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01 Mar 08 - 12:15 AM (#2276300) Subject: BS: A Solar Grand Plan in Scientific America From: katlaughing I have not read all of this article, yet, but it is exciting, imo. Solar Grand Plan. Here are the key concepts: * A massive switch from coal, oil, natural gas and nuclear power plants to solar power plants could supply 69 percent of the U.S.'s electricity and 35 percent of its total energy by 2050. * A vast area of photovoltaic cells would have to be erected in the Southwest. Excess daytime energy would be stored as compressed air in underground caverns to be tapped during nighttime hours. * Large solar concentrator power plants would be built as well. * A new direct-current power transmission backbone would deliver solar electricity across the country. * But $420 billion in subsidies from 2011 to 2050 would be required to fund the infrastructure and make it cost-competitive. I am sure there would be some controversy, esp. over "vast areas" of the Southwest, but there's got to be some solutions to what we are doing now. |
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01 Mar 08 - 07:00 AM (#2276407) Subject: RE: BS: A Solar Grand Plan in Scientific America From: McGrath of Harlow The vast area turns out to be the equivalent of a square of 173 miles - which on a map of the United States is pretty small. It's about the size of Maryland. |
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01 Mar 08 - 07:38 AM (#2276426) Subject: RE: BS: A Solar Grand Plan in Scientific America From: The Fooles Troupe "direct-current power transmission backbone" That was tried in the very early days of electricity. 'Real' Scientists know why it failed miserably, and why high voltage AC is now used... :-) |
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01 Mar 08 - 08:58 AM (#2276480) Subject: RE: BS: A Solar Grand Plan in Scientific America From: MaineDog Normally, the sun heats the earth during the day, and most of this heat energy is radiated off at night, so that the daily effect of the sun does not heat the earth, on the average. When this balance is upset, we have global warming or cooling. As is pointed out in this article, the amount of energy involved each day is huge compared to the amount we can change by things we do in the short term. However, if we start capturing massive extra amounts of energy, as will this plan, and using it (read: converting it to waste heat), we may well cause global warming even if we somewhat reduce greenhouse gasses. I didn't see this problem discussed. Basically, you can't get something for nothing. Any Ideas? MD |
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01 Mar 08 - 10:41 AM (#2276526) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Amos I don't see why it would cause any more waste heat than the present system. Global warming i not occurring because we are heating up objects on the surface of the planet. Greenhouse emissions, cumulatively, cause effects orders of magnitude greater than that. A |
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01 Mar 08 - 10:44 AM (#2276530) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Amos The editors actually DO say "direct curtrent transmission", which is really strange; DC doesn't transmit efficiently over long distances, which is why Edison Electric is not the world's biggest company in electricity, and General Electric is. The transmission would have to be done by conversion to AC, I suspect. A |
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01 Mar 08 - 10:56 AM (#2276539) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Amos The article states"Studies by Oak Ridge National Laboratory indicate that long-distance HVDC lines lose far less energy than AC lines do over equivalent spans. The backbone would radiate from the Southwest toward the nationÕs borders. The lines would terminate at converter stations where the power would be switched to AC and sent along existing regional transmission lines that supply customers." I find this hard to accept, frankly.I will dig into this HVDC concept a bit more. Kat, thanks for the article! A |
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01 Mar 08 - 11:16 AM (#2276546) Subject: RE: BS: A Solar Grand Plan in Scientific America From: McGrath of Harlow if we start capturing massive extra amounts of energy, as will this plan, and using it (read: converting it to waste heat), we may well cause global warming There's a fallacy in that. It would apply of it were a matter of capturing heat out in space and sending it down to Earth, or, for that matter, if we were producing energy from nuclear fission or fusion. But with Earth-based solar power the amount of energy involved stays constant, it just gets moved around. |
