Monday, November 24, 2008
The page can be found here.
Saturday, November 15, 2008
In ordinary conversations about renewable energy, the issue of energy storage is often overlooked. Renewable sources generate energy on their own schedules, not customers' schedules. The difference must be met either by backup energy supplies or by energy storage. This article describes some storage calculations in the absence of fossil-fired or nuclear sources. The calculations can be downloaded from here.
This is a plot of electricity generation for the US. This writer doesn't have data for any other countries and wouldn't presume to offer advice if he did.
For the rest of this analysis, the average generation for the years 2003-2007 will constitute the model year.
First, compare the demand curve with the availability of wind energy. Wind energy is approximately proportional to the cube of wind speed. Density is also a factor, and there is considerable mismatch at very high and very low wind speeds, but those differences won't change the conclusions. This analysis is based on wind-speed cubed.
The data show wind speeds for 265 cities. We have deleted cities with low winds or high differences between high-wind and low-wind months. We also have deleted Alaska cities, owing to their unique characteristics and their separation from the US power grid. 244 cities are left.[NOAA]
Clearly, wind energy doesn't match electricity demand well. Next, compare electricity generation with solar potential. Cities with poor solar characteristics were deleted from the data, leaving 221 out of 238.[NREL]
So we see that solar energy matches the electricity demand somewhat better. For our first cut we shall calculate the maximum amount of solar energy that can be generated and used within a month, and we find that 80.6% of the yearly demand can be met with solar energy on these terms. Now we can consider the remaining demand after all that solar energy is accounted for.
Now we can compare the remaining demand with available wind energy.
The calculations show that 200 billion KWH of storage is required.
We can do the same calculations for other shares of supply from solar energy, with the results shown here:
Our calculations show that the storage requirement ranges from 141 to 386 billion KWH.
There is no way to store that amount of energy. In fact, we'll have to devise a fictional example to illustrate the problem.
Imagine that a lake exists, named Upper Lake Fead, which is equal in size to Lake Mead. Lower Lake Fead is the same size and is located at the bottom of Foover Dam, which is identical to Hoover Dam. However, all the water in Upper Lake Fead can drain through the water turbines.Lake Volume = 30,000,000 acre-feet
Average head at dam = 520 feet
If the efficiency were 100%, then
Energy = volume x pressure = volume x head x weight-density
= 30,000,000 acre-feet x 43560 sq-ft/acre x 520 feet x 62.4 lb/cu-ft
= 4.24 x 10^16 ft-lb
= 16 billion KWH
We'll set the turbine efficiency at 85% and account for pump inefficiency by upsizing where necessary. Thus, Upper Lake Fead is good for 13.6 billion KWH.
So we have calculated that the US would need between 10 and 28 Foover Dams, each with Upper and Lower Lake Feads, depending on how much electricity is generated with solar energy. There are, in fact, no Foover Dams and no locations for building any.
Thursday, October 30, 2008
For example, the International Energy Agency and the Organisation for Economic Co-operation and Development's Nuclear Energy Agency determined the costs as follows:
Cost per MWH in US Dollars
The University of Chicago compared several detailed calculations with a range of discount rates and summarized the results thus:
Cost per MWH in US Dollars
|Nuclear (assuming old designs)||65-77|
|Nuclear (assuming new designs)||36-55|
|Nuclear (assuming advanced-fuel designs)||57-64|
A question that immediately presents itself is, why do the two studies give different numbers? The answer is that every study depends on assumptions, such as interest rates and fuel costs. Both these factors, and other factors such as taxes, pollution controls, and equipment lifetimes vary in time and place. This introduces an opportunity to do mischief, since a motivated commentator can pick-and-choose results to bolster his intended conclusion. These numbers only have significance if they're calculated on equal terms and only if they're read relatively, not absolutely.
A common argument being made now is that nuclear construction costs have risen so fast they have rendered nuclear plants too expensive to build. This argument is anchored on a report about some calculations made by Cambridge Energy Research Associates (CERA) that allegedly show a cost increase of 185% between 2000 and 2007. Imagine, an almost tripling of costs in seven years! However, CERA doesn't publish the results in a public forum; nor does it show the calculations so they can be verified. Indeed, there's no way even to know what methods it used.
It is true, though, that costs have risen strongly since China and India began their notable advances in material progress. These cost rises apply to all kinds of construction and, in particular, apply to alternative energy sources.
Here is some information on the cost of windpower construction, which has doubled:
And some data (Oct. 28, 2008) on solar-electric construction. It has essentially held constant, but at US$4700 per KW rated power or over US$20,000 per average KW, it still is hopelessly expensive. What this shows is that the pressure on material prices has kept solar energy from getting cheaper.
Finally, here is some information from Power Engineering International on nuclear construction costs, which shows a cost increase of 125%, not much different from the increase for windpower.
What all these numbers show is what energy analysts have been telling us right along. Nuclear energy is as cost-effective as any non-fossil energy source, even ignoring the intermittency problem of part-time energy sources. But if intermittency is considered, then the comparison widens. There aren't any practical ways to overcome intermittency, as shown here. But if there were some way, the economic and environmental costs would drive the total cost out of sight.
As the world grapples with this issue, one other point has to be considered. A new generation of nuclear power plants is being born. These new plants use passive safety systems so the active systems can be simpler, thereby reducing costs. Furthermore, they operate at higher efficiencies, lowering fuel costs. As shown in the University of Chicago data, these improvements make nuclear energy cheaper than any alternative other than coal.
Wednesday, October 29, 2008
The point that needs to be understood is that proven reserves are only a fraction of the resources that really exist. For example, the world has less than a three-years' supply of oil if only proven reserves are considered. No one really believes the world will run out of oil in three years. In comparison, projected resources show over 600 years' supply of oil, maybe a thousand years' supply of coal, and 30,000 years' supply of nuclear fuel. Even if all the world's electricity comes from nuclear energy and the rate of electricity use triples, nuclear fuel will last over a thousand years. Renewable energy and energy efficiency can stretch the supply longer. A thousand years should be enough time to develop other solutions, such as fusion energy and energy storage.
The best available information from the most authoritative sources can be found here.
Saturday, July 19, 2008
What to do, what to do.
I would give money to my allies. All the groups that support renewable energy also support me. It's a simple fact of nature that renewable energy sources generate little or no power for hours or even days at a time and what they do generate is unpredictable. Furthermore, there's no way to save enough energy to hold people over from one power episode to the next. Anyone who does arithmetic can see that for himself. Some examples of the arithmetic can be seen here. That means backup energy supplies always have to be standing by when renewable energy sources are in operation.
In the short run, renewables will displace a few percent of my coal sales. But the economics of renewables make them unacceptable. That's because the backup energy sources required cost almost as much to hold in readiness as they do to operate. The result is that energy consumers pay for the same energy twice: once for the renewable energy and again for the backup. When people catch on to that their support for renewable energy will vanish.
There's also a second benefit. The political groups that pose as defenders of the environment ought to be pursuing me as Public Enemy Number 1. Even in the US, thousands of people die every month from coal pollution, as shown here. Worldwide, the deaths run into the hundreds of thousands every year, to say nothing of debilitating diseases, heavy-metal poisoning, and ocean pollution. But if I fund the political groups then they'll never make more than token objections. What they will do is attack my only competition with hammer and tongs. All the groups like Greenpeace and Friends of the Earth will fall over themselves making up lurid and fantastic warnings against nuclear energy. All because of their infatuation with renewable energy.
That's enough, but for a few dollars more I can hire "consultants" who pretend to be scientists. They'll write articles and publish them in popular magazines that don't believe in peer review. They'll probably get away with it because most editors can't tell science from cotton candy. And in the remote chance some of these fake scientists are unmasked, most people won't hear about it anyway because journalists hate to admit they were wrong.
