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      CommentAuthormrflora
    • CommentTimeJan 15th 2010
     
    Since energy from wind is "free energy", I thought it would be appropriate to post these figures here.

    The World Nuclear Association says that the current installed nuclear electric generating capacity worldwide is about 373 GW. The World Wind Energy Association predicts that world installed wind electric generating capacity will be 152 GW when final figures for 2009 are compiled. That's up from 121 GW at the end of 2008!

    Worldwide, nuclear capacity is just about static and may even begin to shrink in the years ahead as older plants are retired. It seems certain that within the next few years wind will surpass nuclear, an event that will make people sit up and take notice.

    Also, it has been estimated that there are 72 terawatts of economically exploitable wind resources worldwide, compared to current world total energy use (all forms) of 15 terawatts. Clearly wind is a form of free energy that can help us tremendously with the problems of global warming and peak oil.

    Regards,
    M.R.F.
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      CommentAuthorQuanten
    • CommentTimeJan 15th 2010
     
    I betcha if you look around wind is used as a suplemental energy. So far as I can tell Nuclear can be made to ramp up at peak, and is always available barring maintenance. Wind is seasonal, not always on, and you can't ask it to be at peak.

    If brownouts are acceptable, sure you can cocnentrate yourself on wind.
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      CommentAuthormrflora
    • CommentTimeJan 15th 2010
     
    Quanten, what you say is basically true. I do not think that we will switch entirely to wind worldwide. Major improvements to the electric grid are required to make wind storable and dispatchable. My point in citing the figures is to demonstrate that it is inevitable that wind will eclipse nuclear as a world power source, and that this event will encourage the decision-makers to make the investments necessary to integrate wind more effectively into the power system.

    Regards,
    M.R.F.
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      CommentAuthorDerrickA
    • CommentTimeJan 15th 2010
     
    A global high voltage DC grid could do wonders for balancing energy supply and demand. For instance, solar power wouldn't need to be stored, if your night-time power comes from the other side of the planet. During the day, your excess capacity would return the favor. As is is always sunny (or windy) somewhere in the world, power would always be available. Of course, as mrflora says, major improvements to the grid would be required. A global DC grid would be an expensive undertaking, involving a high degree of international cooperation.
    • CommentAuthorbc
    • CommentTimeJan 15th 2010
     
    Intermittency is a real problem, we really need some breakthroughs in energy storage technology.
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      CommentAuthorAngus
    • CommentTimeJan 15th 2010
     
    Posted By: DerrickAA global high voltage DC grid could do wonders for balancing energy supply and demand. For instance, solar power wouldn't need to be stored, if your night-time power comes from the other side of the planet. During the day, your excess capacity would return the favor. As is is always sunny (or windy) somewhere in the world, power would always be available. Of course, as mrflora says, major improvements to the grid would be required. A global DC grid would be an expensive undertaking, involving a high degree of international cooperation.


    Why DC?
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      CommentAuthorAngus
    • CommentTimeJan 15th 2010
     
    Posted By: QuantenI betcha if you look around wind is used as a suplemental energy. So far as I can tell Nuclear can be made to ramp up at peak, and is always available barring maintenance. Wind is seasonal, not always on, and you can't ask it to be at peak.

    If brownouts are acceptable, sure you can cocnentrate yourself on wind.


    Which is why I get a little frustrated at some of the nonsense spouted here. The real problem that people should be working on is large scale energy storage, not mini-perpetual-motion machines. And there is some really interesting stuff going on.I myself know of prospects that could be taken far with 14MEuro investment.

    There is plenty of environmental energy to be had. For example salinity difference power generation potential worldwide is another 2000 TWh/y, counting all significant river estuaries. Not a drop of it is yet exploited. All we need to do is manage it better, and that requires storage.
    • CommentAuthorunderunity
    • CommentTimeJan 15th 2010 edited
     
    Posted By: Angus
    Posted By: DerrickAA global high voltage DC grid could do wonders for balancing energy supply and demand. For instance, solar power wouldn't need to be stored, if your night-time power comes from the other side of the planet. During the day, your excess capacity would return the favor. As is is always sunny (or windy) somewhere in the world, power would always be available. Of course, as mrflora says, major improvements to the grid would be required. A global DC grid would be an expensive undertaking, involving a high degree of international cooperation.


    Why DC?

    For the lack of a better word, its easier, though not cheaper, to implement. AC currents have lots of issues that can bring the entire grid down, or wreck equipment.

    Keeping a DC grid within 5% tolerance (the home standard in America) is substantially easier than keeping an AC grid within that tolerance.

    For example, a poorly constructed transmission system might have different instantaneous voltages at different points. My house may be on the top of sin wave while yours is at the bottom (even if the RMS voltage is the same). For a 700kV cable, this means ~1400kV voltage potential difference, and an enormous amount of current will fry everything in between.

