Hacker News Reader

Comment by germinalphrase | Hacker News Reader

Which doesn’t matter if power generation is decentralized and localized?

That's actually what Edison's original DC power network was designed around. DC power lines, and a coal chugging power station every mile. Turns out that all the extra pollution and expense is a bad idea, so AC won out. It's been working just fine for over 100 years. Read more here:

https://en.wikipedia.org/wiki/War_of_the_currents

50 or 60 Hz AC, especially 3-phase, makes it really easy to build and operate electric motors, too, and to transform between different voltages.

The OP’s argument is that solar power generation, plus the fact that most electrical consumption is now fundamentally DC-friendly (LEDs, electronics, electric cars, etc.), may change the equation. The concept of a whole-house rectifier is an interesting one, and something that is already used in some data centers. You still have the problem of different electronics wanting different voltages, though...

As you note, for facilities like data centres that are engineered for a specific type of load, a building-level rectifier makes sense. For a home where you have many devices using a little bit of power at a variety of voltages, you're going to end up with lots and lots of small DC converters everywhere which defeats the point. Just run 120 VAC.

> 50 or 60 Hz AC, especially 3-phase, makes it really easy to build and operate electric motors, too

Three-phase motors are never used in residential settings, and most residential motors would be more efficient as brushless DC. There's no need for sinusoidal AC motors any more except in specialized industrial applications.

I agree - brushless DC motors really make AC motors obsolete in 90% of use cases.

Whilst most devices may use DC internally that may not be true of consumption. You still have electric showers, cookers, hobs, washing machines, dryers, heaters, air-conditioning, vacuum cleaners and kitchen appliances like blenders.

Yes. High-power residential loads like heaters would still work best on AC because HVAC is safer than HVDC.

Even if power generation is distributed and localized, you still need higher voltages than what is in a home to transmit it unless you're talking about not having a power grid at all. You still need voltages on the order of 1 to 40 kV to distribute power around a neighbourhood, for instance. You aren't going to wire your house at distribution voltage - it would be expensive and unsafe.

That's what boost/buck power electronics are for.

Sure, in an ideal world. But economies of scale do exist and everyone having solar panels and expensive personal batteries remain difficult and not a viable solution compared to the larger, distributed system that allows people to draw what they need when they need it.

Reply on news.ycombinator.com