Why Does the U.S. Have Three Electrical Grids?(spectrum.ieee.org)
spectrum.ieee.org
Why Does the U.S. Have Three Electrical Grids?
https://spectrum.ieee.org/podcast/energy/renewables/why-does-the-us-have-three-electrical-grids
155 comments
I come up with a hypothesis: Japan's divided frequency situation made Japanese electric manufacturers to invent inverter for electrics (example: air conditioners, microwave, refrigerators). Inverter primary makes electrics controllable efficiently, also they can ship same product (same performance) for both 50/60Hz area in Japan.
Any "evidence" (or anything substantial) about your hypothesis?
Like, did Japanese companies actually invent inverters, or are inverter air conditioners more common in Japan compared to other countries?
Like, did Japanese companies actually invent inverters, or are inverter air conditioners more common in Japan compared to other countries?
Sorry for bad English, "develop" would be better word than "invent". AFAIK Daikin argues that Inverter Air conditioner is very popular in Japan compared to other developed countries. In Japan, mini-split type a/c is common and almost all producs are runned by inverter compressor (except very cheap one but almost no one buy it).
Here's Daikin's argument (japanese). Green is % of inverter and Japan is 100%.
https://www.daikin.co.jp/csr/information/lecture/act01.html
https://www.daikin.co.jp/csr/information/lecture/images/act0...
It seems that world's first inverter a/c is by Toshiba.
https://toshiba-mirai-kagakukan.jp/en/learn/history/ichigoki...
Here's Daikin's argument (japanese). Green is % of inverter and Japan is 100%.
https://www.daikin.co.jp/csr/information/lecture/act01.html
https://www.daikin.co.jp/csr/information/lecture/images/act0...
It seems that world's first inverter a/c is by Toshiba.
https://toshiba-mirai-kagakukan.jp/en/learn/history/ichigoki...
My parents have an inverter mini-split. It’s amazingly effective at dehumidification. If I ever have to change out one of my AC units I will probably go with a multi-zone mini split. Being able to condition only the rooms that are in use and the super effective dehumidification the systems offer are a significant upgrade over traditional ducted AC systems. Heat pumps on mini splits tend to be far more effective too.
Thanks for the links! I do found that inverter AC seem more popular in East Asian countries. But then again, they don't use central air conditioning in residential as much as the US do, so probably not an apple to apple comparison.
"The total transmission capacity between the two grids is 1.2 GW"
That's a tiny amount for an industrialised nation of 125 million people, considering that the border between the grids cuts right between Tokyo and the other western centres of population.
I think this, and the nuclear power shutdown, lend some context to Japan’s push for a hydrogen economy.
That's a tiny amount for an industrialised nation of 125 million people, considering that the border between the grids cuts right between Tokyo and the other western centres of population.
I think this, and the nuclear power shutdown, lend some context to Japan’s push for a hydrogen economy.
That's only the inter-grid exchange capability, over AC1 <-> DC <-> AC2 transformation, not the total one
If you read the article, the US has about the same inter-grid exchange capability for the west and east coast grids.
Japan has alone over 50 GW of solarpower, and that's only a small share of their energy mix.
They produced 1009 TWh in 2015, that'd be an average of 117.95 GW, and usage is seldom average, but with daily peaks. I'd take an educated guess and say their nets can handle multiple hundreds of GW to up to a TW just fine..
If you read the article, the US has about the same inter-grid exchange capability for the west and east coast grids.
Japan has alone over 50 GW of solarpower, and that's only a small share of their energy mix.
They produced 1009 TWh in 2015, that'd be an average of 117.95 GW, and usage is seldom average, but with daily peaks. I'd take an educated guess and say their nets can handle multiple hundreds of GW to up to a TW just fine..
Oh yeah.. you can definitely tell they have electricity from space at night
One region used American and the other one German sourced generators ... like NTSC vs PAL :).
Europe's integrated power grids can very rarely cause weird problems. A couple of years ago, a dispute between Serbia and Kosovo left some power demand unfulfilled, which lead to the grid frequency slightly dropping, which caused grid-powered clocks to lose about 6 minutes: https://arstechnica.com/tech-policy/2018/04/european-grid-di...
Political tension between Serbia and Kosovo is not entirely unexpected of course, but it's weird if that starts affecting clocks half a continent away.
Political tension between Serbia and Kosovo is not entirely unexpected of course, but it's weird if that starts affecting clocks half a continent away.
German transfers from wind farms at the north to factories in the south and Austria often caused problems in Polish and Czech networks.
https://www.politico.eu/article/germany-austria-energy-europ...
Australia is comparable in size, split by a giant middle desert (literally and figuratively) And has two grids.
Balancing the east coast grid is sometimes hard. Its weak, badly in need of capital investment and somewhat mired in inter-state/federal madness.
Personally, I think privatizing the utility function was insane.
There are some cool things which emerged after the 1970s grounded capital investment: High Voltage DC is very cool. Avoids some of the issues of phase and load mis-alignment between regions, generation models.
Arguments for a different kind of net exist. More local resiliency. More load shedding, more respect for home solar and batteries, as well as storage in the network.
Balancing the east coast grid is sometimes hard. Its weak, badly in need of capital investment and somewhat mired in inter-state/federal madness.
Personally, I think privatizing the utility function was insane.
There are some cool things which emerged after the 1970s grounded capital investment: High Voltage DC is very cool. Avoids some of the issues of phase and load mis-alignment between regions, generation models.
Arguments for a different kind of net exist. More local resiliency. More load shedding, more respect for home solar and batteries, as well as storage in the network.
> And has two grids.
Not just two. There's also the Darwin/Katherine system which serves about 150k customers. The NWIS and Alice Springs system both have 20k+ customers. Australia has some really interesting power systems.
Not just two. There's also the Darwin/Katherine system which serves about 150k customers. The NWIS and Alice Springs system both have 20k+ customers. Australia has some really interesting power systems.
Sorry I didn't capture that. I bet the NT gets better service outcomes than either WA or east coast, sooner (because more focussed)
there's issues with decades of one provider also owning the infra. It got split up in recent years, but we've yet to see new providers connected.
in the top end, fruitbats and cyclonic storms are common disruptions
its got better in the suburbs since lotsa wires went underground, but just a few km down the highway and the grade of service drops.
in the top end, fruitbats and cyclonic storms are common disruptions
its got better in the suburbs since lotsa wires went underground, but just a few km down the highway and the grade of service drops.
Among US utilities, local public utilities seem to work best. Federal run facilities are deeply mired in bureaucracy and acquisition guidelines, while fully private power companies are prone to get bought out by large investor conglomerates and end up too driven by quarterly profit to invest in maintenance.
https://www.abc.net.au/news/2017-07-18/australian-gold-plate...
