In this house, we obey the laws of thermodynamics!
Posted by Paul Sears on December 30, 2008 - 11:11am in The Oil Drum: Canada
When you use energy, the rules are very well defined. The first and second laws of thermodynamics have been well understood for well over a century, and the third for just over a century, but the subject is still viewed by most as being pretty arcane. This is a pity, both because these laws are of such importance, and because almost everyone has a fair understanding of the first and second laws, even if they think they don't. Understanding the implications of the laws is another matter.
There are many facetious versions of the laws. The set I like best goes:
(zeroth law) You must play the game.
(first law) You can't win.
(second law) You can only break even on a very cold day.
(third law) It doesn't get that cold.
These are surprisingly accurate.
The actual laws are, it should be remembered, experimental in origin. The world has been found to work this way.
Zeroth Law
The zeroth law actually states that if two systems A and B are in equilibrium with each other, and systems B and C are also in equlibrium with each other, then systems A and C are also in equilibrium with each other. Another way of putting it is that situations like Escher's "Waterfall" don't occur in real life.
You must play the game.
First Law
The first law is the law of conservation of energy. It includes the equivalence of heat and work, but is more general than that, in that there are many forms of energy that are interconvertible, but with the total for an isolated system remaining constant over time. One point that is often misunderstood is the role of the equation E = mc2. This is usually taken to refer to a conversion of matter into energy, but the reality is simpler. Energy has mass, and the equation tells you how much. No matter what conversions take place in a isolated system, its total energy (and hence mass) remains constant.
You can't win.
Second Law
The second law is the one that results from the observation that hot things lose heat to colder ones. It's a one-way process. Mechanical work can be turned into heat. Heat can be turned into mechanical work, but there are limitations. The implications of this are far-reaching, and a surprising amount can be deduced (and defined) from just this and a thought experiment.
If we have two reservoirs of heat (both conveniently infinite in capacity) at different temperatures, then devices can be constructed that take heat from the hotter reservoir, turn some of it into mechanical work and reject the rest to the colder reservoir. The rejection of part of the heat has been found to be unavoidable, but the amount of rejected heat becomes less as the temperature of the heat source is raised. Without at this stage defining what we mean by the numerical value of a temperature, let us suppose that the maximum possible efficiency of conversion is a definite function of the two temperatures. Engine efficiencies are usually defined as [work out/heat in], but in this case, I'll look at [heat out/heat in] or [1 - efficiency]. If the temperatures of the two reservoirs are T1 and T2 and the heat taken from the hotter is q1, and the heat released to the colder is q2, then we will say that:
q2/q1 = F(T2,T1) F is some as yet unknown function (an algebraic expression) of the two temperatures.
Maximum efficiency implies reversibility of the process. An example of this is that heat transfer from the hotter reservoir to the engine must be achieved without any temperature difference between the reservoir and the part of the engine that absorbs the heat. If there were any difference, the heat engine would operate at a lower efficiency (smaller temperature difference between hot and cold), and it would not be possible to run the process backwards (heat won't flow "uphill"). There can't be any friction either. The engine with maximum efficiency is thus reversible and can be used as a heat pump, pumping heat from the cooler reservoir to the hotter, and requiring mechanical work to do it. The values of q1 and q2 are the same as in the case of the engine, but the direction of flow is reversed and work is put into the system rather than being taken out. The absence of temperature differences between the engine/heat pump and its heat reservoirs also means that the processes will be infinitely slow, but that is the case for all these ideal machines.
Let's now suppose that we have a third heat reservoir at a still lower temperature, T3, and that a second engine operates between the second and third reservoirs. If the heat taken from the second reservoir is q2 (same as rejected by the first engine), and that rejected to the third is q3, then:
q3/q2 = F(T3,T2)
But we could instead have used one engine directly between the first and third reservoirs. This engine must have the same overall efficiency as the combination of the other two, because if it didn't, then heat could be run continuously around the cycle of three engines, using the power from one or two engines to drive the other(s) backwards, leaving a net work output with heat being taken from one reservoir only. This would not be consistent with the way things work. So:
q3/q1 = F(T3,T1)
But: q3/q1 = (q3/q2) x (q2/q1)
So: F(T3,T1) = F(T3,T2) x F(T2/T1)
If you didn't switch off at the beginning of the algebra, it should be evident that this places a very severe restriction on the nature of the function F. In the last equation, T2 disappears from the right hand side, simply as a result of the multiplication. This means that F(T1,T2) must be of the form f(T1)/f(T2), where f is some other function.
So: q2/q1 = f(T2)/f(T1)
You may remember that I started this argument without defining what exactly was meant by a temperature. This equation gives us an opportunity to define a temperature scale, by choosing the function f. This is what William Thomson (later Lord Kelvin) did in 1848. He chose f(T) to be as simple as possible:
f(T) = TSo: F(T2,T1) = T2/T1 and q2/q1 = T2/T1
In other words, an absolute temperature scale can be defined in
terms
of the behaviour of heat engines, independent of the properties of any
particular substance. If an ideal heat engine has a conversion
efficiency of 50% (half the input heat is turned into work and half to
rejected heat), then the ratio of the heat source temperature to the
heat sink temperature is 2 - by definition.
To complete the definition of such an absolute temperature scale, we need to set the size of a degree. If we set the degree size such that the difference between the freezing and boiling points of water is 100 degrees, we have a scale that can match the Celsius scale, but with an offset corresponding to the freezing point of water on the absolute scale. That offset turns out to be 273.15 degrees and we now have the Kelvin scale.
Entropy
The idea of entropy is associated in most people's minds with the
ideas of order and disorder (higher entropy = more disorder).
This is correct, but the origin of the idea comes from the movement of
heat. If an amount of heat q enters a system at (absolute) temperature T,
then the entropy of the system increases by q/T. This is the
definition of entropy. If we look at the first heat engine above, the
entropy of the hotter reservoir decreases by q1/T1, and that of the cooler increases by q2/T2. If the engine is reversible, q2/q1 = T2/T1,
so the overall change in entropy is zero. This is a
characteristic of reversible processes. In real processes, the
change in total entropy is always positive. One example is the
flow of heat from a hot body to a cooler one - the hot body loses
entropy, but the cooler one gains more than the hotter one lost, since
the T in the q/T expression is smaller and the q is the same.
Available work, or Exergy
The maximum amount of work that could possibly be extracted as a process proceeds (i.e., if it proceeds reversibly) can readily be calculated from energy and entropy changes between the starting and finishing states of the process. This is sometimes referred to as the exergy available at the start. Just how it may be derived may be the subject for another posting. Exergy, unlike energy, may be destroyed. The ideal amount of work is never realised of course, but it is reasonably straightforward to show that the exergy irretrievably lost when an irreversible change takes place is equal to the entropy increase associated with the irreversible change multiplied by the temperature of the environment in which the process takes place. That is the lowest temperature at which heat can be rejected by the process. It follows that if the temperature of the environment is absolute zero, there is no loss in exergy or available work, whatever happens.
You can only break even on a very cold day.
Third Law
There are two ways of stating the third law:
The entropy of every pure substance at absolute zero is zero.
It impossible to reach absolute zero in a finite number of steps.
The reason the second follows from the first is that any process that reduces the temperature of a substance must entail a step in which the entropy changes. If the entropy of everything is zero, then no changes of entropy are possible and there is no means of doing any cooling. In fact, the observed law is that the change in entropy is always zero. It is then convenient to declare all entropies zero at absolute zero and this matches the statistical interpretation of entropy. One can get very close (in degrees) to absolute zero - the current record is about 10-10K, but the closer one gets, the more difficult it becomes to cool further.
It doesn't get that cold.
Personnel
Archives
- December 2008 (1)
- October 2008 (1)
- July 2008 (2)
- June 2008 (2)
- May 2008 (6)
- January 2008 (2)
- December 2007 (8)
- November 2007 (9)
- October 2007 (11)
- September 2007 (14)
- August 2007 (14)
- July 2007 (10)
- June 2007 (9)
- May 2007 (11)
- April 2007 (9)
- March 2007 (11)
- February 2007 (11)
- January 2007 (11)
- December 2006 (12)
- November 2006 (16)
- October 2006 (13)
License
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
Thanks for a helpful article. This is a subject most of us don't think about very often. One particular comment I found helpful was
But what about black holes? :-)
Is the gravitational pull exerted coming from outside the Schwarzschild radius or from within (but nothing can escape from within.)
It comes from the curvature of spacetime around the Schwarzchild radius. Though the matter of whether or not anything escapes is still somewhat open, the curvature should also generate blackbody radiation proportional to the curvature (smaller radius ≡ more curvature).
Eh, but with Fusion powered by boron/detrerium you can play the game for a looooooooooooong long time. :)
Except that you haven't the faintest idea how to do it! ... so don't say you can do it, that is an out and out lie! ... and very misleading to people who don't have much of a grasp of how the real world works.
Look out the window, there's a hydrogen/C->N->O->C+helium reactor just waiting to be utilized :) Works like a champ, stable and steady.
If it's night you might see one, but it's pretty hard to utilize the light from a distant star. The Sun's energy is mostly from proton-proton fusion.
It's good to step back and get a larger picture of energy and its dynamics.
What this post brings to mind to me is the amazing set of interlocking energy systems the biosphere represents. It is precariously perched between the molten core of the earth, with more energy than the systems could tolerate, and space, where temperatures approach the absolute zero your refer to.
We have long ignored the precarious nature of this thin layer of livable, balanced energy or assumed that nothing we can do would upset it.