    When you connect the rest of the world, which may have poor quality stations or engineers, you're asking for trouble.
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      CommentAuthorAngus
    • CommentTimeJan 15th 2010
     
    Posted By: underunityFor the lack of a better word, its easier, though not cheaper, to implement. AC currents have lots of issues that can bring the entire grid down, or wreck equipment.

    Keeping a DC grid within 5% tolerance (the home standard in America) is substantially easier than keeping an AC grid within that tolerance.

    For example, a poorly constructed transmission system might have different instantaneous voltages at different points. My house may be on the top of sin wave while yours is at the bottom (even if the RMS voltage is the same). For a 700kV cable, this means ~1400kV voltage potential difference, and an enormous amount of current will fry everything in between.

    When you connect the rest of the world, which may have poor quality stations or engineers, you're asking for trouble.


    I assume that you are talking only about HVDC longhaul links, not distribution.( I can't see that happening in the face of cheaper installed plant. And it wont work at household voltages, as Edison found out. ) HVDC transmission systems are going in here in Canada to get massive power down from James Bay to the US markets, so we are getting on with the job.

    Like storage, the issue of how widely we can extend a grid to smooth out environmental energy generation is also, I guess, a very good one.
    • CommentAuthorunderunity
    • CommentTimeJan 15th 2010
     
    Posted By: Angus
    Posted By: underunitysnip


    I assume that you are talking only about HVDC longhaul links, not distribution.( I can't see that happening in the face of cheaper installed plant. And it wont work at household voltages, as Edison found out. ) HVDC transmission systems are going in here in Canada to get massive power down from James Bay to the US markets, so we are getting on with the job.

    Like storage, the issue of how widely we can extend a grid to smooth out environmental energy generation is also, I guess, a very good one.

    Hmm, I'm not sure I understand.

    I was responding to your inquiry about WHY a HVDC system would be required for a "global" grid.

    HVDC systems are easier to set up, and they are used in the United States to connect "islands" of AC transmission lines such as the East to the West. AC systems are essentially giant capacitors and inductors with enormous amounts of energy stored in each line. HVDC systems are essentially giant resistors.

    If we were to ever make a global grid, we would have to link each AC island (each country) via HVDC links in order to insure that one country going off the grid suddenly (due to whatever) wouldn't cause a massive release of potential magnetic/electric energy which would destroy everything else, etc.
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      CommentAuthorAngus
    • CommentTimeJan 15th 2010
     
    Posted By: underunityIf we were to ever make a global grid, we would have to link each AC island (each country) via HVDC links in order to insure that one country going off the grid suddenly (due to whatever) wouldn't cause a massive release of potential magnetic/electric energy which would destroy everything else, etc.


    Exactly - HVDC is good for long haul transmission where you can get the voltages really high and keep the current down so you don't have large resistive losses. And contrariwise, Edison went broke trying to deliver a few tens of volts around New York because the current had to be so high the resistive losses made it uneconomic and really difficult to engineer. George Westinghouse realised that the energy storage in AC systems helps you out in that respect.

    That said, you are right - we have to manage that stored energy rather carefully. When it goes wrong, as it has done on occasion, you can get widespread blackouts.

    It would be interesting to speculate on how you tie the world energy grid across oceans. I don't think HVDC underwater cables would cut it. Perhaps we would see microwave links coming into play, even with a satellite bounce.
    • CommentAuthorunderunity
    • CommentTimeJan 15th 2010 edited
     
    Posted By: Angus
    Posted By: underunityIf we were to ever make a global grid, we would have to link each AC island (each country) via HVDC links in order to insure that one country going off the grid suddenly (due to whatever) wouldn't cause a massive release of potential magnetic/electric energy which would destroy everything else, etc.


    Exactly - HVDC is good for long haul transmission where you can get the voltages really high and keep the current down so you don't have large resistive losses. And contrariwise, Edison went broke trying to deliver a few tens of volts around New York because the current had to be so high the resistive losses made it uneconomic and really difficult to engineer. George Westinghouse realised that the energy storage in AC systems helps you out in that respect.

    That said, you are right - we have to manage that stored energy rather carefully. When it goes wrong, as it has done on occasion, you can get widespread blackouts.

    It would be interesting to speculate on how you tie the world energy grid across oceans. I don't think HVDC underwater cables would cut it. Perhaps we would see microwave links coming into play, even with a satellite bounce.

    There in lies the problem with HVDC though, getting high voltages is really, really, reaaaaally difficult if I recall correctly. HVDC is still only something 200kV right now, while we've already done 750kV+ AC voltages. What all this means is that while HVDC systems are easier to maintain and don't give migraines like AC systems, they have a higher resistive loss than comparable AC systems.

