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Comment by YossarianFrPrez | Hacker News Reader

Ooh, fascinating. AC is better for long distance transmission, which solar + local storage obviates. Do you happen to know of the efficiency we might stand to gain from switching appliances to DC?

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So you've two competing losses: transformers and voltage drops over long DC circuits.

When I was last looking into this myself -- and lamenting you couldn't find PoE LED lights for love or money -- it sounded like (IANAEE) voltage drops start becoming a thing you have to care about around 50 or 100 feet, depending on the gauge; wiring a house with DC isn't impossible but it might require a little bit of care or some thought.

Being honest it's not a massive amount of loss if your entire supply is coming from the grid. But if you're generating and storing energy at home, then it's much more significant because you add the transformer's losses to the additional losses spent in your inverter.

You need to move to higher voltage DC which will present some challenges you don't get with AC, for example if you get an arc in a switch or a circuit breaker with AC it normally extinguishes quickly at the zero voltage crossing, whereas DC will just keep arcing until stuff starts to burn.

I thought even long distance transmission now use HVDC(High Voltage DC) lines, for various advantages, for example not having lines for 3 phases.

LDx HVDC has a small set of use cases where it is more efficient than HVAC. But yes, in some cases it can work better over distances of hundreds of km.

There seems to be quite a number of HVDC lines in the grid, for example in Europe [0].

[0]- https://en.m.wikipedia.org/wiki/File:HVDC_Europe_annotated-2...

Underwater ! And in many cases connecting grids that are not synchronised ?

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