Yeah, that's the ticket!
Sunday, July 6, 2008
The same surprise came from the Rasmussen poll for July 2, 2008. 52% disagreed with Senator Harry Reid's observation that "Coal makes us sick."
Health experts have been telling us for decades that coal pollution isn't just making us sick, it's killing us. The most authoritative study done, the Abt report, confirms what studies have been showing for decades, that thousands of Americans die every month because of burning coal to generate electricity.
How is it possible that something this important is unknown to most Americans? Clearly, the news media haven't been doing their job. Commentators have complained for as long as I can remember that the news media only cover novel and photogenic stories.
Let's take the accident at Three Mile Island. It received saturation coverage. Ever since, it's been known as The Worst Nuclear Accident in American History. Any time nuclear energy is mentioned in the news, the public is reminded of this stellar fact. What the news stories never mention is that no harm came to anyone because of the accident. See the Kemeny Report for details. Well, the owners of the plant lost big time, but that's not what we're talking about here.
As one would expect, misinformation flowed in to fill the information vacuum. Irresponsible political groups like Greenpeace and Friends of the Earth and their many imitators have fed the appetites of news media for lurid and frightening what-if scenarios. The fact that these scenarios are based on fantasy and not on reality doesn't bother media reporters in the slightest. The misinformation gets stories published and that's all that matters.
Why don't the political groups campaign against coal, since it truly is dangerous? That's more complicated. Greater coal consumption is the inevitable consequence of less nuclear energy. If they publicized the facts about coal, they'd have to admit they were wrong about nuclear energy. We can, however, note with new-found respect that the Sierra Club is intervening to stop the construction of new coal-fired plants. It will be interesting to observe whether or not the Sierra Club breaks ranks with less-credible political groups. Will the Sierra Club ever show the moral courage of environmental heavyweights like James Lovelock and Hugh Montefiore and reverse its position on nuclear energy?
In the meantime, what can be done to overcome the information deficit? The Nuclear Energy Institute does a valiant job of informing the public where it can, even sending spokespersons to public meetings. Anything NEI says, though, will naturally be discounted since its job is to promote a particular viewpoint. One might wonder if spending its budget on a race car really is effective at promoting nuclear energy, but the alternative would be sending out video documentaries no one would watch. One has to hope NEI knows what it's doing.
For the rest of us, the best we can do is inform ourselves as well as possible so we can offer good information whenever the subject comes up around us. This blog is an effort in that direction, as are the blogs recommended in the sidebar. Since the other side is working hard at spreading confusion and misinformation, we just have to hope readers can tell the difference. If people knew the truth about coal, the support for nuclear energy would be much higher than 67%.
Saturday, June 28, 2008
A visitor generously suggested ways to improve the accuracy of this article and its present version was written after receiving his comments.
For as long as I can remember, anti-nukes have been claiming that the Price-Anderson Act protects nuclear power plants from liability. The plants are so dangerous, they claim, utilities won't accept responsibility for them.
The facts are very much different. A copy of the law can be found here.
I should say at the outset that I am not an attorney and therefore am not qualified to interpret law or court decisions. That said, when anti-nukes claim that the law protects utilities from liability, they conveniently leave out the fact that the liability limits only apply to federal courts, not to state courts. But don't take my word for it. Here is an excerpt from the US Supreme Court decision in the case of SILKWOOD v. KERR-McGEE CORP., decided January 11, 1984. [source]
"In sum, it is clear that in enacting and amending the Price-Anderson Act, Congress assumed that state-law remedies, in whatever form they might take, were available to those injured by nuclear incidents. This was so even though it was well aware of the NRC’s exclusive authority to regulate safety matters. No doubt there is tension between the conclusion that safety regulation is the exclusive concern of the federal law and the conclusion that a State may nevertheless award damages based on its own law of liability. But as we understand what was done over the years in the legislation concerning nuclear energy, Congress intended to stand by both concepts and to tolerate whatever tension there was between them. We can do no less. It may be that the award of damages based on the state law of negligence or strict liability is regulatory in the sense that a nuclear plant will be threatened with damages liability if it does not conform to state standards, but that regulatory consequence was something that Congress was quite willing to accept."
On the other hand, even this decision accepts the popular view that the original purpose of Price-Anderson was to encourage companies to enter a new field. Since the field is no longer new, one could ask why the law continues to exist. I think the answer lies in the other benefits. One benefit is that it clarifies the US Government’s responsibilities. Every aspect of nuclear energy, including design, construction, and operation, is supervised by the Federal Government. In the case of an accident, and in the absence of legislation, the Government very likely would find itself in the position of defendant. The act clarifies this point: the Government would only be on the hook after all other coverages, from commercial insurance and owners’ assets, have been paid out. A second benefit is that victims of an accident could recover their damages without suing. Under liability law, they would have to determine who was at fault and prove it in court. The process would take years and, even if they won, they’d lose because lawyers would take most of the money. Under Price-Anderson, they’d only have to show they had taken losses and they’d be compensated.
As it is, Price-Anderson is a requirement for anyone doing nuclear work. It doesn’t limit victims’ ability to recover damages. What it does is to guarantee that money will be there to pay them.
Saturday, June 14, 2008
Mr. Gore says (to Mr. Hastert):
You mentioned nuclear. I am sure that will come up again. I
am not an absolutist in being opposed to nuclear. I think it is
likely to play some role. I don't think it is going to play a
major role. But I think it will play some additional role, and
I think the reason it is going to be limited is mainly the
costs. They are so expensive, and they take so long to build,
and at present, they only come in one size: extra large. And
people don't want to make that kind of investment on an
uncertain market for energy demand.
Heck, Al, renewables cost more to build than nuclear plants. Look at this. If we're going to replace all the fossil-fired plants in the US, do you really think size is going to be a problem?
(To Mr. Inglis)
I think that decentralization is the wave of the future.
And also on liquid fuels for road transport, by the way, and
the next generation ethanol the enzymatic hydrolysis stuff that
is coming on line. But on your core choice, I am not opposed to
nuclear. I have deep questions about it. I am concerned about
it. I used to be enthusiastic about it. Back when I represented
Congressman Gordon's district, TVA had 21 nuclear power plants
under construction. And then later, I had represented Oak Ridge
where we were immune to the effects of nuclear radiation so I
was very enthusiastic about it.
But 19 of those 21 plants were canceled. And I am sure Bart
gets the same questions I used to get about whether those
partly finished cooling towers might be used for a grain silo.
But people are upset still that they have to pay for them and
not be able to get any electricity for them.
And I think the stoppage of the nuclear industry was really
less due to 3-mile island and Chernobyl and environmental
concerns and more due to the fact that after the OPEC oil
crisis of 1973 and 1979, the projection for electricity demand
went from 7 percent annualized compounded down to 1 percent.
You're right on that one, Al. Growth of just about everything died when Jimmy Carter was president. Then natural gas drove out all its competition. Clean and cheap; what else could anyone want?
(To Mr. Upton)
I don't recognize the quote that you used as one
of mine. I am not saying it wasn't, but I don't really agree
with the way that was phrased.
[Quote from Nuclear Energy Information Resource Center: "I do not
support any increased reliance on nuclear energy; moreover, I
have disagreed with those who have classified nuclear energy as
clean or renewable."]
Yeah, you can't trust anything anti-nukes say.
I am not a reflexive opponent of nuclear power,
Congressman. I am just a skeptic about nuclear power's
viability in the marketplace. I think that if we let the market
allow the most competitive forms to surface, what we will see
is decentralized generation, widely distributed, we will see an
emphasis on conservation and efficiency and renewable energy.
But where nuclear power is concerned I have expressed my views,
previously, I am not a reflexive opponent, I think there will
be some new nuclear power plants.
But you mention China. Look at their 5-year plan right now.
