Transition to DC

[Brian H]

Rezwan wrote:

Along the same lines the specified distance between repeaters on early EtherNet cables was set to the standard distance between urban drain covers (in which the early lines between University buildings were laid). Makes you wonder were Big Al was when he invented this stuff. :smirk:

Since it seems to be such a hot topic, I’ve assigned Al Gore his own discussion section (Al Gore Fan Club). Post about Al over there, and please try to keep such discussions out of your other posts.

Thanks!
Trying to keep discussions PC and on-topic is a losing game. A discussion goes where it goes.

[Brian H]

Rematog: is Maihem incorrect in saying that solid-state electronics permits easy DC voltage changes? This is a major consideration.

I also wonder about losses in long-distance DC transmission; it was my understanding that they are much higher with DC. But Maihem says not.

Willit;
I really wonder how “gradual” the phase-out will be. I’ve posed this thought-experiment a few times: suppose you are a utility owner/manager with $XXXmillion to spend over the next few years on maintenance and upgrading. Are you going to put it into sustaining production of power at 20X the cost of the new tech on the block? Or are you going to switch your own plant over as fast as you can physically manage to do so?

[Alex Pollard]

Brian H wrote: I also wonder about losses in long-distance DC transmission; it was my understanding that they are much higher with DC. But Maihem says not.

Focus Fusion shouldn’t require long-distance transmission. DC power users would have a local FF reactor.

[Alex Pollard]

Rematog wrote: Several BIG reasons for AC power.

Transformers. They ONLY work for AC power. Very hard (therefore expensive) to raise or lower DC voltage. So if you have a, say 100,000 volt DC transmission line, how do you get it down to a usable household voltage.

Solid-state semiconductor DC transformers are now available, correct? Also, why would there be 100,000 volt DC transmission lines if DC power users have local decentralised FF reactors?

Rematog wrote:

Motors. AC motors have no brushes to wear out. AC is much more convenient for making things turn, like say a refrigerator’s compressor, or the air conditioner’s compressor.

Please correct me if I my knowledge is lacking: Yes, AC is easier but control circuits can commutate a motor using DC input. The electronics is more complicated but the result is can be more efficient and less electrically noisy during startup?

Due to there being few household devices with electric motors vs devices that transform to DC 24/7, I think using a local DC supply could make more sense.

Rematog wrote:

Lighting. While conventional light bulbs will work fine on DC, fluorescent bulbs use ballasts to make the voltage they need to run. Guess you could use LED based lights, but those are not yet commercial.

LED will be commercial in due course.

Rematog wrote:

And the Biggest reason… Trillions of dollars in both utility infrastructure and industrial, commercial and residential equipment designed for good old 60 hz.

Rematog

I can’t argue with that. New standards generally have to be an order of magnitude better than what they replace to take hold: LPs vs CDs, Video tapes vs DVDs, etc…

Would DC be that much better than AC from a user’s point of view, that is the question…..

[Brian H]

Alex Pollard wrote:

I also wonder about losses in long-distance DC transmission; it was my understanding that they are much higher with DC. But Maihem says not.

Focus Fusion shouldn’t require long-distance transmission. DC power users would have a local FF reactor.

Nevertheless the national grid would persist, and urban centers would certainly require power from external clustered generator forms. Transmission would still be an issue. Remember, it takes 1000 FF generators to produce 5GW.

[Rematog]

The solid state transformers I found on a quick search of the internet are very small (1 amp output or less). Also, all that I found mention of are step DOWN transformers. Unless you generate the power at 100,000 volts (which I really doubt), there will be a need for large step UP transformers.

Solid state technology is, currently (pun), normally limited to relatively low currents. The supplier I checked with stated that there are no solid state transformers available on the commerical market today.

The most common application of solid state power technology today is the variable frequency drive (VFD), which would be generally similar to a transfomer application. For example, a 100 hp motor VFD is expensive (A “VFD” is a “smart” solid state drive the rectifies the AC to DC, then creates AC at a new, controllable frequency (it can also adjust voltage to a certain extent), in order to control motor speed, which can reduce in-rush (start-up) current surge, conserve power at lower motor torque/speed demands, and control the “process” being driven by the motor in question (speed control).