It seems to be both overinvested and underinvested? How can it be both? (Sorry looking for insight not trying to disprove what you say)
It seems to be both overinvested and underinvested? How can it be both? (Sorry looking for insight not trying to disprove what you say)
Gold plating is a bit of a misnomer. Capital investment made in transmission was assured a rate of return above CPI. It was a gold class, form of spending money to earn future revenue under regulation. They didn't invest in the parts which we need now, in the light of shifts in transmission models from Coal and Gas, to both inter-state dependencies on trunks, and the in-local-distribution network storage and generation. They chose to invest in the assets they had, which were not the ones we need to invest in, to cope with variable load in wind and solar, and distributed generation in the home.
Demand management, variable load, need for Syncons and storage and need for more resiliency in the inter-state connections and the "rhombus of regret" are where money needs to go.
the gold plating was not made there. And in any case, its rent-seeking behaviour: its not a good model.
(this is highly subjective opinion btw. A good economist to read on this is John Quiggin, and a good alternative engergy advocate is Giles Parkinson, reneweconomy. They are also partisan, but knowledgeable.)
Demand management, variable load, need for Syncons and storage and need for more resiliency in the inter-state connections and the "rhombus of regret" are where money needs to go.
the gold plating was not made there. And in any case, its rent-seeking behaviour: its not a good model.
(this is highly subjective opinion btw. A good economist to read on this is John Quiggin, and a good alternative engergy advocate is Giles Parkinson, reneweconomy. They are also partisan, but knowledgeable.)
Thanks, that was really interesting.
Always hear one side of news, especially when it's a semi-complex subject and I will have a look at reneweconomy.
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> Everything within those separate zones is synched up. So you’ve got your 60 hertz AC wave; 60 times a second the AC power flow is changing direction. And all of the generators, all of the power consumption within each zone is doing that synchronously. But the east is doing it on its own. The West is on a different phase. Same for Texas.
Folks may not realize that power is transmitted in three phases in the US. AC power is essentially a sin wave, and we use 3 different 'phases', which are just shifted sin waves so that we basically always have at least one phase providing power at any time.
Every generator hooked up to the grid must be synchronized to the same 60 hz phases. There are devices called 'phasors' that assist in ensuring generators are lined up with the grid. And now there are networked versions to help coordinate across large regions.
But if two grids are on different phases, then there will be serious problems in connecting them together -- mostly that generators will be fighting against each other and potentially causing damage to things on the grid expecting clean 60hz power. It gets complicated pretty quickly.
Folks may not realize that power is transmitted in three phases in the US. AC power is essentially a sin wave, and we use 3 different 'phases', which are just shifted sin waves so that we basically always have at least one phase providing power at any time.
Every generator hooked up to the grid must be synchronized to the same 60 hz phases. There are devices called 'phasors' that assist in ensuring generators are lined up with the grid. And now there are networked versions to help coordinate across large regions.
But if two grids are on different phases, then there will be serious problems in connecting them together -- mostly that generators will be fighting against each other and potentially causing damage to things on the grid expecting clean 60hz power. It gets complicated pretty quickly.
Close, Three phase systems actually are a carry over from the days of early induction motors. Three phases can easily be connected to create a rotating magnetic field. We don't just use one phase at a time on the grid. All three are active. Phases A and B and C are all 120 degrees out of phase with each other. (That has nothing to do with the 120volts you know of in your house- it just happens to be another 120 number)
AC has inductive properties. I.e. it can induce electrical currents in wires across a core. (Transformer) DC cannot do this. Before vacuum tubes and other tech AC was one of the few technologies that could be easily stepped up to hundreds of thousands of volts.
Voltage and current have an inverse relationship. So we can step up voltage and reduce the size of the conductor $$$$ other feature is reduced line losses (HVDC actually beats us here but this is another discussion)
Having AC power allows all kinds of cool things! Did you know that your common household 120v feed is simply a single phase being split into two 120v 'legs'. Both 120 degrees out of phase. So if you remember elementary school math the abs() of phase A at its peak of +120 and phase B at it's valley of -120 = 240.
It gets better! We can be cheap on wire with AC systems! I can wire a 'multiwire branch circuit'. With phases a and b that share a neutral. If the current on phase a is 20 amps and the current on phase B is 20 amps what is the return current on my neutral? ( Google Mike Holt Multiwire Branch, Enjoy )
Want more fun. Read about Neutral Earth Voltage and NFPA 70 requirements for agriculture and equipotential planes. :-)
AC is freaking magical. The grid is even more awesome!
AC has inductive properties. I.e. it can induce electrical currents in wires across a core. (Transformer) DC cannot do this. Before vacuum tubes and other tech AC was one of the few technologies that could be easily stepped up to hundreds of thousands of volts.
Voltage and current have an inverse relationship. So we can step up voltage and reduce the size of the conductor $$$$ other feature is reduced line losses (HVDC actually beats us here but this is another discussion)
Having AC power allows all kinds of cool things! Did you know that your common household 120v feed is simply a single phase being split into two 120v 'legs'. Both 120 degrees out of phase. So if you remember elementary school math the abs() of phase A at its peak of +120 and phase B at it's valley of -120 = 240.
It gets better! We can be cheap on wire with AC systems! I can wire a 'multiwire branch circuit'. With phases a and b that share a neutral. If the current on phase a is 20 amps and the current on phase B is 20 amps what is the return current on my neutral? ( Google Mike Holt Multiwire Branch, Enjoy )
Want more fun. Read about Neutral Earth Voltage and NFPA 70 requirements for agriculture and equipotential planes. :-)
AC is freaking magical. The grid is even more awesome!
> Close, Three phase systems actually are a carry over from the days of early induction motors.
It's not just some historical accident. We continue to use multi-phase power because it enables continuous delivery of power (unlike single-phase, where the delivered power drops to zero at least twice per cycle). And two phases require just as many wires as three phases, with more power delivered for a given mass of copper and insulation, so... we use three.
> If the current on phase a is 20 amps and the current on phase B is 20 amps what is the return current on my neutral?
That depends on the (complex) impedance in each branch. In the pathological case, the current on the neutral could be as high as 40 Amps.
It's not just some historical accident. We continue to use multi-phase power because it enables continuous delivery of power (unlike single-phase, where the delivered power drops to zero at least twice per cycle). And two phases require just as many wires as three phases, with more power delivered for a given mass of copper and insulation, so... we use three.
> If the current on phase a is 20 amps and the current on phase B is 20 amps what is the return current on my neutral?
That depends on the (complex) impedance in each branch. In the pathological case, the current on the neutral could be as high as 40 Amps.
