The amount of C14 in organic molecules is extremely small to begin with. When using it for dating it can’t be used for artifacts older than 40,000 years because the C14 levels have dropped too low to be reliably detected. Although I am not a NE, I am fairly sure that the amount of C14 in 20 million year old coal is far below detectable levels. At any rate, it is millions of times less than the amount of C14 in our bodies and the food we eat.
This is an excellent question douglips.
And one which I am not qualified to answer. To do this, one has to be able to quantify a tremendous number of variables and effects in both the short and long term, many of which are not understood well. For example, how does one quantify the effect of the CO[sub]2[/sub] emissions of the coal plants, when there is not yet a good concensus on exactly what the effects of the global environment change would/will be? And at what rate it may be happening?
Also, there are other interesting factors that people do not have good data for, like my post in the other thread about the possible large number of coal trucking accidents that seem to be out there. If we on the SDMB could answer this question, we would be hailed as goddesses and gods, and flowered maidens would throw rose petals at our feet…hmmm…flowered maidens…Una sleep now…
Una, I don’t think that’s what Max is talking about. I’ve heard this canard before, and generally I’ve understood it to mean that the atmospheric emissions referred to are uranium and thorium, which according to you mostly end up in the ash products. This sounds like an urban legend, since you indicate they do not in fact go up the stacks and into our atmosphere.
As you and Dr. Lao correctly point out, [sup]14[/sup]C has decayed away by the time we dig up the coal.
There is very little C14 in coal. The C14 emissions from a coal plant ARE negligible, but still more than a nuclear plant. It has no bearing on the coal vs. nuclear debate; just a little “fun fact”.
Afterthought:
…but it DOES mean that any concern over radiation from a nearby nuclear plant is completely unfounded, and that nuclear power is exceptionally clean.
OK, a little back of the envelope hocus-pocus.
From More on Deaths due to Chernobyl
So, let’s say Chernobyl killed 24,000 people over the lifetime of the disaster (from boom until eternity.)
Let’s take a look at some coal outputs:
From CNN: Air pollution kills, but deaths can be prevented:
Kind of a sensationalist story, but mostly it deals with indoor air pollution (burn a lump of anthracite in your oven without adequate ventilation, and you might as well be smoking 6 packs a day.)
Sounds like 200,000 deaths per year are caused by outdoor air pollution, if we believe this story. So, if we knew what fraction of, say, particulates are caused by coal plants we’d have a comparison of coal power world wide vs. Chernobyl.
The EPA’s AIRSData web site has some great data if you are willing to dig a bit. For example, for particulates less than 10 micrometers in size in the state of Pennsylvania, it says that the number one (in terms of percentage of emissions) industry is “Electric Services” at 41 percent of emissions. Blast furnaces and steel mills come in at 12 percent of emissions. For particulates less than 2.5 micrometers, it is 33 and 15 percent for electric services and blast furnaces, respectively. That is, if I’m using the site correctly.
I’m guessing, but I’m sure Anthracite can correct me, that in Pennsylvania an “electric services” site that produces particulate emissions is on average a coal plant. This is in a fairly advanced society such as Pennsylvania. In China or India, I don’t imagine coal plants are less polluting than they are here in the US, but neither are diesel or two-stroke engines. So, a good hand-waving figure for percentage of particulate pollution caused by coal plants is (drumroll) 25%.
If so, then coal power plants kill 50,000 people a year just by particulate emissions, let alone acid rain, greenhouse, etc.
That’s totally a hand waving, talking out of my arse guesstimate at the toll of coal power. Even if it’s off by a factor of 10 (i.e. coal is responsible for only 2.5% of air pollution deaths) and coal only kills 5,000 by air pollution, it still compares to Chernobyl pretty quickly.
Frankly, I’m surprised that the numbers I came up with were this high. I was expecting a few hundred per year and I’d have to hand-wave about acid rain being bad as well. Sounds like particulates alone are pretty damning.
Of course, if nuclear waste gets dispersed in some kind of explosion, it could once again cause massive deaths, so it’s not like there are clear cut answers. I’m just surprised I’ve come up with so many deaths from coal.
Making some assumptions, like the total deaths from nuclear power accidents < 30,000, coal power killing 10,000 per year just in air pollution for the last 20 years totally blows away nuclear accidents. The question then, is deaths per gigawatt-hour- it doesn’t sound as good for coal as I would have thought at the beginning of this exercise.
Anyone else wanna take a stab at this? It’s kind of fun, but I need to sleep now.
Afterthought:
…when everything goes according to plan and no accidents happen, yes. Coal and other sources produce deaths by design (externalities of the designed-in emissions), while nuclear plants only produce deaths in accident scenarios.
That doesn’t make them the salvation of human kind, though. We still need to find a nice deep hole in which to bury that nuclear waste.
And I still think you were talking about thorium and not [sup]14[/sup]C in your previous post.