Unless we are in deep denial, we now know that we can and have upset this delicate balance. The consequences of this unbalancing are just beginning to show themselves.
I would add that some have termed the Maximum Power Principle the Fourth Law of thermodynamics, stating that organisms and ecosystems which maximize the flow rate of ER/EI, quality adjusted have had an adaptive advantage. My new years resolution is to finish the paper I've started on this topic and post a draft here next week...;-)
Its place as in the three laws of thermodynamics is ill-fitting and doesn't really lend itself to actual understanding of thermodynamics.
Perhaps not, but to know WHY things are the way they are is almost as important.
The "Maximum Power Principle" is endlessly fascinating to me. It somehow attempts to address how you can have turtles and cheetahs both in the same environment.
It has found it's way into literary and philosophical explorations, with folks like Thomas Pynchon and Robert Pirsig dealing with the subject either directly or indirectly. Pirsig in his philosophical explorations in the novel "Lila" attempts to grasp how it is that nature seems to move (if you accept both big bang theory and Darwinist natural selection) from the simple to the complex, i.e., it converts raw simple energy from the simplist atom (hydrogen)upward into increasingly complex structures.
Interestingly, this seems to run backwards to the ideas of good engineering. While engineers attempt to build "elegant" devices with fewer and fewer parts and by way of reducing elaboration(motto of the modernist architects, "less is more") nature seems to make a project of moving from simple to ever more elaborate (from the single celled organism to the complicated multi-celled mammals, again if you accept Darwinism)
The arts while claiming to be more in touch with nature as it progresses actually runs backwards to nature, which is all about elaboration and variety as it develops, while in the arts "minimalism" is "modernism",
Fascinating fundamental stuff I could talk about all day, but I am trying to comply with leanen of TOD US's request for brevity! :-)
RC
Re: Engineering tends towards simpler
It easy to explain really. Nature is built to account for failure through trial and error, engineering is built to avoid failure through predictable design. Engineering has become much more complex over the years, but the idea that reducing failure points increasing predictability of failure has been a tenet of the profession for decades (perhaps centuries). As we become better able to understand and design for the complex, we do, but at any point in time, we try and simplify the design to maintain within the parameters we understand best so that life span of a product is longest and most predictable.
Very old quote:
"An engineer is someone who can do for a pound what any fool can do for five."
I'm not one, btw.
I hope you do finish and post. I am really looking foward to it now. I read a book titled 'Into the Cool' about life from a thermodynamics point of view. The book wasn't that great, but the subject matter is absolutely brilliant.
I prefer the Fourth Law as postulated by Nicholas Georgescu-Roegen
http://books.google.com/books?id=lwUKDaGiO5wC&pg=PA24&lpg=PA24&dq=George...
or http://tinyurl.com/a7gp5y
http://cepa.newschool.edu/het/profiles/georgescu.htm
MARGE: I'm worried about the kids, Homey. Lisa's becoming very obsessive. This morning I caught her trying to dissect her own raincoat.
HOMER: [scoffs] I know. And this perpetual motion machine she made today is a joke! It just keeps going faster and faster.
http://www.snpp.com/episodes/2F19.html
I suspect the loss of respect for these laws has a lot to do with doomers trying to apply them to the universe as a whole.
No. The laws of thermodynamics apply to the entire universe allready. The problem is many doomers misapply them. The classic example that I've seen is invoking the second law as a limit to growth. Thats only true when the entire universe is the same temperature. We're not in any danger of the night sky getting too warm any time soon.
I think it's a bit more subtle than that. You can apply thermodynamics to an "isolated system". There are philosophical problems about regarding the universe as being one. What we see is also big enough that you can't take a snapshot of all of it and get a number for (say) its entropy. There is no universal clock, either, so "now" is more than a bit iffy. What works very nicely for a steam power plant becomes useless for "the universe". You can certainly apply it to defined bits.
Perhaps, Libelle, you might address the interpretation of the second law in far-from-equilibrium systems so that we need not suffer the foolish claims that the 2ndLOT doesn't somehow apply to our current state of affairs (as above).
Morowitz, Harold, (1968). Energy Flow in Biology, Academic Press, New York.
Question Everything
George
The second law doesn't reveal any limitations on growth anytime worth discussing. Its primary relevance is in describing the maximum theoretical efficiency of heat engines (and all physical processes reducable to a model of heat engines.)
Application of the first and second laws leads to the idea of free (or available) energy of processes. All of chemistry is heavily dependent on free energy of reactions. That means all of biochemistry is. The heat engine is the root of the idea of entropy and of the absolute temperature scale, but the implications of both laws cover everything we do and indeed every process.
Dezakin,
You are either out of date in your education re: energy systems and non-equilibrium processes or you are failing to understand that the second law most certainly applies to compartmentalized sub-systems. Life could not exist if it didn't. You may be proclaiming a point of view from that of an engineer working only on classical heat engines but you are woefully wrong regarding growth and the laws of T. Better to study biology and ecology to get an understanding of how energy flows and the laws of T apply to local systems not in equilibrium with their environments.
I've provided a reference. Do your homework.
Did you even read what I wrote?
The second law isn't a limit to growth in any time worth discussing. It's primary application is describing maximum theoretical efficiency of all non-equalibrium processes, and all of these are reducable to models of heat engines; Including biological systems. Its very well that you think I was disagreeing with you, but pick your arguments somewhere else.
I don't know; I'm listening right now to Jason Bradford discuss the primary importance of second law and limitations to growth with Jay Hanson of dieoff.org here on GlobalPublicMedia.
cfm, wasting away in Gray, ME
Dude runs a website called dieoff.org, what did you expect him to say?
I'd never heard Hanson speak and a discussion with Jason Bradford seemed like a good opportunity. I fully expected him to talk about limits to growth. I did NOT expect him to frame it so explicitly and fundamentally on economics and thermodynamic first principles as he did. Those who want to explore those connections will like that podcast.
cfm in Gray, ME
"I think it's a bit more subtle than that. "
Yes, indeed! And the question about the application of thermodynamics to the Universe as a whole is more than a bit irrelevant to the human condition on Earth. I think of the whole Earth as a 'defined bit' (to use Libelle's words) of the Universe.
Also there are formulations of Thermodynamics that cover systems that are not isolated from their surroundings. These formulations are covered in all the standard textbooks, but are too complicated to fit in a nice concise statement like Libelle has give here.
Thermodynamics does not do so well describing systems that are far from equilibrium. e.g. the interior of a hydrogen bomb during detonation. But even there, there is no evidence that energy conservation is violated. For such systems, detailed computer calculations are needed, if one really wants to know - without doing the experiment.
The Earth is not so far from equilibrium as a thermonuclear explosion. I would be very skeptical about rejecting thermodynamic arguments about the Earth merely because it is not perfectly at equilibrium.
The laws of thermodynamics have precious little bearing on doomerism vs. cornucopianism and all points in between. The issues involved are far more pragmatic (maybe mundane would be better if taken in the appropriate sense): what energy is available to us, how much, at what cost, how much is left, what are the conversion costs, what will the atmosphere tolerate, blah, blah, blah.
The post is good, and it's good to be reminded what the laws are, but they play precious little role in deciding any issue except to dispel occasional pieces of arrant nonsense from whatever direction.
I subscribe to a notion called interwoven worlds. Each world, although at some level interwoven all others, is a world unto itself and has its own laws, other worlds impinging upon it as contingencies. That's why a physicist who has a heart attack never vets his cardiologist by asking him if he knows relativistic quantum field theory -- even though the physicist, when he's feeling well, regards this as the most fundamental theory. (Kind of like the old nostrum about there being no atheists in fox holes -- the physicist abandons fundamentalism in cardiac arrest.)
"That's why a physicist who has a heart attack never vets his cardiologist by asking him if he knows relativistic quantum field theory -- even though the physicist, when he's feeling well, regards this as the most fundamental theory. (Kind of like the old nostrum about there being no atheists in fox holes -- the physicist abandons fundamentalism in cardiac arrest.)"
Dave, that is some damn good rhetorical writing! :-)
RC
And yet...if the cardiologist is not intimately familiar with the mechanical and chemical energy pathways within the heart the physicist is SOL. Cardiologist and physicist are engaged in study of the same thing - just using different language and different framework.
Regards
Al
Thermo as we know it gets unhandy when applied at the scale of the universe. How do you calculate the energy transfer between two galaxies that are far enough apart that light from one will never reach the other?
You calculate it as zero of course. Its an inherently obvious answer to whats supposed to be a gotcha question that falls flat. Thermodynamics does still apply to the universe, but different conditions mean that the results of the calculations may be entirely different. For instance heat death never actually occurs in a flat universe because you can play the game forever, but it does occur in a closed universe; And interestingly enough a universe continually expanding is vulnerable to heat death as well due to unruh radiation limiting the lowest temperature of a heat sink.
The laws can be applied to closed systems - and the universe as a whole is a closed system. The 2nd law states that the entropy of the universe is monotonic-increasing on a timescale measured in billions of years. It makes continental drift look fast by comparison.
Doomers invoke thermodynamics because it sounds authoritave and it sounds like it supports their apocolyptic views. Of course, they conveniently fail to note that none of the preconditions required to apply the laws are satisfied.
Fantasy presented as science is of no use to anyone - doomers or realists.
1. It is philosophically impossible to know whether the universe is a closed system or not.
2. If, on a universal scale, entropy is always increasing, how did we get here in the first place? (arms wave, big bangs just 'happen')
I realize the reluctance of someone engaging in a discussion of principles of physics to cross over into metaphysics, but at some point, these questions are encountered and shouldn't be danced around in the process of declared the Laws bulletproof.