The advantage of three phase over two is that three phase can energize the coils of a three-phase motor so as to create a rotating magnetic field. No extra circuitry is needed.
Two-phase cannot do that when the phases are 180 degrees apart; opposite polarity is as good as a single phase. It would work if the two phases were 90 degrees apart.
A two-phase motor operating on single phase (or 180 degree two phase) needs to generate the 90 degree phase signal with extra circuitry.
Three phases is also smoother power delivery and even loading compared to two.
Two-phase cannot do that when the phases are 180 degrees apart; opposite polarity is as good as a single phase. It would work if the two phases were 90 degrees apart.
A two-phase motor operating on single phase (or 180 degree two phase) needs to generate the 90 degree phase signal with extra circuitry.
Three phases is also smoother power delivery and even loading compared to two.
This video actually explains the reasoning for tri-phase power and it's advantages in a succinct manner, for anyone still confused:
https://www.youtube.com/watch?v=4oRT7PoXSS0
https://www.youtube.com/watch?v=4oRT7PoXSS0
If both loads were on the same phase that would be a violation of the US NEC (NFPA 70) because use the load would be 40 amps..... And guessing we are taking 12awg, way over allowed current.
In hindsight I did not specify circut ampacity, or wire gauge. Still the question stands, how much current would you read at the panel on the neutral with those two loads on the line :-)
(In my example you have two phases 120 degrees apart. Think US Residential split phase. The actual result is pretty awesome. It's a common test problem for new electricians.)
I won't spoil the result because it's too cool when you get it.
In hindsight I did not specify circut ampacity, or wire gauge. Still the question stands, how much current would you read at the panel on the neutral with those two loads on the line :-)
(In my example you have two phases 120 degrees apart. Think US Residential split phase. The actual result is pretty awesome. It's a common test problem for new electricians.)
I won't spoil the result because it's too cool when you get it.
Oops should have typed 180 degrees apart for residential.
Three-phase systems are far more than a carry-over from early electric motors. Cars, which have no legacy compatibility issues also use three phases. Three-phase power is a very good balance of simplicity of transformation and rectification with even-ness of loading.
You have to remember that alternators and generators are loading mechanical systems, so it's a bad idea to have huge cyclic variations in the load, which stresses the physical system.
You have to remember that alternators and generators are loading mechanical systems, so it's a bad idea to have huge cyclic variations in the load, which stresses the physical system.
So does my...dishwasher. It actually generates three phase power (maybe stepped sine-wave?) for its main motor.
I did a double-take when I saw it (during the course of an unrelated fix,) considering it's powered off a simple (US) 120V 15-amp branch circuit.
I did a double-take when I saw it (during the course of an unrelated fix,) considering it's powered off a simple (US) 120V 15-amp branch circuit.
Almost all modern motors use inverter circuits to generate multi-phase drive signals. Any time you see a product with a “brushless motor”, that’s what it means.
Interesting. I didn't know that. I always figured that was a method for powering (otherwise) AC motors from DC. I never realized it included multi-phase motors.
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> Three phase systems actually are a carry over from the days of early induction motors
Three phase is better than one for transmission: you can pass more power for a given distance with a given budget of copper/aluminium wire. In other words, you have three wires rather than 2, but they can be lighter overall, and require less materials and fewer and less expensive poles.
Three phase is better than one for transmission: you can pass more power for a given distance with a given budget of copper/aluminium wire. In other words, you have three wires rather than 2, but they can be lighter overall, and require less materials and fewer and less expensive poles.
> Both 120 degrees out of phase. So if you remember elementary school math the abs() of phase A at its peak of +120 and phase B at it's valley of -120 = 240.
I think you mean 180 degrees out of phase.
I think you mean 180 degrees out of phase.
It's not clear what he meant (because this part doesn't really have anything to do with 3-phase), but:
Most houses in the US have 240V service for large loads like A/C, ovens, stoves, dryers, EV chargers, etc. The way you get 240V (in the US) is that you take a single phase, and apply it to a transformer. The transformer's secondary has a grounded center tap, so you get +/- 120V, 180 degrees out of phase (this is called "split phase").
Most houses in the US have 240V service for large loads like A/C, ovens, stoves, dryers, EV chargers, etc. The way you get 240V (in the US) is that you take a single phase, and apply it to a transformer. The transformer's secondary has a grounded center tap, so you get +/- 120V, 180 degrees out of phase (this is called "split phase").
> Having AC power allows all kinds of cool things! Did you know that your common household 120v feed is simply a single phase being split into two 120v 'legs'. Both 120 degrees out of phase. So if you remember elementary school math the abs() of phase A at its peak of +120 and phase B at it's valley of -120 = 240.
The two legs are 180 degrees "out of phase" (that is to say one is simply the negative to the other). The peaks on each are +/- 170 volts, with a total peak across both of 340 volts. But we talk about AC in terms of RMS voltage, which is the DC-equivalent voltage that would perform the same work into a resistor, which is a factor of sqrt(2) for a sine wave, or "120/240 volts".
The two legs are 180 degrees "out of phase" (that is to say one is simply the negative to the other). The peaks on each are +/- 170 volts, with a total peak across both of 340 volts. But we talk about AC in terms of RMS voltage, which is the DC-equivalent voltage that would perform the same work into a resistor, which is a factor of sqrt(2) for a sine wave, or "120/240 volts".
The solution is to connect them with HVDC, right? That might not be a great solution for making a single national-grid, but it would allow the 3 grids to mutually borrow from each other, right?
That's exactly right, but the capacity is limited. ERCOT in Texas, for example, has 5 DC ties to the other grids: http://www.ercot.com/content/cdr/html/real_time_system_condi...
> Peter Fairley: So to give you a sense of just what the scale of the transfers is and how small it is, the East and the West interconnects have a total of about 950 gigawatts of power-generating capacity together. And they can share a little over one gigawatt of electricity.
> Steven Cherry So barely one-tenth of one percent.
From TFA.
> Steven Cherry So barely one-tenth of one percent.
From TFA.
I wonder if this has more to do with "Black Start" planning than actually providing power cross grids.
https://en.wikipedia.org/wiki/Black_start
https://en.wikipedia.org/wiki/Black_start
Interesting suggestion, though AFAIK that typically relies on auxiliary onsite power source at some generating plants, as noted in the Wikipedia article intro?
Anything you can find to support grid interconnects as black-start capacity?
Anything you can find to support grid interconnects as black-start capacity?
Purely speculation based on the small capacity compared to total generated capacity.
From what I understand there can be a number of different techniques for black starting a grid, including pumped storage / hydro generation because they can be started with very modest power. Being able to jumpstart a grid based off of a neighbouring grid seems to make sense.
