Global warming

[Frank]

Just to elaborate. The mean free path for photons in the frequency bands where CO2 absorbs is around 25 meters at sea level. Double the concentration -> halve MFP.

You can model radiative heat transfer as photons diffusing through a medium. When you lower MFP you increase the time it takes a photon to reach space. That means the atmosphere buffers more photons/energy and thus warms.

It is also why the CO2 saturation argument is *completely bogus*

Cheers

Well, the point with absorbing/re-emitting is, that it will be emitted at a different wave length. So, it won't be re-absorbed by another CO2 molecule.

 

[Frank]

Questions? Why on Earth would I seek the input of somebody that is so completely and utterly disconnected from reality that he actually thinks that the Earth isn't warming?

Where did I ever claim that?

Yes, the Earth is warming. Check.

 

[Frank]

I enjoy the Mythbusters, I (like Sxotty said above) just find that often their obvious scientific oversights can be a cause for frustration. It's good that they do the science, but occasionally their controls are terrible or they miss an obvious error in their reasoning. (Their failing on the ice bullet because they couldn't come up with the idea to insulate the ice from the heat continues to annoy me, I actually did this when I was 14 with a .410 shotgun and a light load). This has led to them busting myths in error, just like Frank.

Well, I'm one of those guys that cringe at those stupid things as well. That's half the reason why I rarely watch Hollywood movies.

Then again, Myth busters is first and foremost in it to mace a spectacular tv show, the actual myth busting is an extra.

 

[Frank]

So that was so good question that you chose not to answer it? Interesting.
Fun anecdotal evidence:
the five hottest and coldest months of past ~100 years in Estonia have occurred during past 10 years.

In case you didn't know, "global warming" does not just mean universal warming everywhere but the extremes getting bigger.
I did but I didn't start with making up my mind and then "researching" the papers that would support it.
So basically you think it's too much of a hassle and expensive so we should ignore it?
Can you point out some of those lies? Obviously I expect them to be something that is generally accepted, not random ramblings of a single person.

As shown in the paper, most of the reason they're the warmest years are because the data is adjusted upwards. I expected that you got that, having read it and all.

And I have posted many posts in multiple treads on this board about those manipulations. Yes, even with back-up.

Really, it's not only difficult for you to believe me when I'm all by myself, it is equally difficult for myself. When you're the only one, you're a nut-job by definition.

 

[Frank]

Fine.
Fact: the earth is warming
Fact: CO2 absorbs infrared radiation and heats the atmosphere
Fact: Humans have emitted lots of CO2 since the industrial revolution
Fact: Modeling complex systems is hard

Theory: Humans have caused the bulk of warming through emissions of greenhouse gases into the atmosphere.
Theory: There are a lot that try to link the ppm to temperature. These models are not facts, they are based on certain evidence, but will not be perfect now, nor in the future.

Thanks, Sxotty. Very nice summary.

 

[Frank]

Meh, the line blurs between these things all the time. But to be a bit pedantic, copious amounts of evidence from many different directions support the statement that humans are causing the Earth to warm, primarily as a result of CO2 emissions. The evidence of this is, today, so strong that there is no longer any serious discussion about this. The scientific discussion is, instead, about just how bad the warming will get in the future. And that is a very difficult question to answer ahead of time, unfortunately. But no matter which way you slice it, the outlook is quite dire if we don't do anything.

Sounds rather religious to me, especially if you filter out the message given.

 

[Frank]

simple question to those who believe in AGW. Do you support nuclear power?

I do. But, like with everything, not "all out". Within bounds.

 

[Frank]

As for nuclear power: I would look at Thorium reactors (safe and sound) first, and Fusors (best potential, although not as they are) second.

Everything "natural", like solar and wind, requires a robust grid and a global energy exchange. But when you get there, transmission losses will be quite manageable, because you might buy energy from far away, but it will be an amalgam and the bulk will be delivered from some power plant nearby.

But that will fund those renewable sources around the world.

 

[KimB]

Chanloth you are incorrect about wind sorry. I have given you academic papers on the subject before, but you just ignore them b/c they don't comply with your worldview. We have wind droughts over large enough areas to be problematic. It obviously isnt free either, and if you get enough wind eventually you will start seeing significant weather effects due to slowing the boundary layer.

I have looked. They don't turn over the main point, that wind is a very viable energy generation scheme on large scales.

 

[KimB]

Sounds rather religious to me, especially if you filter out the message given.

