Cycles

Cycles, Energy, Electric Cars

Milankovitch Cycles
It is possible to calculate the solar energy received by the Northern Hemisphere as a result of the earth's movement about the sun and the resulting median temperature. Milankovitch did just that and published it. His calculations cover hundreds of thousands of years because they are cyclical and the orbital parameters are well known. These result in cycles of various periods and net results can be calculated. Calculations can also be made for the Southern Hemisphere, but that is not as interesting as the much greater amount of water and less of land leads to a moderation of effects.

The main and most rapid cycle is the daily 24 hours cycle we call day and night. Most everyone is familiar with it and knows there is a sizable temperature change associated with it. This is modified by weather, terrain, and locality amongst other things, and is heavily influenced by the length of daylight.

This brings us to the second cycle, the annual cycle of the seasons. This results from the tilt of the earth's axis to the plane of its orbit, and the annual orbit itself. As a result, at one time the earth is leaning away from the sun and six months later leaning towards it. Near the equator this does not much matter, but farther north, it makes a big difference. At the latitude of Columbia Missouri, the day and night lengths vary from about 9 to 15 hours. That makes for a lot of net heating during summer and net cooling in winter.

Summer and winter are affected by cyclical changes such as el Nino and la Nina, as well as by rather chaotic and random weather patterens. Some are mild, some are severe, but on the average over a long term, fairly stable.

These two facts, the tilt and the orbit, are widely known. Not so widely known is that the earth's orbit is elliptical, not circular. Currently it varies from about 90 to 94 million miles from the sun. Even less known is that the tilt is describing a slow circle, taking about 26,000 years, if I remember correctly. This precession or "wobble" is caused by the interaction on the earth of the gravitational attraction of the sun, Jupiter, and Saturn. The other planets are not important as the inner planets are too small and the outer planets are too far away. The earth acts as a big gyroscope, and this precession can be seen by playing with a gyroscope or even a toy top. Who these days plays with a top any more? Older people remember them and gyroscopes are sometimes available here and there.

The precession would not be important if not for the elliptical orbit. Over tens of thousands of years, the point in the orbit at which the axis is leaning away (winter) changes from the closest approach (where it is now) to the farthest approach. That 4 million mile difference means milder winters (now) and more severe winters (later and formerly). The summers also change from milder to more severe, but their effect is less, as a result of the strong feedback from snow and ice. Snow and ice strongly reflect solar radiation and drive the earth into and out of the glacials with smaller changes in that radiation received from the sun than you might think.

Each winter, snow fall increases and moves south. The snow line, where it does not melt before the next snow, moves south. Snow and ice reflect a lot of the solar radiation, so cause a further cooling and more snow. Eventually, the heating for the approaching summer breaks the feedback cycle and it begins to melt back north. There is usually a noticable delay in the onset of the movement both directions.

There is another effect, not widely known. The eccentricity of the orbit causes the orbital speed to increase as the earth approaches the sun, sort of going down hill into the gravity well, and decrease as it moves away, sort of climbing the gravity hill. As a result, it takes less than 6 month on the close side (where the orbital speed is greatest) and more than six months on the far side. About a week shift either way. This increases the influence of the winter part.

The net effect of these factors is to give the third cycle, the ice ages; that is, the procession of glacials and interglacials. A glacial starts when the permanent snow line, where it does not melt in the summer, moves far enough south that snow accumulates, packs into ice, and becomes thick enough to start flowing south. That is the contenintal glacier, or ice sheet. The period is in the small tens of thousands of years, and gives a nice match with data from the last four ice ages, and fair match on some before. The record is based upon ice cap cores, which give good data for about the last 400,000 years, and upon sea floor cores going back even farther, but getting less definite farther back. It took years to work out techniques, but they now have a very detailed record, believed to be reliable, giving average temperature and average CO2 levels, and several other things, based upon tiny bubbles trapped in the ice and the isotopic ratios of the elements found in them.

Less important, but still noticable, are various longer period cycles caused by changes in the orbital parameters caused by Jupiter and Saturn. These include changes in the tilt, several degrees each way from the present 23.5 degrees. Changes in the eccentricity amounting to a few million miles, the orbit sometimes more circular, sometimes more elliptical. Changes in the tilt of the orbit relative to the plane of the solar system. These lead to changes in the timing of the onset of glacials and interglacials, and show up in the record.

There are other possible effects from the possibility of a thin disk of material in the plane of the solar system, gas clouds encountered as the solar system orbits the galaxy, changes in solar output, etc. There are also random effects from vulcanoes such as Pintatubo, Tambora, Krakatoa, super vulcanoes such as the one at Yellowstone, outpouring of basalt such as the Snake River Basalts and the Deccan Traps, asteroid strikes such as Sunset Crater and Tunguska, and so on.