From what I understand there can be a number of different techniques for black starting a grid, including pumped storage / hydro generation because they can be started with very modest power. Being able to jumpstart a grid based off of a neighbouring grid seems to make sense.
Most of them are ageing too.
Wouldn't a better solution be to make them all in phase with each other? Then there wouldn't need to be any HVDC interconnect.
A large grid is harder to manage and runs the risk of a cascading failure. Especially as HVDC is a lot cheaper and more efficient than it used to be, there's an argument we should actually be breaking our grids down further.
Indeed. For some reason I keep thinking back to this :)
https://www.youtube.com/watch?v=P0BD4jmTS_M
https://www.youtube.com/watch?v=P0BD4jmTS_M
Consider the distance, and speed of light, and the speed of electricity (1/100th of that). I don't think it's truly feasible to keep that much physical space in sync. Hmm...
The speed of electricity isn't 1/100th the speed of light. IIRC it's something closer to 70% in copper. The speed electrons move is much lower, however something more like cm or m per second (presumably depends on voltage.) However, this isn't related to the speed of electricity which is analogous to how the speed of water through an (already full) hose isn't related to how soon water starts coming out the end when the tap is turned on.
I've also heard, but I can't explain so you'll have to look it up yourself, that none of this matters when keeping a grid in sync anyway. It just works out.
I've also heard, but I can't explain so you'll have to look it up yourself, that none of this matters when keeping a grid in sync anyway. It just works out.
Apparently not a problem to do today.
https://en.m.wikipedia.org/wiki/Synchronous_grid_of_Continen...
https://en.m.wikipedia.org/wiki/Synchronous_grid_of_Continen...
That's not a very large area, to be fair. That's about the size of half of the United States, in distance/spread. Europe isn't a continent in the traditional sense, it's a region, and not a huge one.
This might counter the grandparent poster if Asia was on the same synchronous grid, but it's not.
This might counter the grandparent poster if Asia was on the same synchronous grid, but it's not.
I guess there's two ways of looking at it. The distances spanned by the extreme points net or how dense it is. Not that I have the knowledge to relate any of that to real world use cases or consequences.
Here's the map including all larger powerlines
https://www.entsoe.eu/data/map/
Here's the map including all larger powerlines
https://www.entsoe.eu/data/map/
This is a better example IMO:
https://en.wikipedia.org/wiki/IPS/UPS
It spans 8 timezones.
Europe is just larger in capacity, not breadth.
It spans 8 timezones.
Europe is just larger in capacity, not breadth.
Pretty much. I mean, that's basically what a VSD is: A 3-phase rectifier back to back with a 3-phase inverter. Then you can have the two sides at different voltages and phases and transfer power back and forth at will.
It's a lot of current, so maybe you want superconducting HVDC:
https://en.wikipedia.org/wiki/Tres_Amigas_SuperStation
https://en.wikipedia.org/wiki/Tres_Amigas_SuperStation
Last I heard the whole Tres Amigas SuperStation deal totally fell apart.
>"[W]e basically always have at least one phase providing power at any time."
This isn't really how three-phase power works.
In household settings, you're usually getting only one phase, so all your power comes from that phase. Different neighborhoods get different phases, so they're roughly balanced loads.
Industrial (and some consumer) users get two (208V) or three phases (480V), and they get power from the difference between the phases (for their higher-voltage loads).
Now, if you've ever looked at an oven or a dryer (in North America at least), you'll know that they are higher voltage, and look like they are two-phase... But it's really more like one phase that's been mirrored.
Here's a nice diagram: https://electronics.stackexchange.com/questions/146420/obtai...
This isn't really how three-phase power works.
In household settings, you're usually getting only one phase, so all your power comes from that phase. Different neighborhoods get different phases, so they're roughly balanced loads.
Industrial (and some consumer) users get two (208V) or three phases (480V), and they get power from the difference between the phases (for their higher-voltage loads).
Now, if you've ever looked at an oven or a dryer (in North America at least), you'll know that they are higher voltage, and look like they are two-phase... But it's really more like one phase that's been mirrored.
Here's a nice diagram: https://electronics.stackexchange.com/questions/146420/obtai...
Typical residential service in the US is 240v single phase. The transformer on the pole is putting out 240v, but there's a center tap on the transformer that's bonded to ground. That's your neutral. The other two legs are essentially +120v and -120v relative to ground/neutral. Your dryer hooks up to both legs and sees the full 240v. Don't ask me how grounding works for 240v appliances. I have no idea.
I am not an electrician or EE. I just spent a bunch of time looking into this when I got my 240v table saw and had to hook it up to something.
As proof that I'm not totally bullshitting you: until recently our house had a 120v outlet on a 240v breaker for a baseboard radiator. The electrician was here to fix an unrelated issue, and rejiggered things in the panel to hook it up to a 120v breaker.
As far as I understand it (not very) there is no such thing as two-phase power.
I am not an electrician or EE. I just spent a bunch of time looking into this when I got my 240v table saw and had to hook it up to something.
As proof that I'm not totally bullshitting you: until recently our house had a 120v outlet on a 240v breaker for a baseboard radiator. The electrician was here to fix an unrelated issue, and rejiggered things in the panel to hook it up to a 120v breaker.
As far as I understand it (not very) there is no such thing as two-phase power.
> Don't ask me how grounding works for 240v appliances. I have no idea.
Ground is 'the same' for 240v and 120v on split phase. A usually bare copper wire is run from the ground pin to the service panel, in the main service panel ground and neutral are connected together and to the utility neutral and the grounding rod.
Most 240v outlets are hot-hot-ground, or hot-hot-neutral-ground; some older outlets were hot-hot-neutral and the appliance was supposed to be wired separately to ground (and we can all suppose how often that was done properly, resulting in that outlet type becoming disfavored).
I'm currently rejiggering a 240v wired box for 120v outlets, after finding the wires in the panel and confirming they don't power any other 240v outlets, I'm connecting the white wire to the neutral bus bar, and the black wire to a spare 120v breaker, and then it's normal wiring of the outlet.
Ground is 'the same' for 240v and 120v on split phase. A usually bare copper wire is run from the ground pin to the service panel, in the main service panel ground and neutral are connected together and to the utility neutral and the grounding rod.
Most 240v outlets are hot-hot-ground, or hot-hot-neutral-ground; some older outlets were hot-hot-neutral and the appliance was supposed to be wired separately to ground (and we can all suppose how often that was done properly, resulting in that outlet type becoming disfavored).
I'm currently rejiggering a 240v wired box for 120v outlets, after finding the wires in the panel and confirming they don't power any other 240v outlets, I'm connecting the white wire to the neutral bus bar, and the black wire to a spare 120v breaker, and then it's normal wiring of the outlet.