Religious? Really? How is relying upon evidence in any way, shape, or form religious?

 

[Gubbi]

Incidentally, your earlier post regarding the reasons behind the closure of the MSR programme was incorrect.

The reactor lifetime was halved because of corrosion. That is a fact. As to why the research programme was discontinued, I don't know.

Hastalloy N piping resolved the corrosion problems of the molten salts and I don't believe I've ever heard anybody claim there were any other problems in the processing of the salts. Just a basic industrial process as I understand things.

While Hastalloy-N has great corrsion resistance to LiBe salts, you still have the problem of galvanic corrosion.

And nobody have ever encountered any problems with in-loop scrubbing of primary loop salt because nobody have ever done it. You can remove krypton and xenon easily, but the solid waste isotopes require more effort.

I'm not saying that it can't be done, I'm not saying that it shouldn't be done and I'm not saying that progress hasn't been made since the MSRE was shut down. But you seem to think MSR commercial viability is imminent when both the Chinese and Japanese efforts have a 20 year time scale for their research projects.

Cheers

 

[Sxotty]

Hurm. I can't even imagine how many turbines you'd have to erect for that to actually happen, seeing as the actual area covered by the turbine blades and the pylon they're mounted on is actually quite insignificant compared to the full diameter of the blades themselves.

Now, if each turbine had carried say, eight or ten blades or something like that, maybe that would have been a cause for concern if there had been tons of turbines put up everywhere, but as it is now I can't imagine it to have all that much impact really.

About 25% actually is what I heard for the US. So now you have a number. I don't think you understand the Betz limit if you are quoting things about the turbine blade coverage area.

 

[KimB]

About 25% actually is what I heard for the US. So now you have a number. I don't think you understand the Betz limit if you are quoting things about the turbine blade coverage area.

I really don't understand what you're going on about. The effect of wind turbines on the windspeed available to nearby turbines is just an optimization problem.

 

[Mintmaster]

I have looked. They don't turn over the main point, that wind is a very viable energy generation scheme on large scales.

If you did, then you wouldn't have made that statement. Wind varies a lot, and the variation is well correlated over geographically large areas. You even get daily and seasonal variation.

The intermittency of wind is a huge problem:
-You have to back it up with fast-ramping natural gas
-Ramping them up and down reduces their efficiency substantially, and increases emissions and wear
-That backup is therefore running at reduced capacity factor, increasing LCOE

Add all these up, and 1kWh of electricity produced by wind displaces far less than 1kWh of fossil fuel based production. You can even get increased emissions when trying to reduce output when wind power is plentiful, especially with coal:
http://docs.wind-watch.org/BENTEK-How-Less-Became-More.pdf
Looking at actual data from Texas (lots of wind generation there) this is what was found:

Not only does wind generation not allow ERCOT utilities to save SO2, NOX and CO2 emissions, it is directly responsible for creating more SO2 and NOX emissions and CO2 emission savings are minimal at best.

Wind will work when you can figure out a way to store energy well beyond what we can achieve with the hydro reservoirs we can find and use. Isentropic is promising company pursuing heat storage with 70% efficiency, so I hope that works out.

It obviously isnt free either, and if you get enough wind eventually you will start seeing significant weather effects due to slowing the boundary layer.

Wow, I didn't think the effects could be that significant. Anyway, what is your current position on wind? When I was being negative about it (due to intermittency) you were telling me that it makes a fair amount of sense due to the surplus natural gas capacity the US has. However, I'm sure that much of that surplus is lower efficiency peaker plants.

 

[Mariner]

The reactor lifetime was halved because of corrosion. That is a fact. As to why the research programme was discontinued, I don't know.

While Hastalloy-N has great corrsion resistance to LiBe salts, you still have the problem of galvanic corrosion.

And nobody have ever encountered any problems with in-loop scrubbing of primary loop salt because nobody have ever done it. You can remove krypton and xenon easily, but the solid waste isotopes require more effort.

I'm not saying that it can't be done, I'm not saying that it shouldn't be done and I'm not saying that progress hasn't been made since the MSRE was shut down. But you seem to think MSR commercial viability is imminent when both the Chinese and Japanese efforts have a 20 year time scale for their research projects.

Cheers

From reading through many of the various Thorium/MSR threads and some of the many academic articles available, it would seem that the corrosion issue is well understood and has been investigated but is still not considered a deal stopper. Usefully, it would seem that some of the proponents of fusion have carried out research looking at different fluoride salts as a means of heat transfer and I'm sure some of this would be use in the testing and development of MSRs.