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01 Mar 08 - 11:32 AM (#2276558) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Amos Seems I was wrong about HVDC -- it does have an efficiency factor over the AC equivalent. For example, here's a description of a 780 KM HVDC line being built in India: "In the future, the bipolar 500-kV direct-current transmission system with a power rating of 2500 MW will transport electrical energy with low loss from Ballia in the east of Uttar Pradesh province to Bhiwadi, 780 km (485 miles) away in the province of Rajasthan near New Delhi. In comparison to a conventional 400 kV AC transmission line this HVDC transmission link improves energy efficiency so that 688.000 tons of CO2 will be saved." My aporogies! :D A |
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01 Mar 08 - 03:26 PM (#2276738) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Peter T. How about wasting a lot less energy? Scientific American got anything to say about that? yours, Peter T. |
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01 Mar 08 - 06:12 PM (#2276897) Subject: RE: BS: A Solar Grand Plan in Scientific America From: MaineDog I have to agree that dc transmission makes sense for the long distance "backbone" of the grid. AC was easier in Edison's day, because they did not know how to make generators and motors as efficient as they do today, and of course, they had no solid state technology at all. You need to send power via high-voltage lines to reduce I**2xR losses, but back then, transformers were needed to convert lo-v to hi-v and back, and transformers don't work for dc (sorry, kids, transformers are not what you think they are). My initial point was based on the idea that ground covered with solar cells will absorb more energy from the sun than bare desert ground, and the cells will not radiate that heat back out into space at night, rather, that heat will stay on earth, and end up as waste heat from all the motors etc that are runs by all this energy. It's exactly the same problem as the greenhouse effect, except that we do get some use out of it. MD |
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01 Mar 08 - 06:17 PM (#2276899) Subject: RE: BS: A Solar Grand Plan in Scientific America From: katlaughing PeterT, on the first page of the linked article, they do talk about how much less pollutants there would be if we went more solar and stopped the coal-buring power plants, etc. |
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01 Mar 08 - 08:11 PM (#2276988) Subject: RE: BS: A Solar Grand Plan in Scientific America From: BanjoRay As a world wide energy source it sounds amazing. The only drawback is that the guys who own the oil own all the deserts as well. Ray |
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01 Mar 08 - 08:44 PM (#2277011) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Rapparee Not necessarily. There's a lot of high desert around here -- Idaho, Nevada, and parts of other States have quite a surplus. No reason to concentrate all of the collectors in one place that I can think of. Also, why concentrate on one source? Use a mix: geothermal (we here in the Yellowstone Caldera area certainly have THAT!), solar, wind.... |
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01 Mar 08 - 09:10 PM (#2277028) Subject: RE: BS: A Solar Grand Plan in Scientific America From: BanjoRay That's what I meant - America's one of the guys that owns the oil. Ray |
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01 Mar 08 - 09:36 PM (#2277038) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Rapparee Huh? Australia, China, Russia, the whole damned Sahara, Canada.... If you mix up the sources 'most anyone can play. |
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02 Mar 08 - 07:20 AM (#2277238) Subject: RE: BS: A Solar Grand Plan in Scientific America From: GUEST,Shimrod It seems to me that there are plenty of technical fixes for global warming - and some of them may actually be implementable. The real problems are economic and political - there are a lot of people and organisations out there who are making vast profits from burning fossil fuels and they are not going to stop until the biosphere is burned black and sooty! |
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02 Mar 08 - 08:15 AM (#2277261) Subject: RE: BS: A Solar Grand Plan in Scientific America From: jacqui.c I may be being a bit naive here but would it not help if every new commercial building had to have solar panels installed when construction took place? Initial outlay might be costly but, with mass production over a period of time the price of the panels should reduce. In time, surely, it could be the case that solar panels would be fitted to every new building. From my understanding (and you can shoot me down if I'm wrong) these panels work on light, not just the sun's rays. Mind you, even up here in the North East, there are still plenty of sunny days during the winter. Right now we are starting to see the cost of ethanol as a fuel - higher cost of corn and the resultant hike in cost of any foods involving corn and a reduction in wheat growth as farmers go over to growing corn instead, giving a price hike in the cost of wheat products. I see this every time I go the the supermarket for groceries. There always is a cost involved in any form of energy production. |