You are right, they plan 55 new coal fired power plants per
year. Only three nuclear plants per year. Now why? They don't
have any opposition that they can't overcome pretty easily from
Beijing. But they see the same problems just in practical terms
that a lot of our utilities see. These things are expensive and
complicated. They take a long time and the fragility of the
operating regime has already been seen. I have been to
Chernobyl. I have been to Three Mile Island and I don't want to
exaggerate those problems.
I think that we can come up with solutions for the dangers
of operator error. I think we can come up with solutions for
long term storage of waste. I don't think Yucca Mountain is it.
And I think if you don't skate past the real scientific
evidence of what they found at Yucca Mountain. What they found
on the geology there makes it simply wrong to put stuff that is
going to need to be contained for tens of thousands of years in
a place that is really not appropriate for it. Now that is my
reading of what the geological survey has said about that. But
I am not opposed to it as a category.
I don't think any of this is wrong, Al. But nobody has suggested an easier way to stave off global warming. Maybe we could ride bicycles and starve like the Chinese did fifty years ago, but I'm guessing that's not going to catch on. If we leave it up to the market to decide we'll just keep on using coal because nothing is cheaper; not nuclear or renewable energy and not even conservation. So to beat global warming we have to start building renewable energy sources and nuclear plants because that's the only way we can grow our construction capacity. The other choice is sitting on our hands and watching the habitat melt away. What do you think?
Sunday, June 1, 2008
Cap and Trade
Its most important feature is cap-and-trade covering utilities, industries, and motor fuels. It's aggressive enough, with ambitious goals, but it has so many escape clauses and offramps that its value has to be deeply discounted. Moreover, the emission rights will be auctioned off to support favorite causes, so it is actually a tax. Many analysts believe taxing carbon emissions is the only way to reduce them. Maybe they're right, but if it's a tax it won't fly. That's a given in US politics. People want the services and benefits that come from government largesse, but they won't vote for any politician who makes them pay taxes.
That pretty well makes the rest of the subject moot, but we'll proceed anyway because some other points have to be part of future discussions.
Another major feature is an emphasis on CO2 sequestration. It seems that CO2 producers will get credit for pumping CO2 into the ground. The bill contains provisions for determining the capacity of storage locations, but not for evaluating whether or not the CO2 will stay in place.
To date, no sequestration site in the world has been tested for leakage. Furthermore, no one knows how to conduct such a test.
On the subject of sequestration, Senator Jeff Bingaman makes this remark: "Currently there are no formal site selection criteria for carbon dioxide injection wells that will be used for carbon storage." He goes on to explain that the EPA has no clue how to set the criteria. That reflects the impossibility of sequestering CO2 with any confidence.
Under the terms of this bill, utilities can pump CO2 into the ground and act as though it never was generated, without any assurance it won't leak into the atmosphere some decades later. If it does leak, utilities will have paid large amounts for this program, all for no purpose.
The US Energy Information Administration did a
study to compare the effects of the bill, under various scenarios. What the study showed is especially instructive.
The results seem obvious, but prove that nuclear opponents are wrong. Even under the most optimistic conditions, renewables won't provide the energy the country needs. The simple fact is that if nuclear energy isn't developed to its full potential, then the US will depend more on natural gas, a substance in great demand and short supply, and coal. Moreover, some of the coal combustion would have to be subject to carbon sequestration, an untested and dubious concept.
One hesitates to criticize. The world faces an enormous challenge and it's only natural that practical people would turn to easy-sounding solutions such as carbon taxes and sequestration. Sadly, those won't succeed; one is political poison and the other is imaginary.
Instead, we have to commit ourselves to the hard work of reshaping our energy usage. Instead of auctioning off pollution rights, we have to outright ban the installation of fossil-fueled generating plants, either new or replacement capacity. New electricity demand must be met by a combination of renewable and nuclear sources, and offset by efficiency and the curtailment of low-return energy use. Vehicle efficiency has to be raised much more than the feeble changes Congress has mandated. Bureaucratic obstacles to synthetic fuels like Green Freedom should be cleared and, if it's necessary, subsidies that currently go to fossil-fuel producers should be directed toward offsetting the cost difference between petroleum fuel and synthetic fuel.
That's what it will take to beat this problem.
Monday, May 19, 2008
The hard part of the problem is motor fuels. We don't have a good substitute in place. Biofuels won't ever supply a major part of our motor fuels, for reasons we've discussed before. But take heart. Two chemists at Los Alamos National Laboratory have devised a process using current technology that could replace petroleum as as source. F. Jeffrey Martin and William L. Kubic have published Green Freedom: A Concept for Producing Carbon-Neutral Synthetic Fuels and Chemicals (Patent Pending).
A Simple Description
As you can imagine, turning atmospheric CO2 into gasoline takes a huge amount of energy. In this process, the energy inputs are in the form of heat and electricity. Lots of both.
The electricity could come from a number of sources, but the process is most effective if the electricity supply is steady, which effectively limits it to nuclear. That's just as well, though, because the CO2 capture requires spraying a potassium-carbonate solution into an air stream. That requires something very much like a wet cooling tower, so the wet cooling tower for the nuclear plant can do double duty as a CO2 collector.
Once the CO2 is collected, it can be extracted from the solution by an electrolytic process, originated by Martin and Kubic. They claim that this is their chief innovation and that all the other features of the process are standard to the chemical industry. The electrolytic process is more energy-efficient than other means of separating the CO2, and generates hydrogen at the same time, reducing the amount of hydrogen that has to be generated elsewhere.
In their baseline design, Martin and Kubic propose to use water electrolysis for generating the additional hydrogen needed. They chose this because nuclear plants in the US are all capable of providing the electricity needed. As they point out, more-recent technology can improve efficiencies substantially. Steam electrolysis consumes less energy and advanced nuclear reactors can generate hydrogen thermochemically; this last technique can be essentially 100% efficient, since the leftover heat can generate electricity.
Once the hydrogen is generated, commercially-tested processes can be used for converting CO2 and hydrogen into methanol, and for converting methanol into gasoline. Alternatively, hydrogen, CO2, and steam can be combined over catalysts in the Fisher-Tropsch process to produce any kind of hydrocarbon compound, including diesel oil and aviation fuel.
As the authors take pains to make clear, the process depends only on equipment in commercial use today. There are no technological barriers to implementing it. There is a cost consideration, however. Their calculations show that the gasoline could be sold at the pump for $4.60 per gallon. Since we're dealing here with known technology they probably are not understating it by much, taking into account that projects of all kinds end up costing more than the planners expected.
But there are ample reasons for believing the actual costs would be lower. As they explain, newer technology will improve efficiencies considerably. Moreover, their analysis assumes their nuclear plant, which comprises the main capital cost, would be dedicated to producing hydrocarbon fuel. In practice, the nuclear plant will sell electricity during times of peak demand, especially when renewable energy is in short supply. This will become more apparent when fossil-fired power plants are phased out and all electricity depends on renewable and nuclear sources. We can look forward to an economy in which nuclear plants produce all our hydrocarbon fuels during off-peak hours. This sharing of costs will greatly reduce the cost of producing liquid fuels.
What we can say for sure is that it will take a massive energy investment to free the world from dependence on petrofuels. Straight hydrogen doesn't look promising because of the difficulty of onboard storage and because the inevitable leaks will threaten the ozone layer. Batteries for powering freight-hauling trucks don't seem like a reasonable hope, given the paltry improvements batteries have seen in the last few decades. Biofuels won't do the job, as discussed earlier. Since this process is already practical, it's not much of a stretch to predict that something very similar will be our fuel source in the future.
Saturday, April 26, 2008
But then the climate gremlins struck. Skeptics believed themselves fully vindicated when temperature data showed the global-average temperature to have declined during the last five years, with a very sharp drop in the last year. Here are two plots that show the striking effect.