Oddly enuf, Doug- the figure i heard (I think it was from the American Lung Assoc.) was about 10,000 folks a year dying from coal-powered plants- and mainly the aged, sickly, and children. And that figure was just the USA (and maybe Canada)(and did not count the lives lost from mining coal).
tretiak- there is a HUGE shortage of Natural gas now-a-days out here in CA- driving the Big 2 power companies into near bankruptcy, and causing threatened black-outs. So- CNG is not the answer.
So, altho it seems odd= Nuclear is WAY safer than coal. Lives lost in USA thru Nuclear plants= about zero. Lives lost thru Coal plants- some half a million+.
However; hydro-electric is better than either.
Funnily enough, this is within my area of expertise. Comparisons between the external costs of different power generation cycles have been carried out. Generally, the results are reported in terms of money per kilowatt-hour.
These figures are arrived at as follows: For each environmental “burden” (such as SO[sub]2[/sub] emitted), you figure out the impacts (how many excess cases of childhood croup, reduction in crop yields, years of life lost to respiratory illnesses, etc.). Each impact is assigned a value in money terms, and the total is referred back to the amount of electricity produced.
One such study is called ExternE and examined generating plant in 15 European countries. The results can be found here. You have to register, but it’s quick and painless.
The nuclear cycle was investigated in 3 countries, Belgium, Germany and the Netherlands. Using a 3% discount rate, the results are:
Belgium (excluding accidents): 0.12 to 0.7 mEUR/kWh
Belgium (accidents): 0.0008 to 0.35 mEUR/kWh
Germany (excluding accidents): 0.6 to 3.3 mEUR/kWh
Germany (accidents): 0.0005 mEUR/kWh
Netherlands (excluding accidents): 7.28 mEUR/kWh (NOTE: @ 0% discount rate)
Netherlands (accidents): 0.058 mEUR/kWh
The results for the coal cycle in the same three countries (this makes comparison easier) were as follows:
Belgium (case A; no FGD or SCR): 109 to 240 mEUR/kWh
Belgium (case B; with FGD and SCR): 23 to 157 mEUR/kWh
Germany: 17 to 138 mEUR/kWh
Netherlands: 14 to 148 mEUR/kWh
So, for these three countries, and taking the high values in each case, the total external costs of the coal fuel cycle are 150 times, 42 times and 20 times greater than those of the nuclear fuel cycle.
You will also note that taking major accidents into account does not change the balance significantly.
If you have any questions about how these figures were arrived at, or what is or is not included, I’ll do my best to answer them.
Just so I am being most accurate - I want to modify what I said earlier. Earlier, in my table, I said “in ash”, which may imply that all of the thorium and uranium end up in ash. In reality, there a small percentage which is emitted from the stack. Also, coal mining inself releases very measureable quantities of radon to the atmosphere, and coal itself will release tiny amount of radon when burned. Radium is also found in coal as well. In fact, there are a very large number of trace metals and elements found in coal - one technical paper I have back at the office (I’m at home now) reports that in some quantity nearly every naturally occuring element can be found in coal.
I also did not mention earlier the other heavy metals in coal, which include antimony, arsenic, chromium, cadmium, selenium, strontium, vanadium, etc. Most of these are measured in the ash in levels of 0.001 to 0.1 ppm, which if you consider that the ash is often “roughly” (ugh, how I hate being rough in figures re: coal) 10% of the coal, you are talking parts per billion in many cases for these metals. Of course, if your plant burns 30 million tons per year, you reach a billion tons in 33.33 years…
More than parts per billion. Check this out (unfortunately I don’t know what coal they were using for the analysis:
Element Quantity (ppm)
Silicon 26,000
Aluminium 25,500
Sulphur 15,000
Iron 13,200
Nitrogen 12,000
Calcium 9,500
Magnesium 3,700
Chlorine 3,400
Potassium 2,300
Sodium 1,470
Phosphorus 1,000
Vanadium 145
Copper 130
Manganese 85
Zinc 60
Chromium 60
Lead 50
Cobalt 47
Nickel 25
Arsenic 10
Selenium 7
Cadmium 3
Antimony 2
Mercury 0.3
And this:
Worst case projection for emissions to atmosphere:
Metal t/Mt mg/Nm3 Metal t/Mt mg/Nm3
Fe 693 60 Co 10 0.87
Mg 195 17 Se 6.5 0.56
K 121 10 Ni 5.5 0.47
V 30 2.6 Mn 4.5 0.39
Cu 27 2.4 As 2 0.17
Zn 12 1.1 Cd 0.6 0.06
Mo 11 0.95 Sb 0.4 0.03
Pb 10 0.91 Hg 0.3 0.03
(Both these tables are adapted from an ecological impact assessment study carried out before the plant was built. I don’t have historic data.)
I’m with you thus far, but my first real question and one that has swirled around the EPA’s PM2.5 controversy is “How are they proving these deaths are due to air pollution?” This is the first thing that needs to be established IMO. Also, it was a little unclear how you got to 200,000 deaths due to pollution from the links above - perhaps I misread, or did you make an assumption of some sort I missed?
I agree with you - in fact, I can think of little else that would qualify.
