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High-Temp Superconductors To Connect Power Grids
physburn writes "Somewhere in a triangle between Roswell (UFO) NM, Albuquerque (Left Turn) NM, and Amarillo (Do you know the way?) TX, a 22.5 square mile triangle of High Temperature Superconductor pipeline is to be built. Each leg of the triangle can carry 5GW of electricity. The purpose to load-balance and sell electricity between America's three power grids. Previously the Eastern Grid, Western Grid and Texan Grid have been separate, preventing cheap electricity being sold from one end of America to the other. The Tres Amiga Superstation, as it is to be called, will finally connect the three grids. The superstation is also designed to link renewable solar and wind power in the grids, and is to use HTS wire from American Superconductor. Some 23 years after its invention, today HTS comes of age. "
Each leg of the triangle can carry 5GW of electricity.
5GW is a lot of power; to put that into perspective, the entire state of New York uses about 30GW at peak load on a hot summer day; the great power of Niagara Falls gives us about 5GW (Canadian + US generators).
The three power grids are out of phase with each other. Are they doing a AC->DC->AC conversion? It was my understanding that the biggest technical hurdle to connecting the grids was the difficult problem of shifting the phase of one grid to another.
When I was an intern (1996) I worked in the power-forecasting department of a municipal power company. We used to estimate 4kW peak average per house, worst case. Obviously, every house occasionally pulls more, big houses pull more than small houses, etc, but at about 5pm on the hottest day of the summer, we could count on having a power usage of approximately 4kW * number of houses. So, roughly 1.25 million houses.
Not sure if it'd be more or less now. Houses and HVAC are more efficient, but people tend to use more power when they're active now.
For those who aren't sure where that triangle is, a map.
Native and current resident. New Mexico is no different than the rest of the states. The rural areas are seeing a steady migration out, the urban areas are seeing a steady migration in.
Some areas like Farmington (North west) or Artesia, Roswell, Carlsbad (east side) are highly susceptible to boom/bust natural gas/oil cycles. Areas like Albuquerque are chugging right along and were hit about the national average by the recent recession. Most of the state is agricultural and is slowly sliding into oblivion like the rest of the nation's non corporate-run agriculture though not merely so hard hit as the wheat belt region.
The current governor is a bit of a twit at times but he's done a decent job getting some higher tech interest in NM. The combination of alternative energy as both a producer of energy and producer of materials, light rail interconnect for Rio Grande corridor and of course the space port may end up putting NM in an promising position.
The state isn't overly rich in resources/industry and agriculture is not a money making proposition for any state/country. The state's future is either in energy or tech or it's doomed to a tail end of the pack future much like most other low pop poor states.
In short I think you've overstated the destitute nature of the state compared to most other comparable states. On the other hand I agree that this newest venture is yet another energy/tech venture within the state which is needed or your observation regarding the state may be prophetically accurate.
Then again all the above it's pretty much true for the nation as a whole.
You need superconducters because of the amount of current that will be transported. The loss across the wire increases with the square of the current ( p = (v)i or p = (i/r)i ). That's not a big problem when you're running a vacuum cleaner (although the wire will ususally get warm). It's a huge problem when you're talking about moving thousands of amps. The longer the wire, the more losses there are. In fact, it's common for the main conductors coming out of power plants to be made of pure sodium metal submerged in oil, due to the fact that sodium has a very, very high conductance at normal temperatures.
That's why electric companies sink so much money into transformers. You step up the electricity to high voltage / low current for transmission, then back to low voltage / high current for consumption.
A superconductor has a critical current, if you go above the critical current, the superconductivity breaks down (and you are screwed). The critical current density depends on: material, temperature, and the magnetic field (basically, the critical current decreases when the temperature or magnetic field increases).
Since there is always a magnetic field present (the earth magnetic field), there is always a maximum current a superconductor can carry.
Does that honestly seem to you like such a huge and difficult problem
Yes, as a matter of fact, it does.
During a sudden large drop in demand you have fractions of a second before the turbines spike the hell out of the voltage frying unprotected electronics and maybe a few seconds before the turbines start to tear themselves apart. That's how much time the grid controller has to receive messages from and analyze the system state across the entire grid and decide which turbines across the entire grid to slam the emergency brakes on so that the remaining ones are properly loaded.
It isn't possible, not with any kind of safety margin. As a result, the grid isn't built that way. Instead, each generating plant has a local safety system on the turbines. If the demand changes faster than the speed regulator can compensate they go into emergency safe mode and shut down entirely, after which it takes days to run through the startup checklist and come back online. The grid controller can affect this only indirectly - by stabilizing the demand hitting each generating plant before the safety systems trip.
Which means that any time a sufficiently large capacity set of transmission lines fails, that failure cascades through the system dropping plant after plant.
This isn't just speculation, by the way. Go read http://en.wikipedia.org/wiki/Northeast_Blackout_of_2003 . When the cascade failure finally gets underway, it moves really fast. 150 seconds for the whole blackout in 2003. There's no time to fix it. Either your local portion of the grid transmits or receives so little power from the rest that it can instantly disconnect and absorb the change in demand or else it collapses along with the rest.
Moderating "-1, Disagree" is simple censorship. Have the guts to post your opinion.