Since we are determined to follow the science where it goes, not where we want it to go, this startling development demanded a cold-blooded analysis, not defensive handwaving.
The puzzle gains difficulty when we look at the data for the northern and southern hemispheres separately, as shown here. The northern hemisphere is continuing to warm up while the southern hemisphere has cooled a surprising amount. Before we can proceed, we have to understand why the two hemispheres would be so dissimilar. In particular, the skeptics can't claim to be right unless they can explain why the northern hemisphere is warming.
As we look at the data for the two, we see that they agree only in broad strokes. When we look at them in detail, we see that there are notable differences. For example, the southern hemisphere was warming in the 1960s while the northern hemisphere was cooling.
That doesn't help us much to understand what's going on, though. What does help us is the explanation of la Niña events, as given here together with some surface-temperature data, given here. The data show the effects of la Niña events, in which stronger winds over the South Pacific cause ocean water to turn over, bringing cold water to the surface. That explains the cooler average surface temperature over the southern hemisphere. The average temperature seems to be headed down; what actually is happening is that the last el Niño event (a period of relative calm over the South Pacific) was fairly strong and the current la Niña event is especially strong, putting a kink in the curve. It is not the case that the world is cooling off; rather, warm water is being driven down to lower depths and colder water is being raised to the surface.
So that's where we stand. La Niña events explain why the southern hemisphere is showing a cooler average surface temperature. Only global warming due to greenhouse gases explains why the northern hemisphere is warming.
It seems reasonable that global warming could be causing the stronger and more-frequent la Niña events, but that's a question for experts.
Monday, April 21, 2008
According to the dust jacket, Dr. Spencer holds a PhD in Meteorology and is a Principal Research Scientist in Climate Science at the University of Alabama. His expressed skepticism about human-caused climate change would, therefore, seem to be the clearest possible vindication of the skeptics' view on that topic.
Since Dr. Spencer is a professional scientist writing about his own specialty, one would expect any book he writes to be jammed with scientific information about this complex subject. But one would be disappointed. In fact, his scientific coverage extends over two pages, from page 80 to 82. In this short passage, he sums up the knowledge about climate change thus:
"First, we know that mankind is producing carbon dioxide as a result of our use of a wide variety of fuels, from coal and petroleum to natural gas and wood."
"A second observation we are certain of is that the carbon dioxide content of the global atmosphere has been slowly increasing. We are now about 40 percent of the way to a doubling of the pre-industrial concentrations of atmospheric carbon dioxide."
"Thirdly, we know that carbon dioxide is a greenhouse gas, which means that it traps infrared radiation and so tries to warm the lower troposphere to a higher temperature than if the gas was not there."
"Finally, we are pretty sure that the globally averaged surface temperature of the Earth is at least 1° Fahrenheit warmer now than it was about a century ago."
This is as clear a proof of climate change as could be imagined. Yet, Dr. Spencer demurs from stating the natural and obvious conclusion. Why, you may wonder. He says that he's withholding his conclusion because temperature rise and CO2 concentration rise might occur together only by coincidence. That is, global warming might be due to natural variability.
Natural variability is outside our experience with thermodynamic systems. We know why car engines warm up; it's because of fuel being burned. We know why houses warm up; it's either because the sun is beating on them or because of their furnaces. Our bodies warm up because we're exercising muscles or because the temperature control mechanisms are impaired by illness. But Dr. Spencer thinks it is realistically possible that Earth could just naturally change temperature without any cause. And that possibility prevents him from accepting the prevailing scientific view.
After seeing the subtitle of the book, though, one might wonder if that really is the reason. The other 180 pages could have been transcripted straight from hate-talk shows on AM radio. Environmentalists put the needs of wildlife above those of humans. Governments and philanthropic foundations reward and punish scientists according to their positions on climate change. Europeans prospered 1000 years ago because of unusually-warm conditions. People overreact when cities are wiped out by hurricanes. Scientists don't know as much as they think they do. Global warming is a religion. Politicians are using it as a trick for taking money away from working people. Scientists are milking it like a cow. Reducing emissions will harm the economy. The Precautionary Principle is wrong. Global warming is good for poor people. Left wingers killed millions of people by banning DDT. The United Nations works to make everybody poor.
Why is all this right-wing propaganda in a book written by a scientist? Since it takes up the largest part of the book by far, we can in all fairness ask if Dr. Spencer's skepticism is really due to scientific rigor or if his political views have overcome his objectivity.
Sunday, March 16, 2008
It probably could only have been written by Mr. Pearce. He's been following the global-warming story as a journalist since about 1990 and because of that he was able to interview many of the principal researchers in the ongoing struggle to understand the process.
He presents four topics of interest. First, he explains the mechanics of climate change. If you're a little fuzzy on the ocean conveyor or methane clathrates he'll bring you up to speed. Second, he lays out the limits of knowledge. The parameters cover large ranges and he keeps clear the distinction between what is known and what isn't. Third, he covers the slipperiest part of the whole topic: tipping points; how they work and what happens when we reach them. He also discusses what the consequences of climate change are likely to be, bearing in mind the limits of certainty. We're going to say a little here about tipping points, based on the author's remarks.
Skeptics dismiss the concept of tipping points. You can't prove them, they say. Actually, you can prove some of them but it's not clear what will activate them. Some others aren't understood to the point they can be considered certain. It goes the other way too, though. There's no justification for traveling up the Keeling curve with insouciance. Before we jump into a pot of hot tar, common sense tells us we ought to find out how hot the tar is.
I'll go through the main tipping points the author describes.
* Shrinking ice caps. This one is maybe the most basic. As the ice caps shrink the world is absorbing more energy from the sun. Furthermore, the water released lubricates the glaciers' movements, causing the process to accelerate.
* Clearing of rain forests lowers the amount of rainfall downwind from them, whether it's done on purpose or by natural fires that result from drying out. As the vegetation burns and exposes the soil to sunlight, large amounts of CO2 are released.
* As frozen bogs thaw in the extreme north, rotting tundra releases methane, a terribly effective greenhouse gas.
* CO2 dissolved in the oceans is removed by marine organisms that use it to build structural body parts. If the CO2 level rises too high, ocean water becomes too acidic for the organisms to live and this CO2-removal mechanism disappears.
* Clathrates are layers of methane lying in deep ocean trenches where the pressure and temperature are extreme enough to keep them frozen. If ocean temperatures rise enough to thaw some of the methane then inevitably it will enter the atmosphere. But it could be worse: there are layers of methane gas under the clathrates, kept unfrozen by warmth from the earth. If the ocean melts through spots in the clathrates, large amounts of methane will escape.
* Clouds are a subject of considerable uncertainty. As water evaporates we expect to see more white, fluffy clouds that reflect solar energy. That may be why the world hasn't warmed more than it has. But if the atmosphere gets hot enough we'll see fewer fluffy clouds and more high, thin clouds. They admit more solar energy and intercept energy that otherwise would escape.
* The ocean conveyor is a superlong ocean current; one of the things it does is carry heat from the tropics to the north Atlantic, warming the US coast before it swings over and does the same for northern Europe. As it moves north to the Arctic region it cools and drops down to return under the north-moving stream. What if Greenland's ice melts? If it happens fast enough, a real possibility, the fresh water would cause the saltier and heavier water of the current to short-circuit; it would drop down to the return stream prematurely. Northern Europe would see severely cold conditions. Meanwhile, the tropics would warm up because of losing the Arctic cooling.
The author makes the point that this issue is different from the issues we're used to. Usually, when you learn more about a concern you find that it's not as alarming as you thought before. With global warming, the more you learn the more there is to worry about.