> As far as I understand it (not very) there is no such thing as two-phase power.
Because it's obsolete (but still exists in some places like center city PA). Two phase has two windings in the generator 90 degrees apart. Service was delivered via 3, 4, or 5 wires. Three phase beat it for a number of technical and economical reasons.
Because it's obsolete (but still exists in some places like center city PA). Two phase has two windings in the generator 90 degrees apart. Service was delivered via 3, 4, or 5 wires. Three phase beat it for a number of technical and economical reasons.
The 240V that you're talking about is what I mentioned as 'mirroring'. There definitely is such a thing as two-phase power, my electric car charger is 208V from two industrial phases, and our reflow oven is 208V, from two similar phases.
That's two phases of a three-phase supply.
From your car's or oven's perspective, it's still just single-phase power that happens to be floating w.r.t. ground.
From your car's or oven's perspective, it's still just single-phase power that happens to be floating w.r.t. ground.
Well, it would be the same as single-phase power (to the device) if the devices were not connected to the neutral. The oven actually takes one of the phases (along with the neutral), and uses it to power some accessories.
With the massive caveat that I don't have a first principles understanding of any of this: I don't thing any individual load in your oven takes both legs and the neutral to do work. They're all either 120v or 208v single phase.
Aside: a lot of motors can run on either 240v single phase or 208v single phase (or, presumably, anything in between?). Take a look at Grainger or McMaster-Carr.
Aside: a lot of motors can run on either 240v single phase or 208v single phase (or, presumably, anything in between?). Take a look at Grainger or McMaster-Carr.
That's still single phase as the power you're seeing is the vector sum of the two phases.
At least in Sweden, all houses have a 3-phase, 400V supply. This is very different from the US which just supplies one phase to each house even if the supply itself is 3-phase. This is why you commonly see 200+A main breakers on a house in the US whereas in Sweden, 25A is a pretty common main breaker size.
(It's as if the US grid characteristics were decided by the copper vendors... ;-)
(It's as if the US grid characteristics were decided by the copper vendors... ;-)
>It's as if the US grid characteristics were decided by the copper vendors...
It was designed without an issue with copper usage. Europe had very little development and quit a bit of rationing while building out the grid post-WW2. The US had no such issue and spent no time working within those constraints.
It was designed without an issue with copper usage. Europe had very little development and quit a bit of rationing while building out the grid post-WW2. The US had no such issue and spent no time working within those constraints.
Well, you have to consider that the USA (and Canada) were on the bleeding edge of technology when they adopted electrical grids. They were left with a... legacy, including the type-A plug and 110V single-phase power to residences.
In your case, I believe each prong of your two-prong plug gets a different phase, so you have 3 possible pairs of phases to power each circuit from. This has the advantage of requiring smaller wires, but the disadvantage of increasing the risk if one is electrocuted.
In your case, I believe each prong of your two-prong plug gets a different phase, so you have 3 possible pairs of phases to power each circuit from. This has the advantage of requiring smaller wires, but the disadvantage of increasing the risk if one is electrocuted.
> but the disadvantage of increasing the risk if one is electrocuted.
Avoiding this was one of the design parameters of the "Schucho" plug design that is reasonably standard across Europe. You'll note the three prong plug has a longer ground that makes a connection before any hot one does. The US three prong is supposed to work that way too but the ground pin isn't long enough.
I continue to be amazed how many devices still ship with only two prong plugs (everywhere: Europe, North America, Australia...) even if those prongs are polarized.
Avoiding this was one of the design parameters of the "Schucho" plug design that is reasonably standard across Europe. You'll note the three prong plug has a longer ground that makes a connection before any hot one does. The US three prong is supposed to work that way too but the ground pin isn't long enough.
I continue to be amazed how many devices still ship with only two prong plugs (everywhere: Europe, North America, Australia...) even if those prongs are polarized.
> I continue to be amazed how many devices still ship with only two prong plugs (everywhere: Europe, North America, Australia...) even if those prongs are polarized
Because most devices these days have plastic cases (Class II double insulated), so there's nothing metal to touch to get shocked even in the case of a fault. That coupled with how GFCI/RCDs are being widely adopted as well leads to grounding not being as important.
Because most devices these days have plastic cases (Class II double insulated), so there's nothing metal to touch to get shocked even in the case of a fault. That coupled with how GFCI/RCDs are being widely adopted as well leads to grounding not being as important.
I'm (mostly) with you on the plastic casing, but in general (in the US at least) you only see GFCI in kitchens and bathrooms.
Meanwhile I'm sitting 2 feet away from a nearly completely metal lamp with a two-prong plug.
Meanwhile I'm sitting 2 feet away from a nearly completely metal lamp with a two-prong plug.
Find this very scary not having RCD on some plugs even with 120 Volts. Sure 240v with RCD will give you a massive shock but still will very unlikely kill you. No RCD on the other hand can be fatal on 120V:
https://edition.cnn.com/2017/07/18/health/teen-bathtub-elect...
> 110V single-phase power to residences.
The US is 120V, or split-phase 240 V. Depending where you are, it's allowed to be ±5% at the meter. NEC guidelines say no more than 3% voltage drop from there.
The US is 120V, or split-phase 240 V. Depending where you are, it's allowed to be ±5% at the meter. NEC guidelines say no more than 3% voltage drop from there.
Yeah, I got the number wrong, 120/220 always messes me up; will leave previous comment as-is so that yours makes sense.
You might have 208V and not 240V if you have two 120V phases 120 degree apart.
Not just Sweden. In Netherland, 3x25A is also pretty standard. To our surprise, our house turned out to have 1x35A, so when we got a big induction cooker, we had to upgrade to 3x35A.
ConEd standard* service in NYC provides 120/208 three or four wire service from a wye connected transformer bank. With the density of the city it's easier to just run three phase all over and let homes pull alternatingly off the hots. So homes connect A-B, B-C, A-C and so on.
Three wire service means you get two hots and a neutral and is considered a single phase "open wye" service. BUT you can reconstruct the third phase from the two half vectors in each phase using transformers.
Four wire gives you full three phase service so you can run big motors, machinery, lots of lighting and such.
*Though plenty of neighborhoods are fed 120/240 or mixed. I'm on 120/240 yet the next block is 120/208. Sucks because I want my three phase.
Three wire service means you get two hots and a neutral and is considered a single phase "open wye" service. BUT you can reconstruct the third phase from the two half vectors in each phase using transformers.
Four wire gives you full three phase service so you can run big motors, machinery, lots of lighting and such.
