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Post by edireland on Apr 6, 2013 20:28:33 GMT 9.5
5kW?
We are talking charge loads in the megawatt range if these supercapacitors work.
25kWh Nissan Leaf battery charge in 90 seconds.
People don't like overnight charging because of the fact it puts a hard limit on how far they can drive during the day.
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Post by engineerpoet on Apr 7, 2013 0:27:12 GMT 9.5
By my reading of the tea leaves, that would need the nuke to heat air (not steam) to drive the turbine, its modules would need to be small enough to be trucked in and out, and its still-hot core small enough to be helicoptered away to its next place of work. If you will be moving any heavy processing equipment, ores or products, you won't need to helicopter the reactor. Just use the same transport system the rest uses. Since dropping a reactor would be a Bad Thing, just leaving it at the site pending final removal is probably a good idea. When all your energy costs are pre-paid the threshold for operating profit is going to be much lower, so you are less likely to shut down due to market conditions in the first place.
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Post by edireland on Apr 7, 2013 2:14:45 GMT 9.5
Inside that radius, there are scores of mines on diesel. There are many more mineral deposits that don't have enough power and water to run a mine. And any number of the value-adding industries that could grow up around the fresh product, if they had enough power and water. This is where you would expect nuclear to trump diesel. It would for a mine that can thus grow big and its town become permanent. However small mines need a variable 20 MWe or so, can't supply cooling water and need most of the nuke to be transported out and in as operations close and re-open. By my reading of the tea leaves, that would need the nuke to heat air (not steam) to drive the turbine, its modules would need to be small enough to be trucked in and out, and its still-hot core small enough to be helicoptered away to its next place of work. You could probably use HVDC Light to link every mine within a couple of hundred miles into a single grid and then supply electricity from a single midsize power plant. That avoids the whole mobile thing, since with appropriate lightweight posts HVDC cables could be dismantled and moved around as required. Air cooled condensers have been developed for LWR type reactors, which reduces the losses to the marginal losses from the primary steam loop. An SBWR/ESBWR type reactor could also have sufficient water stockpiled in staging tanks to cover emergency cooling use at fairly low cost.
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Post by David B. Benson on Apr 7, 2013 6:22:52 GMT 9.5
The question is, as always, how to remove the reject heat at the bottom of the thermodynamic cycle. Past the condenser possibilities which are non-evaporative are air cooling and ground loop water. Both have been used; the former consumes 5--8% of the generated electricity and the latter requires additional capital expense to lay the ground loop.
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Post by Roger Clifton on Apr 7, 2013 20:50:20 GMT 9.5
A mass-produced small reactor with air (not steam) as the working fluid, and a desalination plant for energy storage, does stand to compete with diesel for the 5-20 MWe market. That is, away from the grid of course. Points of comparison are more to do with (hidden) convenience cost, rather than the cost per kilowatt-hour –
As a mass-produced system with only the modules of core, reactor, generator and air cleaner, it would be about as transportable as the diesel equivalent of engine, generator and fuel store. Remoteness or rugged terrain are equally surmountable.
Its installation time would depend only on the earthmoving for its neutron shield. Both systems would require concrete footings. Assuming that desalinated water was valued on location, desalination plant would be needed for both systems too.
Obviously, it would have much lower carbon intensity, an attractiveness dependent on the carbon price. However, its freedom from a fuel supply line means that a nuke can continue operating even when the area is cut off by flood, chaos or politics.
Above all, such a simple system would be as removable as its diesel equivalent. When a heavier duty generator is moved onto the site, both systems can be moved profitably elsewhere. Developing nations would be able to use such a system to start a fast-growing local grid, especially on islands, then move it on when superseded.
In the case of mines, local power demand can collapse entirely when operations pause or cease. It is important for environmental approval of a mine, at least in this country, that all equipment be removed from the site when the mine finally closes. Similarly, during mothballed periods, such valuable equipment can be moved elsewhere to resume working profitably.
Conceivably a small mass produced design like this would be cheap enough for a commercial operator to own a fleet of them to hire out to a large number of small power users.
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Post by Roger Clifton on Apr 15, 2013 18:04:41 GMT 9.5
to remove the reject heat ... non-evaporative (options) are air cooling and ground loop water. You've mentioned the latter before. Please tell how a buried pipe in heated dry ground would continue to lose heat over a long period. Surely it would radiate to space and conduct to air better if supported above ground?
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Post by David B. Benson on Apr 16, 2013 7:45:05 GMT 9.5
Ground loop cooling is used in a few power plants in northern Europe. Maybe in the Netherlands and across the north German plain the ground is never dry?
