Wire and Cable Technology Blog

Why not transform it to high voltage at each site for the transmission lines? Sound familiar?

Sorry about the smart ass reply. Hmmf. uh. Do you mean you don't think we should wait for the reactive, knee-jerk, "free market" to kick in? Think we should actually plan for the future?

I know you have see the huge towers carrying the high voltage tranmission lines.

1000's of towers already exist ! What is mean is they already have tower up just add the wind mill close by ! The power companys hold the right of way under and beside those power lines and there are millions of place where wind mills could be setup along side or even under the lines.

I know the power companys are skidish about anything under the lines so accepting the liability for any damage were a line to fall on the wind mill would be part of any agrrement with them.

Actually the main problem is that the best place for a wind farm is not necessary close where the existing power lines run. It is a waste of time to put them in areas where, although convenient to connect up, won't produce much electricity. There are actually only a few WORTHWHILE places to stick wind turbines, you cannot just stick them anywhere. The land and weather conditions have to be just right to produce a high average wind speed to make them work and produce worthwhile power to offset the resources necessary to produce them (no use building a wind farm that costs more energy and resources to build than you will ever get back). The same goes for bunching up lots of wind turbines together in one place, or operating wind turbines low to the ground (such as on the top of someones home) and expecting them to work well (or at all). It just doesn't work that way. Wind farm engineering is actually a lot more complicated than it seems when you first glance at it.

Same goes for <cringe> solar farms. Vast areas of cheap land are required. You do NOT want to start placing these things on local farm land, you want to stick them on wasteland or the fringes of the desert.

How about Tidal? Most major cities are on the coast so they have realatively good access to the resource (i.e. the ocean being dragged around by the moon).

With the disclaimer that my research is limited to one hazey memory of a suggestion I once heard, I suspect tidal does not give a consistant enough source of energy, i.e. every 6 1/4 hours the tidal force is 0.

Could the tidal stations be used to power the grid during peak ebb and flow, but have other power stations still online? This would reduce our fossil fuel usage on the days that peak ebb and flow are at peak power usage times.

Too much frigging around to be useful?

Tidal still suffers from the problem of not having any power lines nearby to connect to. Remember tidal power generators need to be in areas where large variations in wave strength, direction, height (or a combination of these) occur. It's the difference that allows tidal power generators to work. Generally these conditions are not going to be very close to shore to make tidal generation efficient enough to be viable, so long runs of power cabling will still need to run to connect them to the power grid.

Tidal power is still being developed and refined and does look promising as an alternative energy source in the future.

Hmm. Edison wanted DC power lines. Should we revisit that option?

If our home power were at, say, 320v, we would benefit from the small size of switchmode (switching) power supply technology more easily. It seems that electromagnetic environmental fields would be reduced, as an extra benefit, by the more constant electric and magnetic fields involved with DC current flow.

Any other benefits and drawbacks to this idea?

Hmm. Edison wanted DC power lines. Should we revisit that option?

DEAR GOD NO. Switching to a DC supply network is a very, very bad idea. One of the main reasons is that stepping up and down DC is SO much harder and more expensive than with AC (and the whole power network would need to be changed to run on DC). Same problem occurs if you try to switch to two or three phase supply in existing homes (plus it is rather hard to find a microwave or TV that will run on either).

I admit the stepping up and down as a problem area.

Yet, TV's run off of DC power. They must derive that from the AC through rectification. A television in Europe that can operate off of 240VAC will also operate off of 320VDC. Hook up the power without concern about polarity in that case, and the internal full-wave rectifier will rectify a negative voltage to positive.

The only way is the classical one: transmission using high voltage (low current). The only thing I would change is the higher frequency that will make transformers much smaller.

I'm not sure higher frequency would be good since that should cause capacitive losses to increase.

If power transmission were DC, the power would get chopped to as high a frequency as needed by the device at the point of use. That is how modern devices do it now anyway. It would eliminate the rectification process and other electronic circuitry in many gadgets.

DC power lines should make it easier to feed power back into the lines from local production sources like solar and wind generators as well. There would be no need for frequency synchronization, just easier and simpler regulation.

Power factor correction would become unnecessary.

There may be other advantages, too. For example, I understand that DC is less of a shock hazard than AC.

One disadvantage that I am aware of is that switches arc more with DC. Switches would require beefier contacts that separate further.

Also, I am not sure how to step up and down DC voltage easily.

There may be other advantages, too. For example, I understand that DC is less of a shock hazard than AC.

low voltage DC is just as dangerous as AC. Both can electrocute you, but where touching ac with your hand will generally repel and force your hand away (potentially stopping you heart and throwing you across the room), touching DC with your hand will cause the muscle's in your hand to contract preventing you from letting go.