**
Contrary to what public opinion believes, the US has the most strict requirements overall for coal plant emissions in the world. Stricter than Japan, Germany, and the EC. So you are correct.
Possibly. If you had figures for the total amount of particulates emitted per year in the US, you could look at my figures of particulates from the stack in GWhr per year, multiply by 2.5 (since the standard limit for particulate emissions is 0.1 lbm/MBtu, not the strict 0.02 lbm/MBtu of this “best case” plant I did, and most plants come to half that limit, or 0.05 lbm/MBtu), and then multiply by the total GWhr per year of coal generation in the US (posted in two other threads by myself) - that might get us much closer to an actual percentage.
Yes, I agree. I still really wonder tho about how these deaths are tied back to the particulates et al from coal plants, or any other source for that matter. Lead poisoning was a little different matter - such as when cars were all burning leaded fuel here, and this was the source of the vast majority of lead in our atmosphere.
Coal would look much better on a per GW*hr basis, but still bad using these assumptions.
hibernicus, I would say that is a reasonable looking coal analysis, but have come to a couple conclusions looking at it:
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It must be referring to ppm coal, not ppm coal ash.
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The calcium and sodium content make it look like a Southern Montana coal, but the sulfur is too high. The silica, alumina, sulfur, nitrogen, chlorine, sodium, and calcium content make it look like it is Abernant Stovesse from England, but the potassium and iron are too high. Interesting - it could be South African too, but the silica and alumina seem low. A puzzle.
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Your coal sample there does contain some high levels of trace metals, higher than I am used to seeing in US coals and Polish and Spanish coals certainly. I will post some representative samples from US coals in a bit, if we care. But you make your point with your sample there - it would be nice if you could tell which mine and country it is from. Just as a side point, and in now way accusing or hinting at all that you are doing anything improper, I can produce samples of coal from many US mines that are nearly unburnable due to their high sulfur, high chlorine, or high trace elements. Since coal quality will normally vary so tremendously from country to country, mine to mine, seam to seam, and even week to week, I think we will much more than the small sampling either you and I can provide here. Let me see if I can find some better composite values for US coals at least.
Correct
Switching to cheaper coals for power generation (IEA, 1999)
p.74
Contents of trace elements in fly ash from coals of different rank (in ppm) (after Swaine, 1995)
…US Bituminous…
Sb 3 - 35
As 21 - 360
Ba 200 - 2000
Be 9 - 31
B 171 - 1700
Cd <1 - 38
Cr 151 - 310
Co 4.5 - 88
Cu 70 - 189
Pb 51 - 948
Mn 160 - 600
Hg <0.02 - 0.24
Mo 43 - 100
Ni 97 - 568
P 300 - 1700
Se 7 - 24
Tl 11 - 42
Th 22 - 31
U <6 - 43
V 162 - 380
Zn 90 - 2100
The table contains data for Australian, US and UK bitunminous, and for German and US lignite.
So, if a power station releases 50 mg/Nm[sup]3[/sup] of total suspended material, this will contain 3 to 21 ug of uranium and 1.1 to 1.55 ug of thorium.
At 190 t of TSP per TWh, this amounts to 4.2 to 5.9 kg of thorium and 1.1 to 8.2 kg of uranium per TWh produced, assuming the precipitators don’t favour these materials.
Some good-looking ranges, hibernicus, and I like IEA’s info pretty much. If I make it out of my sickbed today and into work at all I will try to post some ranges I have if they are very different, but I think yours are likely pretty good anyhow.
A good point - I took the article I linked to as gospel for the sake of hand-waving calculations. The 200,000 I got from the statement that “of the 3 million annual deaths, 2.8 million are from indoor air pollution.” To me, this means that 200,000 are from outdoor air pollution.
We are still left with the question of how they know for sure that air pollution is causing these deaths.
Way cool. This is exactly what an economist would want to see, the exact monetary value of the externalities associated with power generation. It sounded like the costs you were quoting were just for externalities, and thus must be added to the cost of operating the plant itself - please clarify if I’m wrong.
Unfortunately, while it’s easier for me to compare costs and say “Coal is 42 times more expensive to the environment, lets build more nukes!”, most people I think are going to want more touchy-feely numbers like “Coal power kills 3,928 hamsters/gigawatt!”. Or something - that’s why I was doing my handwaving exercise.
Hibernicus, do you have any data about deaths/injuries specifically?
Ah. I was oddly unobservant for some reason. I understand now.
Believe me, I know the California situation as well or better then almost anyone on the board. However, almost all the new generation being built in California is combined cylce plants that use Natural Gas. My point was simply that the OP mentioned that coal was the only/main alternative to Hydro and nuclear. That simply is not true. While NG is expensive now, combined cycle NG palnts require less capital costs to build. And their operating costs are comparable to coal. NG is cleaner then coal in general, as well (although coal can be made quite clean at a high cost). The decision to build new generation, almost all of it NG is a pretty good indication that it is a very viable and probably better (for California) source of generation.
That last line should read:
The decision to build new generation, almost all of it NG is a pretty good indication that it is a very viable and probably better (for California) source of generation than coal.