Saturday, March 8, 2008
Senator John McCain
Senator McCain has co-sponsored, with Senator Lieberman, legislation that would establish cap-and-trade measures for dealing with greenhouse-gas emissions. He tends to favor technological solutions over behavioral changes. In line with that view he supports federal support for nuclear energy.
Of the three candidates, he may have the most realistic views. At a time when millions of people are driving motor homes, yachts, and private aircraft around for recreation, buying houses bigger than they can afford, and treating flying vacations as a divinely-ordained right, perhaps it's too idealistic to suppose the greatest number would give up such indulgences.
As advocates of nuclear energy, we applaud his support for that technology. On the other hand, the view here is that what the country needs are coherent energy and environmental policies. If fossil fuels weren't subsidized with tax credits and if air-quality standards were reasonable, utilities would pursue nuclear and renewable energy without any federal support. Besides, nukes can't do the whole job, not even with cap-and-trade. The country needs some serious leadership on conservation as well.
Senator Hillary Clinton
Senator Clinton offers what looks more like a wish list than a plan. Cap-and-trade, R&D and subsidies for renewable energy, higher efficiency standards, and something called "home-grown biofuels." In the past she has said nuclear energy has to be kept on the table, but such sentiments don't appear on her website.
From here it looks as though she (or whatever staffer writes her energy positions) doesn't grasp the magnitude of the challenge or the urgency. Perhaps she knows better but doesn't want to offend the bicycling-and-winetasting crowd. We can sympathize, but it's not a point in her favor.
Senator Barack Obama
Senator Obama's positions are so close to Senator Clinton's it's hard to tell them apart. Possibly, the main difference is that he sets out his policies in more detail, so they come together as a plan. He understands the importance of setting stricter clean-air standards. He understands the value and the limitations of renewable energy sources, including biofuels.
He recognizes the importance of nuclear energy, but sets out four issues that must be addressed: public right-to-know, security of nuclear fuel and waste, waste storage, and proliferation. Then he proceeds to describe the measures he will take to address these same four issues. As advocates of nuclear energy, we are convinced that these issues have been addressed successfully and that any administration that looks at them clearly will work hard to develop nuclear energy.
Senator Obama seems to have the most comprehensive plan for dealing with global warming. Senator Clinton's might be as comprehensive, or possibly could be identical, but she doesn't spell it out and she doesn't mention nuclear energy; that's a major omission. Senator McCain is pro-nuclear; that's good but it's not enough.
It's appropriate to point out here the main problems with cap-and-trade, since it's the most important feature in all three candidates' positions. First, there's the ethical problem of letting polluters decide the price of pollution rights. Surely the victims ought to be setting the price. Second there's this political problem: call it what you like, cap-and-trade is a tax. Republicans won't allow it. Democratic politicians facing tough challenges won't vote for it. That means we have to weigh the different plans discounting the cap-and-trade part or any part that depends on it.
If we weigh the plans this way, Sen. McCain has only support for nuclear energy and Sen. Clinton has good intentions. Sen. Obama still has a plan.
Monday, March 3, 2008
This problem is compounded by competition from immigrants from countries where people have even fewer opportunities. In this regard, the only plausible solution is for other countries to solve their own economic problems, for which this article is a template.
The second problem is too much cash floating around. Credit has been so easy to acquire that people have reached the saturation point with stuff, even buying houses they can't afford. Furniture, appliances, electronics, sports gear---how much stuff can a person own? The first time a cold economic wind blows, everyone stops shopping. Of course. It's time to conserve cash and pay down debts. Our federal government has come up with an economic stimulus plan so absurd it sounds like a joke. The government will borrow billions of dollars and dole it out to people in the hope they'll spend it on things they don't need. President Bush's biggest fear is that people will behave intelligently and do otherwise.
Now let's look at the environmental problems. Fossil fuels account for nearly all the air-pollution problems and a big part of the water-pollution problems. Even outweighing those is climate change caused mainly by burning fossil fuels.
As the other articles in this blog have shown, the most important solution to these problems is to convert from fossil fuels to renewables, especially windpower, and nuclear energy. What are the barriers to improving this situation? You saw this coming, didn't you? First, there aren't enough trained workers. Second, it takes a lot of capital investment.
So we see that the solution to our environmental problems is also the solution to our economic problems. When people go to work manufacturing the equipment for renewable and nuclear energy sources, or constructing the facilities, they can earn good pay because these are highly productive jobs with a big economic payback. Furthermore, and for the same reason, these are splendid investment opportunities. With the low interest rates presently being paid on investments and the low interest rates charged to borrowers, people have little incentive to save. But given this excellent investment opportunity, people can direct their earnings toward long-term financial security.
Is this sleight of hand? Voodoo economics? Not at all. It's simply the transfer of money away from wasteful consumerism toward long-term investment. It will transform the country in magnificent ways but it's not a magic trick.
The economic pressure driving this change is so powerful it won't be contained; the only point in question is how long it will take to start it. My opinion is that the only thing holding it back is an administration that believes consumerism is the sole engine of wealth. If I'm right, then next January we'll see the beginning of an avalanche of economic drive. All three of the leading candidates understand that prosperity depends on growth, not on spending.
Get ready and hold on.
Monday, February 11, 2008
Now, how could anyone know all that? The estimable Dr. Hansen actually says
"The Energy Department says that we're going to continue to put more and more CO2 in the atmosphere each year--not just additional CO2 but more than we put in the year before. If we do follow that path, even for another ten years, it guarantees that we will have dramatic climate changes that produce what I would call a different planet--one without sea ice in the Arctic; with worldwide, repeated coastal tragedies associated with storms and a continuously rising sea level; and with regional disruptions due to freshwater shortages and shifting climatic zones."
Dr. Hansen goes on to make concrete suggestions, such as a cessation of building new fossil-fired power plants. He offers the possibility that in ten years it might be necessary to bulldoze all the existing ones.
Actually, a better plan would be to replace all the boilers with nuclear reactors. Most of the construction cost and effort is in the generating portion of the plant, anyway, so replacing the boilers will be much cheaper and faster than building new nuclear plants from scratch.
His other recommendations, such as financial incentives and improving the efficiency of buildings and vehicles, agree with the views of just about everyone who's looked at the issue.
But besides oversimplifying Dr. Hansen's remark, the kids are presuming to know more than they do.
We don't know how long it will take to build nuclear plants. In Japan they can build them in less than five years. If other countries got serious and cranked up their capacities for building them they could do it even faster.
The new designs are simpler than the earlier designs. The designers have incorporated features into them that make them inherently safer so that the risk of accident is lower even while the safety systems are less complex. Furthermore, manufacturing and construction technology has advanced in the last few decades. Just as office buildings can be put up faster and cheaper, so can power-plant structures. Computers and laser-guided machine tools have revolutionized the manufacture of heavy machinery. New testing techniques ensure quality control both cheaper and more thorough.
Besides, wind farms take more construction effort than nukes. Consider that a 1000 MW nuke will average over 850,000 KW. A very big (rotor-tip height ~ 450 feet!) wind turbine rated at 1.5 MW will average less than 500 KW. So 1 nuke equals more than 1700 big turbines.
As luck would have it, the British House of Lords studied the question and compiled some comparative data (and you wondered what the lords did!). A good measure of the construction effort is the energy inputs required for manufacturing and construction. What they show is that a 1000 MW nuke takes 6280 terrajoules per average GW, while a 25 MW wind farm takes 20,575, more than three times as much.
This is not an energy comparison, because that's much more complicated. We're only using these numbers to represent the manufacturing and construction effort.
What it shows is that the kids got it wrong. Again. Even if wind could provide full-time power, it still couldn't outpace nuclear in converting away from fossil fuels.