For a 100 HP drive a quoted list price is $13,000. I’d assume a solid state transformer to process the power from a 5 MW (6,670 Hp) Focus Fusion power generator would cost around the $500,000 your assuming the generator would cost.

Based on $13,000/2 /100 x 6670 = $434,000, (cost of 100 hp VFD / 2 for economy of scale / 100 to get per Hp x 6670 HP of 5 MW FF generator).

hmmm….

[Brian H]

Rematog wrote: The solid state transformers I found on a quick search of the internet are very small (1 amp output or less). Also, all that I found mention of are step DOWN transformers. Unless you generate the power at 100,000 volts (which I really doubt), there will be a need for large step UP transformers.

Solid state technology is, currently (pun), normally limited to relatively low currents. The supplier I checked with stated that there are no solid state transformers available on the commerical market today.

The most common application of solid state power technology today is the variable frequency drive (VFD), which would be generally similar to a transfomer application. For example, a 100 hp motor VFD is expensive (A “VFD” is a “smart” solid state drive the rectifies the AC to DC, then creates AC at a new, controllable frequency (it can also adjust voltage to a certain extent), in order to control motor speed, which can reduce in-rush (start-up) current surge, conserve power at lower motor torque/speed demands, and control the “process” being driven by the motor in question (speed control).

For a 100 HP drive a quoted list price is $13,000. I’d assume a solid state transformer to process the power from a 5 MW (6,670 Hp) Focus Fusion power generator would cost around the $500,000 your assuming the generator would cost.

Based on $13,000/2 /100 x 6670 = $434,000, (cost of 100 hp VFD / 2 for economy of scale / 100 to get per Hp x 6670 HP of 5 MW FF generator).

hmmm….

Well, that’s pretty much it, then, game-set-match. There is no reasonable way ($$$) in prospect even today for commercial large scale DC transformers, which means strictly local DC power and electronics.

BTW, TeslaMotors chose AC motors for their BEV Roadsters and upcoming Model S for the exact reasons you cite. Their 115-lb watermelon-size motor puts out ~250hp, and accelerates the car 0-60 in 3.7 seconds (Sportster performance model) — using a single-gear transmission. More or less flat torque 0-14,000 rpm, =~125 mph.

[Aeronaut]

Two applications where DC would be a distinct advantage are in vehicles such as locomotives and ships, as well as to replace the RF power switching in inductive furnaces. DC would work best where the FF unit(s) are designed structurally and electrically into the load(s) to minimize resistance losses. This would drive down the cost of aluminum, copper, and possibly steel almost as much as the fuel savings.

Brian H wrote:

The solid state transformers I found on a quick search of the internet are very small (1 amp output or less). Also, all that I found mention of are step DOWN transformers. Unless you generate the power at 100,000 volts (which I really doubt), there will be a need for large step UP transformers.

Solid state technology is, currently (pun), normally limited to relatively low currents. The supplier I checked with stated that there are no solid state transformers available on the commerical market today.

The most common application of solid state power technology today is the variable frequency drive (VFD), which would be generally similar to a transfomer application. For example, a 100 hp motor VFD is expensive (A “VFD” is a “smart” solid state drive the rectifies the AC to DC, then creates AC at a new, controllable frequency (it can also adjust voltage to a certain extent), in order to control motor speed, which can reduce in-rush (start-up) current surge, conserve power at lower motor torque/speed demands, and control the “process” being driven by the motor in question (speed control).

For a 100 HP drive a quoted list price is $13,000. I’d assume a solid state transformer to process the power from a 5 MW (6,670 Hp) Focus Fusion power generator would cost around the $500,000 your assuming the generator would cost.

Based on $13,000/2 /100 x 6670 = $434,000, (cost of 100 hp VFD / 2 for economy of scale / 100 to get per Hp x 6670 HP of 5 MW FF generator).

hmmm….

Well, that’s pretty much it, then, game-set-match. There is no reasonable way ($$$) in prospect even today for commercial large scale DC transformers, which means strictly local DC power and electronics.

BTW, TeslaMotors chose AC motors for their BEV Roadsters and upcoming Model S for the exact reasons you cite. Their 115-lb watermelon-size motor puts out ~250hp, and accelerates the car 0-60 in 3.7 seconds (Sportster performace model) — using a single-gear transmission. More or less flat torque 0-14,000 rpm, =~125 mph.