ET,
If there was a working rating system here, I'd give you a +10.
You are absolutely right. We humans cannot know what the entirety of the Universe is. We can only know of those portions that become apparent to us.
However, in those portions that have been made apparent to us, it appears that "time" is a one way arrow and energy follows the one way arrow of time by tending to flow from a region of concentrated energy (i.e. a high temperature, high pressure zone) to a region of unconcentrated, more-thinly-distributed energy (i.e. low temperature, low pressure zone: a.k.a. outer space).
So? We're only concerned with the Earth, and the expansion of the universe makes it an effectively infinite heat sink.
(If the universe was static, it would fill up with heat and there would be no temperature differences to drive processes like biology. As someone said quite some time ago, "I am, therefore the universe expands.")
Because it started in a low-entropy state (mostly hydrogen), and the conversion of hydrogen to heavier elements and relatively high-entropy photons can go on for billions of years.
We don't know what the physical laws of the pre-Big Bang were. Time may not have existed, and if time doesn't exist then neither does the one-way arrow of entropy.
Fixed that one for ya.
Seriously, I've seen a lot more 2nd Law abuse by cornucopians - but can't anything be distorted and misrepresented by the overzealous?
It is intuitive but nonetheless strange that ordering a system should require energy, but increasing its disorder doesn't necessarily give you your energy back.
It is also true that all hyper-cornucopian perpetual motion machines violate the thermodynamic laws, and using them effectively is one of the best ways to illustrate their impossibility.
The good ones always end up with cold-fusion at their core. :)
Strip everything else away. There is a specific physical energy requirement to lift oil (and gas under less pressure) out of the ground. As available resource goes from best to moderate to worst, the lifting (and other energetic) costs will increase. This has all happened while population and non-energy inputs have also increased. In the US, we have gone from 100+:1 energy return on oil and gas extraction to 30:1 to 10-17:1 to something lower (possibly much lower). This is the relevant application of an aspect of thermodynamics to the discussion on hand which is peak oil. There is a heat loss at each exchange. It says nothing about other energy in the system (embodied in uranium, hitting the earth as sunlight, etc.), only that the 'heat loss' as a % of total stocks of fossil fuels will likely outpace the technological attempts to slow it. There are windows of time (e.g. the 1990s) when energy return will interrupt the long term downtrend and actually increase for a time, but to think that aggregate energy gain (net coal, net gas, net NG, net hydro, etc.) will continue to increase goes against first principles. It's not thermodynamics per se, but to me the 'second law' translates in our current socioeconomic system to 'there is a cost' associated with each transformation and there is a finite amount of usable low entropy stocks.
It's not authoritative nor apocalyptic, just a fact.
As long as there's a hot sun in an otherwise cold sky, the laws of thermodynamics aren't in themselves limitting. We've pumped out the easy oil first and the remaining oil has higher lifting costs. The petroleum engineers wouldn't have done their jobs if it was otherwise.
Right! My point is that the 'friction' cost is often overlooked by energy cornucopians. Harnessing the thousands of quads of solar energy too, has a cost. Those BTUs don't magically make it into our gas tanks.
So in the overall thermodynamic sense (our universe), none of this makes much of a dent. But on human timescale, individual parts of the bigger picture matter a great deal. So to me at least, 1st and 2nd law implies: 1)no abiotic oil on any timescale to matter and b)there are measurable costs associated with slicing and dicing the stocks we 'found' and flows we have 'access' to.
While NH's point is absolutely correct, the energetic limitations on lifting oil or coal or potash represent the most optimistic limiting case, which ignores the constraints imposed by kinetics.
In P. Chem we used to say that if delta G is positive the reaction cannot proceed; if delta G is negative the reaction may proceed. Rates are important too!
Or as y'all put it so eloquently on TOD, it's not the size of the keg, it's the size of the tap.
I consider myself in neither the doomer camp nor the cornacopian camp.
I'm in the "we can have all the energy (or metal or food etc.) we want but it will cost us" camp. We know how to make solar electricity for 20 cents a kWh and the amount of solar energy dwarfs forseeable human needs. The ERoEI of of oil only effects the economics because we can pump oil with a pump running on solar electricity even if the EROEI is less than one. I'm not saying this is the most sensible way to run a transportation system. Only that it is doable. A close look at metals shows that none of the non-platinum metals are geologically contrained. We may have to mine more dilute ores at higher cost but for a price we can have all the copper, fill in the blank, we want.
There's been "friction costs" as you put it in acquiring energy since hunter-gatherers spent X hours a day gatherring firewood. There's nothing new here. It's fair to point out that after we gather all the easy oil, or for that matter the easy firewood, additional supplies will take more effort. By itself, this is not limitting. Europe been running on $10 gasoline forever and their standard of living is comparable to the USA. The doomers have failed to make the case that expensive oil will cause civilization to collapse. Make people drive more sensible cars yes.
Absolutely right, Nate.
It's important to note that in the new reality of lessening resource quality and technological disappointment, the marginal barrel or cubic foot or carload of fossil fuel generally has the lowest net energy (EROI). On the production margin, the pull within the economy from the rest-of-the-economy to the energy producing sector is at its greatest.
Attempting to expand supply creates strains within the overall economy. Among other material and financial issues, there is localized hyperinflation (e.g. Fort MacMurray) in producing regions and loss of money-in-circulation in consuming regions (J.Rubin describes how this works on a worldwide scale, but it also occurs within national territories as some percentage of the investments in funds and flows do not recirculate, or only do so slowly).
Because some of the oil now being shut in is not at the production margin, we might expect that there is room for a period of relatively stress free economic growth, once a set of functional economic devices are reassembled from the bits and pieces strewn about as a consequence of the 2005-2008 oil price/energy production cost shock.
On the other hand, North America, the UK and some other areas may just get to the point of recovery, however temporary, without enjoying it because of a natural gas surprise.
There is so much less to be done.
Invocations of thermodynamics by any side are off base in the PO and peak energy debate because it's not relevant. If an astronomers looked up at the sky and said a huge meteor was heading straight for the earth, and all other astronomers verify it, then that's not doomerism, that's realism. It can only be decided by looking at the sky.
If someone says hydrocarbons are peaking, will drastically decline in the coming decades, and that no combination of alternatives will be available to replace them on any where near the scale they at currently used -- well that person has made a statement which may be wrong, and there may be compelling arguments against it. But it's not wrong because its being true would be unpleasant.
Now none of this applies to calling cornucopians cornucopians, because as we'll all know, they are simply re-incarnations of Dr. Strangelove. :)
Entropy can be viewed also as the obsession of nature for sharing potential energy
Quite conveniently, the second law can be deduced by the statistical definition of entropy, and the equipartition postulate (and, of course, causality).
So, yes, the second law can be viewed as the sharing of energy, quite literaly.
Statistical thermodynamics was for me one of the most eye-opening parts of university chemistry. I don't think I'm going to get into the details of it here.
Another way of stating the zeroth law?
"Nature abhors a gradient."
That would include transitive gradients too.
The obvious question is; If "nature abhors a gradient", why is there so much gradient in the system now?
Because nature took her time in producing a species that would find an unused gradient and puzzled out how to use it, quickly.
Because a gradient is an abstraction we use in understanding physical systems. The notion of the naturally occurring immutable boundary is an artifact of philosophy. We have good and evil, plus and minus, heaven and hell, income tax brackets, etc. Call it the perversion by western thought.
We see levels of separation - "gradients" - whereas other cultures only see continuity, or "oneness".
The western mode has served well for the industrial revolution, but may fall well short for the coming challenges and changes.
For the record, I use gradients every day in high voltage electrical engineering. It really helps in understanding the abstract of electro-magnetic fields, but I can't go out to a high voltage line, throw dust into the air and see the equipotential lines emanating from the circuit.
I think the point is more "why is there oil?".
On the surface, it seems to violate the laws of thermodynamics, because it took lots of diffuse energy and concentrated it. Of course that is only part of the story, as much of that energy came from the sun (very low entropy) and some from geothermal (also low entropy).
The sun's energy at the earth is relatively diffuse, but high-quality. It's 6000K radiation (very low entropy, as you say). Nothing about the formation of oil contradicts the second law.
All of that energy came from the sun or geothermal (which in turn came from an older star, rather indirectly).
Plant life used vast quantities of high quality solar energy and some of the biomass they built with it became oil. Much more of the energy became waste heat, but there was just so freaking much of it made for so long that it happens to have conveniently left millions of years of solar energy lying around in a useful form for us to liberate further, which we're happily doing over the course of a few ridiculously short centuries.
The great big input of the sun over billions of years leaves any discussion of the second law, as applying to processes on earth, somewhat moot.
The more-to-the-point is that those trillions of barrels are a piddling amount compared to the volume of the whole planet.
Partially because thermodynamic models are somewhat complicated by gravity.
This is the theme of the book 'Into The Cool'
An excellent book which I recommend to anyone interested in the relationship between life and energy.
However, I think they got it backwards. I would say "Nature loves a gradient." Saying "nature abhors a gradient" is like saying I hate food, so I get rid of it as fast as possible.
Were it not for energy gradients, 'Nature' would not exist. 'Nature' is forever and everywhere looking for an energy gradient to exploit (eat?).
I have some homemade beef stew energy gradient to go take care of now. Yumm!
In addition to being empirical laws, they can be derived from some rather simple theoretical concepts, namely the kinetic theory of gases, and statistical mechanics, which is essentially the application of the equipartition law (any two accessible states of a closed system are equally probable). With a bit of mathematical messing around you get things like entropy, and the Boltzman distribution function, which gives the relative probability of two states with different energies. So in addition to having been observed experimentally, there is also a very good theoretical foundation of them.