Sunday, February 10, 2008
First, here's the pertinent statement in BEIR VII
"At doses of 100 mSv or less, statistical limitations make it difficult to evaluate cancer risk in humans. A comprehensive review of available biological and biophysical data led the committee to conclude that the risk would continue in a linear fashion at lower doses without a threshold and that the smallest dose has the potential to cause a small increase in risk to humans." [A typical person in the US receives 3 milliSieverts per year.]
That's a tepid justification for retaining LNT, but compare that with the statement from the National Institutes of Health:
"It is very difficult to detect biologic effects in animals or people who are exposed to small doses of radiation. Based on studies in animals and in people exposed to large doses of radiation such as the atomic bomb survivors, scientists have made conservative estimates of what might be the largest doses that would be reasonably safe for a person over a lifetime. But these calculations are estimates only, based on mathematical models. Low-level exposures received by the general public have shown no link to cancer induction. Even so, the U.S. Government uses these estimates to set the limits on all potential exposures to radiation for workers in jobs that expose them to ionizing radiation. International experts and various scientific committees have, over the years, examined the massive body of knowledge about radiation effects in developing and refining radiation protection standards."
And with the statement from the Health Physics Society"
"There is substantial and convincing scientific evidence for health risks following high-dose exposures. However, below 5–10 rem (which includes occupational and environmental exposures), risks of health effects are either too small to be observed or are nonexistent."
"In view of the above, the Society has concluded that estimates of risk should be limited to individuals receiving a dose of 5 rem in one year or a lifetime dose of 10 rem in addition to natural background." [5 rems would be 50 milliSieverts.]
Professor Bernard Cohen goes on to estimate what would be the health effects of low-level exposures and compares them with other health risks, using the LNT model even though he shows in his analyses that it overstates the adverse effects and probably understates the beneficial (hormesis) effects of low-level radiation.
As an exercise we'll do something simple here. The BEIR report says ten million mSv would cause 1140 deaths. And it says that, on average, 304 million Americans receive 3 mSv per year, so the total would be 912 million mSv. So all of the radiation-induced deaths add up to 104,000 per year. Of that number, according to the report, 0.2% are due to nuclear energy, the rest mainly being due to natural radiation. If the LNT hypothesis is right, 208 deaths per year can be attributed to nuclear energy.
In comparison, every study done shows that tens of thousands of Americans die every year from the pollution generated by coal-fired power plants. The most comprehensive study done so far puts the range between 33,000 and 121,000 per year, just counting adults over 25. In 2006, according to DOE, coal generated 1930 billion KWH of electricity and nuclear generated 787 billion KWH, so if nuclear replaced coal an additional 510 deaths would take place, but at least 50,000 lives would be saved.
And all of the radiation-related deaths depend on a hypothesis that hasn't been proved and which specialized professionals don't believe.
Here's the kicker: Coal plants emit more than ten times as much radioactivity as nuclear power plants. If the LNT hypothesis were true, 5000 of the coal-related deaths would be avoided by converting to nuclear energy just because of reducing radioactive emissions.
If some form of renewable energy could provide full-time power, this might be a harder decision to make. As we saw in an earlier article, though, there aren't any that could.
So those are the two options. We can let over 50,000 Americans die every year from coal or we can switch to nuclear energy and start cleaning up the environment while minimizing the threat of global warming. What to do, what to do.
Saturday, February 9, 2008
The authors make the point that if you increase plant cultivation for biofuels, you either have to displace existing crops or clear additional land. But if you displace existing crops then the demand for food leads to the clearing of additional land, anyway. And it's the clearing of additional land that causes the problem. This seems obvious if the clearing is done in forests, as it usually is. A mature forest contains decades' worth of accumulated carbon so if the forest is burned then most of that carbon goes into the atmosphere as CO2. It's not as obvious but, according to the authors, plowing up grassland to grow biomass also releases more CO2 than it saves.[LA Times]
It's been known for a long time that ethanol is a loser.[source] It takes as much fuel to produce it as the process yields. So, in the US at least, it's always been a boondoggle aimed at making farmers rich. Still, some researcher think switchgrass can offer a better payoff ratio.
There's been some hope that oil-bearing crops could produce biodiesel, but so far the results aren't much more promising.[source]
So that seems like a daunting challenge by itself. But then we look at the land requirements and the prospects are even more dismaying. As we showed in another article, there isn't enough arable land available to grow the amount of biomass that would be required.
Maybe all this attention will do some good. Most people whose knowledge of enviromental subjects comes mainly from popular media have the idea that biofuels are a practical solution. A closer look shows that, by themselves, biofuels can at best be only an expensive non-solution, an illusory exercise that benefits a few people financially but only aggravates the problem.
As we face this bleak outlook, there's only one thing going for us. Hydrogen can increase biofuel yields by a factor of three. Then, biofuels can function mostly as a medium for hydrogen. They provide an imperfect means for onboard storage of hydrogen fuel for motor vehicles.
The most efficient way to convert water to hydrogen is with high-temperature processes, at temperatures nuclear reactors can provide. The nominal efficiency is over 45%.[source] But the heat left over from the conversion can be used to generate electricity, so the hydrogen production is effectively 100% efficient.
If we're lucky, a better way of storing hydrogen will be invented so biofuels won't be required. Either way, hydrogen is going to be the fuel of the future. The best way to produce hydrogen is with nuclear energy.[source]
Friday, February 8, 2008
This article could end right here, but maybe it's worthwhile to offer one example of his explanations. Since safety is the one place where most people's knowledge of nuclear energy is dodgy, what follows makes a good sample.
RISKS OF NUCLEAR ENERGY IN PERSPECTIVE
With the benefit of this perspective, we now turn to the risks of nuclear energy, and evaluate them as if a large fraction of the electricity now used in the United States were generated from nuclear power. The calculations are explained in the Chapter 8 Appendix, but here we will only quote the results.
According to the Reactor Safety Study by the U.S. Nuclear Regulatory Commission (NRC) discussed in Chapter 6, the risk of reactor accidents would reduce our life expectancy by 0.012 days, or 18 minutes, whereas the antinuclear power organization Union of Concerned Scientists (UCS) estimate is 1.5 days. Since our LLE from being killed in accidents is now 400 days, this risk would be increased by 0.003% according to NRC, or by 0.3% according to UCS. This makes nuclear accidents tens of thousands of times less dangerous than moving from the Northeast to the West (where accident rates are much higher), an action taken in the last few decades by millions of Americans with no consideration given to the added risk. Yet nuclear accidents are what a great many people are worrying about.
The only other comparably large health hazard due to radiation from the nuclear industry is from radioactivity releases into the environment during routine operation (see Chapter 12). Typical estimates are that, with a full nuclear power program, this might eventually result in average annual exposures of 0.2 mrem (it is now less than one-tenth that large), which would reduce our life expectancy by another 37 minutes (see Chapter 8 Appendix). This brings the total from nuclear power to about 1 hour (with this 37 minutes added, the UCS estimate is still about 1.5 days).
If we compare these risks with some of those listed in Table 1, we see that having a full nuclear power program in this country would present the same added health risk (UCS estimates in brackets) as a regular smoker indulging in one extra cigarette every 15 years [every 3 months], or as an overweight person increasing her weight by 0.012 [0.8] ounces, or as in raising the U.S. highway speed limit from 55 miles per hour to 55.006 [55.4] miles per hour, and it is 2,000  times less of a danger than switching from midsize to small cars. Note that these figures are not controversial, because I have given not only the estimates of Establishment scientists but also those of the leading nuclear power opposition group in this country, UCS.
I have been presenting these risk comparisons at every opportunity for several years, but I get the impression that they are interpreted as the opinion of a nuclear advocate. Media reports have said "Dr. Cohen claims . . ." But there is no personal opinion involved here. Deriving these comparisons is simple and straightforward mathematics which no one can question. I have published them in scientific journals, and no scientist has objected to them. I have quoted them in debates with three different UCS leaders and they have never denied them. If anyone has any reason to believe that these comparisons are not valid, they have been awfully quiet about it.
