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ThePowderhorn t1_j0cll0s wrote

Reply to comment by YawnTractor_1756 in 5 second toaster and kettle by F1NNTORIO

Count me among the clueless. One of the things that's been percolating in my mind as more and more devices run on DC and batteries is when the electric grid as it currently exists will be an anachronism for its then-current (no pun intended) use cases. Your mention of conversions brought this to the fore.

I get that pretty much everything short of solar is turbine-driven, which if I recall correctly is why we have an AC grid (high-school physics was a while ago, so I don't remember why). Since solar is the only residential-scale generation option, at what point does it start making sense to keep small-scale (say, neighbourhood level) DC needs separate from the AC that industry is designed around? I can't imagine there's anything to be gained from DC-AC-DC conversion.

edit: typo

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PM_ME_YOUR_WOLOLO t1_j0cuuq8 wrote

I had to look this up because I didn't remember why either https://energyeducation.ca/encyclopedia/Alternating_current#:~:text=Alternating%20current%20(AC)%20is%20the,transmitting%20electricity%20over%20long%20distances. but apparently it's more efficient (less energy loss in most circumstances)

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PsikoticWanderer t1_j0duw2u wrote

I am an electronics engineer. AC current travels long distances on a conductor while losing very little energy. DC current loses energy in the form of heat as it travels on a conductor. Centralized power grids liked we have today based on DC are not possible.

When AC shorts to ground a local thermal event occurs causing localized damage. When DC+ shorts to DC- it heats the whole conductor path from the point of contact back to the source and damages or destroys all conductors in that circuit. In the event of a short AC repairs will be much cheaper.

Google Edison Tesla, they had a years-long feud over AC vs DC power grid. An elephant may have been involved.

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PM_ME_YOUR_WOLOLO t1_j0dv3kp wrote

Thank you for the explanation! Yeah I do recall learning about Edison and Teslas feud over AC vs. DC. I’m a software engineer so this isn’t my wheelhouse at all

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PsikoticWanderer t1_j0e7gap wrote

I do software too. Test dev for an automotive manufacturer so I get to build test stands and program them. Fun stuff.

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Tree-farmer2 t1_j0egvx8 wrote

Didn't DC motors at the time cause sparks and AC solved this?

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YawnTractor_1756 t1_j0dc6g6 wrote

All renewables require a DC-AC conversion. And we would need tons of them. And they use rare metals.

Broadly conversion also means voltage transformation. If you want to run more current (because we make more electricity, because we need more electricity, because we charge cars and shift from cooking with gas to electric etc etc) then you either need more wires (and more towers, and transformers) or you need better wires and better transformers.

There is additional problem with maintaining electric frequency. Currently it is done via fossil generators, nuclear is not suitable for that purpose because of how it's generation is used. Renewables are expensive at that. In future of renewable energy it has to be done with storage. If storage is used for it then storage would not just be a 'backup battery' now, it would become a grid forming part, with added requirements.

I googled a good article about that, here: https://www.greentechmedia.com/squared/dispatches-from-the-grid-edge/solving-the-renewable-powered-grids-inertia-problem-with-advanced-inverters

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ThePowderhorn t1_j0ddzp1 wrote

Thanks for the link! Usually I have a distance excuse to not do further research, but given that I get my power from Austin Energy, learning more should be rather doable.

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