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02 Mar 08 - 12:18 PM (#2277408) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Amos They do work on light, Jacqui, but the direct light from the sun produces energy much more efficiently than the re-directed, reflected ambient light you get from, say, bright moonlight, or during an overcast day; the reason is that the energy density is much greater in direct sunlight. This is also why PV is more economically viable the closer tot he equator you get. A |
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02 Mar 08 - 12:31 PM (#2277416) Subject: RE: BS: A Solar Grand Plan in Scientific America From: McGrath of Harlow As Shimrod says, there is no shortage of potential solutions - solar power, wave power, tide power. The problem is the political will to do it, and an economic system that isn't geared to the long term. Plus the fact that the damage to the planet's environment is impacting at this stage mostly on poor communities rather than on the wealthy and powerful. |
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02 Mar 08 - 12:43 PM (#2277425) Subject: RE: BS: A Solar Grand Plan in Scientific America From: MaineDog An interesting scheme we used to think about was this one. We build our solar arrays in orbit around the earth. Since they are weightless there, they don't need a lot of structure to keep them together, and they can be really huge, so we don't have to worry about efficiency. Even if they are only 5% efficient, it doesn't matter, since all that 95% of waste heat stays out in space, and doesn't come to earth at all, so there is no potential for "greenhouse" problems. What does come to earth is pure energy in the form of coherent microwave beams, which are directed at appropriate receiving stations all over the earch, so we don't need any grid backbone except for outages. The frequency of the microwave radiation can be chosen to penetrate normal weather, so we won't have rainy day problems. Since the power satellites are high up and spread out around the earth there is no microwave night. the Converting the microwave energy to AC for our tv sets is a lot more efficient than running a heat engine (turbine or diesel) because it is already electrical and cohereht. Of course, in today's technophobic society, microwaves are almost as bad as lard, so I don't expect to see people backing this system any time soon. MD |
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02 Mar 08 - 12:55 PM (#2277444) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Amos ANother aspect that is grossly under-estimated is the thermal difference between surface temperatures (or rooftop) and the temperatures ten or twenty feet under the ground. I haven't dug into the numbers but I suspect there is enough difference between the two levels to drive a Carnot cycle engine, a Stirling engine, with enough power to actually support a household. Especially if you use solar concentrators in warm climates for the high band. Do any of the engineering types out there know what the DeltaT would have to be to produce a working equivalent of, say, 2000 square feet of PV paneling, which at present is about what an individual family would need to run entirely on PV? A |
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02 Mar 08 - 05:28 PM (#2277694) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Skivee Hey McGrath, old bean, I am compelled to to correct an earlier error besmearching my glorious home state. The total area of Maryland is closer to 12,400 square miles as opposed to 173Sq. m. We ain't those pip-squeaks in Rhode Island or Deleware. |
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02 Mar 08 - 05:42 PM (#2277701) Subject: RE: BS: A Solar Grand Plan in Scientific America From: McGrath of Harlow A square of 173 miles by 173 miles is not 173 square miles. It is nearly 30,000 square miles. But I was wrong about Maryland - I read the wrong column in the list.. You are 32,133 square kilometres, but only 12,407 square miles. I should have picked another state for an equivalent size - maybe South Carolina at 32,020 square miles. |
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02 Mar 08 - 05:57 PM (#2277710) Subject: RE: BS: A Solar Grand Plan in Scientific America From: pdq Dist. of Columbia: 68.34 (square miles) Proposed energy complex: 173 Rhode Island: 1,545.05 Delaware: 2,489.27 Israel: 8,000 (approx.) Maryland: 12,406.68 |
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02 Mar 08 - 07:03 PM (#2277766) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Skivee Okay, MacGrath. I now feel that the honor of my state has been restored. As to MY error, I'll just fall back on the old saw," "Extremism in the defense of liberty is no vice." It doesn't exactly apply here, but if I smoke-screen enough folks may not notice. |
