does anyone have objective info on how far electricity can be "shipped"?

[yurbud]

here is CA, I know the energy traders sold our electricity out of state, but I don't know how far out it can go.

What I'm wondering is why the sunbelt couldn't do enough solar to take care of not only themselves but the rust belt too.

[Coyote_Bandit]

1. Ummmm

My guess is that the issue isn't related to how far the energy can be shipped as much as it is related to whether or not the existing infrastructure can handle additional power or demands for power. I have a family member that works for an electric company. The infrastructure here in the midwest has not been maintained and is currently stressed by additional demands resulting from new construction.

[yurbud]

3. the other solution is make your own with solar, wind, or whatever

The corporate energy companies are obviously going to continue playing this game of letting the infrastructure decline to produce articial shortages, which makes their product look more costly.

The energy internet, with people feeding into the grid as well as taking out of it, would substantially neuter those assholes (a mixed metaphor, I know).

[hpot]

2. Answers.com: Power Loss

"Electrical power is invariably partially lost during transmission. This applies to short distances such as between components on a printed circuit board as well as to cross country high voltage lines. Loss power is proportional to the resistance of the wire and the square of the current.

Ploss = RI2

Because of this relationship, it is favourable to transmit energy with voltages as high as possible. This reduces the current and thus the power lost during transmission."

http://www.answers.com/topic/electric-power-transmission

[zeemike]

6. And the ideal is to generate it on site.

And save a tremendous amount on losses.
That is why it has always seemed to me the best system is photo voltaic cells on the roof that separated Hydrogen from water and used it in a fuel cell when electricity is needed. .

[yurbud]

9. how well do photovoltaics work up north where it's cloudy for months

at a time?

[zeemike]

10. Not very well I would think.

But a large part of the country has plenty of sun to make it work.
But that is why one needs a storage system like the Hydrogen and fuel cell to store it up when the sun shines for use as needed.

[skids]

14. Hydrogen hype...

There are three devices most promising for low-cost home battery backup, and none of them are H2 fuel cells:

www.beaconpower.com
www.vrbpower.com
http://thefraserdomain.typepad.com/energy/2006/01/eestor_ultracap.html (see other DUthread for this, btw.)

FWIW. The PEM in fuel cells was a great technological acheivement (and is even used in one of the above,) but when the rubber meets the road there are better storage mediums for electrical power.

[zeemike]

26. That capacitor storage system is interesting

I wonder how big one would have to be to supply the power for one house?
It would be perfect for Photo voltaic systems.

[skids]

27. One or two units should do...

Each being about 400 pounds, and of unknown physical size.

I like the high speed flywheels a bit better myself, at least until the useful lifetime of the eestor cap is ascertained -- there seems to be no real data on that yet, and I'm not sure either of the day-to-day leakage power loss of the cap whereas the flywheel's power retention is acceptible.

[jpak]

19. Ahem....

http://www.solarhouse.com/

On the fog bound coast of Maine...

(also, there are a well over a thousand off-grid and grid-tied solar homes in Maine - solar works just fine "up there")

[hunter]

28. Must be nice to have money and two acres overlooking a wildlife refuge...

You want to save energy? Become a vegetarian, move to a small flat in a big city and walk to work. If you are looking for environmental impact bragging rights you'll blow these self-congratulatory people right out of the water.

You want to do something that will trump anyone? Study medicine, go to a place with a high birthrate, learn the language and open a Planned Parenthood clinic.

:woohoo: (Sorry, couldn't help it.) :woohoo:
Without NNadir this place is missing some snarkiness.

[jpak]

38. Snarkiness in the E&E Forum???

Pshaw!!

:evilgrin:

[eppur_se_muova]

34. check out solar power in Toledo, OH, and vicinity...

http://www.cmse.utoledo.edu/cpeh/array.htm

http://home.earthlink.net/%7Ealcompaan/


This rooftop array was designed to provide all the elecrical energy needed by the house with enough left over to
charge a battery-operated electric pick-up truck that is used for commuting about 20 miles per day. Typically the
panels feed excess power to the grid during the day and use much of that electricity at night when the lights are on
and truck batteries are being charged. This system takes advantage of the net metering regulations of the Public
Utilities Commission of Ohio which requires the utilities to pay small green-power producers the retail price for any
electricity delivered to the grid. After about one year of experience, this 4.3 kW array is providing essentially all the
electricity needs of the home and the electric truck. More details of this system and its performance can be found
at: http://home.earthlink.net/~alcompaan/

[Throckmorton]

15. AC power also suffers from;

In addition to I2R loses, other loses that effect high voltage transmission systems. Eddy current losses, or Currents generated in non-power carrying metal objects by interaction with transmission line magnetic fields.
Hysteresis losses, loses incurred by resetting the residual magnetism in transmission lines, bus work, circuit breakers and transformers.

