|
Post by edireland on Dec 11, 2012 14:54:21 GMT 9.5
Small grids are probably more likely to be solved in most cases by improvements in VSC HVDC technology (see HVDC Light and whatever the Siemens version is called... I can't remember off hand).
They are going to be powering a North Sea oil/gas rig complex from a shore installation.
Almost all places that currently make do with isolated microgrids are sufficiently close to a place that has or soon will need a full sized grid to make simply connecting them with HVDC practical.
|
|
|
Post by edireland on Dec 1, 2012 20:41:44 GMT 9.5
I'm no chemist, but I thought the reaction might have needed air and sunlight to trigger it? I don't know... anyone? Finally a reason to use my expensive Chemistry degree! Mg2SiO4 + 4 CO2 + 4 H2O —> 2 Mg2+ + 4 HCO3 - + H4SiO4 I can't imagine these guys would have forgotten dumping it in the ocean as an option. After all, they mention using beaches and tidal areas. Does it need to be near the surface of the sea to work? Well silicates tend to slowly undergo hydrolysis into silica and a variety of hydroxides when exposed to water under certain reaction conditions. (Indeed, portland cement is chiefly Calcium Silicate which hydrolyses into silica and calcium hydroxide) The reaction is very slow but with the hundred micron powder proposed by this paper I am pretty sure you should get measurable rates of reaction. Magnesium Hydroxide is almost totally insoluble in normal conditions but since the particles are very fine it is likely enough will dissolve rapidly enough to cause an equilibrium between the hydroxide and various acidic species (chiefly carbonic acid). It all depends on whether or not the powder can be suspended in the water column for significant periods of time prior to dropping out. They seem to mention the possibility of scattering the material in shallow oceans in the paper. One major concern may be ensuring that the material remains in the oceanic surface layer long enough to absorb large amounts of carbon dioxide. An alternative to using fields in the tropics may be to build nuclear power plants in various areas with lagoons into which rejected cooling water is dumped before being allowed to return to the sea. That would allow warm wet conditions to prevail at almost any latitude.
|
|
|
Post by edireland on Dec 1, 2012 19:10:01 GMT 9.5
Spreading the olivine would be horrifically expensive both in carbon dioxide and monetary terms.
The reaction works in the sea so how about simply dumping the powdered olivine into the sea and using the sea's surface as a carbon dioxide collector?
Reduing the acidity of the ocean back to preindustrial levels would cause it to soak up more and more of the atmospheric carbon dioxide.
|
|
|
Post by edireland on Nov 28, 2012 1:51:10 GMT 9.5
That is not really accurate, since that would imply that the warming driven feedbacks would happen despite there being no warming to drive them.
If we reverse all warming occuring now, we don't get into the thermal runaway that is supposed to occur.
|
|
|
Post by edireland on Nov 21, 2012 22:47:13 GMT 9.5
A better option might be just to cover the entire thing in huge amounts of greenhouses.
Dam off a bay that if fed by one of those supermassive glaciers that is going to be melting soon and tap off all the meltwater to irrigate teh entire thing.
|
|
|
Post by edireland on Nov 16, 2012 18:37:26 GMT 9.5
Also the yields of crops at that time would be so low that they would never be insolation limited.
They are far more likely to be now that they are not likely to be nutrient limited, atleast in the west.
|
|
|
Post by edireland on Nov 16, 2012 9:54:59 GMT 9.5
This is the only resource that I have no yet worked out an effectively infinite source yet. (As some of you have seen I have already proposed methods to allow meat production, and thus food production, to be scaled up enormously while reducing the amount of land required to grow feed, and also allowing forage fish harvesting to stop).
|
|
|
Post by edireland on Nov 15, 2012 21:26:44 GMT 9.5
The west won't starve, SCP will make sure of that.
But before you go on about how Siberia and the like will be agricultural powerhouses, you have to note that there is rather less land at higher latitudes than lower latitudes (indeed, short of Antarctica, which is likely to remain cold, there is effectively no land south of 54 degrees south).
You essentially loose Africa and most of South America and don't gain a similar land area back again, Siberia and northern canada is nowhere near as large as you seem to think it is.
Also Siberia's climate is rather unstable even now, 50 degree celsius temperature swings are not considered particularily unusual and it wouldn't take much to cause massive heat death in crops located there.