Similarly the problems of the ongoing reprocessing has been thought about a great deal. I like the idea proposed in the following article:

http://energyfromthorium.com/2006/0...lopment-of-a-reprocessing-system-for-an-lftr/

A 'dry run', so to speak.

I realise that Thorium MSR designs are not finalised and ready for immediate implementation but the bulk of the leg-work was carried out 40 years ago and the concept is good so I'm just disappointed that no government other than the Chinese is actively funding a research programme into the technology. At least there are finally some research projects taking place around the world (albeit most of them with limited funding) following years of inertia. As Flibe Energy is attempting to work with the US military to create small, modular reactors, I'm hopeful that they will have active test reactors quite some time before the Chinese have finished their civilian power project. Such proof of concept devices ought to show the enormous benefits of the LFTR fuel cycle and prompt faster development of larger civilian reactors.

I just can't help but wonder where we might be now if just a fraction of the vast sums of money wasted on sodium cooled fast reactors had been spent on developing MSRs over the past few decades. Or some of the vast subsidies being handed out to renewables had gone the way of MSR research, for that matter.

Fundamentally, in addition to the issues of Global warming, I'm also thinking how we are going to support the enormous and ever-increasing population of the planet. Energy will be of vital importance and the current fad for wind and solar power just isn't going to be able to support the vast populations of the future.

For now, I'd be building Gen III+ reactors (as the Chinese are) to keep things ticking over and reduce the reliance on fossil fuels but the political classes aren't interested in this now. The MSR programme was cancelled for political reasons and now nuclear power is being ignored for a different set of political reasons, none of which makes much sense. None of the politicians can explain how renewables are going to supply all our power yet all are rushing headlong towards this aim because they want to show each other who has the best 'green' credentials.

Yep, pretty much most politicians are a waste of space!

 

[Sxotty]

Wow, I didn't think the effects could be that significant. Anyway, what is your current position on wind? When I was being negative about it (due to intermittency) you were telling me that it makes a fair amount of sense due to the surplus natural gas capacity the US has. However, I'm sure that much of that surplus is lower efficiency peaker plants.

I am in favor of wind, but it is unrealistic to think we can build as much as we want with no consequences. What I am saying is we can get 25% which is very high. It will give us other headaches first. We can integrate more than we have now though.

 

[KimB]

If you did, then you wouldn't have made that statement. Wind varies a lot, and the variation is well correlated over geographically large areas. You even get daily and seasonal variation.

Define large. Because from what I've read, once you go beyond a few hundred miles, the correlation drops off dramatically.

The intermittency of wind is a huge problem:
-You have to back it up with fast-ramping natural gas
-Ramping them up and down reduces their efficiency substantially, and increases emissions and wear
-That backup is therefore running at reduced capacity factor, increasing LCOE

Not at all. There is no good reason whatsoever to use power plants to cover the variation of wind power generation within a single day. Energy storage is the only viable solution there. And the variation between days tends to be very slow, much slower than the occasional shutdowns of more traditional power plants. Both solar and wind have large intra-day variations, and as a result need power storage schemes to compensate. Attempting to use fast-changing fossil fuel generation instead is just plain stupid.

http://docs.wind-watch.org/BENTEK-How-Less-Became-More.pdf
Looking at actual data from Texas (lots of wind generation there) this is what was found:

I don't see why you'd be linking to what looks like a natural gas company front to support your arguments.

 

[Sonic]

Mintmaster, what's so bad about solar? Obviously the further towards the polls the worse it gets during the winter seasons, which sucks. But it would be just fine during spring, beginning of fall, and especially summer. Is it the costs, is it the dismal amount of energy produced? The tech keeps getting better, and really all i sneeded is breakthrough in energy storage and we should be set.

 

[Sxotty]

Solar is about 1 order of magnitude more expensive than wind which is bad.

 

[epicstruggle]

Mintmaster, what's so bad about solar? Obviously the further towards the polls the worse it gets during the winter seasons, which sucks. But it would be just fine during spring, beginning of fall, and especially summer. Is it the costs, is it the dismal amount of energy produced? The tech keeps getting better, and really all i sneeded is breakthrough in energy storage and we should be set.

Solar is about 1 order of magnitude more expensive than wind which is bad.

There is nothing bad about wind or solar, but neither are ready to be prime energy generating sources for the world. If you want clean energy, nuclear is the way to go. In a few years, that might change. However it is not today.