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02 Mar 08 - 07:13 PM (#2277779) Subject: RE: BS: A Solar Grand Plan in Scientific America From: McGrath of Harlow No pdq. A square of 173 miles on each side is 30,000 miles (actually it is 29,929 square miles.) |
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02 Mar 08 - 07:53 PM (#2277824) Subject: RE: BS: A Solar Grand Plan in Scientific America From: pdq "In our plan, by 2050 photovoltaic technology would provide almost 3,000 gigawatts (GW), or billions of watts, of power. Some 30,000 square miles of photovoltaic arrays would have to be erected. Although this area may sound enormous..." ~ from article McRath...why did you convert this to miles squared...to confuse? BTW, this idea is a total crock. There will be environmental destruction caused by making these arrays as well as destruction of the land on where they will be placed. A concept from Fantasy Land, about like putting nuclear waste in rockets and sending it to Mars. |
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03 Mar 08 - 02:01 AM (#2277979) Subject: RE: BS: A Solar Grand Plan in Scientific America From: JohnInKansas While the "concept" in the SA article quite possibly is feasible, it should be noted that: 1. It would be very expensive in "whole form," requiring an incredibly coherent political backing that in our present legislative environment is so unlikely as to be considered "ridiculous." 2. The article claims "significant improvements" in PV products that are not true certainties. While many researchers expect to be able to improve PV device efficiencies, even in the ranges postulated, there is no certainty of success. Even if "lab models" achieve the requisite improved efficiencies, the road to commercially producible devices quite likely will take several years - if not decades. 3. The HVDC transmission lines postulated are not an essential requirement for "PV Farms" that could contribute significant amounts of power. Conversion to AC could be done at the farm, and existing conventional grid distribution could be done. If the "efficiency benefits" of HVDC are really as great as postulated, existing grids (for long distance transmission) should be immediately considered for conversion to HVDC as a separate project apart from any changes in methods of generation. Has anyone heard of this being suggested? 4. All articles found in a quick web search on HVDC are accurate up to a point; but I found only one article touching on "environmental impacts" of HVDC. In an ideal installation the impact should be small; but in several schemes proposed there could be major impacts. 4a. Only one article mentioned "corona discharge" likely from the very high voltages used and anticipated. Many proposals are for "monopole" transmission using "earth return" paths. A GAO study, done on demand from Congress, proposes using existing right of way (railroads and/or oil and natural gas pipelines) to save costs. 4b. The GAO study in particular did not examine the likelihood that such high DC voltages will eat the crap out of adjacent rails or pipes due to galvanic leakage, without absolutely fail-safe and rigidly monitored load balancing and perfect electrical isolation between the lines and adjacent terrain. While it's fine to propose a "one-site solution to all our energy problems" a more practical approach would be to provide appropriate incentives for several smaller distributed PV farms, to permit the required development and "proofing" of the concepts and the equipment before launching a transfer of "all our eggs in one basket" to "all our eggs in one other basket." 5. Several "highly likely" changes predicted by the International Committee on Climate could suggest that the ideal sites for PV farms now may be much less suitable in one or two decades - or that some now densely populated areas might be just about perfect in 20 years or so ... John |
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03 Mar 08 - 05:36 AM (#2278052) Subject: RE: BS: A Solar Grand Plan in Scientific America From: McGrath of Harlow ...equivalent of a square of 173 miles" What's confsuing about that? I find it much easier to envisage that in my head than "30,000 square miles", that's why I wrote it that way. |
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03 Mar 08 - 08:49 AM (#2278161) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Donuel Tesla was the first to build a direct DC transmission tower. He also "invented" AC. ........................ THe one thing I could never understand was his claim that there is a special horizontal wave of electromagnetic energy that is distinct and eluisive relative to electricity and light. was he thinking in another dimension? .............. The Russians took his "death ray" seriously. We have spy pictures of the scaler Electric weapons in Russia...we think. ............ The best Economic engine for the USA now I believe is the alternative energy quest and procuction. |