Refer to Wikipedia for more information (and don't try the above at home).

Ahhh, good points.

Put 2 projects togeather.

Build elevated high speed rail system and use the support structure for the new power grid.

Re:

dadw5boys:

Build elevated high speed rail system and use the support structure for the new power grid.

... That's great, as long as everyone wants to get to the windmill site really quickly...

I concur that we can't afford to not invest in the necessary infrastructure. The decisions to be taken are not whether, but where. Hopefully, it is not too early to apply logic to the planning process.

I think we need to arrange to have high electricity consumption close to the production. (Like how they barge aluminium ore to norway or western canada to smelt it with cheap hydroelectricity). Perhaps rather than expanding the powerlines, we need to get back to canals and railways to transport the stuff (with far greater energy efficiency than trucks on roads) to and from the wind and solar sites. I think cement production and quicklime and hydrated lime production needs heat so stick them near to good solar areas and use solar thermal to cook off the co2 in the lime. I bet even now you could sell solar lime to the do-gooder earthen house market at a premium. Lime plaster is tougher but more energy intensive and produces much more CO2 in the making than the earthen plasters that they typically use. But if you cook the limestone with solar, it is almost carbon neutral. Anyways, that is my take on one way to avoid the big power lines.

Earlier today, I just happened read that in Australia there was talk of doing away with wall warts, you know those mini power adapters that take up to three outlet spaces on your power strip. DC power distribution would make them smaller or obsolete anyway.

With DC power distribution, the two standards of 50 and 60 Hz could be phased out, no pun intended.

There has been talk in the industry of an in-house distributed power supply but it is powered off a large ac-to-dc power supply. The idea is that as more DC-powered products (like phone and camera charges) are standardised into a few voltages then the 'wall warts' can be replaced by a central DC power supply (increasing conversion efficiency and reducing electronic waste associated with 'wall warts'). At the moment there are too many different voltage levels to make it worthwhile (to many converters needed). Given the way product standardisation is going it is getting better, but the home DC network it is not really a viable alternative yet for the average consumer.

It is quite a waste to get a new cellphone or laptop charger every time you want to upgrade or you drop your cellphone in the toilet.

With DC power distribution, the two standards of 50 and 60 Hz could be phased out, no pun intended.

Sorry, that won't happen. AC distribution is still necessary, and the cost and resources necessary to change it is astronomical. You cannot just take existing 220kV or 33kV overhead and underground power lines, fittings and switchgear and put DC or even high frequency AC or switched DC (in the case of switched-mode power supplies) thru it. Virtually all of it would have to be ripped out and replaced due to problems such as electrical insulation breakdown, capacitive and inductive losses due to incompatibility, contact arcing, etc. This is also completely ignoring the fact that the distribution power network needs a reserve built in to handle variations in load but to still allow the voltage to remain constant. In the case of the power network this reserve is achieved due to the power factor (something you don't have available if you use DC).

As any power engineer will tell you, the power network is MUCH more sophisticated and complicated than it appears at first glance. There are very good implementation, cost and safety reasons why we stick to high and low voltage AC for distribution and extra-low voltage DC for the end consumer.

The new system would have to be built while the old one is still n use. Then, as DTV is being done now, there eventually would be an official switchover date. Though I greatly prefer NTSC to DTV.

I predict that the 50 and 60 Hz system will be scrapped sooner rather than later, barring entrance into a new dark age. I just don't know what the replacement system will be like. I'm just saying straight DC is a possibility even though it looks hard to implement with the present system in place.

As any power engineer will tell you, the power network is MUCH more sophisticated and complicated than it appears at first glance. There are very good implementation, cost and safety reasons why we stick to high and low voltage AC for distribution and extra-low voltage DC for the end consumer.

One of those reasons wouldn't be all the copper needed in all of the transformers.

Cannot agree with that, the cost-benefit analysis shows that there would have to be a MASSIVE difference between the new technology and the existing 50 and 60Hz transmission to make it viable. We are talking about trillions of dollars just for the US to change over from AC to DC. It just won't happen, AC has far more going for it for power transmission and distribution than DC, not only that but the infrastructure is already in place.

Even superconductor technology (which looks like the next generation of power storage and transmission by the way) would need to be done in small stages and interface to the existing 50 and 60Hz grid. This is the only technology I see as being a viable contender to replace the existing 50 and 60Hz aluminium and copper distribution grid. Oh, experimental small sections of the US power grid have been upgraded to superconductors for field trials so far. Given that superconductor technology and theory is still in its infancy, it will take some time to work the bugs out and become a viable means of power transmission.

Hi JackOfAllTrades - We have a company you may have heard of here in Schenectady, NY (not far from Edison's old GE plant in downtown and in the region I live in) called "SuperPower", http://www.superpower-inc.com/, specializing in providing the superconducting technology you mention.

