night generating electricity. At the end of the day transcontinental power transmission just has too many losses for the cost of the infrastructure. I honestly think its a pipe errr wire dream to have an under sea cable that distance.

Look at a map if they were serious they would be looking at closer Southern Hemisphere locations (Australia??) as anywhere (generally speaking) north of say 35 degrees has a larger heating demand than cooling and to be clean we need to heat with electricity. Cooling with solar is relatively easy. Lots of sun makes it hot and makes lots of power.

The losses in such storage systems are also not negligible; I believe hydroelectric turbines are about 90 pct efficient. Add to that the efficiency of the pump to elevate the water during the day, and suddenly losses of long distance transportation don't appear to be that problematic.

Of course this only works (within the USA) for transportation Eastward as has been noted before.

 

[Rusty18]

And I’m sure it’ll be stepped up higher than 138kv. Parallel Feeds would also help greatly. A challenge for sure but it’s doable.