The main cycles are definite, the more subtle ones less so, and perhaps because of random effects or subtle ones not yet appreciated, some of the more subtle cycles are not always seen. For example, a 100,000 year cycle is missing the last 2 or 3 times around and no one knows why. Nevertheless, the Milankovitch cycles explain the record of glacials and interglacials so well there is little doubt they are the cause.

During the last four glacial - interglacial cycles, CO2 has followed temperature, going from about 125 ppm in the glacials to 250 ppm in the interglacials. It should be pointed out that it is rather definite that the cycles are caused by the Milankovitch cycles, so the CO2 levels are following, not causing them. The CO2 level may act as feedback, but it is not clear why it changes. Perhaps weathering of carbonate rocks being reduced while covered with ice, perhaps absorbtion in the oceans. At any rate, none of this could have been caused by man burning fossil fuels, although man may be involved after about 8000 years ago with the development of agriculture.

The most recent glacial ended about 12,000 years ago as the ice sheet began to retreat. As recently as 6000 years ago there were still remnants of the ice sheet. Since then, there have been a number of swings. One of the most notable was the Younger Dryas, just after the start of the current interglacial, when Europe became very cold and dry again for about 130 years, pretty well uninhabitable. From about 800 AD to 1300 AD there was the Medieval Warm Period when a colony was established in Greenland and flourished. This was followed from about 1300 AD to 1850 AD by The Little Ice Age, during which the colony in Greenland had to be abandoned. Since that time, about the last century and a half, the earth has been warming again. Rebound from The Little Ice Age? General rebound from the last glacial? Burning of fossil fuels, which started about then? Actually hard to tell.

CO2
That brings up the current uproar about CO2. The level in the atmosphere has increased on up to about 350 ppm and that has happened mainly in the last century and is plainly caused by burning fossil fuels. No argument. During that time, the average temperature has edged up a half degree. Also no argument. What is the effect of the CO2 and what will be the further effect? Well, therein lies much uncertainty and argument. Much nonsense, much jumping to conclusions, much passion, little dependable information. To say it is higher than at any time in the last half million years is debateable as the record is not of fine enough resolution to be sure there were no spikes at intervals before now.

CO2 is definitely a greenhouse gas; that is, it absorbs in the infrared, so allows visible radiation from the sun to pass through, but the infrared (heat) radiation going back is absorbed and re-radiated, slowly working its way out. Greenhouse gases such as CO2 act as a blanket of insulation and slow the loss of heat, thereby raising the temperature.

Thank goodness, else the earth would be an ice cube. CO2 is a known greenhouse gas. No argument. The trouble is methane also is and is about 23 times as effective. Water vapor also is and is even more effective, although it tends to stay in the troposphere while CO2 is also found in the stratosphere, so CO2 may be more effective overall than you would expect. Water vapor amounts vary widely, and there are also clouds that are very effective at reflecting visible radiation before it ever reaches the surface, and vary widely in extend over time. Hard to say what the effect of water is. Possible feedback, such as more clouds when warmer (or colder) further complicate estimates.

It all gets very complicated and no one knows just how to account for it all. There are models, and one for CO2 has predicted the raise in temperature over about the last 2 decades fairly closely, but has apparently failed over the last 5 years, showing a raise that has not occured. All very complicated and not the sort of thing to hang your hat on. Yet there are people so convinced we are destroying the planet, or will within 10 years, that they will just about jump on you and stomp you if you suggest maybe it isn't quite so definite. Algor predicted the 10 years to doom about 2 years ago, so I guess it is only 8 years now until the earth burns up or something.

You have to realize there are people who actually believe him and of course it would be serious if true. The fact that it may not be is of no concern to zealots. Unfortunately, political decisions are being made based upon these assumptions being true, and you have to realize that, to understand what is going on. Heck, they might even be true, but in that case we are probably doomed anyway, because there is no way we can quickly get off fossil fuels. I really don't like people who are shallow thinkers and don't bother thinking a few levels deeper. Sudden dropping of fossil fuels would condemn lots of people to death, and ignoring that is not rational. Maybe there are too many people on this planet. I think so. A lot of problems would be easier to solve if there were a few billion fewer people. What we should probably be discussing is how we choose all those billions who have to go and how we are going to get rid of them. That might be cruel, might be inhumane, might be inhuman, but at least it would be rational. It wouldn't be easy because people tend to have the annoying habit of trying to stick around in spite of your best plans. At least it would be rational. Getting rid of fossil fuels suddenly is irrational.