I'm just not so sure, if they actually apply to the entire universe, what with weird stuff like dark energy, and the fact that the total amount of stuff in the universe we can see is continually going down (most of the universe is now beyond the horizon of our space time, and stuff on the far edges effectively disappears over the horizon. But given a length scale of less than hundreds of millions of light years there is no reason to expect them to fail. But in many cosmologies, the universe is the ultimate free lunch!
I'm not intending to get into statistical mechanics here, even though it's really eye-opening stuff. :)
Disclaimer for Idiots: Citing figures, theories and thought experiments that imply steady state or contracting resource reserves, economies, or human populations are not 'doomerish' activities, they are logical explorations of probable resource depletion outcomes by rational people. Blanket dismissals of resource depletion scenarios as 'doomerish' are acts of psychological projection. If you are feeling 'Anti-Doomerish' please discuss with your therapist. Group projection and denial can be practiced at www.peakoildebunked.blogspot.com
Sustainable or Green Economic Development (Growth) programs are becoming all the rage in the face of GHG emissions and global warming.
Absent the element and/or energy source foreverium an economic system can not 'develop' indefinitely.
This poses the question of whether we should determine when continuously developing economy will deplete a critical resource, or if we should declare that the economy is large enough now and should enter a steady state, or if the economy is already in an overshoot state and should be downsized.
Thermodynamics says foreverium can not exist and by corollary neither can everythingium or anythingium.
This suggests that learning to live in a steady state or contracting economy is a necessity.
Hallmark of a steady state economy: The money supply must remain constant so there can be no interest on loans or savings.
Hallmark of a contracting economy: The money supply must be reduced so savings and loans will have negative interest rates.
These economic conditions also mandate stable and contracting human populations, respectively.
A steady-state economy prices/taxes use of non-renewable resources and overuse of renewable resources and rewards remediation and improvements to our environment such that our collective ecological footprint declines to a more beneficial level. However standards of living can increase and investments can yield positive returns. The government can still create money and cause price inflation.
Perhaps a fixed money supply is sensible, but I don't see it as inevitable. However without the growth ideology supposedly "floating all boats" the spiraling inequalities generated by capital accumulation (rent and interest) will be less acceptable, and redistributive taxation and death duties will become more important. Perhaps usury will be banned.
If we can get the resource price mechanisms right, then parents contributing to overpopulation (overconsumption) will be automatically penalized. I doubt this will happen before the topsoil/aquifer/food/fertilizer/diesel/climate change crises provide a more "natural" solution for most of the world's population.
I think that the so-called Laws of Thermodynamics, which are a short description of the engineering principles involved in the workings of heat engines (originally steam engines), are almost totally irrelevant to the subjects addressed at this site.
I doubt that one in a thousand people who post here can even apply them to steam engines.
With a degree in Chemistry, and a dad who designed Stirling heat engines for a living, I can only assume that more than one thousand people read this site.
Your moniker does you no favours at this site :)
LOL.
Does econguy stand for "economics major guy"?
Here are the Three Laws of Terminal-economics:
1. Money is not conserved but rather whipped up out of thin air by governmental agencies. A government can create trillions of dollars out of thin air in a microsecond and distribute it to the rich and powerful at its leisure.
2. Money tends to flow from the poor to the rich.
3. Absolute wealth means having all the money in the world, in which case you have no wealth at all.
Economist: a politician with lipstick.
Or something like that...
Check and check. What happened to the rating system?
Second law...(always a loss)...;-)
(Super is still working on it.)
re: The ratings system,
"(Super is still working on it.)"
I suggest conservation, just leave it off.
It seems I have read more openness of discussion since people don't worry about whether they will be "down arrowed" or "up arrowed" because of what they say. Folks are actually willing to say something controversial now!
RC
Leaving the rating system off means that people are less likely to know if there is controversy in what they've posted. Meaning that people won't learn how to avoid it or deal with it.
I suggested in the software upgrade thread that the rating system be change to show the up and down votes separately, so it would show a +3/-3 instead of a big fat zero.
But at least the rating system as it was implemented before allowed readers or casual posters to show their agreement or disagreement. While not taking up as many resources as a posted reply, it allowed a measure of constructive feedback.
Yup. (In the interest of brevity) :-)
Yet, your clarification was something on the order of 9 times longer than the answer you clarified.
Sometimes I just love the heck out of language.
Note: I have posted this for absolutely no reason whatsoever, except that it was fun to do.
Cheers
I think the system needs to be even more detailed than that, ala Slashdot:
It would drive home specifically what's right or wrong (and ratings like "Funny" would give hints to the satire-impaired).
Agreed, but we probably need to understand how to walk before we start doing somersaults and backflips. :)
We already adequately discussed the rating system in a thread when it was introduced, and the pro-rater case was firmly trashed by various powerful objections from the anti-raters.
Please refer back to it for details.
The comment I liked most was along the lines that the ratings offered a means of expression for those who cannot find any rational/factual justification for their opinions but still wish to express them.
Engineer-would-be-Poet above makes one of the more incisive points, which ultimately leads to the absurdum that it would make more sense just to post actual comments so everything is made plain. There's enough bahhing sheep out there without bringing them in here.
Reductio, eh?
Do be careful not to make
Your own absurdum.
Yes, some objected.
Lots of words went back and forth,
Yet ratings happened.
Ratings have value.
Would you care to denigrate
Olympic judges?
I see your problem
You cannot see how to spin
A "-1, Flamebait".
a message
posted in verses
war of words
-------------
Haiku
in only three lines
one stanza
-------------
five-seven-five
wordy in English
not Japanese
(Well... one-half out of three ain't bad...)
Cheers
I am so glad you pointed out our shortcomings and stupidity. I guess we can all go home now.
You provide no substantiation for your first statement and as to the second, what is your point?
I posit that not one in a thousand here could describe photoionization in detail either, but that's not what we are discussing.
I tend to agree with econguy. Perhaps it can be argued that thermodynamics has some useful model characteristics for discussion of earth's petroleum resources, but given the huge free thermonuclear reactor providing more energy in one hour than the world used in one year.
"The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year.[11] In 2002, this was more energy in one hour than the world used in one year." Energy from the Sun - Wiki
Makes computing earths thermodynamic equilibrium a bit pointless. Aside, let me anticipate the "yeah buts" doomers by pointing out that efficient and economical solar thermal electrical generation with storage construction requires little more than some smelted bauxite for aluminum structures, melted sand for glass, insulated tanks of sand and gravel for thermal storage (fiberglass insulation is just melted sand) and about 3 months of net energy producton of the resulting system.
Print a map of the Sahara desert on standard paper, the area required to supply ALL ENERGY PLUS NECESSARY DESALINATED WATER FOR PEOPLE PLUS IRRIGATION for ALL of Europe, Middle East and North Africa takes the space of a postage stamp. See Clean Power from Deserts - The DESERTEC Concept for Energy, Water and Climate Security - Club of Rome
For independent engineering backup, see Assessment of Parabolic Trough and Power Tower Solar Technology - Cost and Performance Forecasts - Sargent & Lundy LLC Consulting Group Chicago, Illinois
Ah yes, the mirage of paradise...
but for the thermodynamic problem captured in accounting as depreciation,
but for the haboob,
but for _________, ___________, ____________,...
All hail Cornucopia!!!
I'll agree with you insofar as treating the earth as a closed system for the purpose of thermodynamics without including the sun is pretty stupid and would lead to bad results.
I don't think anybody is stupid enough to do this, though. If you looked at the Earth thermodynamically without considering current solar energy, you would come to the conclusion that we all must have died a while ago.
This is the problem with all models, thermodynamic, economic and otherwise;
According to my model, I should have been at work an hour ago ...
Yes, there is a comparable infinite amount of energy out there, but it's the DENSITY that matters. Regardless of the energy source, it has to be harnessed, modulated and transmitted in ways that provide a relative high density, or rate.
What is constantly overlooked in energy discussions is RATE. The cornucopian M.O. is about doing adding and subtracting, when the reality lies in doing the multiplying and dividing. There are many simple examples to make this understood whether it is explaining rate of use or EROI.
1) If one had a job where they had to spend $2 for every $3 they earned, they wouldn't be doing that job very long, would they?
2) One has the whole continent of Australia for themselves with an infinite supply of wood for heat and cooking, but it is non-renewable dead wood lying on the ground. For the first few years, a day's worth of wood can be collected in less than an hour. At about the 10 year mark it takes 3 to 4 hours to collect a day's use of wood. By 20 years, one is spending 15 of their 16 waking hours collecting wood, but there is still lots of wood out there. After 20 years, although wood is still plentiful in Australia, it doesn't have any value as an energy source because the EROI is too low.
Or, there was the recent specious media hub-bub about massive amounts of methane on Io (or one of Jupiter's moons). Enough to fuel the whole planet's needs for thousands of years they claimed! The problem is, we would use up every last drop of useful energy to get the ships to Io, and then they would probably consume 7/8's of their cargo transporting it back to Earth.
Yes, there is huge potential for solar powered energy but we have to get it from there to here. There is lots of geothermal energy available, but again we have to get it from there to here. Whatever the renewable energy source, (geothermal doesn't count by the way - we would eventually cool the Earth's core and then be in real big doo-doo!), the densities will not support BAU. Or, whichever we exploit, is going to mean a whole lot more high voltage transmission lines crisscrossing our landscape.