Also, both AC and DC lose energy due to insulator bleed over. Which is stray current to ground that leaks over the surface of insulators.

The long and the short of it is that AC power at 60 Hz loses about 50% of its energy after 400 Miles. DC transmission works much better in that respect, about 600 Miles, but DC has significat conversion loses at both ends of the line.

My charging current for one of my 345 KV lines out of the station is 4.5 Amperes, and that is for about 1 mile of transmission lines. This is the measured current Downstream of the Generator Step-Up Transformer, basically between the Station Main Disconnect and the SF6 Gas Blast Breaker output bus work at the ISO's Sub-station ring bus. This is measure with the ring bus Air Disconnect open.

That works out to 1.55 MVA, or about 1 Megawatt at a 65% Power factor. Multiply that by 3, one for each phase, for our total transmission lose just to the Sub-station. in aggregate we lose 0.25% of our Net Generation to the ether over just about 1 mile.

[hunter]

23. So, you are a giant computing machine ?

Connected to the grid by 345 KV power lines?

(Sorry, I switched into science fiction mode there... my own mind doesn't have to plugged in. It is often powered by beans, rice and green tea.)

:P

[Throckmorton]

37. Why Yes, I am,

isn't everyone?

[JohnWxy]

40. Any interesting research on ways to reduce these transmission losses?

This would seem to be a promising area to focus on, given the magnitude of the losses.

[hunter]

4. The topic you are looking for is "HVDC"

High Voltage Direct Current power transmission. A power grid covering the entire Continental United States would be possible using this technology.

[Dead_Parrot]

22. One problem with that...

There's no such thing as a DC circuit breaker: If there's a problem, you'd loose the whole grid at once.

[hunter]

24. It depends how you built it.

These big thyristors are amazing things.



http://pepei.pennnet.com/Articles/Article_Display.cfm?Section=ARTCL&ARTICLE_ID=237724&VERSION_NUM=2&p=17

[gulfcoastliberal]

36. The South Americans have us beat on this technology from the grid from the

Itaipu dam. The new HVDC is called "HVDC light". Solid-state components rather than huge mercury switches.

http://www.abb.com/industries/us/9AAC751068.aspx?country=BR

[hunter]

39. The machine in #24 is solid-state, not a mercury arc valve.

This "HVDC light" is interesting because it uses transistors, not thyristors. This changes the nature of the machine and its control circuitry quite a bit.

The link to abb.com is very good, especially for anyone like the original poster who wants to explore this subject further.

Thanks!

[TreasonousBastard]

5. Dunno if there's enough sun for that...

down there. :) Takes a lot of solar panels to create enough usable juice.

Before I start looking stuff up, I seem to remember that a single solar cell creates around a volt or so, so you've got to string a lot of them in parallel to get the 50,000 volts or so needed to transmit over long distances and create the amount of current needed. And you've got to convert the DC the cells create to AC. We're probably talking square miles of cell arrays to power a small city.

Technically not a problem, but it costs money, and every step in the process creates losses. Right now it's much cheaper per kilowatt produced to just expand a coal plant. Building a bunch of windmills is more expensive per megawatt produced, too, but not by nearly as much as solar panels.

Around here, it costs about 25-35,000 bucks or so to install solar panels for one house and the panels cover most of the roof. People do it because of huge rebates they get, but even with economies of scale, take that cost and size and think about what it would take to power a town.

[zeemike]

7. But a single solar cell is less than one square inch

50,000 square inches is about 400 square feet.
And the only reason to change DC to AC is to operate electric appliances that are made to operate off of AC. If you had them designed to use DC there would not need to convert it except for special purposes.

[TreasonousBastard]

12. Two small things...

OK, you made me look up stuff.

Regardless of the voltage, a cell can only create "X" watts per square inch or whatever. Right now, the commercially available cells have an efficiency of 12%, which means 120 watts per square meter at full power. 40% cells are in the works, though.