[Rematog]

I couldn’t comment on DC being better for ships and locomotives. (but a wood burning, triple expansion steam engine powered, paddle wheel river boat works for me). I am just making the board aware that 60 hz AC will be the flavor of power used in US in the forseeable future for local transmission and distribution. DC has some advantages for very high voltage long distance transmission. But if FF becomes a reality, long range transmission would be un-necessary very quickly.

Even I concede that there would be no reason to site plants outside the region the power is needed in. They just need to be outside of town and out of sight of the NIMBY’s.

[Aeronaut]

Alas, the persistence of standards. Paddle wheel steamers work for me, too. What I had in mind with my last post was DC powered diesel-electric submarines. Locomotives may have been a stretch, lol.

[Rematog]

Power-wise, FF is a good match to locomotives. Currently, around 6,000 Hp is a really big diesel electric. FF at 5 MW would be about this size. So, just need to be able to mount it on a locomotive frame and provide cooling, etc.

[Aeronaut]

Rematog wrote: Power-wise, FF is a good match to locomotives. Currently, around 6,000 Hp is a really big diesel electric. FF at 5 MW would be about this size. So, just need to be able to mount it on a locomotive frame and provide cooling, etc.

No idea what a locomotive frame looks like, but I’m sure the form factor will work without the diesel fuel tanks. What I really like, though, is the idea of melding an elegant energy solution (heat first, and electric as it evolves) into an aluminum or copper processing plant with minimal use of transformers.

[Brian H]

Aeronaut wrote:

Power-wise, FF is a good match to locomotives. Currently, around 6,000 Hp is a really big diesel electric. FF at 5 MW would be about this size. So, just need to be able to mount it on a locomotive frame and provide cooling, etc.

No idea what a locomotive frame looks like, but I’m sure the form factor will work without the diesel fuel tanks. What I really like, though, is the idea of melding an elegant energy solution (heat first, and electric as it evolves) into an aluminum or copper processing plant with minimal use of transformers.
Aluminum refining is almost entirely electric already. It is a huge power user. As mentioned, 1/3 to 1/2 of the cost of production, and the industry is desperate for improvement there. Copper I know less about, but as it is easily melted out of ore (almost as easy as gold or silver, historically; it was the first base metal found and used), it would be in plating and other processes that the main benefit would come there, I think. But you’d have to know the entire cycle to see what opportunities for efficiencies would be possible with cheaper power.

[Aeronaut]

Brian H wrote:

Power-wise, FF is a good match to locomotives. Currently, around 6,000 Hp is a really big diesel electric. FF at 5 MW would be about this size. So, just need to be able to mount it on a locomotive frame and provide cooling, etc.

No idea what a locomotive frame looks like, but I’m sure the form factor will work without the diesel fuel tanks. What I really like, though, is the idea of melding an elegant energy solution (heat first, and electric as it evolves) into an aluminum or copper processing plant with minimal use of transformers.
Aluminum refining is almost entirely electric already. It is a huge power user. As mentioned, 1/3 to 1/2 of the cost of production, and the industry is desperate for improvement there. Copper I know less about, but as it is easily melted out of ore (almost as easy as gold or silver, historically; it was the first base metal found and used), it would be in plating and other processes that the main benefit would come there, I think. But you’d have to know the entire cycle to see what opportunities for efficiencies would be possible with cheaper power.
Glass, plastics, and the metals I listed above have low melting temperatures. Since a great deal of the electricity goes to making heat, I’m thinking along the lines of a FF module producing ~13MW/hr of useful energy to apply to the process.

[Rematog]

Aeronaut,

Small nit to pick. Megawatts are a unit of power, which is a rate (like velocity), for 13 MW-hr is a measure of energy (like distance) and 13 MW/hr is a rate of change (like acceleration). Steam power plants have load change limits, typically around 5 MW/min change in output.

Yes, cheap electric power would be a god-send to the primary metals industry. Electro refinining, such as for copper, and as a sorce of heat for casting plants, etc.

Also, waste could be reduce using a plama arc furnace, turning it into fully oxidized gases and glass slag. So, so many things become possible and/or cheap if the power is cheap….

FF would be the next best thing to “Friendly Aliens” providing us with high tech……remember “To Serve Man”….(Twilight Zone episode, google it.)

[Author]

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