As you're aware, this technology is intended to reduce losses over long-distance AC transmission lines. For disclosure, I have no connection to SP, other than having organized a tour for my local ASME chapter and your typical engineer's geeky interest in a useful new technology.

Maybe while the long-distance transmission lines are being upgraded, they could also be optimized for broadband-over-powerlines?

I get the feeling some smart EE's, executives at Google, and maybe even T-Boone Pickens himself have already quietly given this a look. :) - april05

For all intents and purposes, no problem with that. It's not happening anything like immediately, but it will happen that the 50/60 Hz standard will change with almost certainty. Just the fact that there are the two standards of 50 and 60 Hz is pressuring change.

I predict within 100 years, though, 50/60 Hz power lines will be disappearing like most old technologies do after a time. For you and I, that may be practically equivalent to never. But new discoveries and knowledge place obsolescence pressure on old ways and turn the tables on apparent monetary barriers. The third world countries of the future will likely retain their old energy structure like areas in Africa still cook with wood over open fires.

Unfortunately the only technology I see as an even viable replacement for the existing power transmission and distribution network is superconductors, but it is going to take far longer than 100 years for large scale implementation. From my experience in the power industry I cannot see a MASSIVE change like converting from 50 and 60Hz copper and aluminium wires and switchgear over to, say superconductors for a few really good and valid reasons.

1) The incredible cost - It would be enormous. Truly enormous. A partial changeover from copper and aluminium transmission lines is viable (although major developments in superconductor technology would be necessary to be able to produce large amounts of superconductor wire) but even the cost of doing this enormous using current technology.

2) The necessary resources - Superconductor (the most viable alternative so far by far) is not actually a conductor, it is an insulator that only conducts when cooled down close to 0 Kelvin (or there abouts). This type of conductor requires lots of liquid nitrogen (or similar). Developments are continuing for a truly high temperature superconductor that could work near room temperature, but the transformers would also need to be replaced to make the superconductor gains worthwhile.

3) Incompatibility - Superconductor technology, pulsed DC, DC, etc are not compatible with the existing power transmission transformers, switchgear, fuses, insulators and fittings, cables, etc. Must or all of it would need to be modified or replaced entirely. See point 1).

4) If it ain't broke don't fix it. Is it worth changing - The benefit of doing away with our 50 and 60Hz current system at the cost of MANY trillions of dollars and replacing it with something slightly better is the same as pulling every single motor vehicle off the road, scrapping it completely and building brand new motor vehicles. A 10-20% increase in efficiency is not going to come near offsetting the cost of the replacement.

5) Reliability - One of the main reasons small sections of the power grid are running superconductor cable at the moment is that they are field trialling the technology. You need to know how a new technology will perform over time, especially in a critical application as power transmission. It is something that cannot be fully predicted and so real-world field trials and tests have to be performed. This takes a great deal of time. If we had a perfect superconductor solution right now it would still take years or even decades to implement on a wide scale as field trials would need to be conducted.

6) Resource consent, who will pay for it in the end (obviously the end user), etc -

7) Compatibility with existing equipment and products - No one (be it consumer or industry) wants to be told that they have to change all of their electrical equipment as it is no longer compatible with the voltage or frequency of the power grid. Small variations can be accommodated using existing cheap transformer technology and more expensive switched-mode power supplies, but only to a point.

In the end the answer is it is possible but is highly unlikely unless major developments are made that greatly increase the benefit, greatly decrease the cost, and allow existing transformers, and switchgear to be used with and directly replaced by (eventually) the new technology. I can see partial replacement such as existing high energy use industrial (steel and aluminium smelting, etc) and new maglev infrastructure going superconductor quite quickly, but not the rest of the grid.

In the end the pros of the new technology (reduced losses, increased reliability, increased capacity, etc) would need to outweigh all the cons (cost, compatibility, reliability unknowns, resource usage, etc).

We will just have to disagree on this. There are possibilities that will look not even slightly apparent until future times. One of them may involve lots of relatively mini power producing devices. Maybe each building will have its own electricity producer. It could involve technology that we can't even imagine right now.

Cheers

"I am enough of an artist to draw freely upon my imagination. Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world." -- Albert Einstein

Hi All,

I just read a lot of good ideas here. I particularly liked the ones that suggested putting several needs together - power, wind and high-speed rail. It kind of reminds me of how they tried sailing accross the prairies in the 1800s. The difference here is that the sails stay in one place.

Another thing I haven't seen mentioned is beam energy. Isn't that what Tesla was working on? Now that raw materials are in shorter supply maybe it's time to reexamine his idea. Or are those pattents tied up by Edison?