And I'm not even doomerish by nature. I work in energy systems. At every turn of the energy technology's wheel, the fuel and systems are exponentially increasing in complexity. At some point, there is evolutionary limit imposed by nature and thermodynamic corrections occur.
Here's a recent example. I'm doing electrical engineering for run of river hydro electric stations. Those constructed recently have automated and manual controls for the generators. The automation is done by PLC's (programmable logic controllers), discrete controllers, protective relaying and some human inputs. The manual controls are the good ol' hand switches and analogue meters. Either one can be used to start up and run a generator, but not both at the same time. The salient question we have these days is, "Who knows, or can operate the manual controls without potentially destroying a $20 million machine?" I'd rather not put in the manual controls except for safety stops. (Plus, I'm lazy as the duplicate control system creates four times the work).
This notion of technological dependency is not new (er,...um Luddite). However, one needs to keep the scale of the energy field in mind. (I just coined that phrase). As the technology complexity increases, the size of the energy field increases - that is, inputs are required from locations and cultures farther away. The result can be the net energy return could be less (i.e. nuclear fusion) than the apparent local energy gain. It's just a matter of perspective. nuff said.
Entropy wins - every time...
A whole lot of fluff in all above, with no backup. Put up a credible reference, or can it.
Thermodynamics is not irrelevant to this site! I have an engineering degree, and post on this site.
It takes energy to make energy....conservation of energy is very relevant to oil production and consumption. Since most electricity generation involves heat production, it is relevant to that too. That is why is makes more sense to use wind and water to generate power without heat. Heat loss makes coal, oil, and gas plants much less efficient.
Please explain, in simple words (for us non-engineers), how the energy cycle that results in hydro-electric or wind power does not involve heat. Keeping in mind that the energy source for both is solar energy from the sun.
I think the point is that we didn't have to mess around with the heat - it was done for us and we just use the mechanical energy that arises from it.
Aha! A trick question laid to trip up us cornu-fools!
The point is that burning coal, oil and gas to produce heat to make electricity is wasteful and causes pollution. Only a small percentage of the heat is converted into electricity. Same is true for gas burning cars. There is a better, cleaner more efficient way to use the Sun's heat energy.
But unfortunately there is no better way to use the concentrated solar energy that hit the earth a hundred million years ago; all that's left of that bounty is fossil fuels.
"It takes energy to make energy"
You mean "it takes energy to MOVE energy", because at the end of the day, you can never make it, at least not if you take the laws of thermodynamics as valid.
If we could convey to the average folks that ONE LAW, that humanity does not and CANNOT make energy, we can only move it to where we can use it, we would have accomplished so much.
RC
Yes! Yes! Yes!
I have received so many blank looks when I explain that a hydroelectric dam, coal fired plant or PV panel does not produce energy, it only converts it from one form to another.
One particularly frustrating time, I was explaining the difficulty of hydrogen storage (boil-off and/or pressure vessels).
The reply was: "Well then, why don't you just make it as you need it?"
We have a ways to go......
When I get around to the next post, I hope that people who read it will understand how to do just that.
Now, thermodynamics has everything to do with energy.
In other words, you are telling us you are stupid, but because 999 in every thousand are stupider than you, it doesn't matter.
Thank you for that clarification.
The properties of heat engines were used to get the concept of entropy and an absolute temperature scale, but the laws of thermodynamics apply to everything we do. Hence this version of the zeroth law:
You must play the game.
Maybe the rule should read, "The game must be played." Because "I" or "you" will stop playing the game when we're dead, though the game will continue to be played with our remains.
If you want to lay a wager, I'll be happy to take your money (purred the engineer as he eyed his Rubber Bibles and copy of Sonntag & Van Wylen).
I would bet more than 1 in 100 can do it justice soup-to-nuts, and at least several in 10 can follow the work and do the math. I could have done it all 20 years ago, but I can still follow along just fine.
Fine.
Describe the maximum and typical efficiency of a wood-burning steam engine of the sort appropriate to drive a 19th century locomotive, in an ambient temperature of 25C, including the derivation of these answers from basic physical principles. Describe the difference when using coal instead of wood.
I am not saying that you can't do it. I remember studying these things myself in an introductory college physics course. But, I think that if you do it, and show here what is involved, it will establish two things:
1) The principles of thermodynamics are almost completely irrelevant to the topics discussed at this site, and;
2) Maybe 1 in 1000 people here could do what you do.
Fine.
Describe the maximum and typical efficiency of a wood-burning steam engine of the sort appropriate to drive a 19th century locomotive, in an ambient temperature of 25C, including the derivation of these answers from basic physical principles. Describe the difference when using coal instead of wood.
I am not saying that you can't do it. I remember studying these things myself in an introductory college physics course. But, I think that if you do it, and show here what is involved, it will establish two things:
1) The principles of thermodynamics are almost completely irrelevant to the topics discussed at this site, and;
2) Maybe 1 in 1000 people here could do what you do.
As I said above:
The properties of heat engines were used to get the concept of entropy and an absolute temperature scale, but the laws of thermodynamics apply to everything we do. Hence this version of the zeroth law:
You must play the game.
First Law of Thermodynamic Rhetoric:
The Laws of Thermodynamics are used by people who know nothing about thermodynamics to convince other people who know nothing about thermodynamics of things that have nothing to do with thermodynamics.
Tell me I'm wrong. But be prepared to talk about steam engines in detail.
The next posting will cover internal energy (E) and enthalpy (H), and move on to Gibbs free energy (G). From there I'll move first to apply these to chemical reactions and then to power generation flow systems. The power generation flow system will be a steam turbine circuit, kept to four basic components (pump, boiler, turbine and condenser). This has been my bread and butter for more than thirty years (chemistry first, mechanical stuff later). The challenge here is to keep it concise enough that people will read it, yet accurate enough that it will stand critical examination. I dislike having to gloss over some points, but if I don't, these pieces will be far too long.
It may be a few weeks before the next piece appears - I do have other things to do. I might add, though, that I have made a pair of presentations on thermodynamics and its application to power generation to a group of economists who work in my organisation. The presentations went down well, and I'm very glad I did it. It is essential that scientists, engineers and economists learn to understand each other.
Yes, there is a lot of BS about. I try very hard not to add to it!
Suggest you edit and blank your duplicate comment.
What's your wager? If you want this as a contract job instead, my rate is $100/hour.
Some think that by melting sand, mining iron ore, etc, electricity from mirrors in Morocco can displace oil and gas within a few decades. Not so simple. As BC_EE just said, solar's diffuse.
Add up the cost of enough mirrors or troughs, steel framing, boilers and molten salt or pebble storage tanks to deliver the equivalent of a barrel/day or a kilowatt (the units don't matter, as long as one makes a like-for-like comparison). Compare this to the cost of the equipment to pump (concentrated) crude oil up out of the ground, refine it and deliver to consumers at the same rate.
When others did this calculation, e.g. Amory Lovins of RMI, they concluded that energy from most renewables (or nuclear) cost one to two orders of magnitude (10 to 100x) more in capital investment than energy from oil, gas and opencast coal.
So then we'd look to borrow in round numbers £10,000,000,000,000 or more likely £100,000,000,000,000 (a hundred trillion) for a massive worldwide shift from oil & gas to solar & wind. This looks problematic, especially now that there's a growing difficulty in securing credit; see www.theautomaticearth.blogspot.com et al.
Perhaps it's surmountable but the most useful way forward is to focus on the scope for energy efficiency investments which are generally cheaper, closer indeed to the costs of oil and natural gas, which reduces the amount of renewable energy needed. If as others speculate, we've left it too late to finance any kind of changeover, it'll be a mess.
DavidOliver - you've hit the nail on the head there. These are the most fundamental points that need hammering and hammering and hammering! (But I think that "if" is a "now that".)
Since the hydrocarbons are or soon will be in decline, and will continue declining, it seems to me that not only are you right, you are more right than you say -- i.e. we have to retrench and continue retrenching all the way down the decline curve. This means much more that just efficiencies, it means that over the next few decades there needs to be retrenchment to sustainability, i.e. retrenchment to surviving off above ground resources.
More fluff. Credible reference documentation, please.
If the entire world's transportation were today powered by solar electric and someone proposed switching over to "this newly discovered petroleum material we're calling gasoline and diesel", you would all have exactly the same number of fool arguments why that would be impossible.
Don't give me such statements as "solar energy is incredibly difuse" and expect to sit back and declare the argument won. Give me ENGINEERING CALCULATIONS on EXACTLY WHY you think that solar thermal is an impossible proposition, or reference same.
First off, solar power is incredibly expensive. For example, these solar panels are an incredible $3.60/Watt delivered. According to reviews initial output is ~15% above the rated output at 70W and at 25 years it's still warrantied for 80% of it's rated output, or 45W, so in an area w/ an average ~6 hours of peak sunshine per day, Los Angeles for instance, over it's warrantied lifetime energy from that model solar panel would cost a whopping 8.3c/kWh, and in Fairbanks would cost 12.4c/kWh. W/ the U.S. average at 11.3c/kWh, with 14.5c/kWh and 16.3c/kWh in high price areas like California and Alaska respectively. Since it'll continue to output a declining amount of energy after those 25 years, probably till it's 50 years old and maybe beyond, it would cost an incredible 5.5c/kWh over it's lifetime in LA, and a tremendous 8.1c/kWh in FA.
