Energy From Thorium Discussion Forum

It is currently Aug 20, 2018 12:30 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 82 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next
Author Message
PostPosted: Jan 27, 2014 2:09 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1546
KitemanSA wrote:
E Ireland wrote:
It appears that Ross Shelf Ice is contaminated with seawater as additional Sea Ice freezes onto the bottom of the 'sheet'.
It will be gone before the berg gets there.

I am not so sure, if anything I would expect the iceberg to become more contaminated during transit as a result of wave action, sea spray and uneven melting of the ice producing filligrees that are more easily infiltrated by salt water.

KitemanSA wrote:
E Ireland wrote:
This would not normally be a problem as the mass is fairly small but the ice will tend to melt from the 'top' due to sunlight and surface water action. (The water at the bottom of the iceberg will be colder since all water very deep below the surface is).

You now have to ship it 13000km through the tropics to somewhere like SoCal.
Ever noticed the count of icebergs that have survived a tropic transit?
Ever seen a berg towed/pushed by a proper number of tugs?

So now its more than one tug? Your capital cost just skyrocketted.
As did your crewing costs.

Especially if these are nuclear powered tugs, you will need dozens of naval grade reactors.

KitemanSA wrote:
E Ireland wrote:
Projections for tapping ice from the Greenland Shelf suggested 40% would be lost at least just getting it to the Canary islands, 4000km south of them.
IIRC, bergs from Greenland calve off pretty small and are therefore quite non-hydrodynamic. Such bergs would be hard to tow and have a large surface to volume ratio. Sections of the Ross Ice Shelf could be long and as wide as needed to balance loss rate to tow velocity.

Which is precisely why I do not want to use icebergs.
I was proposing to melt ice directly off the top of the pack and ship it across the relevant straights using either sea bottom immersed tunnels as inveted siphons or using archimedes bridges for the same purpose.

Additionally using ross ice shelf ice is a bad idea because it will tend to melt from the top and reduce its thickness far faster than it reduces its width and length, this will make it likely to break-up mid transit.

KitemanSA wrote:
E Ireland wrote:
While the Northern Hemisphere transit will be in 'winter' you still haev to transit the entire Southern Hemisphere in its summer conditions, deal with rough seas in the southern ocean (just because its summer doesn't mean it isn't still the roughest seas in the world).
You could easily lose 80% of the iceberg before you even arrive.
20% on an iceberg the size of Deleware is still a LOT of water. :mrgreen:

And how exactly do you plan to move an iceberg massing potentially billions of tonnes without an enormous fleet of tugs?
And where exactly do you plan to 'moor' such a huge iceberg.
Since you are shipping it in the Southern Hemisphere summer you will end up in the Northern Hemisphere Winter/Spring, which means you will need a sheltered anchorage to avoid a storm breaking it to pieces before you are finished.

Additionally you cannot chose too compact an anchorage because then the environmental consequences of reducing the temperature of the water in said anchorage will become significant.

KitemanSA wrote:
E Ireland wrote:
And now to the logistics of towing it, the Canary Island projections required 141 days to cover 4000km, which implies well over a year to tow from the Ross Ice Shelf, so if you want regular arrivals you are going to need a huge fleet of expensive nuclear tugboats.
Again the size and shape of the berg will have a significant bearing.


Too streamlined and you will lose the berg when it brakes into pieces on melting.

KitemanSA wrote:
E Ireland wrote:
How is this going to be cheaper than a few thousand kilometres of aqueduct and some pumps?
Don't know, but it seems likely to me.
Of course using LFTRs to desalinate water would probably be cheaper still.


Almost certainly not, the capital costs of desalination plants are insane.
While it might sound grandiose, building an infrastructure that can transport tens of cubic kilometres of water per second is going to be ridiculously smaller than the desalination capacity with the same capacity.

Then there are the salt dumps which will have every environmentalist on the continent raving as they potentially create giant fish kills.