And this is all assuming that figures for wild plants, which are indeed nutrient and sometimes carbon dioxide limited, can be applied to farmed plants which may in some cases be insolation limited now.
|
|
|
Post by edireland on Nov 15, 2012 10:34:32 GMT 9.5
Are you sure this is really a factor? During the other half of the year, high latitude locations receive more sunshine overall. If that was true, the average temperature in high lattitudes could be expected to exceed that in the lower latitudes during the summer. There would be no significant near-sea level year round polar ice in that case, it could never have accumulated in a repeated freeze-thaw scenario Once you get up to 60 degrees latitude you get half the light output per square metre as the equator (at the equinox). Even assuming the light output remains constant all the time you only just compete with what you get at the equator, and it doesn't do that.
|
|
|
Post by edireland on Nov 15, 2012 0:58:03 GMT 9.5
Yields at higher latitudes are drastically reduced on account of the reduced insolation over the course of the year.
Sun never gets high in the sky.
|
|
|
Post by edireland on Nov 14, 2012 18:55:29 GMT 9.5
If these figures are accurate.... we need a crash nuclear programme now (to the point of a significant percentage of total global GDP devoted to reactor construction), seawater greenhouses in all areas likely to be desertified and lots and lots of geoengineering. (The fact that atmospheric capture of carbon dioxide and conversion to syngas with off peak electrolysis may now be commercially viable is significant I think).
Sulfur use has some issues unfortunately, but I don't think there is that much choice at this point.
If those figures are accurate.
|
|
|
Post by edireland on Nov 12, 2012 15:22:45 GMT 9.5
There is a factor that is not often considered in these debates. One of the primary concerns with fish and livestock farming is supplying sufficient high quality protein, with most of it being provided by animal products like fishmeal or by things like soybeans which are relatively inefficient in terms of energy fixed per hectare. Even then proteins are just collections of amino acids and get broken down into same in the digestive process so just making the amino acids synthetically would work (though biological methods are probably the way to go, especially if you want them handed). Indeed, I've been thinking about 'synthetic food' for a long time, and the yields are just too low if you are attempting to manufacture chiral products with the corrrect chirality. This is why I was rather happy when I found out that there are bacteria that produce high quality protein that can be fed on a rather simple non chiral molecule. (In this case methanol). If the syngas can be produced affordably this means methanol can be, at which point we can make Single Celled Protein from bacteria like Methylophilus methylotrophus in large fermenters (such a process was briefly commercialised as "Pruteen" but suffered from major increases in methanol prices compared to that of soybeans in the 80s). The biggest worry I'd have about using methanol in such a process is making sure no methanol gets into the food humans eat. But it seems that can be dealt with (if it's been done before they must have found some way). Several SCP plants have indeed been shut down due to problems with substrate contaminating the product, but these were primarily yeast based SCP plants running on n-paraffins. Methanol has the advantage that it is fully miscible with water so can be removed from the product by simple repeated washing whereas the paraffin requires more.... drastic measures. It turns out the Soviets were very big on SCP, far greater than anyone in the west, possibly because they needed ever more animal feed to support the "Meat plan" which led to them importing ever greater amounts of grain from the West. They also had access to huge amounts of relatively low price oil in the early 80s. (Contrary to popular belief Soviet grain production actually exploded during the 80s, the imports were a result of meat production growing even faster). So what effect on carrying capacity does it have if almost all the arable land used for soybeans (leaving only production for direct human consumption) and similar crops can be replaced with a few chemical works and about a sixth as much land devoted to oil palms (to replace soy oil)?
|
|
|
Post by edireland on Nov 11, 2012 16:20:08 GMT 9.5
There is a factor that is not often considered in these debates. One of the primary concerns with fish and livestock farming is supplying sufficient high quality protein, with most of it being provided by animal products like fishmeal or by things like soybeans which are relatively inefficient in terms of energy fixed per hectare.
However there an alternative. It looks like coelectrolysis of carbon dioxide and steam using solid oxide electrolysis cells may permit competitive production of petroleum products via syngas and either FT or the MTO process when using off peak electricity.
If the syngas can be produced affordably this means methanol can be, at which point we can make Single Celled Protein from bacteria like Methylophilus methylotrophus in large fermenters (such a process was briefly commercialised as "Pruteen" but suffered from major increases in methanol prices compared to that of soybeans in the 80s).
This means off peak electricity is now animal feed. If you are allowed GM I am pretty sure you could make a GM strain of Fusarium Venetatum that can munch methanol or something similarly simple to manufacture, which means you can then make Quorn from electricity.