    But you are right, HVDC systems ARE more economical long-range.

    Underwater HVDC is probably the way to go, to be honest, because IIRC, you can bundle wires together and not worry about capacitance issues.
    • CommentAuthorbc
    • CommentTimeJan 15th 2010
     
    There is a Euro plan to link up with solar in the Sahara, sounds like another Euro boondoggle. I don't know if any funding has been allocated yet.
    • CommentAuthorunderunity
    • CommentTimeJan 15th 2010
     
    Posted By: bcThere is a Euro plan to link up with solar in the Sahara, sounds like another Euro boondoggle. I don't know if any funding has been allocated yet.
    And here I thought Europeans were done stripping other continents of resources ;)

    But I heard the Japanese are getting in on the whole thing. Theyre leasing an enormous amount of land, to grow crops on, from some African country that can barely feed its own people.
    • CommentAuthorbc
    • CommentTimeJan 15th 2010
     
    Posted By: underunityAnd here I thought Europeans were done stripping other continents of resources ;)

    It does sound a lot like that. There was also a hydro-electric plan to drown a big chunk of Africa and sell electricity to Europe. I doubt it would help the average African much.
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      CommentAuthorThicket
    • CommentTimeJan 15th 2010 edited
     
    There is an inherent problem comparing nuclear power output with wind power output.

    A nuclear power plant will average 92% of its maximum production over many years. The other 8% is for scheduled and unscheduled outages.

    A wind farm will average about 30% of its maximum output over many years. The other 70% is because wind is too low for maximum output, too high for the generator to run safely, and for scheduled and unscheduled outages. The 30% varies with location, but it's a good average number.

    If you want to compare the power output of nuclear and wind on an even basis, you have to divide the wind power generation number by three.
    • CommentAuthorunderunity
    • CommentTimeJan 15th 2010
     
    Posted By: ThicketThere is an inherent problem comparing nuclear power output with wind power output.

    A nuclear power plant will average 92% of its maximum production over many years. The other 8% is for scheduled and unscheduled outages.

    A wind farm will average about 30% of its maximum output over many years. The other 70% is because wind is too low for maximum output, too high for the generator to run safely, and for scheduled and unscheduled outages. The 30% varies with location, but it's a good average number.

    If you want to compare the power output of nuclear and wind on an even basis, you have to divide the wind power generation number by three.

    Correct, IIRC, when they say "15MW" solar plant, what they mean is that the plant as the capability to generate 15MW at peak output. Of course, that only happens during the day, for a 15MW solar plant, you're getting about 3 MW average a day, I believe. For a 15 MW nuclear powerplant, you'd get 13-14MW.
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      CommentAuthorping1400
    • CommentTimeJan 15th 2010
     
    Posted By: underunityThere in lies the problem with HVDC though, getting high voltages is really, really, reaaaaally difficult if I recall correctly. HVDC is still only something 200kV right now, while we've already done 750kV+ AC voltages. What all this means is that while HVDC systems are easier to maintain and don't give migraines like AC systems, they have a higher resistive loss than comparable AC systems.

    Corrections:
    1) Standard commercial HVDC connections nowdays have ± 450 kV (total of 900 kV)
    2) DC has less losses than AC and can transport power cross much larger distances
    Example: NorNed cable connecting Norway and the Netherlands
    http://www.abb.com/cawp/gad02181/8c5558c304d0eb13c1256f77003a33a1.aspx
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      CommentAuthorping1400
    • CommentTimeJan 16th 2010
     
    Posted By: bcThere is a Euro plan to link up with solar in the Sahara, sounds like another Euro boondoggle. I don't know if any funding has been allocated yet.

    Desertec initiative, backing of several German banks and biggest power industry companies.
    Allocated funding exceeds 50 billion Euro (70 billion Dollar).
    http://www.desertec.org/en/actions/events/desertec-industrial-initiative-assembly/
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      CommentAuthorping1400
    • CommentTimeJan 16th 2010
     
    Posted By: QuantenI betcha if you look around wind is used as a suplemental energy. So far as I can tell Nuclear can be made to ramp up at peak, and is always available barring maintenance. Wind is seasonal, not always on, and you can't ask it to be at peak.

    Nope. Nuclear is baseload. Ramping up/down of nuclear wears components down, that are very difficult to replace.
    The only way France (>60% nuclear) can handle all the nuclear they have is by using the hydro pump storage capacity of Switzerland. Same like windpower. You need to combine with storage capacity to be able to be flexible in time between demand and supply. From this viewpoint nuclear and wind have the same 'problem', but also the same solution. Countries like Norway (with huge unused possibilities for hydro capacity) can become the 'battery' of Europe using HVDC links cross the North-sea, connecting the planned 60.000 MW of off-shore windfarms.