Oh and with regards these icebergs, if you are using very large ones, this means you will need titanic water reservoirs to store it all in because we can't consume all our water in a few weeks and then not drink for the rest of the year.
And then there is the fact that all these pumps, water heaters and such things will have to be mobile so they can be set up on the berg after it has reached the dismantling site.

Static systems involving melting ice off the ice sheet itself are likely to be cheaper/less manpwoer intensive - and that is not counting the amount of water you can capture from surface runoff or simply building a barrage across the end of a glacial valley.


Top
 Profile  
 
PostPosted: Jan 27, 2014 2:13 am 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1335
Location: NoOPWA
E Ireland wrote:
It would only be a few times the length of the California Aqueduct.
Well, if a few equals about 15. And it is over some of the biggest mountains in the world and thru huge expanses of tundra. And how are you going to melt the ice and KEEP it molten thru all that tundra without badly effecting the environment?

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
PostPosted: Jan 27, 2014 2:29 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1546
KitemanSA wrote:
E Ireland wrote:
It would only be a few times the length of the California Aqueduct.
Well, if a few equals about 15.


The California Aqueduct system is ~1130km including its various branches.
The distance from the North of Greenland to So Cal is going to be about 6000-7000km, so not 15 times the length of the Aqueduct.

KitemanSA wrote:
And it is over some of the biggest mountains in the world and thru huge expanses of tundra.


Thanks to major advances in hard rock tunneling we can now drive TBM bores 15m or more in diameter, this number is constantly increasing.
With TBM drives of lengths comparable to existing projects it is possible to cross the Rockies into the Columbia watershed at roughly 1100m elevation with roughly 120km of route tunnel (most of which is actually under farmland so additional tunnelling access sites are available).
For example you could have a portal in one of the valleys near Fairmont Hot Springs.

KitemanSA wrote:
And how are you going to melt the ice and KEEP it molten thru all that tundra without badly effecting the environment?


Reactors deployed in greenland would use waste heat from electricity production to melt the water. (The electricity will be used to pump the water later on as required thanks to long HVDC connections, or if insufficient electricity is required we can simply build simpler steam generator reactors).
Water transport over the tundra will involve simply allowing the surface to freeze while making the channel deep enough that water can continue to flow underneath, if additional generation is required beyond that to melt it then the reactors will be deployed to release waste heat into the canal.

Where possible water interaction with local sources will be avoided.
Underground sections (cut and cover or bored) will also help avoid large scale issues with freezing, as would deployment of suitable lagging on underwater sections.


Last edited by E Ireland on Jan 27, 2014 2:32 am, edited 1 time in total.

Top
 Profile  
 
PostPosted: Jan 27, 2014 2:30 am 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1335
Location: NoOPWA
E Ireland wrote:
Almost certainly not, the capital costs of desalination plants are insane.
While it might sound grandiose, building an infrastructure that can transport tens of cubic kilometres of water per second is going to be ridiculously smaller than the desalination capacity with the same capacity.
The capital costs of desalination are such that desal is the cost effective method to get fresh water in many parts of the world. Another benefit is that you can build up capacity while enjoying the fruits of capacity already built.
E Ireland wrote:
Then there are the salt dumps which will have every environmentalist on the continent raving as they potentially create giant fish kills.
Either dilute the brine into the waste water after you use the water, or dry the brine for salt. Other options exist.
E Ireland wrote:
Oh and with regards these icebergs, if you are using very large ones, this means you will need titanic water reservoirs to store it all in because we can't consume all our water in a few weeks and then not drink for the rest of the year.
The berg IS the reservoir!
E Ireland wrote:
And then there is the fact that all these pumps, water heaters and such things will have to be mobile so they can be set up on the berg after it has reached the dismantling site.
And?

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
PostPosted: Jan 27, 2014 2:34 am 
Offline

Joined: Jun 05, 2011 6:59 pm
Posts: 1335
Location: NoOPWA
E Ireland wrote:
KitemanSA wrote:
E Ireland wrote:
It would only be a few times the length of the California Aqueduct.
Well, if a few equals about 15.