This changes the calculations on carrying capacity in a rather major way.
|
|
|
Post by edireland on Nov 3, 2012 4:41:20 GMT 9.5
This is a rather crude generalisation. It all depends on how the market is constructed - in many cases, prices have gone down due to optimisations introduced by private companies. Perhaps, my only experience is the UK where it now appears that the reductions in electricity price at privatisation of the CEGB were purchased by cutting corners in grid renewals and allowing the grid to operate at closer to the failure point, as well as abandoning the state mandated nuclear programme in favour of the first "dash for gas". Now that the CEGB constructed infrastructure is nearing retirement we have National Grid panicking and demanding major increases in the transmission charge for the Supergrid because they haven't been spending enough on renewals for the last 15 years. It isn't, really. It's about introducing competition to the electricity sector to drive down costs. Wholesale generation markets with government-owned distribution and transmission networks can work. A retail market (which essentially involves who charges customers and pays for the electricity they consume etc.) is optional. Competition did work in the UK in the short term but now we have an absurdly overcomplex system with hordes of lawyers fighting over who pays for what and trying to blame failures on other people..... rather like the railways really. I am not convinced that the huge infrastructure required to support the market costs less than the supposed "inefficiencies" that would be introduced in a single vertically integrated operator (which could be kept under control, IMO, by something like the Freedom of Information Act which we already have). This directly conflicts with I've thought for quite a while that one of the biggest pools of capital is pension and superannuation savings Which I can attest actually happens. I have visited a power station that is in-fact majority owned by a superannuation fund (Newport Power Station in Melbourne, Australia). So the appropriate non-state actors exist, there probably just aren't enough of them. As far as I can tell Newport 'D' Power Station was constructed by the State Electricity Commission of Victoria. It was then sold to a variety of people before ending up in the hands of said Superannuation fund (as far as I can tell). As construction on the plant started in 1977 it is likely that it was sold off with a significant portion of its cost already deprecated, reducing both the length of the remaining loan (as the plant has used up substantial portions of its life) and the size of said loan per megawatt. As it is a gas fired station I would wager that it had a relatively low capital cost to begin with. This is not really comparable to taking out a loan to build, not purchase, a nuclear power plant with a huge capital cost and an at-least 60 year lifetime. Also, in respnse to the question about the ABWR, it is not a Gen III+ plant as it has no passive cooling system, it is merely a Gen III reactor with massively redundant active systems.
|
|
|
Post by edireland on Nov 2, 2012 0:59:30 GMT 9.5
* the EU is bent on competition in the power sector, when it is likely that it is a natural monopoly or at the very least prone to an oligopoly. You're half-right. Distribution networks (municipal grids that connect to consumers) are a natural monopoly, as it is highly inefficient to duplicate those sorts of networks. Transmission networks (connecting generators and load centres together) also tend towards being natural monopolies. However, it is quite possible (and has been proven) to have regulated generator markets with individual market generators acting as market participants as well as having unsynchronised grid interconnections included as 'virtual generators'. As long as you have good regulations for such markets you can quite easily bootstrap a little bit of capitalism into the industry. Retailers that buy electricity on behalf of consumers and bill them accordingly are another area of the market that can be deregulated, although the benefits of such markets are dubious (and I say that as a resident of a state with a quite deregulated electricity retail market). The fundamental issue facing such markets is access to large amounts of long-term (decadal time scale) credit. Traditionally this sort of credit has only been available to sovereign nations, but the advent of globalisation may be able to substitute for this. The problem with "electricity markets" with such private generators is that you require huge amounts of surplus transmission capacity to support electricity being traded over long distances, and that you require an enormous customer control bureaucracy that decides which unit of electricity is being paid for by which company and when users switch companies they have teams of lawyers argue over everything to determine who pays for a particular day's use and other things that would be trivial in an integrated system. The net result is a system that is no more efficient than the original vertically integrated state owned one, but simply provides huge profits for various private equity funds which is the objective anyway. Without a retail market the wholesale market is pointless since why should they be forced to trade electricity with all the overheads concerned when they can simply generate more themsleves at a lower overall cost to themselves? This is especially true in the era of things like Solid State Ammonia Synthesis and electrolysis which promise an effective way to turn peaking power requirements into baseload capacity requirements. Additionally as stated above nuclear power is killed in the private sector because of the capital requirements that can only effectively be provided by state actors who have access to sufficiently long lengths of finance. The private sector just doesn't deal in 60 year duration loans, which is really what we need to make nuclear competitive.