These people are already paying 14.5-16.3c/kWh for electricity, how can you Cornucopians expect them to pay 5.5-8.3c/kWh for cleaner electricity that's insulated from fuel price swings and has far fewer externalized costs, well on it's way towards sustainability? Toss in state and federal tax credits and there's no way we can transition to solar power. Profits don't grow on trees hustla! Sustainability don't make money, and the abuse of the 2nd law of thermodynamics when fear mongering is all about money. Cash cash money money playa! It's about d00ds who are so gangsta they can shoot a guy in the face and he'll apologize to them for it, cuz it's so horrible that his face got in the way. Pump the markets like it's a bounce house then pull the plug and walk wit da cash, start a couple wars so you get soma that Iraqi gold (First time the majors have been in Iraq in decades) fo yoself, drive up food prices fo yo homies in da midwest, cash is king biatch!
You best be respectin' da d00m3rs Cornucopian...
;)
Too much money for the amount of real natural wealth on the planet. That's why no one wants to lend, because the lenders understand it can't be paid back. And secondarily, no amount of money will suffice to create mechanisms to concentrate (entropy and Maxwell's Daemon) all the solar energy - in the deserts or Morocco or elsewhere. [ No amount of money - not even if you increase it exponentially - will create more real natural resources; it will only dilute the "share" of that real natural wealth attributable to each unit of currency.] RC wrote in this thread "takes energy to create energy" - which should be "to order it" and maintain order - that's what the solar collectors do. Bring these points together and one can understand that it would be enormously difficult to organize enough already concentrated wealth (not only financial but real natural wealth and resources) to build the mechanisms to concentrate the diffuse energy arriving in solar form. Sorry if that seems a bit convoluted.
cfm in Gray, ME
Some people on this site (naming no names) are clearly living in cloud-cuckoo land. How should we respond to them? Surely not by humouring/mocking. Referring (on or offline) to psychiatric services? Taking seriously? Ignoring? Challenging their assumptions?
I myself favour the latter where possible, else the preceding.
Just so I know, is "cloud-cuckoo land" a scientific definition, and if so can it be expressed mathematically?
We just want to keep thinks scientific here, right? :-)
RC
I think that was a Lightning Seeds album. One of the first CD's I ever bought.
ThatsIt - since you ask, I was using a slangish expression by way of trying to be tactful. For more scientific terminology, "psychotic" would mean something more serious. Precisely what I mean is "having a level of wishfulthinking so high as to prevent perception of important facts or implications thereof". This leaves the question of how high that is and whether there's any way of measuring wishfulthinking anyway. I've always considered the supposedly easy sciences of human behaviour to be really the most difficult just because of these difficulties/impossibilities of measuring the most important variables (as opposed to the less crucial variable IQ). My fuller discussion of measuring competence variables is at www.zazz.fsnet.co.uk/validmea.htm later developed in http://www.lulu.com/content/140930 pages 40-65.
Hi RobinPC,
"How should we respond to them?...Challenging their assumptions?"
Challenging an anti-doomers assumptions is like trying to nail water to a wall.
In the face of thousands of peer reviewed and accepted scientific papers and articles on the validity of Peak Oil and its ramifications, anti-doomers insist that the negative ramifications of Peak Oil do not exist and us Doomers have somehow colluded to propagandize 'negative' Peak Oil outcomes for some unexplained reason.
Try to reconcile this header from www.debunkingpeakoil.blogspot.com
"Peak Oil Debunked
Debunking peak oil hype with facts and figures, and exposing the agendas behind peak oil.
DISCLAIMER FOR IDIOTS: This site officially accepts that oil is finite, and will peak someday."
Try to post anti-anti-doomer materials to www.debunkingpeakoil.blogspot.com. No matter how rational your posts, JD will banish you from his quality, but anonymous, blog.
Best to refute their statements but only if you can locate your sources, otherwise they harp [correctly] that you are spewing propaganda, not facts.
Thanks for posting such a clear presentation on thermodynamics. I've always been interested in the process by which complexity arises out of simpler forms, given the tendency of entropy to deconstruct and simplify everything. I have some understanding of chaos theory, and how energy inputs can drive structures to bifurcate.
I think that one point that should be made about that is that the creation of order in one place is made possible by the creation of a heck of a lot of disorder elsewhere. Using the sun's radiation to drive plants that get eaten by animals that then may eat each other, and then pass quite a small amount of information to their offspring is a fascinating process, but an exceedingly inefficient one.
I'd have preferred a more idiot-friendly presentation of Libelle's point as follows.
The growth of complexity in the biological world is made possible only by the energy input from the sun shining on the planet. The sun meanwhile is getting less complex, along with the solar system as a whole. (I apologise for butting in uninvited here and I trust I haven't violated any laws of Libelle.)
Exceedingly inefficient, yes, and tremendously resilient.
Peter Atkins has a new book, Four Laws that Drive the World which has some applications worked into the concepts. This makes it a good follow up to Libelle's article. Atkins also has a short book, "The Second Law" and a chapter on thermo in "Galileo's Finger". Most biochemistry texts give a good short intro on how biology systems are explained through the use of Free Energy. The Journal of Chemical Education has many discussions about how to teach thermo concepts. The real take home book for the application of thermo to the enviroment is Howard Odum's "Environment, Power and Society". Parts of Odum's work can be obtained at dieoff.org.
Hmmm, I'll ponder those thoughts.
Off topic:
I just had a chat with God and requested the dissolution of the physical plane nation of Israel within the week. God's answer was - It is your duty to inform humanity of that request if you wish it to be implemented. You have been duly informed.
I strongly recommend you do not delete this comment.
NO PREDJUDICE AGAINST ANY INDIVIDUAL NOR ACTION BY ANY INDIVIDUAL IS REQUIRED. GOD USES NATURAL PLANETARY FORCES TO IMPLEMENT DIVINE WILL.
I am willing to make disambiguations should they be required.
The title of this post should have been "In this house we do not ignore the laws of thermodynamics".
The laws of thermodynamics are self-enforcing. There is nothing to be debated here. You have to learn these laws just like every student of physics does. Contrary to some rather philosophical discussions above the laws of thermodynamics govern the future of alternative fuels and technologies. In particular, all EROEI (energy returned on energy invested) calculations depend on the laws of thermodynamics.
Didn't we just have this:
Welcome to The Oil Drum: EROI
http://eroi.theoildrum.com/node/4784#more
3 days ago. Already forgotten?
I'm inclined to agree, but the Simpsons connection was too good to resist!
Oh, dear god, we have a hit a tipping point...
;)
The laws of thermodynamics govern energy systems and therefore are necessary to determine efficiencies of a process involving exchange of heat and conversion of energy. The basic idea of converting chemical energy of fossil fuels into another energy type (kinetic like moving a car, potential like electricity, and other forms like light/electromagnetic) still have relevence to thermodynanics. This is because some of the chemical energy is converted by a process into something we want, such as moving a vehicle or making electrons flow. The fossil fuels are broken down in a reaction making heat (higher temperature) which is then converted to useful work with heat left over (rejected at the lower temperature) and loss of entropy (more molecules at the end of the process than at the start).
Thermodynamics has a great bearing on how we use energy in processes, but not much on where the energy actually comes from.
One more comment about thermodynamic equation in second law. The term "Enthalpy" describes energy loss or gain in matter due to change in temperature or change in phase. For example: water which is in a gaseous state (steam) can release energy in change from gas to liquid while not changing temperature, although the pressure does change. Thus energy is theoretically extracted at a constant temperature. In actuality a small temp change is required for this process of phase change to produce real work as in a steam turbine. Also the efficiency of extracting mechanical energy from steam is much higher when large temperature differences between boiler temperature and condensor temperature are present.
Nice basic description of "thermo" laws Libelle.
No, that's part of internal energy. Enthalpy adds the product of pressure and specific volume, thus capturing the amount of energy transferred when something crosses a control boundary.
Yes, I do thermo analyses. For my own personal edification (you can call it "fun" if you want).
Thermodynamics, and in particular measuring efficiencies in exergy, can illuminate many energy choices confronting us. It clarifies pitfalls - such as the "100% efficiency" of wasteful electric resistance heating - as well as opportunities - such as drawing power from cold sinks as well as hot sources. Much of this is very well explained in the book "Smelling Land" by David Sanborn Scott. But his point is to argue for nuclear generation of hydrogen, and subjects peripheral to his mission, such as oil depletion, get careless treatment.
Have you read this book, Libelle? I'm hoping you can clarify his sketchy comments about exergy in chemical reactions. In a footnote he says, "Some chemical engineers may think exergy is nothing more than a new name for free energy. But free energies are a property of only the material, not of both the material and the environment, as is exergy." Can you clarify this, or point to some writing that does? Do specific chemical reactions correspond to specific temperatures, placing them on an energy quality scale?
Errm - could anyone clarify quite what it is about electric heating that is peculiarly wasteful? Sure, apart from supply resistance losses there is a guarantee of substantial inefficiencies at the generation end. But are we comparing apples with apples anyway? Hydro can only produce either electricity or on-site mechanical. Nuke is unlikely to be efficiently used for anything non-electrical. Coal-fired electricity generation has high inefficiency but is anyone seriously proposing any much more efficient ways of using that coal? I can only see a strong ground for complaint in respect of excessively using oil and gas for electricity generation.
I think you should bear in mind that one great plus of electric heating is its great flexibility - at this moment (-3 outside) I have just a little 500w radiant pointed towards this corner of the room, which I'm about to turn off anyway (and I should clarify that for reasons related to the Ronan Point collapse no non-electric heating is available at this address anyway!).
If low grade heat is required, say for space heating, then using the same amount of electricity in an advanced reasonable cost air heat pump typically gets you 3-5x more heat compared to electrical resistance heating. In other words, you save 3-5x the electricity using the air heat pump. The recent CO2 transcritical cycles have a large operating range, so can be used even in colder climates with much better efficiency than electrical resistance heating.