The California Aqueduct system is ~1130km including its various branches.
The distance from the North of Greenland to So Cal is going to be about 6000-7000km, so not 15 times the length of the Aqueduct.
Oh puleeease! Counting all the minuscule side branches is just absurd. Its akin to saying I'm 15 ft tall cuz my torso, head, arms, legs, fingers, toes, and hairs add up to that long. Hmmph. Your arguments are specious. Are you a troll?

_________________
DRJ : Engineer - NAVSEA : (Retired)


Top
 Profile  
 
PostPosted: Jan 27, 2014 2:40 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1546
KitemanSA wrote:
The capital costs of desalination are such that desal is the cost effective method to get fresh water in many parts of the world. Another benefit is that you can build up capacity while enjoying the fruits of capacity already built.


And yet are so high that they prohibit the deployment of desalination on the scale required to make a significant difference to aquifer depletions and similar environmental problems worldwide.

KitemanSA wrote:
Either dilute the brine into the waste water after you use the water, or dry the brine for salt. Other options exist.


If you are going to deploy it on anything like the scale required, you will lose most of the product water to transpiration before it ever gets near the sea.
And you will rapidly produce more salt than you can ever use.

KitemanSA wrote:
The berg IS the reservoir!


Forget 80%, you will lose 95% or more.
You will have the berg sitting in warm coastal waters for weeks or months after it has arrived?
Every day that it is has not been dismantled is another day for the iceberg to lose mass.

KitemanSA wrote:
And?


That is going to cost billions upon billions of dollars if you want to actually capture a significant portion of the icebergs mass.


Top
 Profile  
 
PostPosted: Jan 27, 2014 2:43 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1546
KitemanSA wrote:
Oh puleeease! Counting all the minuscule side branches is just absurd. Its akin to saying I'm 15 ft tall cuz my torso, head, arms, legs, fingers, toes, and hairs add up to that long. Hmmph. Your arguments are specious. Are you a troll?


I'm sorry that your hairs have a significant fraction of the cross section of your drunk.

And according to the California Department of Water Resources the main line section of California Aqueduct is something like 710km long in its own right.
Which means you are looking at 9-10 times at most, not 15.


Top
 Profile  
 
PostPosted: Jan 27, 2014 3:05 am 
Offline

Joined: Jun 19, 2013 11:49 am
Posts: 1546
I actually ran numbers on the insane aqueduct option.

Assuming there is no runoff to collect in significant quantity (I would be interested to see if you could drill through the cap and tap the layer of liquid water that gathers underneath it to lubricate its motion) and it would appear that the thermal energy necessary to melt the ice is far greater than I realised.


It would appear desalination is going to be the wave of the future, assuming a salt dump that doesn't cause massive environmental issues can be designed.


But we are still a long way from getting desalination cheap enough.
Bring on the advanced RO membranes.


Top
 Profile  
 
PostPosted: Jan 27, 2014 11:34 am 
Offline

Joined: Jul 28, 2008 10:44 pm
Posts: 3065
Desalination is deployed so costs are not impossible. By combining water production with electricity production I believe we find that the water costs are quite reasonable. Start with a need for electricity. Option 1 is to build a nuclear power plant just to produce electricity. Suppose the turbines run with a high temp around 550C and a cold temp around 50C. The theoretical efficiency then is (550-50)/(550+273) or 60%.
Option 2 is to run the turbine from 550 to 150 and then run the desal from 150 to 80C. The theoretical efficiency for electricity is then 48% and you have around 15% of the energy available for water desal. Converting that lower temperature energy is the most expensive (and physically the largest) part of the turbine. So you pay a bit in reduction of electrical output but you gain in water production. This idea shows up repeatedly because it makes economic sense.

It won't compete with surface runoff or ground water supplies. In regions where these are available desal won't be cost effective. BUT there are many places were these cheap water options are not available and there the cost of desal water is workable. (Probably not for flood irrigation but for city consumption or for drip irrigation).