|
|
|
Post by edireland on Nov 1, 2012 1:30:34 GMT 9.5
It doesn't matter how much more complex it is, the ABWR has and is being built across the world. It is a far more sound investment decision for a large roll-out like Horizon compared to the ESBWR because it is not a paper reactor with precisely zero other clients. Even the AP1000 is more proven than the ESBWR. # Firstly six reactors is not really a "large" roll out by British and European standards, the AGR programme ran for 14 reactors and we all know how humongous the French PWR programme was. Secondly site preparation works for six ESBWR units have apparently commenced near Kovvada in India, which means the reactor would have atleast one other client. This would take it up to even to the six ABWR units I know being built or under construction in east Asia. Additionally it is a serious contender in the Okiluoto 4 competition, especially since the EPR appears to be repeatedly shooting itself the foot next door. The only reason to build ABWRs instead of ESBWRs is because there is no need to choose the cheaper and more efficient design because Horizon knows to an absolute certainty that the Government has become so commited to the glorious free market providing new nuclear that any attempt to do it itself would be an impossible ideological U-turn. This means they can work a cartel with EDF and charge as much as they want for nuclear electricity (currently the figure stands above $200/MWh) which removes all the normal competitive pressures that would drive them to suggest the very minor risk of building ESBWRs instead.
|
|
|
Post by edireland on Oct 31, 2012 12:55:45 GMT 9.5
Actually the ESBWR is more advanced in the General Design Approvals Process.... ie, it has been entered into said process. (And as I understand it the ESBWR is only a few months at most from being approved by the NRC as well, and it will take years to wrangle permission to actually start construction on the site anyway)
Its at step 3 in the GDA whereas ABWR has not been entered at all.
The passive safety advantages of the ESBWR are not what has sold me on the design compared to the ABWR, ti is the higher power nature of the design and its simplicity compared to the enormously complex ABWR, with its huge number of recirculation pumps and its multiple diesel generator backup systems.
All that gear is expensive. I suppose those that ABWR is similar enough to the ESBWR that operating and construction experience from one will accrue to the other (indeed it appears many of the construction modules for the ESBWR are the same as the ABWR) but it appears we are going to end up with a zoo of different reactor types. (Atleast two, soon to become three if PRISM goes ahead)
This is going to cause huge increases in costs compared to the French model of picking one design and running with it.
|
|
|
Post by edireland on Oct 31, 2012 1:30:50 GMT 9.5
Its very annoying as this means Hitachi are going to be commited to building part of a giant zoo of PWRs despite being a primary vendor for BWRs.
EDIT: Oh wait, they are going to be building ABWRs?
Why no attempt to build ESBWRs instead?
It would seem to be a no brainer.
|
|
|
Post by edireland on Oct 27, 2012 9:15:45 GMT 9.5
With regards to transuranics leaking into the fission product stream.
If this is a problem you could dissolve the accumulated pyroprocessing salt into water (since it is a mix of alkali and alkali earth halides) and then run it through PUREX, except now the fissile content of the waste stream is rather lower than in the original fuel, and thus your criticality issues go away.
And since it doesn't contain any of the Uranium the mass of material to be processed is drastically reduced.
Could do pyroprocessing on site and ship the salt for processing at a central facility that is better equipped to do PUREX.
|
|
|
Post by edireland on Oct 23, 2012 19:58:11 GMT 9.5
So this potentially cuts construction time by half to two thirds? Assuming no limits such as maximum rate of concrete pouring are hit? That would be rather impressive and allow nuclear to actually approach coal plant construction time.
|
|
|
Post by edireland on Oct 22, 2012 1:54:37 GMT 9.5
The ESBWR General information schedule maintains that the ABWRs in Japan took 36 months from first concrete to fuel loading (and that ESBWR would be broadly comparable).... is there any chance that could be cut to 24 months if you were to go for a "war emergency" schedule with three shifts running around the clock?
I assume you wouldn't want to rush the 6 month commercial shakedown period at the end of that but you might be able to manage a 3 year overall schedule? (Ignoring the lead times neccesary to source long lead items which would tkae it up to approximately 4 years probably)
And Americans still get time-and-a-half for overtime?
|
|
|
Post by edireland on Oct 20, 2012 12:45:56 GMT 9.5
The low capacity factor is indeed by design, the whole idea is that minor equipment failures, which are apparently still depressingly regular, will not result in a reactor scram as the cooling system consists of numerous parallel trains which means that heat exchangers and cooling loops can be shut off with only a loss of a small amount of reactor output.
That keeps the CF up even in the face of equipment problems.
Based on the above Sheffield Forgemasters schedule and the schedules listed in the ESBWR documentation I estimate 91 months from project start to the first reactor being available for commercial service with reactors then arriving once every 2 months after this time.
Unfortunately that is very slow and it could do with atleast a couple of years cutting off the start time.
EDIT: Does anyone know if the reactor construction time assumes a single shift working 8-12 hour days or if it assumes multiple shifts working 24 hours a day? The reactor building speed seems rather low considering it supposedly contains rather less concrete and steel than Gen II PWRs do.
This would seem to be a way to rapidly accelerate construction although it would likely require a large itinerate work force that would have to be housed at significant cost.
|
|