If high grade heat is required, it's a different story, as the equipment becomes more complex, and the theoretical coefficient of performance drops off, but even high temperature industrial heat pumps will still be more efficient than an electrical furnace. IIRC heat pumps can't operate under really high temperature lifts, like an electrical arc heating furnace for tungsten or something, and theoretical COP is close to 1 anyway (so little difference compared to resistance heating). But for most applications, heat pumps offer a serious efficiency bonus, so in that sense much electrical resistance heating today is wasteful.
RobinPC asks for clarification on the wastefulness of electric resistance heating. Electric energy, like mechanical energy with which it is essentially interchangeable, is "high-quality", "ordered", or in Scott's choice of words, "structured". Heat energy can only produce such energy in the proportion determined by the temperature drop between the source and the sink, as a fraction of absolute temperature. So it inevitably takes several kilowatts of coal heat to produce one kilowatt of electric power. But if you burn that off in a resistor you just get one kilowatt of heat back. A heat pump, although capital expensive of course, might get you back several kilowatts, because it is only raising existing heat a few degrees - the reverse of the same dynamic. Just burning the coal directly for heat would also be much more efficient.
Costs and practical inefficiencies of existing hardware of course impose further constraints. But Second Law analysis distinguishes inefficiencies and opportunities which might yield to ingenuity, from the obdurate constraints of nature itself.
Thanks for your replies. I forgot to mention I'm 170ft above ground here. I suppose I could air-source a heat pump but a lot of cost and bother for a rather inflexible system. All I need is an occasional bit of radiant in this half of the room. Meanwhile the last thing I want is air-heating as I already have to use a humidifier to counter the dry air 170ft above a city full of others' heaters!
I think I'm on safe ground in reckoning that resistive is the most efficient way of converting electricity to radiant.
Nope, you're on thin ice with that statement. Resistance heating is almost certainly the lowest investment cost, and the easiest (cheapest) to install and maintain. But heat pumps are always more energy efficient than resistance heating. And if you burn the fossil fuel with reasonable efficiency to generate electricity to power a modern air heat pump, that will be more efficient overall than burning the fossil fuel directly too.
http://www2.kankyo.metro.tokyo.jp/sgw/asianetwork/presentationfile/heatp...
One of the most efficient and comfortable systems is an air heat pump coupled to fluid based (pipes in the) ground heating systems. But they are very expensive for existing buildings, and if you're in a high rise building, odds are the floor isn't suitable.
If you live in a rediculously cold climate, heat pumps are problematic. My suggestion would be: go live somewhere warmer ;)
Chemists like to consider "stuff" and consider what happens in a reaction that can be related to the amount of stuff that undergoes a change. By controlling conditions of the reaction, the amount of energy that is released (or absorbed) by a reaction corresponds to the amount of stuff that is reacting. In the same way, the change in the structure of the "stuff" corresponds to the entropy change occurring in the reaction. These two concepts are combined into a "free energy" change which can be considered as the amount of energy available to make things happen. As a reaction occurs the free energy is degraded into heat, and if the reaction occurs in the proper reaction vessel, work can be accomplished. Chemists have established rankings of the free energy content of substances so that the amount of energy available can be determined by calculating the differences in the reference values of the materials that react and the materials that are produced. There are experimental constraints that are used to make these calculations, which limit their usefulness in very dynamic situations. Their best use may be in biological systems that opperate at constant temperature and pressure. Standard biochem texts give good examples of the thermodynamic basis of life.
I have not read his book. He was pushing hydrogen close to thirty years ago, and I once watched in fascination as a lecture hall of graduate students (mostly chemical engineers) asked initially polite questions about where the energy to make the hydrogen was going to come from. No answer (at all) was forthcoming, and they tore him to shreds with further questions. I have never seen anything like it. Everything I wanted to say was said for me. He is still advocating hydrogen. He fares much better with politicians than with engineers. I have seen him talking to politicians with no problem at all.
I did spend a while talking to him at a peak oil-related meeting about ten years ago. He said then that you can get the energy from anywhere you like, which seemed unhelpful at best. He did not recall the earlier experience, which surprised me. It seems he has now decided to go the nuclear route. That is not to my mind a "hydrogen economy" but a nuclear one, and I for one can't see much of a future for hydrogen in it even then.
I would have to read all of what he says about exergy, but from your quote above, it looks as if we are looking at a distinction between G (Gibbs free energy) for a substance and delta G for a reaction or process. I can't recall ever using G for a substance - it's always delta G that is useful. I'll do my best to clarify in another thermodynamics posting. It's very closely related to exergy. The answer to your last question is no, and I can't elaborate further without writing the next posting. :)
I like to think of entropy in chemical reactions as a jigsaw; the pieces have to fit nicely together. With hydrogen, there's your problem. Paul Dietz has an excellent clarification of this inherent inefficiency.
http://pfdietz.blogspot.com/2005/11/direct-carbon-fuel-cells.html
Unfortunately, we can't make (store energy in) elemental carbon through electrolysis so as an electrical energy storage system with high cycle efficiency this gets problematic - it's more of a way to increase fuel (coal, biochar) efficiency. Thoughts?
In investigating and evaluating our economy, our infrastructure, our society, our biology, thermodynamic considerations are one important part of the analysis. I propose there are two others.
In the real world, there is also a physical framework through which energy flows. The framework may be a circuit board under power, a plant cell performing photosynthesis, a neuron resetting, an electrical grid, a telephone ringing, a heart beating, a brain thinking, an engine firing, or a crowd rioting. The availability of a framework through which energy flows is governed by the conservation of mass.
The conservation of mass, the second part, specifies that "Within some problem domain, the amount of mass remains constant--mass is neither created nor destroyed." (nasa.gov) This is relevant to us because the framework through which energy passes comes from somewhere. The physical materials are depleted in one area (mines, ores, inventory), recombined, and added to another area to build an infrastructure (eg., to lay pipelines, string electrical wire, pave roads, provide food to increase population).
The third part is the thorniest, yet it has fundamentally to do with the interaction between energy and the framework, and the construction of the framework itself. This is the problem of complex or chaotic systems. While there doesn't yet exist a consensus on an accepted definition of "complex systems", complexity and chaos can be thought of as the analysis of the difference between what one person, neuron, or water molecule does, and what groups of them do interacting with each other.
Further discussions into chaos, complexity, the butterfly effect, phase spaces, fractals, self-organization, auto-affinity, differential equations, iterative systems, and emergent behavior may be beyond the scope of this post, but I would recommend the following:
"Chaos: Making a New Science", James Gleick, 1987. 300 pages. James Gleick is a Pulitzer Prize-winning former reporter and editor at the New York Times. The book reports on not just the ideas that led to new ways of thinking but also the dozens of players involved, including Benoit Mandelbrot and the late Edward Lorenz. An excellent introduction for anyone, especially the systems neophyte. It's available at Amazon and likely your local library.
"Nonlinear Dynamics and Chaos", Steven Strogatz, 1994. 500 pages. Strogatz is a professor of applied math at Cornell. The book is suitable for a graduate-level text on chaotic and dynamical systems, with explanations, diagrams, differential equations, and problem sets. Well-written. Available at Amazon, your local library, and on the net if you know where to look.
MIT OpenCourseWare - Nonlinear Dynamics and Chaos. Online class with downloadable syllabus and materials from 2004. Uses Strogatz's text above. Freely available at the link from MIT.
Strogatz has also produced this year a 24 lecture (12 hour) series for The Teaching Company on chaos theory which I have not yet seen. It's about $250 for the DVD set, Google "teaching company chaos" to find it.
To sum up, I think it is the complex interaction between energy flow and the underlying physical frameworks which needs to be understood.
710,
Excellent recommendations. I began studying "chaos" theories about 10 years ago and still consider myself a rank amateur. But even with my limited understanding of complex adaptive systems it's very difficult to see our political system ever dealing with such realities. Just watching the current effort to "correct" the economy with, IMHO, little understand (or at least acceptance) of the potential unintended consequences is rather scary. So much emphasis on “goals” with so little attention to cause and effect.
Well, modern chaos theory is not even 50 years old yet. While it has roots going back to Newton's calculus, the late Edward Lorenz is considered the father of chaos theory with the publishing of "Deterministic nonperiodic flow" in 1963.
I don't think our political system, our legal system, or many of our social conventions are going to deal with the realities very well.
It comes down to a central issue: why do most new things fail? New genetic mutations are likely to be deadly, pre-planned communities are likely to dissolve, new business ventures are likely to go under, and then here we have our first attempt at complexity beyond the tribe, civilization, which is about to collapse in a rather devastating way.
So why do most new things fail? There's an answer to this question which I can see within an understanding of complex systems. Unfortunately, so far my initial attempts at describing this in writing have been incredibly unsuccessful.
But that most new things don't work as intended is visible all around us. Alpha, beta, or 1.0 versions of any software. Attempting to describe the dangers of energy depletion to the uninitiated.
Heat pumps are useful if all your primary energy comes in the form of mechanical work or electricity; e.g. a hypothetical country with nothing but tidal, hydro and wind power.
If your energy is in the form of high-grade heat; e.g., solar, biomass, geothermal it's probably a better idea to use it in a heat engine, produce electricity and reject heat at the temperature needed, which might be 30 degC for heating glasshouses or 70 degC for producing domestic hot water or heating buildings (70 degC is about the minimum taking heat exchangers and mains losses into account).