Thursday, February 7, 2008
LOW LEVELS OF IONIZING RADIATION).
In the very first paragraph of the summary brief, is this sentence:
"A comprehensive review of available biological and biophysical data supports a “linear-no-threshold” (LNT) risk model—--that the risk of cancer proceeds in a linear fashion at lower doses without a threshold and that the smallest dose has the potential to cause a small increase in risk to humans."
This is a statement that could warm the heart of the most discouraged anti-nuke. NIRS jumped into this like a kid into a pond. Let's compare how NIRS represents the report with what the report says when you get past the first paragraph.
NIRS: "There is no safe level or threshold of ionizing radiation exposure."
BEIR: "At doses of 100 mSv or less, statistical limitations make it difficult to evaluate cancer risk in humans. A comprehensive review of available biological and biophysical data led the committee to conclude that the risk would continue in a linear fashion at lower doses without a threshold and that the smallest dose has the potential to cause a small increase in risk to humans." [A typical person in the US receives 3 milliSieverts per year.]
This is quite a different statement. The report admits the data don't support the view that the risk continues all the way down to zero exposure, but concludes that it does anyway. This is the conundrum radiation safety analysts have struggled with for as long as there have been radiation safety analysts. The only way to be sure is to assume the worst case, so that's what we'll keep on doing.
The BEIR report gives anti-nukes what they want most, a solid-gold slogan, and then says something different in the explanation.
NIRS: "Radiation causes other health effects such as heart disease and stroke, and further study is needed to predict the doses that result in these non-cancer health effects."
BEIR: "Radiation exposure has been demonstrated to increase the risk of diseases other than cancer, particularly cardiovascular disease, in persons exposed to high therapeutic doses and also in A-bomb survivors exposed to more modest doses. However, there is no direct evidence of increased risk of non-cancer diseases at low doses, and data are inadequate to quantify this risk if it exists. Radiation exposure has also been shown to increase risks of some benign tumors, but data are inadequate to quantify this risk."
In this case NIRS turns the BEIR report upside down, attaching a conclusion for high-level radiation to low-level.
NIRS: "It is possible that children born to parents that have been exposed to radiation could be affected by those exposures."
BEIR: "Studies of 30,000 children of exposed A-bomb survivors show a lack of significant adverse genetic effects."
What does NIRS mean by "possible?" Is it possible in the sense that our atoms could all rearrange themselves and each of us could turn into linoleum flooring? The evidence says it hasn't happened, but it's still possible? That certainly isn't what BEIR says.
What is especially significant is what the anti-nukes don't say about the BEIR report. The report shows that of all the radiation a typical person receives, less than 0.2% comes from all of the nuclear fuel cycle. In comparison he gets sixteen times as much radiation from consumer products.
The report already has told us nothing can be concluded about doses under 100 mSv and at the end of it we learn what is needed:
Continued research is needed to further increase our understanding of the health risks of low levels of ionizing radiation. BEIR VII identifies the following top research needs:
• Determination of the level of various molecular markers of DNA damage as a function of low dose
• Determination of DNA repair fidelity, especially double and multiple strand breaks at low doses, and whether repair capacity is independent of dose.
• Evaluation of the relevance of adaptation, low-dose hypersensitivity, bystander effect, hormesis, and genomic instability for radiation carcinogenesis.
• Identification of molecular mechanisms for postulated hormetic effects at low doses.
• Reduction of current uncertainties on the specific role of radiation in how tumors form.
• Studies on the genetic factors that influence radiation response and cancer risk.
• Studies on the heritable genetic effects of radiation.
• Continued medical radiation and occupational radiation studies.
• Continued follow-up health studies of the Japanese atomic-bomb survivors, 45% of whom were still alive in 2000.
• Epidemiologic studies to supplement studies of atomic-bomb survivors, for example studies of nuclear industry workers and persons exposed in countries of the former Soviet Union.
Setting out its own limitations makes the report more valuable. And it emphasizes the folly of drawing strong conclusions as NIRS has done.
The final irony is that anti-nukes have succeeded only in forcing the world to use more coal. And coal-fired power plants emit more than ten times as much radioactivity as nuclear power plants.
Wednesday, February 6, 2008
Wikipedia has some good information on reprocessing. For information on the difference between uranium and plutonium bombs, the US DOE has a good page on their history.
The first difference is the length of time the material is in the reactor. As the reaction goes on, some of the U238 turns into Pu239, going through some intermediate steps. If the material stays in much longer, some of the Pu239 turns into Pu240.
Pu240 makes the material unsuitable for weapons because it fissions spontaneously. When the bomb mechanism combines the fissile material into a critical mass, the fission of Pu240 causes it to pre-detonate, causing the material to separate, and the bomb only burbs instead of exploding.
So, in production reactors, the fuel has to be extracted in some short time, months instead of years, and sent to the separation facility. In power reactors, the fuel stays in for years and accumulates a high proportion of Pu240. To make the spent fuel into bomb material requires isotope separation on top of chemical separation. If a country has the resources to separate the plutonium isotopes, it would be better off separating uranium isotopes, because that would save it the trouble of operating a production reactor.
The second difference is the chemical process. For the weapons program, the whole point of processing was to separate out the plutonium. For commercial power, that's not necessary. It's cheaper and easier to keep the plutonium mixed with the leftover uranium.
Most (I think all) of the countries presently reprocessing spent fuel use the acid process, called PUREX, or something similar. In the US, a new facility is being developed at Savannah River, South Carolina, for an entirely different process based on molten salt instead of acid. This other process uses less energy and emits no significant amounts of greenhouse gases. In theory, it's less vulnerable to proliferation due to diversion of spent fuel; as we just saw, though, proliferation with spent fuel from commercial power plants isn't really a concern.
Tuesday, February 5, 2008
So, Associated Press ran a story that warned nuclear plants could face power decreases or even shutdowns because droughts have lowered some stream flows. That indeed is a concern, and it applies every bit as much to fossil-fired plants. It's just curious that AP chose to mention only nuclear power plants.
Not having much to talk about, anti-nukes crowed that "Water is the nuclear industry’s Achilles’ heel. You need a lot of water to operate nuclear plants. This is becoming a crisis."
This is silly, of course, because there are alternate ways to cool power plants. In most cases, the problem is that stream flows are so low that adding waste heat would raise the stream temperature unacceptably. The solution is to add cooling towers. What's the penalty for doing that? The US Department of Energy did a study of all the thermal (fossil and nuclear) plants in the US. They found that if 100% of the power plants in the US (except in the Southwest) that rely on stream water were retrofitted with wet cooling towers, the energy penalty could be as high as 3%, but only during the hottest 88 hours of the year.
In an extreme situation, stream flows could be so low that wet cooling towers couldn't be used because of the water consumption. In that case, dry cooling towers can be used. Then, the penalty could be as high as 10%, again during the hottest 88 hours of the year. The authors didn't attempt to evaluate conditions for plants that were designed for dry cooling, but acknowledged that the penalty would be lower. Probably, the penalty would be about the same as for the ten percent of plants best suited for retrofit, which is about 1%.
As we look into the future, we can see that as long as new plants are designed to accommodate cooling towers, the penalties will be minimal.
In the meantime, as small as these penalties are, even they can be avoided most of the time. When stream flows are adequate the cooling towers can be bypassed. And when they are operated, it'll be unusual that the plants have to rely entirely on them; the cooling load can be shared between the cooling tower and the stream, or between a wet cooling tower and a dry one.
But the best solution will be to use the waste heat productively, as industrial heat or for heating homes and businesses. The waste heat can even be used for air-conditioning, by use of absorption chillers.
So drought and low stream flows won't be a hindrance to nuclear energy in the future. That means nuclear power plants will be able to provide backup to wind and solar energy.