More seriously, one simply has to make the ground loop long enough. This is sufficiently expensive that it only is used for council heating when there is a nearby community. The only exception I know about is a German NPP (now turned off) which warmed a neighboring field to prolong the growing season. In that case I assume the utility did that to make the project acceptable to the neighbors.
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Post by Jagdish Dhall on Apr 16, 2013 17:45:20 GMT 9.5
The question is, as always, how to remove the reject heat at the bottom of the thermodynamic cycle. Past the condenser possibilities which are non-evaporative are air cooling and ground loop water. Both have been used; the former consumes 5--8% of the generated electricity and the latter requires additional capital expense to lay the ground loop.
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Post by Jagdish Dhall on Apr 16, 2013 17:54:27 GMT 9.5
The question is, as always, how to remove the reject heat at the bottom of the thermodynamic cycle. Past the condenser possibilities which are non-evaporative are air cooling and ground loop water. Both have been used; the former consumes 5--8% of the generated electricity and the latter requires additional capital expense to lay the ground loop. The best way to dispose of the 5-8% 0f energy in used nuclear fuel is to use it. For cooling, 10 years used fuel can be placed in a lead-tin bath in place of a water tank. It can transfer the heat by convection to a heat exchanger to water/steam, which can run a small power plant. When it cannot produce useful steam, it can be stored dry or recycled.
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Post by Roger Clifton on Apr 16, 2013 20:50:15 GMT 9.5
Ground loop cooling is used in a few power plants in northern Europe Could it be that a ground loop like that would be a limited heat supply to a customer, rather than a full scale return-to-reservoir of exhaust heat ? After all, a 350 MWe steam-driven PS dumps 1000 MW of heat. At (I guess) 1 kW/m, that suggests 1000 km of pipe. If all the heat was sent out in desalinated water, it would already be diluted, but the pipe would still be dumping heat into the near-surface environment. Not that it would need to cool right down to surrounding temperatures from the consumer's point of view, just enough to avoid cooking the environment and corroding the pipe.
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Post by David B. Benson on Apr 17, 2013 7:53:14 GMT 9.5
Roger Clifton --- Other than council (or district) heating, I don't know. But if a business could use the reject heat for some industrial process, than would be another possibility. It would then not be ground loop.
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Post by David B. Benson on Apr 17, 2013 13:42:11 GMT 9.5
The heat rejected is thus a function of the pipe depth, pipe spac- ing, greenhouse width, and greenhouse length. The required heat load of 1.16 GW can be rejected from the plant assuming the pipes in the soil are 0.5 m apart and placed 0.25 m beneath the soil; each greenhouse is assumed to be 100 m long and 100 m wide with an inlet water temperature of 45 °C. A total of 530 such greenhouse units are required with a total greenhouse footprint of 5,300,000 m2. from Leffler, R. A.; Bradshaw, C. R.; Groll, E. A.; and Garimella, S. V., "Alternative Heat Rejection Methods for Power Plants" (2012). CTRC Research Publications. Paper 159. docs.lib.purdue.edu/coolingpubs/159
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Post by edireland on Apr 17, 2013 22:19:31 GMT 9.5
5.3 square kilometres of greenhouses to reject 1.1GWt?
That is going to get very large with normal nuclear plant sizes.
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Post by David B. Benson on Apr 18, 2013 9:44:29 GMT 9.5
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Post by engineerpoet on Apr 18, 2013 10:23:10 GMT 9.5
In locations with high air temperatures in the summer, the normal air cooling must be replaced by water evaporative cooling. That's only required if you need to maintain specific output. If you are willing to accept the efficiency loss that comes with high turbine outlet pressure, you can do without the evaporative assist even with steam turbines.
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Post by cyrilr on Apr 20, 2013 1:26:22 GMT 9.5
The indirect dry cooling system (sold commercially as Heller systems) are one of the most attractive for nuclear powerplants. A direct contact condenser is used (think steam jet blasting into a waterfall in a vacuum chamber). Then the waterfall condenses the steam, the heated up water is drained and pumped to a surface condenser.
This system gets better condenser vacuum (higher plant output) with dry cooling. It also doesn't use the huge fan power of a standard air cooled condenser. Another advantage is less stress on the condenser tubing in the surface condenser because it doesn't operate under vacuum. This makes inleakage of air impossible, which is important for safety reasons in nuclear plants and operability reasons in all powerplants.
There's a Russian nuclear powerplant that has this dry cooling system, plus hundred plus GWe of fossil plants (coal and CCGT), so it's already proven.