Wireless long-range beam transmission has (and is still) being explored. It is only really viable when looking at how to easily transfer energy from an orbital or moon-based power collector (such as solar satellite, high altitude wind kite farm or <cringe> moon-based helium-3 isotope fusion plant). There are a few problems with pointing a large high-power laser or microwave beam back at the earth however, but it is still better and safer alternative than recharging car batteries in orbit and then dropping them by parachute back to earth.

RE: There are a few problems with pointing a large high-power laser or microwave beam back at the earth...

Um, I would imagine so!

Hmm, generate enough energy to power Vegas, and direct it to a collector in the middle of the dessert. If a bit of space junk bumps your transmitter and puts it off course by a fraction of a degree, there goes Vegas, lit up like never before!

The chances of anything coming from Mars, are a million to one, they say... But I'm sure we can bugger things up much better and much quicker ourselves!

For a water and pipe guy it sounds like cheating to increase the voltage and reduce the conductor size. It would be nice if water could work on the same principle but the intention of the water to move won't help for a thirst.

Maybe Tesla had a point - if one increase the voltage high enough one can do away with the cable altogether.

This of course was the principle behind hydraulic power systems such as the one used throughout the City of London in the 19th and early 20th century to power cranes, lifts(elevators) and dentist drills. It used high pressure water and small pipes driven by pumping stations. (Many of the pipes are still in use today as conduits for a fibre optic network). Even Tower Bridge was operated by its own hydraulic system although it a self-contained system.

Hi Chankley - Very interesting - I wonder what the losses were. Why did they not Google or posted on CR4?

For information on the hydraulic power systems in London see:

http://en.wikipedia.org/wiki/London_Hydraulic_Power_Company

http://www.subbrit.org.uk/sb-sites/sites/h/hydraulic_power_in_london/index.shtml

http://www.nationmaster.com/encyclopedia/London-Hydraulic-Power-Company

http://www.atypon-link.com/doi/pdf/10.1680/imotp.1894.20105?cookieSet=1

and the other 303,000 entries on Google!

The last entry is a detailed description of the system from 1893 which discusses generation losses, I haven't had time to read it all to see if it covers distribution losses.

I agree that the infrastructure would prohibit any change from AC to DC power. From the consumer's perspective why have your home rewired for such an expensive change? IMHO solar power should have advanced significantly and should allow for the average individual consumer to produce 40-60% of their daily electrical usage directly from their rooftops by that date. Reasonable first steps should be taken such as a requirement for all new construction to allocate a percentage of roof space to solar collectors. This would generate a significant amount of power that could reduce dependence on the grid and would cost less as an upgrade than to rewire a building. As far as the affordability of new power transmission lines, I don't see how we could justify not building them. It's obvious to anyone who drives or pays bills (gas/electric) that the current system will become more expensive over time. An ounce of prevention...

The straightforward answer is that if we need the power from these alternative sources, and that need gets large enough, then we will build the connection to the consumer. We do not need to start building them now, especially under some government program, or for fear that we need some new technology to transmit power. In use now are some very high power DC systems to connect between AC systems because it made economical/technical sense (Hydro Quebec and the East - West grid inter-tie are two I think).

Someone who eventually puts in the alternate power generation will surely have the wits about him to check what it will take to connect to the grid when he is doing his site study. Unless he knows that he can whine to the public and get the taxpayers to pay for it.

As the price of Oil increases, the need for alternatives will increase because alternatives will become more affordable - and at that point, the transmission lines will be built to connect to them. Just like they always have been. Can we afford it? Yep, if we want to keep using energy.

Whilst dc is not a viable option for the whole power grid, it is used on a few long distance lines to avoid capacitive losses. It is most widely used on submarine power cables, an example being the HVDC connection between the Britain and France. Apart from preventing capacitive losses, it avoids the need to synchronise the two grids.

Another example are the under-sea DC cables linking the North island of New Zealand to the South island, also for the reasons mentioned above.

Thanks for the details Chankley and Jack - I didn't know of those other DC ties. My point was to the discussion early in this thread about whether we needed new technology or was AC or DC the answer. And I think current technology will be up for the task.

BTW, In other places some have proposed using superconducting tubes filled with liquid hydrogen to transport both hydrogen and electricity, but just one "warm" spot on the tube wall could have catastrophic consequences.

And the fact that unlike liquid nitrogen, liquid hydrogen has to be pressurised to maintain is cold liquid state. Maintaining a pressurised stream of hydrogen for both liquid transport and cooling a superconductor is not as simple is it would first appear. That and the general nature of superconductor cables makes it totally un-viable to run large-diameter spans of hollow core superconductor cable (let alone under pressure) as you would stainless steel pipe (or similar).