Submitted by Gari_305 t3_z4lezu in Futurology
Krunch007 t1_ixtufbf wrote
Reply to comment by misterhamtastic in Covering a cylinder with a magnetic coil triples its energy output in nuclear fusion test by Gari_305
Generating energy via mechanical energy is very simple, very easy, has fairly low losses , is efficient, and also generates natural multi phase sine waves.
Artificial sine waves, such as produced by inverters that have to transform the DC output of solar panels into multi phase AC, also unfortunately introduce harmonics into the system, which you can think of as noise and voltage/current spikes. I won't get into the weeds, but essentially you need more voltage and current filtering to get high quality, stable electricity.
Turning a motor, on the other hand, to get you 3 phase AC for example can go straight through a transformer and into the supply.
I massively oversimplified it but hopefully you get what I mean. It's much cheaper and more convenient while we still use an AC distribution system.
Martin_RB t1_ixu5bhb wrote
That's true (and I don't see steam turbines going away anytime soon) but more of our distribution system is becoming DC every year, particular high voltage transmission lines.
So over time the advantage of inherently produce three-phase power will reduce, maybe even becoming a drawback.
Krunch007 t1_ixu67a6 wrote
Doubtful, you still need to convert to AC to transform power to high enough voltages for transmission. Transformers only work in AC after all. There are ways to convert DC power to a higher voltage, like the boost converter, but those aren't really applicable at the kinds of voltages you need for power transmission, 100kV to 800kV... Far too high for any solid state converters.
So if we have to use a transformer to raise the voltage for transmission and then convert to DC, it won't make a difference if we have to feed it AC as the supply anyway. I don't think it will ever become a drawback, just maybe DC power generation will become as advantageous as AC is now.
AC power is incredibly convenient and has served us well for decades, its only drawback really is that you need to sync AC transmission systems so that they're in phase. That is something HVDC transmission does address, but aside from that, power generation in AC is likely to still be more convenient, if only for local distribution.
Penisanthonydoubs t1_ixu92w8 wrote
Solid state transformers use converters from LVDC to high frequency AC, which uses a much smaller transformer for transforming, then back to HVDC. Best of both worlds, but not really applicable to an AC grid without unnecessary rectification first.
Christiaanben t1_ixu9brt wrote
Yeah, no. The power where I live is definitely not a pure sine wave.
Krunch007 t1_ixuaqrg wrote
It's not just the supply introducing harmonics and deformed power. Consumers do too, and every single rectifier plugged into the network contributes to that.
Think of every phone charger, every laptop charger, every device that uses a rectifier to power its electronics essentially draws non-sine current. There are standards for these devices of course, but it's the supply that has to compensate.
Add on top of that the fact that AC carries reactive power as well, which means that every asynchronous motor plugged in the system will further destabilize it, and you have quite a chore on your hands!
It's honestly a marvel of engineering that your supply is as close to a pure sine as it is :P
Soviet_Canukistan t1_ixun891 wrote
It's a really not a big problem. We can use inverters to inject anti-harmonics and provide reactive power support. Spinning turbines are find and dandy. But solar PV could do everything a turbine can do, and depending on what fuel is spinning the turbine, often for less cost. And very clean, modern inverters are getting to less than1% THD. I get it, spin make pure sine wave good. But you need a broader perspective on power quality.
I'll agree that ac distribution is still very much the way to go. DC has the low end of power usage, even some lighting is going to POE style now, and the high end HVDC transmission, but distribution will likely be AC for some time to come.
Krunch007 t1_ixvb31e wrote
I know, I only got my bachelor's in EE and never went into the field, so I'll be the first to admit I'm not quite up to date on distribution technology. Was just offering some perspective on why generating electricity via motors is still so widely used for now.
Soviet_Canukistan t1_ixvosb4 wrote
Fair enough. I'm just a Technologist 3yr diploma. But I worked in technical support for an inverter manufacturer, among other various electrical QA type work. There's no doubt you are right, it's just that it's really hard to underestimate the advances in inverter technology. Ultimately rotating machines require maintenance that solid state devices do not. Sure inverters need replacing and optocouplers fail, IGBTs fail, etc. It comes down to rotating machines being bigger and needing more care and lubrication etc. Eventually the computerized electrical power is cheaper to distribute (distributed generation) and maintain.
That said, if you have cheap fuel, or enhanced geothermal, turbines are king. Even some exotic concentrated solar, molten salt storage with steam turbines makes sense,. But I can put 10 kW of solar PV on a building and basically set and forget. Not possible with turbines, everything has its place.
Prineak t1_ixufij0 wrote
I’m still totally bewildered that at any given time, all these generators feeding energy into the system are synchronized.
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