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Water versus Energy

Posted: Mon Aug 17, 2009 9:38 am
by BenTC
While obvious that cheaper electricity would benefit many parts of the planet to produce potable water from desalination, it wasn't obvious to me the importance of the method of electricity generation. Scientific American had an enlightening article describing the tension between water and energy. Water production requires large amounts of electricity, but (traditional) electricity production requires large amounts of water. The pB11 Polywell with direct conversion would be one way to break this Catch22.

Scientific American "Catch 22: Water vs Energy"
Cleantechnica "Energy Versus Water: Is Blue the New Green?"

Really, really cheap power...

Posted: Mon Aug 17, 2009 6:16 pm
by Nik
If power costs approach 'too cheap to meter', reverse-osmosis desalination may be by-passed due to the expensive membranes and bio-fouling...

Old-fashioned, low-pressure distillation plus heat-pump energy-recovery (to minimise thermal pollution ;-) may be the way to go...

Re: Really, really cheap power...

Posted: Mon Aug 17, 2009 8:06 pm
by MSimon
Nik wrote:If power costs approach 'too cheap to meter', reverse-osmosis desalination may be by-passed due to the expensive membranes and bio-fouling...

Old-fashioned, low-pressure distillation plus heat-pump energy-recovery (to minimise thermal pollution ;-) may be the way to go...
Polywell would be ideal for a 35 MWe thermal plant with the waste heat (rejected at about 200 deg F) used for desalinization. High pressure (temperature) exhaust simplifies a lot of things in plant design (turbine size, condenser size, etc.) and operation. It reduces efficiency though. It may not matter if electricity is a byproduct or used in plant operation (condensate pumps, feed water pumps, water degassing pumps, etc). Plant efficiency should come in at around 30 to 35% thermal to electrical with the rest going to desalinization.

Or you might want to apportion between direct conversion and desalinization.

Lots of happy uses if we can get it to work.

Posted: Wed Sep 02, 2009 12:26 pm
by Stoney3K
Given that there is an abundance of power (e.g. Polywell), the best course of action would be to install plants near the coastlines, especially near the West of Africa.

The Polywell plant can do three things at once: Extract B11 fuel from the ocean water, convert it into drinking water, irrigate the deserts nearby and provide them with electricity in the process. And while we're at it, why not manufacture hydrogen on the spot as well, for transportation.

If H2/water production provided by the plant is not sufficient, secondary stations could be fed off the HV lines from the main station, but decentralized Polywell stations (few hundred MW each) would be more favorable.

A station like that would not be much bigger than today's natural gas power plants, and could be made more compact for shipboard (submarine) or spacecraft applications.

Posted: Wed Sep 02, 2009 2:06 pm
by KitemanSA
Stoney3K wrote:Given that there is an abundance of power (e.g. Polywell), the best course of action would be to install plants near the coastlines, especially near the West of Africa.

The Polywell plant can do three things at once: Extract B11 fuel from the ocean water, convert it into drinking water, irrigate the deserts nearby and provide them with electricity in the process. And while we're at it, why not manufacture hydrogen on the spot as well, for transportation.
NRL (Naval Research Lab) is working on a way to take in seawater, extract the C02 and so H2 and create JP5 for their jets. All it takes is a source of energy. Polywell anyone?

Water, Power, Fuel. Instant civilization?

Posted: Wed Sep 02, 2009 2:46 pm
by Stoney3K
KitemanSA wrote:Water, Power, Fuel. Instant civilization?
That pretty much holds in a lot of situations. Water vapor is a greenhouse gas (albeit not as powerful as CO2), and basic needs for civlization can be created out of water and some support materials which may be found on-site.

Colonizing Mars and Europa would be possible in the short term if the Polywell concept is proven.

Materials for producing food and fuel (in particular, carbon) might need to be found at the target site, or carried on expedition vehicles, although most worlds have amounts of hydrocarbons present.

Given enough energy, you can synthesize pretty much anything from materials to food from the basic building blocks. If you have H, O and C, just mix and match.

Posted: Wed Sep 02, 2009 6:09 pm
by tombo
If power costs approach 'too cheap to meter', reverse-osmosis desalination may be by-passed due to the expensive membranes and bio-fouling...
Reverse osmosis desalination works very well thank you.
Any system has costs and maintenance. Fouling is controllable by proper design and intelligent preventative maintenance. One of our older plants has gone 10 years without a membrane failure and we know how to do them better now.
Membrane costs are mostly a matter of small manufacturing volume and of them being specialty items. It will go down with increased market.
Distillation is expensive too.
There is a reason that all new major desalination plants are reverse osmosis i.e. $$$.
Current RO system water cost per gallon is about 3 times the cost of city water from a reservoir and watershed that were bought and built when real estate prices were a few dollars an acre. And, it tastes a whole lot better.


'too cheap to meter'? never. someone needs to make a profit on it or it won't happen.