The CHP system in Copenhagen, Denmark delivers 1 kWh of hot water to consumers' radiators or DHW tank while burning 0.12-0.13 kWh of high-grade fuel (mostly gas and biomass nowadays).
An electric heat pump with a COP of 3.2 in the UK (overall efficiency of power generation 0.36) would deliver 1 kWh of hot water to the radiators or DHW tank while burning 0.85 kWh of fuel (mixture of gas and coal) in the power plant.
So CHP uses quite a lot less fuel than electric heat pumps. Why? Mainly because large gas and steam turbines can be built to approach the theoretical maximum performance (see the 2nd law) more closely than small refrigeration plants sized for a single house.
I do believe you left a few details out there, because it implies a violation of the First Law.
More than a few. They make use of cogeneration, industrial waste heat and waste biomass combustion, I believe. The "high-grade fuel" (natural gas) is used in boilers required at peak demand only.
As an interesting sidenote to this discussion, has anyone else here seen the "Nova" episodes (2 hours total)"Absolute Zero" that has been being repeated on PBS recently? If you a fan of the history of science and thermodynamics, it is worth watching, very good. The history of research in the area of thermodynamics has proven how easily it is to be certain we know things, only to find out later that we were beginning from completely false premises. Very thought provoking by the standards of normal television.
RC
"Maximum efficiency imples reversibilty of the process"
This makes me think a spellchecker might be useful.
Also, why no reference to the glorious über-human who gave you the title?
Thanks for finding those. I've fixed them. I'm using Seamonkey as an HTML editor - I'll see if I can get a spellchecker going.
As to the title - there is a link to sound file in the first part of the article. I'll be more explicit with a number of things in future.
I'm surprised you have time to look here these days!
Libelle—you correctly point out in your discussion of the Second Law that if a supposed third heat reservoir existed at a still lower temperature, T3, and a second heat engine operates between the second and third reservoirs, then q3/q2 would be F(T3,T2), and that the sum of the efficiencies would be the same as that which would be obtained from a single engine operating reversibly between the first and third temperature reservoirs.
Later, in your discussion of Entropy you conclude with the statement that “you can only break even on a very cold day”--and that furthermore that, “it never gets that cold”, referring to absolute zero being a hopelessly unachievable target.
The fact of the matter is that recovering energy for humanity’s use has never has been about “breaking even” in the sense that you describe it, but rather “getting the most out of what is available to us”.
I this case, I submit that your comparison, instead of elucidating a thermodynamic concept, becomes instead, a case of “the perfect being the enemy of the good”. Your countryman, Louis M. Michaud, P.Eng., has pointed out that there is, in fact, a huge reservoir (or repository) to which heat (q3) may be rejected which is not at absolute zero, but rather at (220 K to 250 K), which is the temperature of the tropopause.
Nature uses this repository frequently during thunderstorms or hurricanes to generate huge amounts of kinetic and electrical (lightning) energy. The Atmospheric Vortex Engine, which Mr. Michaud has patented, represents a reasonable attempt to copy what nature has achieved while accessing this reservoir. As yet, no one has provided proof that the concept cannot or will not work as described(ref:http://vortexengine.ca)
If this reservoir can be accessed, as he believes it can, the implications are indeed tremendous. In particular, all the q2 we have been rejecting at T2 (historically the temperature of the earth’s surface) can become a “heat source” instead of a rejected heat, now available for conversion to work, with the unconverted balance be rejected at T3. In fact, with the huge amounts of energy available in warm seawater within 100 m of the surface, as well as abundant geothermal, most places on the planet could be supplied with virtually unlimited amounts of low-cost power (at least until the earth started to freeze up again) :)
I'll check it out.
• Heat input 1000 MW.
• Electrical output 200 MW.
( http://vortexengine.ca/PPP/AVE_Basic_Introduction.pdf )
So much for harnessing the power of tornadoes. Clearly not going to make much impact on any energy crisis.
I think the idea is to use CHP such as nuclear-thermal or solar thermal. That's one very tall bottoming cycle!
If only it wasn't total... vaporware.
Pardon the pun.
If your dismissal of the AVE is based on its efficiency (nominally 20%) I would remind you that about 500,000,000 automobiles are operated daily that achieve less than this figure (on average) in their heat to work (drive wheel) conversion efficiency. Further, they cause depletion of a valuable fuel while adding carbon to the atmosphere.
If it is based on comparison to nuclear plants, these achieve a maximum of only about 30% based on (already enriched) nuclear fuel burned in the plant and power exported at the plant gate. When you include the mining, enrichment, waste management costs, overheads, "equivalent energy costs" set aside for decommissioning and increased power losses for transmission based on their more remote siting, I would be suprised if they netted 20%. Furthermore and AVE would not be as exposed to the possibility of future fuel price increased due to depletion of its feedstock.
While there are other disadvantages of nuclear compared to the AVE that are too numerous to list, Mr. Michaud suggests that initially, the AVE be made to operate on the waste heat emanating from existing coal, nuclear, or natural gas plants.
If your criticism is based on it's nominal capacity, what you don't have in size, you can make up for in numbers. If operated on "purely environmental" energy (CAPE), you could cluster 4 or more of these into "energy parks" (two spinning in one direction, two spinning in the other, that might take up only 4-8 km2 in area. As with windmills, this would not exclude the possibility of farming withing the zone.
Please understand, the numbers provided are only "nominal" Ultimately, we don't yet know how large a single vortex could be made and controlled--that will be determined as the development process advances. As for total availability, about 6 TW of energy is transported upward by convection each day--thousands of times what man released during the burning of "fuels" be they fossil or nuclear.
I can't speak for Robin, but the whole thing just looks like vaporware to me. I'll believe it when a full scale prototype is operating reliably.
FYI, the AVE looks like vaporware to me too, with unrealistically high projections for thermal efficiency to boot; I don't see how you'd get 20% out of it even theoretically, once you start figuring the myriad routes for losses.
FYI--the conversion of thermal to kinetic energy in a typical hurricane, operating between similar temperature extremes, has been estimated by researchers to be close to 33% (sorry--am still searching for the reference).
However, this is missing the point. Even if it were to come out to be just 15%, or even 10%, in contrast to the alternatives, the "fuel" is not only free, but doesn't produce any objectionable waste. Further, the potential energy not captured mechanically, winds up in the tropopause where its heat content can be more easily radiated to outer space, and therefore acts as a surface "ventilator".
Good grief, folks--if we continue to make energy decision using terms like "just looks like", we're never going to get anywhere.
I'm sure it "just seemed like" heavier than air flight would be impossible to 99.99% of the population before two determined brothers named Wright proved otherwise at Kitty Hawk in 1903.
I don't use this reference casually because what the Wright brothers knew (probably just intuitively) was that flight could be achieved by adding Vorticity (downward deflection) to an oncoming air stream, using a suitably designed airfoil from which weight could be suspended.
Why then, does it seem so far-fetched to many, that by arranging a large number of airfoils, oriented vertically, in a ring structure, vorticity could be added to incoming air, and released from inside the ring in a vertical direction to which it would go due to its natural buoyancy?
Finally, the word "vaporware" doesn't sound that bad when put alongside it's main energy producing competitors, "Chemical-poisonware", and "Nuclear-poisonware".
Unless you're at risk of freezing in the dark, in which case the latter two sound pretty good even if you have attempted to prejudice the issue with your choice of nomenclature. People would probably call them "saviorware" after a close call with a vaporware scheme.
I'm sure it "just seemed like" the Earth was flat to 99.99%. HTA flight, not so much; almost everybody on the planet with eyes has seen birds.
The "fuel" you've been touting is the product of the chemical and nuclear "poisonware" you object to above.
Engineering-Poet--Let me rebut the comments, point by point, given by you in the "white zones" above.
Of course the term "vaporware" can be used in (at least) two senses. The first one is the "literal" sense, which I used, referring to the fact that the working fluid consists primarily of a stream of vapor (humid air) from which mechanical energy can be extracted, with the residual buoyancy allowing it to rise to great heights with the aid of vorticity.
The second sense is one implying lack of value, or substance, which (apparently) was the one used initially by Cyril R., who, if that was his intention, you should be blaming for prejudicing the discussion, not me.
You need to explain what you mean by a "close call with an (AVE) scheme." Do you mean trillions of dollars invested to suddenly find out they "don't work"?--Can't happen here like it could it the case of many of its competitors, including carbon sequestration and some renewable schemes. Either it will be shown to work adequately within about three years of its initial (full speed ahead) funding, which would be less than $100,000,000, or it will be a failure. Nobody will "freeze in the dark" as a result of its pilot implementation.
With regard to your HTA comment, I admit that you are technically correct. However, I think most people understood that birds were "designed biologically" for this and it would be disingenuous to believe that more than a tiny fraction of the population believed that "human" flight would be possible.
Lastly, the use of these fuels (waste heat from existing thermal plants) would be utilized only during a transitional phase in which it would be impractical to shut down all existing plants of this nature. It would be difficult to initially provide high population density areas with electricity only from renewables, so it is recommended that "hybrid" schemes be used for a period ot time.
Ultimatley it has been shown that there is plently of non-fossil based heat sources that could be used to power enough AVEs to supply electricity to everyone for a long time, including geothermal, urban-generated waste heat, as well as residual Convective Energy in the troposphere (CAPE) supplemented by warm sea or lake water.
Helpful. My favorite intuitive relationship with thermodynamics is food. That's a form of energy we all understand. My analogies are:
There is no free lunch
Lunch always costs more than it's worth
Without lunch you die
I got to see the second law in action yesterday when my dog pooped in a snowbank.