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04 Mar 08 - 01:24 AM (#2278940) Subject: RE: BS: A Solar Grand Plan in Scientific America From: The Fooles Troupe "We build our solar arrays in orbit around the earth...." Hey - anybody remember the story - not sure if it was Asimov - about MW broadcasting being manned by robots. they got "Religion", and caused great panic... I won't give the spoiler... :-) Amos - any useful links you came across on HVDC? 1) Galvanic action is of no consequence with AC... :-) and it's a REAL BASTARD to fight... :-) Hmmm 500KV DC vs 400Kv AC.... Well each time you change AC-DC & DC-AC, you get a loss - I don't see normal households being able to cope with a DC power feed - which is why "which is why Edison Electric is not the world's biggest company in electricity, and General Electric is"... (guess which one went with AC and which with DC...) And interestingly - DC - at a fixed voltage vs AC - ah - MEASURING the VOLTAGE at AC is a game all in itself!!! RMS, leading/lagging phase etc... As well anything near the HVAC line that is in any way conductive sucks power by induction (so HVDC seems better). But, any corona will be exciting - with DC it just won't stop! OK AC will keep arcing too... :-) Would like to find out more... especially with the long term full scale tests... I'm old enough to know about 'theory vs practice'... :-) |
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08 Mar 08 - 12:16 PM (#2282941) Subject: RE: BS: A Solar Grand Plan in Scientific America From: GUEST,Mike in DC There will never be a single replacement for fossil fuels such as coal and gasoline. There are, however, several technologies that, in combination, can meet the need. These include photovoltaic solar, concentrated solar, wind, geothermal, biomass, and tidal. The alternative with the greatest potential for reducing greenhouse gas emissions however is improved energy efficiency through such means as tighter appliance standards, improved manufacturing processes, better transmission, and green building construction. Unfortunately, in the U.S. at least, Federal energy subsidies are heavily tilted toward politically connected fossil fuel industries rather than emerging renewable ones or energy efficiency. Mike |
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08 Mar 08 - 01:10 PM (#2282996) Subject: RE: BS: A Solar Grand Plan in Scientific America From: JohnInKansas Perhaps of interest here: Solar farm to rise over 3 square miles Spanish company to build, operate $1 billion plant based on mirrors, turbine The Associated Press updated 8:52 a.m. CT, Fri., March. 7, 2008 PHOENIX - A Spanish company is planning to take 3 square miles of desert southwest of Phoenix and turn them into one of the largest solar power plants in the world. Abengoa Solar, which has plants in Spain, northern Africa and other parts of the U.S., could begin construction as early as next year on the 280-megawatt plant in Gila Bend — a small, dusty town 50 miles southeast of Phoenix. The company says it could be producing solar energy by 2011. Abengoa would build, own and operate the $1 billion plant, named the Solana Generating Station. Arizona Public Service, the state's largest utility, would pay Abengoa $4 billion over 30 years for the energy produced, estimated to be enough to supply up to 70,000 homes at full capacity. APS filed for approval of the plant with Arizona's public utilities regulator last Thursday. The plant also hinges on an extension of the federal solar investment tax credit, which APS and Abengoa said they're confident will happen. ... ... ... [More at the link] There's a nice (but small) "artist's concept" picture of what the whole plant might look like, near the bottom of the page. John |
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08 Mar 08 - 01:49 PM (#2283031) Subject: RE: BS: A Solar Grand Plan in Scientific America From: Q (Frank Staplin) Certainly much can be done with solar energy. Undoubtedly more plans such as the one proposed in Arizona will be forthcoming. Electric power grids are mostly powered by energy from coal. There are several schemes for reducing the pollution from coal-fired plants, but large scale control remains elusive for cost and engineering reasons. Solar power would get around most of this problem, and reduce destruction of the landscape (much coal comes from strip-mining) and reduce pollution of both surface water and subsurface aquifers. But gee, folks, don't use it to reduce gas and gasoline consumption. Western Canada is the largest supplier of oil to the United States, and it is our turn to get rich! |
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09 Mar 08 - 07:20 AM (#2283519) Subject: RE: BS: A Solar Grand Plan in Scientific America From: The Fooles Troupe Have heard that a plant like the Spanish one is scheduled for Australia. Of course Little fascist Johnny claimed that such plants couldn't exist... of course he is now being paid to for a lecture tour in the USA... hahahahahaha! |