Top
 Profile  
 
PostPosted: Jun 17, 2015 8:38 pm 
Offline
User avatar

Joined: Nov 14, 2013 2:34 pm
Posts: 177
Location: Here and There
I'm dredging this one up again. California is still in a drought. Are they building de-salination plants?

http://sacramento.cbslocal.com/2015/06/16/california-water-cuts-leave-city-days-away-from-running-out-of-water/

Years ago the people of California used to be far sighted. Seems like the Jarvis amendment some years back was a turning point for the state.


Top
 Profile  
 
PostPosted: Jun 17, 2015 10:03 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3733
Location: Alabama
California has to want to be saved badly enough to let go of their failed leftist ideology. So far, they appear to be doubling down on failed approaches instead.


Top
 Profile  
 
PostPosted: Jun 17, 2015 11:38 pm 
Offline
User avatar

Joined: Dec 29, 2011 10:14 am
Posts: 217
California celebrates production of eVs of energy, and when someone improves that meager output by 5 percent there is cause for major celebration, cheers and headlines. The state has policies to promote eV based power and transportation. Good luck with desalination with that, and pumping water as well. Oh, LFTRs are MeVs of energy, just a million times better but they are not on the California radar. How does any of that kind of thinking make sense? It is like assuming we can just add more butterflies, millions of them, and can provide the power needed, and is it not swell that butterflies do not have to take a break or sleep? My point is logic demands a different solution than the state of California promotes -- not a good policy for dealing with their difficult and pressing problems. It is a policy that will cause more fossil fuel power plants.


Top
 Profile  
 
PostPosted: Jun 18, 2015 7:04 pm 
Offline

Joined: Dec 19, 2011 7:04 pm
Posts: 41
Location: Berkeley, CA
Nuclear might get some unintended positive press/public support from the drought:

http://www.sanluisobispo.com/2015/06/03/3663220/diablo-canyon-desalination-plant.html


Top
 Profile  
 
PostPosted: Jun 18, 2015 9:12 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3733
Location: Alabama
Eino wrote:
How could even the most ardent left wing Berkeley environmentalist complain about this gift of clean water?


Because in their twisted mind the price of this "gift of clean water" is the generation of the dripping dregs of Hell that will torment mankind and scramble their DNA for millions of years, mutating them into troglodytes who curse the Berkeley liberal for drinking that glass of clean water that robbed them of their humanity and scarred their children.

(dang, I could be a pretty good anti-nuke...)


Top
 Profile  
 
PostPosted: Jun 19, 2015 4:20 pm 
Offline

Joined: Jan 21, 2008 9:12 pm
Posts: 310
Location: idaho falls
The numbers suggest that the implementation of any sort of genuinely affordable/practical nuclear power system could indeed save California.

What are those numbers?

Since the majority of CA's total water is used for agriculture, mostly in the Central Valley, & the amount devoted to that purpose during "normal" years is about 5 million acre ft (https://en.wikipedia.org/?title=Central_Valley_Project), that figure represents a realistic "water need" number.

Since 5 million acre ft translates to 7.8 billion cubic meters & the energy required to purify 1 cubic meter of seawater via reverse osmosis (RO) is currently about 3kwhr, we're going to need about 2.11 GWe's worth of nuclear power to produce it (this is a realistic "reactor" need number)

Since the projected/contracted cost of Saudi Arabia's latest, big (one million m3/day), RO plant is $1.89 billion (https://en.wikipedia.org/?title=Desalination) and it'd take 21 such plants to generate 5E+6 acre ft of water per year, their capitol cost should be about $32 billion in today's dollars (a realistic "desalination capitol cost" number).

Other WIKIPEDIA entries say that the value of the Central Valley's produce, etc. represented about 8% of the USA's total agricultural value/income in 2002 & that the total value of US ag production in 2012 was $406 billion. This means that the value of what's being grown in the Central Valley is currently on the order of (also) $32 billion per year (probably a bit more).

In toto these numbers suggest that California could be "saved" with just two full-sized (not "modular") reactors & that the cost of implementing such a permanent "nuclear fix" for its water woes probably represents under two year's worth of its Central Valley's agricultural production.

_________________
Darryl Siemer


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 82 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group