*Though plenty of neighborhoods are fed 120/240 or mixed. I'm on 120/240 yet the next block is 120/208. Sucks because I want my three phase.
The speed of light is an issue as well - it takes about 1/60 of a second to cross the US.
This means it's impossible to synchronize the entire grid. The synchronization depends on the length of the path across the US.
I'm not sure actually how they propose to deal with this.
Edit, found this: https://news.ycombinator.com/item?id=16536121
This means it's impossible to synchronize the entire grid. The synchronization depends on the length of the path across the US.
I'm not sure actually how they propose to deal with this.
Edit, found this: https://news.ycombinator.com/item?id=16536121
I always love this one explanation of why three phase and not some other number of phases, like six or twelve[0]
Starting there is of course an infinite rabbit hole just on youtube to understanding power generation anywhere in the world and how it changed through history
[0] https://youtu.be/HqZtptHnC2I
Starting there is of course an infinite rabbit hole just on youtube to understanding power generation anywhere in the world and how it changed through history
[0] https://youtu.be/HqZtptHnC2I
You mention the challenge with connecting out-of-phase grids. This is I believe why the proposed interconnects are high-voltage DC, as mentioned in the article. Power will be loaded in from one AC system, transported, and then offloaded as AC properly synchronized to the recipient grid.
> then there will be serious problems in connecting them together
No there won't. The article mentions DC power converters. They are not cheap, but since HV DC lines are better for long distance power transmission than three phase AC, it's killing two birds with one stone.
No there won't. The article mentions DC power converters. They are not cheap, but since HV DC lines are better for long distance power transmission than three phase AC, it's killing two birds with one stone.
I am not sure what your point is. It is possible to change the phase of a signal. In fact, a simple capacitor or inductor will do it.
With high power systems it might not be practical to do it with a single capacitor or inductor but it still can be done.
With high power systems it might not be practical to do it with a single capacitor or inductor but it still can be done.
Interesting explainer: Why 3 Phase Power? Why not 6 or 12?
https://youtube.com/watch?v=HqZtptHnC2I
(Substation complexity.)
https://youtube.com/watch?v=HqZtptHnC2I
(Substation complexity.)
"Folks may not realize that power is transmitted in three phases in the US"
My office in the UK has three phase power (I own it.) The phase shift thing is to enable putting more power into a place and nothing to do with "so that we basically always have at least one phase providing power at any time." whatever that means.
My home only has one phase because I don't need to draw that much power here (yet.)
My office in the UK has three phase power (I own it.) The phase shift thing is to enable putting more power into a place and nothing to do with "so that we basically always have at least one phase providing power at any time." whatever that means.
My home only has one phase because I don't need to draw that much power here (yet.)
The main point of this article has nothing to do with the technical details of power transportation and everything to do with politics and corruption of our academic/research institutions. It’s amazing how an anti-fact leader can have such corrupting influence on institutions that are building tomorrow’s leaders.
You'd be hard pressed to find too many facts in a study like this. These are largely conjecture with a list of assumptions and simplifications longer than the study itself. NREL is particularly famous for these. The reality is there are as many people who think the grid should be split into more pieces as there are people who think it should be unified.
But it's a fair point regarding the political influence in these type things, though it's not just the current administration. In a couple of months we will all be changing the verbiage of our proposals from resiliency, security back to renewable integration to satisfy our funding overlords.
But it's a fair point regarding the political influence in these type things, though it's not just the current administration. In a couple of months we will all be changing the verbiage of our proposals from resiliency, security back to renewable integration to satisfy our funding overlords.
Pratically Chinese in having a political officer embedded in the conference who reports violation of political correctness to senior political appointees who can then have it shut down.
I've flagged the article for such a reason.
Everyone's apolitical until the lights go out.
Too much efficiency is dangerous: it makes the overall system more vulnerable because it removes redundancies, increasing systemic risk. Decision processes are not scale-invariant: politics, and therefore susceptibility to corruption, increases, transparency decreases.
Not saying a unified grid is not worth it, but there are downsides that might not be immediately obvious.
Not saying a unified grid is not worth it, but there are downsides that might not be immediately obvious.
I definitely picked up on the same thing, remembering the east coast blackout in 2003.
https://en.wikipedia.org/wiki/Northeast_blackout_of_2003
https://en.wikipedia.org/wiki/Northeast_blackout_of_2003
You don't know the contra positive though, would the spare capacity in the rest of the system have prevented it?
My point is that the spare capacity would evaporate, as the higher-cost power plants would be shut down.
Yup - just in time manufacturing means we often rely on critical parts delivered from foreign countries. I wish I could remember the article I read over five years ago that was pointing out that many utilities do not have backup equipment at larger substations and often rely on replacement devices from overseas sources.
Hopefully we have gotten a bit better and stockpile spares for critical infrastructure such as the electrical grid, especially when we have lost so much of our internal manufacturing capabilities.
Hopefully we have gotten a bit better and stockpile spares for critical infrastructure such as the electrical grid, especially when we have lost so much of our internal manufacturing capabilities.
Of some relevance here:
Transformers that are small are often on hand and easy to swap out. But some of the bigger ones have months long lead times. The facility we were at had transformers that had a 6 month lead time from Germany to replace them and they had to be sent via boat as they wouldn’t fit in planes.
https://news.ycombinator.com/item?id=24318278
Transformers that are small are often on hand and easy to swap out. But some of the bigger ones have months long lead times. The facility we were at had transformers that had a 6 month lead time from Germany to replace them and they had to be sent via boat as they wouldn’t fit in planes.
https://news.ycombinator.com/item?id=24318278
The argument for more unified grids would have had more leg before the 2003 outage, where a failure was propagated through the grid and resulted in a blackout for a large part of the US. With multiple separate grids, at least you reduce the impact of such event.
The article makes this seem like it's a US problem but, the interconnects lay in Canada and Mexico too. I'm guessing that unification is a low priority for them since it seems that the US stands to gain the most from it.
"DC power lines transmit power more efficiently than AC lines do"
This is not at all what is taught at school. Looking into this is interesting. 100 years ago people were debating about whether AC or DC is a better means of transmitting power and, it looks like answers still aren't clear now. I'm interested in knowing what an expert in this thinks.
"DC power lines transmit power more efficiently than AC lines do"
This is not at all what is taught at school. Looking into this is interesting. 100 years ago people were debating about whether AC or DC is a better means of transmitting power and, it looks like answers still aren't clear now. I'm interested in knowing what an expert in this thinks.
What is taught in school is generally a simplification of the truth. However just because that is the case doesn't mean that the "answers still aren't clear now" -- it's just the reality of the limits of the education system (if you tried to explain every topic correctly from first principles you would never get past Newtonian mechanics).
