AC or DC?

[bolo]

If we were starting over from scratch, would we still have AC electricity distribution or would DC make more sense?

An increasing share of generation is no longer from machinery rotating at 60 Hz (YFMV). Solar produces DC, and while wind produces AC, it's not at a fixed frequency so it's converted to DC immediately anyway. If you store energy in batteries, they produce DC when the energy comes back out again.

On the usage end, lighting is increasingly LEDs, which means each bulb needs its own internal AC-to-DC conversion. Computers and other electronics all want DC, so they all need their own power bricks also, or chargers that take AC input and put out DC to a USB plug or similar.

If it weren't for the obvious costs of changing over, would it better just to use DC throughout?

[Martin_B]

I'm trying to remember the physics I learnt at school (~35 years ago now!) but I think high voltage AC is preferable for transmission to prevent current losses, especially over long distance.

[Gfamily]

I'm trying to remember the physics I learnt at school (~35 years ago now!) but I think high voltage AC is preferable for transmission to prevent current losses, especially over long distance.

I had the same school learning (48+ years ago), but I think (then) it was the higher voltage rather than specifically the AC that was preferable.
A quick case of "I do my own research"/"I did a ask of google" suggests that high power DC is generally a bit more efficient than high power AC, and (what surprised me I think) is that DC-DC voltage conversion is 'seemingly'* more efficient than AC-AC voltage conversion.

* based on results posted on page 1 ...

[Grumble]

All the long distance interconnectors are DC, not surprisingly the reasons for choosing AC or DC are a bit more complex than we learnt at school - here’s an interesting exchange about it:
http://engineering.stackexchange.com/qu ... /ddg#19765

[dyqik]

The right kind of AC transmission can be much lower loss than DC (transmission lines, with the energy largely transferred via the fields around the conductors rather than by currents in the conductors), but that's hard to maintain on grid scales, and prefers higher frequencies.

As an extreme case, solar panels can be viewed as AC-DC converters