Monday, February 4, 2008
This came up again on another blog, which uses a lot of scientific language but is dedicated to the proposition that the laws of nature can be over-ridden if they're inconvenient.
In this case, the writer of the article is determined to show that part-time energy sources can provide full-time power, if you just do enough mathematical manipulations.
First he cites "Supplying Baseload Power and Reducing Transmission Requirements by Interconnecting Wind Farms" by Cristina L. Archer and Mark Z. Jacobson, which argues that if enough wind turbines are interconnected they can provide base-load power. According to the authors, the part of the average output that can be considered 87.5% reliable is between 33% and 47%, depending on how many wind turbines are interconnected. However, the area they studied, centered on the Texas and Oklahoma panhandles, has the most reliable winds in the US and their results don't translate to the country as a whole. Even so, they show that wind farms would have to be oversized by a factor of at least 2. They elect to call it base load, but that's not appropriate. It only can be base load if there is also some form of load-following power.
That's a problem. Without fossil fuel and nuclear energy, load following is limited to whatever hydro and pumped storage can be made available, and at most that can only be a few percent.
The article writer also cites "Improving the Technical, Environmental and Social Performance of Wind Energy Systems Using Biomass-Based Energy Storage" by Paul Denholm, which recognizes that problem and suggests using biofuels for backup. But there are a couple of problems here. One is that nowhere does he consider the fuel required to grow the biomass and convert it into biofuel. Currently, it takes up to a gallon of fuel to produce a gallon of fuel, and certainly a big part of a gallon. It seems unlikely that it will ever take no fuel to produce a gallon of fuel. In the absence of better information, his study has to be considered extremely optimistic.
His optimistic estimate is that it would take 6.9 hectares or .0266 sq mi to produce biofuels that would generate 1000 MWH per year. The US uses 4 billion MWH/year, so the area required would be 106,400 square miles, out of 650,000 square miles of arable land. Suppose wind energy allows us to reduce that in half, which would require a half-million 1.5 MW wind turbines (rotor height = 450 feet!); we still need 53,000 square miles. Since we're using almost all the arable land for food and fiber, it's not clear where the 53,000 square miles will come from. Also, to farm land of this magnitude means using less-productive land. He assumes 11.3 tonnes/hectare yields, which would require prime Iowa land, so the land areas would be much greater and very likely would require irrigation, for which water will not be available. That's enough trouble already, but consider that the need for motor fuels will vastly outweigh the need for bio-electricity, because there is another, better, way to generate electricity but no alternative way to produce non-fossil motor fuels.
So we're still where we've always been. Wind energy doesn't work without a backup, and biofuels won't provide the backup.
As we explained in an earlier article, nuclear energy allows solar and wind to play their maximum part in providing electricity. Further, it allows them to contribute efficiently to the production of hydrogen, by taking some load off the nuclear plants. This is the kind of solution that will minimize global warming. Trying to paper over the limitations of renewable sources with scientific-looking obfuscations, if it's successful, can only keep the world on its present reckless path to self-destruction.
But anti-nukes don't get this. They believe you can change reality by manipulating data. You want windmills to turn when there's no wind? No problem. Just crank out fifteen pages of equations, tables, diagrams, and charts and they'll turn themselves!
Sunday, February 3, 2008
One elephant wants to build nuclear power plants. The other wants to shut down all the nuclear power plants, force everyone to ride bicycles, and run the world with windmills and solar panels.
Lost in the noise and dust is a program that has accomplished wonderful changes by lowering the strain on the world's natural resources and saving huge amounts of energy and allowing people to live fuller, richer lives.
For years, Simpler Living has been saving people from the rat race: too many people work long hours to earn money to spend in the futile hope it will make them happy. It's usually not hard to convince people that a simpler life will do them a lot more good. Simpler Living shows them how to achieve it.
It sounds much like the first three parts of Buddhism: Life is full of suffering; Suffering comes from attachment (in this case, to spending); Freedom comes from giving up attachments. Buddhism then teaches that you have to live like a monk to give up attachments. Simpler Living teaches that you just have to make thoughtful choices.
As in Buddhism, there's a whole discipline involved here. Having spent your adult life spending as though you were cleaning out your pockets, you probably won't change just by announcing to yourself that from now on your spending will be thoughtful.
To do it right, you have to follow the program. It's a little troublesome, but very enlightening. The standard text for this subject is Your Money or Your Life by Joe Dominguez and Vicki Robin. Amazon has it; in line with your new philosophy, see if your public library has it before you buy it.
I'll outline the process here so you'll understand what's involved. Please don't shortcut the process.
| ||First, you keep track of everything you spend. Actually, you might do this for a long time. JD Rockefeller did it his whole life and claimed it was the reason he became rich.|
| ||Next, you analyze where your money went.|
| ||Then, you redesign your life, imagining how you want it to be.|
| ||After that, you base all your money decisions, even small ones, on how they fit your target.|
It doesn't mean that you don't spend money, only that you do it consciously. For most people, their spending shrinks and their carbon footprints shrink along with it.
This is the attitude environmentalists have been advocating for as long as there's been an environmental movement. If the executives who run the organizations will catch onto this, we'll make some real progress. It will reduce environmental damage, including global warming, more than all the pamphlets Greenpeace hands out could ever do.
Saturday, February 2, 2008
Another issue is, what kind of carbon-offset schemes work? Some offer tree planting, maybe in some exotic place. But planting trees won't work, because trees all die eventually and give back all the carbon they've absorbed. It only could work if land was set aside permanently for new forests and if somehow it could be guaranteed that the land would never be cleared. There's no way such a guarantee could be made. At the rate the world population is growing, all the arable land will be needed for growing biofuel, not to mention food. In fact, global warming is likely to reduce land productivity.
But a different scheme could work. Non-fossil energy costs more than fossil energy. That's why we use so much fossil fuel, especially coal. So you could pay your local utility to buy your share of electricity from non-fossil sources, with you paying the difference in cost voluntarily. If this plan were structured properly, nuclear would be one of the non-fossil sources. It never is, though. All or nearly all the energy will come from wind turbines.
If you do that much, why couldn't you pay extra to make up for other CO2 emissions?
Here's some CO2 emission rates you can get from the US EPA's website.
For each KWH of electricity, you generate 1.37 lbs of CO2.
For each gallon of gasoline, you generate 20.4 lbs of CO2.
For each gallon of diesel fuel or heating fuel, you generate 22.3 lbs of CO2.
For each 1000 cubic feet of natural gas, you generate 120.6 lbs of CO2.
The EPA doesn't give this figure, but for commercial air travel, figure 50 passenger miles per gallon, or 1000 / 50 * 20.4 = 408 lbs of CO2 per 1000 passenger miles.
Now you can calculate your footprint in pounds of CO2 per year. If your utility has a green-energy program, ask what the premium per KWH is for green energy. At my utility, the rate is 1.25 cents, so the cost of becoming carbon neutral is 1.25/1.37 = 0.91 cents/pound.
|Electricity||5000 KWH||6850 lbs|
|Gasoline||1000 gallons||20,400 lbs|
Cost of offset = 27,250 * 0.91/100 = $248/year, or $21/month.
So if our example consumer donated $21/month to the green energy program, he'd be carbon neutral, just like former US VP Gore. If your utility doesn't offer such a program, find one of those companies you have confidence in and donate it there. Just don't pay to plant trees.
Now that you're guilt free, let's discuss this sensibly. The only reason carbon offsets work is that we generate electricity in the most stupid way possible. As we move toward non-fossil energy sources, this system will break down. If all the electricity came from nuclear power plants and windfarms, there'd be no way to offset motor and aviation fuels. That means the world has to shift toward hydrogen, battery-powered cars, and electrified rail transit.