The reason why AC is taught as being "more efficient" is that if you use AC you can easily use a transformer to increase the voltage (decrease the current) of the electricity being transported. That makes the transport more efficient because of I²R power losses. The reason why AC is "easier" to transform is because the classical transformer (two coils of wire and a laminated iron core -- no moving parts and incredibly efficient) requires AC input. Most power grids do use AC because this makes the grid much simpler to produce and
However the part that is missing from high-school education is that AC travelling down power lines at the same voltage as DC is less efficient and more expensive per kilometre. There are many reasons for this -- but the main ones are that the skin effect means AC current only travels on the outer parts of a wire causing higher current density and thus higher losses, the generation of RF interference, and the fact that AC lines have to transport reactive power (AC current reverses direction every half-cycle which essentially means more power loss).
So the most efficient transport mechanism for long distances is to generate AC, transform it up to a high voltage, and then rectify it to DC for the actual transport (and reverse the procedure on the other side). However the rectification procedure requires expensive equipment, which is why HVDC transport is only used for long-distance power transportation.
The reason why AC is taught as being "more efficient" is that if you use AC you can easily use a transformer to increase the voltage (decrease the current) of the electricity being transported. That makes the transport more efficient because of I²R power losses. The reason why AC is "easier" to transform is because the classical transformer (two coils of wire and a laminated iron core -- no moving parts and incredibly efficient) requires AC input. Most power grids do use AC because this makes the grid much simpler to produce and
However the part that is missing from high-school education is that AC travelling down power lines at the same voltage as DC is less efficient and more expensive per kilometre. There are many reasons for this -- but the main ones are that the skin effect means AC current only travels on the outer parts of a wire causing higher current density and thus higher losses, the generation of RF interference, and the fact that AC lines have to transport reactive power (AC current reverses direction every half-cycle which essentially means more power loss).
So the most efficient transport mechanism for long distances is to generate AC, transform it up to a high voltage, and then rectify it to DC for the actual transport (and reverse the procedure on the other side). However the rectification procedure requires expensive equipment, which is why HVDC transport is only used for long-distance power transportation.
To transmit power without loss you have to increase the voltage. The easiest way to do this (And in the late 19th century the only way) is with a transformer, and therefore AC.
However, since the 1930s we’ve been able to build high voltage DC lines, and costs have plummet in the last 30-40 years (as we moved away from Hg rectifier tubes to Si high power electronics).
DC has many advantages:
- No capacitive coupling to ground - No reflections due to Z mismatch - You can lay a cable underwater (basically impossible with AC) - you can connect incompatible grids
HVDC is still fairly expensive (obviously compared to a lump of laminated steel) so it’s used for very long lines, or other special needs.
But it’s revolutionized the field.
AC still has many advantages and won’t go anywhere, especially last-mile to medium range:
- arguably safer since an arc fault can self extinguish - switches are much cheaper to build - cheap electric motors - cheap ability to scale V
However, since the 1930s we’ve been able to build high voltage DC lines, and costs have plummet in the last 30-40 years (as we moved away from Hg rectifier tubes to Si high power electronics).
DC has many advantages:
- No capacitive coupling to ground - No reflections due to Z mismatch - You can lay a cable underwater (basically impossible with AC) - you can connect incompatible grids
HVDC is still fairly expensive (obviously compared to a lump of laminated steel) so it’s used for very long lines, or other special needs.
But it’s revolutionized the field.
AC still has many advantages and won’t go anywhere, especially last-mile to medium range:
- arguably safer since an arc fault can self extinguish - switches are much cheaper to build - cheap electric motors - cheap ability to scale V
It looks like most of those points are because you wouldn't necessarily be transmitting power over frequency like you would with AC. But, if we're transmitting over long distances wouldn't we end up transmitting the DC in frequency to avoid attenuation loss?
AC current is more efficiently transformed between voltages.
DC current is more efficiently transmitted (conducted) over long distances at high voltage.
Since the early 20th century, DC transformers have become more efficient, as others have noted.
Given that electric grid transmission occurs at a wide range of voltages (~275kV generation, ~100kV long distance, 50kV local, 110/220V residential/commercial drops), efficient, reliable, cheap transformers were required, giving the initial edge to AC.
https://en.wikipedia.org/wiki/Electrical_grid#Voltage
DC current is more efficiently transmitted (conducted) over long distances at high voltage.
Since the early 20th century, DC transformers have become more efficient, as others have noted.
Given that electric grid transmission occurs at a wide range of voltages (~275kV generation, ~100kV long distance, 50kV local, 110/220V residential/commercial drops), efficient, reliable, cheap transformers were required, giving the initial edge to AC.
https://en.wikipedia.org/wiki/Electrical_grid#Voltage
HVDC is much better than anything else for long distance transmission. But the gain is because of the high voltage part, not the DC one.
The one thing that pushes people into DC is that phase synchronization is a huge problem on high voltage. So, for indirect reasons, DC gets to be the winner right now.
The one thing that pushes people into DC is that phase synchronization is a huge problem on high voltage. So, for indirect reasons, DC gets to be the winner right now.
“But the gain is because of the high voltage part, not the DC one.“
What do you mean by that? My understanding is the HVDC lines are still lower V than an AC line (the Soviet even had 500lV lines), and therefore DCs advantages are no coupling to ground, no Z reflections and ability to connect to any grid.
What do you mean by that? My understanding is the HVDC lines are still lower V than an AC line (the Soviet even had 500lV lines), and therefore DCs advantages are no coupling to ground, no Z reflections and ability to connect to any grid.
A quick search will lead you somewhere like here: https://en.wikipedia.org/wiki/High-voltage_direct_current.
> Most HVDC links use voltages between 100 kV and 800 kV.
By contrast, high voltage AC lines are around 10kV to (very rarely) 100kV. AC presents some more problems to high voltage than just phase synchronization (so even two point lines are DC), but the gains come mostly from the HV part, and AC is avoided because it doesn't play well with HV, reverting the gains.
> Most HVDC links use voltages between 100 kV and 800 kV.
By contrast, high voltage AC lines are around 10kV to (very rarely) 100kV. AC presents some more problems to high voltage than just phase synchronization (so even two point lines are DC), but the gains come mostly from the HV part, and AC is avoided because it doesn't play well with HV, reverting the gains.
Lots of good answers in the replies here, but one more thing to keep in mind is that, when the DC vs AC argument was going on in the late 1800s and early 1900s, we were still 40 years away from discovering semiconductors.
Nowadays, a lot of residential loads at least would probably be more efficient with DC coming into the house with the popularization off brushless DC motors and all the technology around the house.