So, for one house using 15K peak, would need 125 square meters of cells plus whatever is needed to cover various conversion losses-- which would not be working all the time because of clouds and nighttime, making electrical storage, or a second source, a necessity. That's over 1345 square ft. for one house and it still might not do the whole job.

8,000 square meters per megawatt= >86,000 square feet, or well over two acres of cell area alone, plus all the other hardware and stuff needed.

AC isn't produced simply because our appliances use it-- a long time ago Westinghouse shoved Edison's face in it proving that AC has much lower transmission losses than DC, and DC actually has a very limited transmission distance. While DC is very useful for some lighting and small motors, flourescents require AC, many things from clocks to TV sets use the 60 Herz pulses for internal timing, and larger motors use the phases from AC to reduce internal losses and produce more power from less total current.

[Throckmorton]

16. Not actually accurate

Westinghouse should that transmission loses could be compensated for using transformers, such that the product delivered to the customer could be of a consistent voltage. Not efficiently done with the DC control technology of the time. Alternators (AC Generators) are also inherently more reliable, as the high energy portion, the stator, doesn't move. Unlike the DC generators of the time which used brush and slip-ring technology, which required frequent maintenance.

That coupled with the issues involving the switching of High Voltage DC (No Arc Quench) and it's danger at even relatively low voltages, made it lose out.

AC actually has higher transmission loses than DC.

[TreasonousBastard]

32. Interesting. I was always under the impression...

that reversing the flow increased the range.

[hunter]

17. AC/DC

Modern power handling technology makes the distinctions you list much less important. It is often easy, efficient, and economical to switch between AC and DC and back again, even in a throw-away device like a compact fluorescent bulb. In modern compact fluorescents the 60Hz AC current is first converted to DC and then converted back again to AC at a frequency of about 20,000 Hz. Television sets haven't used line frequency for synchronization for a long time now. Clocks often do use line frequency because it is adjusted to be accurate over long time periods by the utilities even though the short term drift can be pretty bad. Larger industrial motors these days often have DC controlers in which the one or three phase power is first converted to DC and then to AC again in order to optimise the motor speed and efficiency.

At the supply end, HVDC systems operating at a million volts or more are a mature technology. HVDC links between, say, the deserts of the Southwest and the rest of the continental United States would be very feasible. The Pacific Intertie linking Los Angeles with the Pacific Northwest was completed in 1970 with a capacity of 1600 MW, and has been upgraded to a capacity of 3100 MW as the technology has improved.

[Throckmorton]

18. Yes, please note I was addressing the history

of power transmission and why AC won out over DC.

Not the state of the technology today.

[hunter]

20. I was replying to post #12.

It's interesting to think about how a power system might be designed from scratch using modern technology.

One thing I'd really like to see is a standardized 12 volt power plug that is NOT an automobile cigarette lighter adapter. Such a thing would be incredibly useful. So would a 12 volt compact fluorescent light bulb socket, one that could be semi-permanently installed within a regular light socket.

Such things would make small scale off-the-grid solar installations much neater, safer, and attractive. And maybe they would spread into common use as the standard power connector for all low wattage devices.

[TreasonousBastard]

31. You're spot on about the 12V socket...

years ago I started to put a 12V circuit in the house for lights and other stuff. A windmill charger and a few deep charge batteries would have done trick. Lights from the auto parts store, a few trips to RV and marine dealers and some 12V appliances... Never finished the project but at the time there were no codes for 12V use so no standardized sockets (still true, I guess) so I found some obsolete plugs and sockets to use. Not the best solution.

[TreasonousBastard]

33. Interesting. Most of...

my time playing with electricity was small circuits and I never did spend much time dealing with the engineering of power generation. Not at all up on the newer technologies.

Back in the dark ages before decent crystals were affordable, or usable, I found it easier to hook on to 60H for some timing requirements than to come up with a reliable oscillator, but, yeah, there are easier and more reliable ways to do things now, so there probably isn't much of that going on any more. And, yeah, without need for a lot of the huge transformers monster oscillators, diodes and other stuff from years ago, a lot of AC/DC conversion is now fairly convenient, or unecessary. Incandescent lights have a longer life on DC, toasters don't care...