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Post by edireland on Apr 20, 2013 11:39:41 GMT 9.5
Even in Australia you are hard pressed to find an area more than a thousand kilometres from the sea.
Doesn't that mean nuclear plants could just be provided at the coast and the power shipped in via the aforementioned HVDC Light type systems? using whatever cheaply deployed cable is considered best (either the shallow ploughed type or somesort of lightweight tower system).
About the only area that is hard to serve due to distance from the sea and other significant water sources is the Sahara.
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Post by David B. Benson on Apr 20, 2013 12:43:11 GMT 9.5
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Post by anonposter on Apr 20, 2013 16:09:39 GMT 9.5
Even in Australia you are hard pressed to find an area more than a thousand kilometres from the sea. I named Alice Springs off the top of my head. Admittedly it only has a population of about twenty five thousand and about forty thousand in the region. About the only area that is hard to serve due to distance from the sea and other significant water sources is the Sahara. The Sahara is pretty wide so it'd be the best candidate for not being able to use something situated at the coast. But of course you still get the issue of water which may have to be piped from coastal desal plants.
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Post by sod on Apr 20, 2013 16:44:18 GMT 9.5
The Sahara is pretty wide so it'd be the best candidate for not being able to use something situated at the coast. But of course you still get the issue of water which may have to be piped from coastal desal plants. This illustrates perfectly, how your focus on nuclear power as a solution to everything is disturbing any sense for realistic solutions. (remember, title of this topic is "hidden cost of energy"...) we need extra power because of additional air conditioning on a couple of hot days? let us build nuclear power plants! We need power in the sahara desert? Nuclear power plants must be the right solution, let us focus on how to cool them (ignoring the HIDDEN COST of such cooling!)! solar power in the sahara desert could power the globe. Why would anyone even think about how to build nuclear power there? It simply doesn t make any sense! PS: funny side note: security check for this reply was the term "moot point". I guess the "system" is reading your posts...
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Post by anonposter on Apr 20, 2013 18:21:52 GMT 9.5
sod: I wasn't referring to cooling water, but drinking water (I wouldn't bother with desalination if the water were only intended for cooling, any reactors there would likely be air cooled anyway).
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Post by Roger Clifton on Apr 20, 2013 18:53:05 GMT 9.5
It is good to see that future nuclear power stations will be able to use air cooling instead of seawater. Apart from being physically exposed to future climatic disasters delivered by sea, more NPPs on the coast would be exposed to a fearful public conflating their increasing presence with the increasing furies of nature. Would the Monju fast reactor have fallen victim to public hysteria were it not situated so prominently on the crowded Japanese coastline? en.wikipedia.org/wiki/Monju_Nuclear_Power_Plant
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Post by anonposter on Apr 20, 2013 18:57:08 GMT 9.5
It is good to see that future nuclear power stations will be able to use air cooling instead of seawater. Apart from being physically exposed to future climatic data disasters delivered by sea, they would be increasingly exposed to a fearful public conflating their presence with the furies of nature. Would the Monju fast reactor have fallen victim to public hysteria were it not situated so prominently on the crowded Japanese coastline? Was Superphenix on the Japanese coastline? Was it on any coastline?
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Post by Roger Clifton on Apr 20, 2013 19:29:32 GMT 9.5
The fast reactor, Superphenix, was situated for cooling on the banks of the River Rhone, which is about the biggest river in France and possibly the busiest: traveltips.usatoday.com/biggest-rivers-france-102688.htmlYes, like Monju, Superphenix's impressive architecture was, now it seems excessively, exposed to the view of the fearful. A power station cooled by air, instead of water, could be moved into less populated areas and dressed more modestly. If the local power station looked vaguely like a warehouse somewhere in the industrial area of town, it would not present a symbol to be dreaded by passing traffic. en.wikipedia.org/wiki/Superph%C3%A9nix
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Post by edireland on Apr 20, 2013 20:57:02 GMT 9.5
Even in Australia you are hard pressed to find an area more than a thousand kilometres from the sea. I named Alice Springs off the top of my head. Admittedly it only has a population of about twenty five thousand and about forty thousand in the region. I make Alice Springs roughly 890km from the sea in Great Australian Bight and roughly 915km from the sea in the Carpentarian Bay. About the only area that is hard to serve due to distance from the sea and other significant water sources is the Sahara. The Sahara is pretty wide so it'd be the best candidate for not being able to use something situated at the coast. But of course you still get the issue of water which may have to be piped from coastal desal plants. Indeed but you have to do this anyway. So we can't really count it against the power plants in question.