Posted: Wed Sep 02, 2009 6:24 pm
by KitemanSA
tombo wrote:'too cheap to meter'? never. someone needs to make a profit on it or it won't happen.
But they don't necessarily have to meter. You may wind up paying $50/month as a power subscription fee, much like cable or local phone service. Heck, even long distance has become too cheap to meter in most cases, there is just a set fee. Too cheap to METER, never too cheap to charge. :wink:

Posted: Wed Sep 02, 2009 6:25 pm
by D Tibbets
I hadn't considered producing jet fuel in situ on carriers. This would change the dynamics of carrier operations considerably. There are presumably huge spaces inside current aircraft carriers dedicated to storing the large quantities of aircraft fuel needed, and still for continous operations, frequent resupply from oil tankers is needed.

As far as water vapor's greenhouse effect I believe it is stronger than CO2 in both effect per molecule (?) and, by far, in quantity. I'm guessing the debates about CO2 greenhouse effects at the low concentrations in the Earth's atmosphere is due to the (debated) catalytic or positive feedback effects of CO2 on the atmospheric water content. Co2 warns the atmosphere a tiny amount, but this tiny amount allows more water vaper before the atmosphere saturates, leading to more heating, which leads to more water vapor, which leads to more ....


Dan Tibbets

Posted: Wed Sep 02, 2009 6:30 pm
by KitemanSA
D Tibbets wrote: As far as water vapor's greenhouse effect I believe it is stronger than CO2 in both effect per molecule (?) and, by far, in quantity.
At least water vapor condenses eventually, and when it does if provides a great reflector for incoming solar energy. Does water vapor help or hurt. They can't even decide on the sign, so how good can their models be? Oh God, not anought AGW argument. Please, no, not that!!!! AAHAHAHAH!

Posted: Wed Sep 02, 2009 8:47 pm
by D Tibbets
KitemanSA wrote:
D Tibbets wrote: As far as water vapor's greenhouse effect I believe it is stronger than CO2 in both effect per molecule (?) and, by far, in quantity.
At least water vapor condenses eventually, and when it does if provides a great reflector for incoming solar energy. Does water vapor help or hurt. They can't even decide on the sign, so how good can their models be? Oh God, not anought AGW argument. Please, no, not that!!!! AAHAHAHAH!
Well, like the Polywell, lets just say that the predictions are... er, cloudy. :wink:

Dan Tibbets

Posted: Wed Sep 02, 2009 10:25 pm
by Professor Science
and 400 kilo's is a decades worth of polywell fuel. What's the energy cost for extracting boron out of the ocean? what's the concentration in sea water? when can i move to a self sufficient island city?

edit 1:cursory google search reveals answer to question 2, 4-5 PPM, haven't read the article yet, it's not loading, but the google blurb had that in it.

article

edit 2: this article also corroborates with the blurb, and i've succeeded in loading it. 4.5 mg/L boron in sea water, assuming it's ubiquitous in deep the middle of the Atlantic doesn't seem unreasonable. now according to "Safe, Green, Clean The p-B polywell report" by Flint, a 100 megawatt takes 1.3 mg of boron a second. so you only need to filter a third of a liter a second for continous power, criminy I'm still getting used to how these suckers just sip fuel.

article

Posted: Wed Sep 02, 2009 10:46 pm
by Stoney3K
KitemanSA wrote:
D Tibbets wrote: As far as water vapor's greenhouse effect I believe it is stronger than CO2 in both effect per molecule (?) and, by far, in quantity.
At least water vapor condenses eventually, and when it does if provides a great reflector for incoming solar energy. Does water vapor help or hurt. They can't even decide on the sign, so how good can their models be? Oh God, not anought AGW argument. Please, no, not that!!!! AAHAHAHAH!
I was thinking more along the lines of using water vapor as a crude terraforming agent on planets/moons that have water present, such as Europa and Mars.

On Earth, though, having plenty of it could mean we can bring rain to the deserts on the moments they need it, but that can also be done a lot more efficiently by just running pipelines (and creating artificial oasis).

Posted: Fri Sep 04, 2009 12:55 pm
by Professor Science
Continuing on with the adventures at sea polywell, I realize that boro-nitride compounds would be readily available, you're already skimming plenty of boron from the sea water and there's plenty of nitrogen in atmospheric gas.

You could potentially also produce ammonia since you've got all the hydrogen and wattage you could handle.

Elements a nautical polywell town will have to work with while trying to come up with a product: Cl, Na, Mg, S, Ca, K, Br, B, Sr, and Si

Also a polywell ocean village would make for a great marine biology/oceanography lab. I wonder if you could come up with good fertilizers in that mix, or if it's mostly an iron deficiency that's keeping ocean areas down.

Posted: Fri Sep 04, 2009 3:43 pm
by KitemanSA
Professor Science wrote:... or if it's mostly an iron deficiency that's keeping ocean areas down.
Hmmm. There's an idea. Iron matrix syntactic foam floats left to... well, float, around the tropical Pacific in order to boost algea production. Maybe we don't need polywell after all.... HA HA HA HA HA! I just slay myself sometimes. :D