'Tis still my understanding, though, that while small motors are more easily controlled by varying the DC voltage, there's a torque problem at low voltages and speeds that AC motors don't have because they somehow play with the phases for speed change. A little trickier to design the speed controller, but more efficient at all speeds and more torque at lower speeds.

[jpak]

21. Most homes don't require more than a few (2-4) kW of roof mounted PV

and most roofs can accommodate these systems.

Also, PV cells with >20% efficiency are on the market today.

...and two acres would accommodate 1 MW of PV capacity - enough to power a large subdivision (250 homes).

[Nihil]

35. Not to mention ...

... that it gives a major incentive to REDUCE CONSUMPTION!

:-)

[zeemike]

25. Thanks for doing the research

And 1300 sf is less than the roof area of a normal house.
And besides I saw that a guy is not building a factory to make the cells that can actually be used as shingles on the roof and will be much cheaper than what we have now.
And you are right it is current not voltage that counts. but what I would really like to know has more to do with chemistry than electricity. And that is how much energy does it take to separate Hydrogen from watter, because a fuel cell could deliver the needed power when it is needed and the Hydrogen can be made when the sun shines.

But Edison argued, and I think he may have had something there that AC was dangerous because of the induced voltage from the alternating current.
And His power plants were all local so there was no problem with transmission losses.
EVery thing that can be done with an AC motor can be done with a DC motor and in face in some cases it is better. and 100 volts AC will deliver the same power as 100 volts DC. The space station operates quiet well on DC power.

[yurbud]

8. simple example: here in Santa Monica, parking spot and a half sized

panel can make enough electricity to run a car for a day.

There are cheaper ways of doing solar too, like solar thermal, focusing the sunlight to heat water or something else to run a steam engine or turbine, or something I've just seen recently, a solar chimney that creates heat the way your locked car does in a parking lot on a hot day, but has a chimney for the heat to escape and the updraft turns a fan.

[hunter]

11. It would probably be more economical to put your solar in the desert...

... and ship the power to Santa Monica.

It's bad for the desert getting bulldozed over like that, but then your solar machine doesn't have to deal with salt spray, diesel soot, vandals and thieves, seagull and pigeon poop, marine layer cloudiness, etc.



You live in Santa Monica? Santa Monica always makes me sort of sad. A lot of very interesting people were forced out by much less interesting people with empty heads and too much money. I got busted for sleeping in my car there once, so maybe I'm bitter.

But then again maybe I shouldn't talk. The last time I visited I did have money and stayed a few days at the Fairmont Miramar.

:P

[yurbud]

30. we are trying to stay economically diverse, but money interests keep

pushing HARD.

The Third Street Promenade used to have funky, one off businesses, but they are gradually being replaced by the soulless chains.

[TreasonousBastard]

13. I know that...

there are experimental solar cars running off of cells glued all over the body, but It's tough to believe that a panel can charge a real car to run for a day. Small panels are commonly used to power some lighting, LED traffic lights and a lot of other things, but high current usages are something else.

Boiling water in "solar stills" is an old trick, with kits pretty common on sailboats and such, and there have been a lot of experimental solar steam generators. Almost built one myself with a parabolic relector and Pyrex tubing. A huge Fresnel lens could work, too.

Again, though, we're talking about the total installed cost and efficiency, and they're not quite there yet. All this stuff is fun to play with and may eventually work well, but it'll take some time to get it right.

Besides, where do you get all that water to boil in the desert?

[yurbud]

29. we get the water from other states. Suck them dry like a vampire

[JohnWxy]

41. I can't say I agree with your statement that coal is cheaper than wind:

from www.awea.org

http://www.awea.org/faq/wwt_costs.html#How%20much%20does%20wind%20energy%20cost (click on Comarative Cost of Wind Power)

Fuel Levelized costs     (cents/kWh) (1996)

Coal             4.8-5.5
Gas             3.9-4.4
Hydro             5.1-11.3
Biomass             5.8-11.6
Nuclear             11.1-14.5
Wind (without PTC)       4.0-6.0
Wind (with PTC)        3.3-5.3

The cost of natural gas has increased since 1996, so that the levelized cost of gas–
fired power plants would now be considerably higher. In January 2001, the cost of
natural gas generated power was running as high as 15 cents to 20 cents per kWh in
certain markets <3>. The cost of wind power, meanwhile, has declined slightly.
Four additional points about the economics of wind energy should be considered