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Post by edireland on Apr 20, 2013 21:04:27 GMT 9.5
The Sahara is pretty wide so it'd be the best candidate for not being able to use something situated at the coast. But of course you still get the issue of water which may have to be piped from coastal desal plants. This illustrates perfectly, how your focus on nuclear power as a solution to everything is disturbing any sense for realistic solutions. (remember, title of this topic is "hidden cost of energy"...) What realistic solutions? Magical power stations that are made of fairy dust and dreams? Solar is a disaster and will be for a forseable future. we need extra power because of additional air conditioning on a couple of hot days? let us build nuclear power plants! Building nuclear plants makes a lot more sense than building 2000MWe of solar capacity just to shave a few hundred megawatts off the peak demand (as that Melbourne study you cited suggested), deliberately positioning them for peak reduction rather than energy production, which makes the produced electricity even more expensive. We need power in the sahara desert? Nuclear power plants must be the right solution, let us focus on how to cool them (ignoring the HIDDEN COST of such cooling!)! No, I didn't say that we needed power in the Sahara Desert, I simply said that it is one of the few places I could find that has significant areas more than a thousand kilometres from the sea. What "hidden cost", since any hypothetical plants on the edge of the Sahara would be cooled using the world ocean, which is apparently the cheapest way to cool a thermal plant. solar power in the sahara desert could power the globe. Why would anyone even think about how to build nuclear power there? It simply doesn t make any sense! Solar power in the Sahara is a pipe dream, if for no other reason that the Europeans would have to use such power would then be completely at the mercy of the Saharan nations who could just demand we pay twice as much for electricity one winter or be left to freeze. (The Swiss Defence would prevent us from simply seizing the facilities) PS: funny side note: security check for this reply was the term "moot point". I guess the "system" is reading your posts... Well your posts are even more pointless since you consistantly propose insane ideas involving spamming more photovoltaic panels everywhere. We have more important things to do with land surface that build the enormous solar farms you propose. And I am not convinced that the solar panels on rooftops are significantly better (especially considering the cost of them) than simply covering roofs in shiny aluminium plates.
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Post by anonposter on Apr 20, 2013 22:14:01 GMT 9.5
I make Alice Springs roughly 890km from the sea in Great Australian Bight and roughly 915km from the sea in the Great Carpentarian Bight. Yes, just checking in Google Earth it is about that distance from the seas, though any realistic transmission line would be unlikely to be a great circle segment. But of course you still get the issue of water which may have to be piped from coastal desal plants. Indeed but you have to do this anyway. So we can't really count it against the power plants in question. Solar would require the collectors to be regularly washed so sod's favourite solution suffers from a much more serious water issue than nuclear (which as mentioned can be air cooled). Solar power in the Sahara is a pipe dream, if for no other reason that the Europeans would have to use such power would then be completely at the mercy of the Saharan nations who could just demand we pay twice as much for electricity one winter or be left to freeze. (The Swiss Defence would prevent us from simply seizing the facilities) I understand some Africans are opposed to such schemes because of the possibility of energy colonialism. BTW: Swiss Defence?
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Post by edireland on Apr 20, 2013 23:52:25 GMT 9.5
The Swiss Defence is "defending" something by threatening to destroy it if someone attempts to take it away from you.
In this case they would have the expensive and fragile parts of the photovoltaic infrastructure wired for demolition and blow the whole array to pieces if we invaded.
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Post by anonposter on Apr 21, 2013 0:28:45 GMT 9.5
Given how big the solar collector would need to be they'd need a lot of explosives, somehow I doubt they could install them without the foreign owner (most likely renewable energy farms in the developing world exporting to the developed would be owned by a company in the developed world) knowing and taking action to stop them.
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Post by edireland on Apr 21, 2013 0:41:30 GMT 9.5
Given how big the solar collector would need to be they'd need a lot of explosives, somehow I doubt they could install them without the foreign owner (most likely renewable energy farms in the developing world exporting to the developed would be owned by a company in the developed world) knowing and taking action to stop them. Wouldn't even have to wire the panels themselves, if they are on trainable heliostats they could just use small amounts of explosives to wreck the elevating mechanisms and cause the whole things to topple. The fall would probably seriously damage at-least some of the panels and getting the surviving panels on new mounts would take months. So from the point of view of a Europe facing a cold winter with none of its power generation infrastructure intact... they are effectively destroyed. Whether the plant's owners know or not is another question, the executives in Europe will just wake up one day to discover that the entire plant security detail has been interned and there are lots of African engineers running around their plants. And if they did try to seize them, working out a way to overrun a force defending a power plant without wrecking the power plant would give military men fits.
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