Nowadays, a lot of residential loads at least would probably be more efficient with DC coming into the house with the popularization off brushless DC motors and all the technology around the house.
Always interesting to learn such details about infrastructure "hidden in plain sight". One more I can add is the separate traction power network in Germany, Austria in Switzerland, which is necessary because the railways here use a frequency of 16,7 Hz. It is fed in part by dedicated power plants (or dedicated generators in shared power plants), in part by converters.
https://en.wikipedia.org/wiki/Traction_power_network
https://de.wikipedia.org/wiki/Bahnstromnetz#/media/Datei:Bah...
https://en.wikipedia.org/wiki/Traction_power_network
https://de.wikipedia.org/wiki/Bahnstromnetz#/media/Datei:Bah...
There is a wonderful YouTube channel called practical engineering. You might like that. It's primarily about hidden in plain plain infrastructure and the engineering behind it.
IIRC, one of the reasons Texas has a separate grid is to avoid Federal regulation: The source of the US’s power to regulate electricity is the interstate commerce clause in the Constitution, which doesn’t apply if nothing crosses state borders.
I also heard that having its own power grid makes it an appealing place to build data centers. Especially for the military who are worried about power-grid-hacking.
As I read this and started to see the politics rise up, I was reminded of a similar set of arguments and regs around electronic road toll collection. The US govt has mandated (the MAP-21 act of 2012) thst we move to a single standard so a sunpass from FL will work just like an EZpass from NY. Wired did a nice summary a few years ago on the lack of progress (https://www.wired.com/story/national-tolling-system/)
Worth mentioning here that China has massively invested in HVDC for over a decade (and still is [0] ... about a half-trillion/year lately).
The longer that N.A. drags its heels on this, the longer it'll take to move to renewables. (Just another infrastructure need that might have been paid for by funds thrown into Forever War.)
[0] https://www.youtube.com/watch?v=rThkjp-bp8M "China's MILLION VOLT Energy Superhighway" (12m)
The longer that N.A. drags its heels on this, the longer it'll take to move to renewables. (Just another infrastructure need that might have been paid for by funds thrown into Forever War.)
[0] https://www.youtube.com/watch?v=rThkjp-bp8M "China's MILLION VOLT Energy Superhighway" (12m)
At least part of the reason is regulatory. The national grid regulator (FERC) gets its foothold through the interstate commerce clause. Since Texas heavily restricts the interstate interconnections it is not regulated federally (or at least less regulated). Of course this doesn’t explain the East/west non-interconnection, I think historically the Rockies do most of that though (as the article mentions). The issue is only partially technical and largely administrative.
The source article was a far more digestible read of the same content: https://www.invw.org/2020/08/20/who-killed-the-supergrid/
Wikipedia has a nice map showing the coverage of various grids in N. America:
https://en.wikipedia.org/wiki/North_American_power_transmiss...
https://en.wikipedia.org/wiki/North_American_power_transmiss...
> your article imagines, for example, the sun rising in the West
This isn't a useful thought experiment. What was the author thinking?
This isn't a useful thought experiment. What was the author thinking?
Rewrite as: "Imagine that as the sun rises in the western U.S. ...".
I dunno there's like 300 million people living here, it feels like we should have more than just three
> California had more rolling blackouts
> Let's consolidate it with the other grids
How about no? Centralization means single point of failure. If anything we need more, smaller, localized grids that are reactive to their localized needs.
How about no? Centralization means single point of failure. If anything we need more, smaller, localized grids that are reactive to their localized needs.
Granted the immense infrastructure investment, but why not ditch electrical and natural gas for hydrogen? Hydrogen is much safer, cleaner, and less lossy than either.
Bulk hydrogen production from electricity is more expensive than natural gas. It's also more expensive than making hydrogen from natural gas, which is why lots of fossil fuel companies like "clean" hydrogen.
(It can also be lossy, as the atoms are small enough to leak through metals, causing hydrogen embrittlement along the way)
(It can also be lossy, as the atoms are small enough to leak through metals, causing hydrogen embrittlement along the way)
Texas.
Why east and west are separate is probably more interesting.
Why east and west are separate is probably more interesting.
> If you look at lists of the 100 greatest inventions of all time, electricity figures prominently. Once you get past some key enablers that can’t really be called inventions—fire, money, the wheel, calendars, the alphabet
Well that's a doozy of a way to start. How is electricity an invention but those listed after are not?
Well that's a doozy of a way to start. How is electricity an invention but those listed after are not?
Indeed, I was about to say that with electricity, we know when and by whom it was invented, but then again, the development of electricity as a useful power source was the work of multiple inventors over the span of decades. With those other inventions, possibly centuries, who knows. So I'd still call them inventions.
Fire is a natural phenomenon and I don't see how it can credibly be called an invention. That would be like calling water an invention.
The others, though, are certainly inventions.
The others, though, are certainly inventions.
I would argue that the ability to make controlled fires was an invention and perhaps the first chemistry humans intentionally performed, but I think it's just a point of semantics.
Well, by that logic neither is electricity, since lightning exists.
And magnets certainly do occur naturaly, and so does nuclear fission and fusion.
And magnets certainly do occur naturaly, and so does nuclear fission and fusion.
I agree. To say that a natually-occurring physical process or phenomenon was invented is nonsensical.
Electricity is not the same as electric power, just as nuclear fission is not the same as a nuclear weapon, just the same as fire is not the same as a coal fired power plant.
Electricity and nuclear fission were discovered, not invented.
Electricity is not the same as electric power, just as nuclear fission is not the same as a nuclear weapon, just the same as fire is not the same as a coal fired power plant.
Electricity and nuclear fission were discovered, not invented.
I see a lot more natural electricity (lightning, monthly) than I do natural fire (wildfires? Never)
Almost as though methods to prevent wildfires are one of the earliest human inventions.
I mean, the reason I have never seen a wildfire is because they are exceedingly rare in my local biome. Nothing to do with artificial wildfire prevention.
[deleted]
Do you think that electricity can credibly be called an invention?
No, but I distinguish between Electricity, the physical phenomenon, and Electric Power, the application of electric charge to energize a device. Lightning is the obvious example of electricity that is not electric power.
Why not distinguish between fire the physical phenomenon and controlled fire the application of fire to heat up objects or provide light?
The line between capability and invention is ... broad and ill-defined.
I stumbled over that comment as well, though the article doesn't hinge on it.
I stumbled over that comment as well, though the article doesn't hinge on it.
Ugh, another way the Trump administration is holding back the country. The frustrating thing is this time the scientists almost got away with it. If they just did not invite any political DOE officials to their presentation, they might have published the paper.
https://en.wikipedia.org/wiki/Electricity_sector_in_Japan