Of course by now it has become something of an excuse to transfer weath from the developed countries to undeveloped ones, allowing them to generate the CO2 so their standard of living can rise, giving benefits to more total people. The fact that our standard would drop is considered desireable as this envy of the more fortunate would like to see us punished. It all gets very complicated, and though I am not much concerned by the plight of polar bears, I am concerned the snow pack out west is melting earlier, which can lead to a water shortage. Fights over water could become serious.

I find it amazing that something so basically harmless as CO2 can be so feared, but that is what has happened. Rational thought is out the window. The glaciers are retreating! Well, they have for a long time. They may be retreating a bit faster lately, but the very idea of ice ages developed by observing retreat of alpine glaciers and correctly interpreting clear signs of earlier retreats. They have been generally retreating since the end of the last glacial. Maybe they advanced a bit during the Little Ice Age, maybe retreated a bit faster during the Medieval Warm period, but in general, they are retreating. After all, we are early in an interglacial. What do you expect, colder waeather? The next glacial will not be along for awhile.

We can't drill in the Arctic National Wildlife Refuge, purportedly because of the wildlife (what little there is up there), but the real reason is fear of CO2 from burning that fossil fuel. There is even concern about the polars bears in ANWR, but last I heard polar bears eat seals. They hunt them in Hudson Bay when it freezes over. How many seals are you going to find inland at ANWR? Mountain seals perhaps? The real reason is opposition to CO2. Within the last year a new refinery and additions to another near the tip of Lake Michigan were turned down. CO2 bad! A coal fired power plant in Kansas was turned down. CO2 bad! Anything that emmits CO2 (other than a loud mouthed politician) is likely to be opposed and prevented. We also can't drill more in the Gulf of Mexico although other nations are. There is lots of oil down there and off the coast of South America, but to use it would add CO2. CO2 bad!

The use of ethanol is not only tolerated, but encouraged, on the mistaken belief that it is CO2 nuetral. The theory is that the corn picks up all the CO2 from burning the ethanol. That would imply no energy expenditure to produce it. Since it takes as much energy to plant and harvest the corn and turn it into ethanol and distribute it as you get from the ethanol, that simply isn't true. Or more correctly, every ton of CO2 from ethanol use is matched by a ton of CO2 produced by burning fossil fuel to produce it. Since the zealots are not being rational, that does not seem to bother them. Suggest methanol, which would probably be produced from fossil fuel, and they have a fit.

That abomination of an energy bill calls for greatly increasing the supply of ethanol, but not of oil or coal. The amount of ethanol sounds impressive, but we are already using 10 times that much gasoline, and it will take all the corn to produce most of it and the rest will have to be imported. We import ethanol to lessen our imports of oil? How does that make sense? We are now importing about 13% of our gasoline for lack of refinery capacity, because we have not been allowed to build or upgrade refineries for some 35 years.

Then there is the commitment to develop hydrogen. Of course political commitments can and often are dropped as quickly as they are made. Hydrogen is a great fuel in some ways. High energy content, about 2.5 times as much as gasoline BY WEIGHT. Thus 6 pounds of hydrogen has about 2.5 times the energy of 6 pounds of gasoline, but the 6 pounds of gasoline is just 1 gallon, at atmospheric pressure. A liquid, easily handled. Hydrogen is a gas, a very very light gas. Those 6 pounds will occupy about 8000 gallons at atmospheric pressure. How big is 8000 gallons? About the size of an 18 wheel fuel tanker you see on the highway. It hauls 48,000 lbs, 24 tons of gasoline. Even with the 6 pounds being equivalent to 2.5 gallons of gasoline, that means you would have to have your car followed by about a half dozen tankers to supply you with enough atmospheric hydrogen to equal a tank of gasoline.

Begin to see the problem? Of course you could compress it. At 350 atmospheres, about 5000 psi, you would only need two 40 gallon tanks of hydrogen to equal a 16 gallon tank of gasoline. Want to play with 5000 psi hydrogen? It leaks readily. It embrittles steel, so can't be distributed by pipe line. It would just about have to be produced locally, either by reforming a hydrocarbon, such as methane (natural gas), or by electrolysis of water. The former produces CO2 (CO2 bad, think reforming will be allowed?), the latter will require a lot of electrical capacity, requiring coal fired plants, and guess what, more CO2. Of course they think in terms of the electricty being generated by wind or solar, but that is too limited and a bit more expensive. How in the world will you get hydrogen without offending the zealots? Remember, hydrogen is just a means of moving energy like the distribution lines for electricity. It is not a source of energy like coal or oil.
Rather than run electricty to a hydrogen plant, it would be simpler and more efficient to just run the electricity to a recharging station for an all electric battery car, provided you could recharge quickly, and now you can. More later.

Hydrogen does have a real advantage in a fuel cell. It is about the only material for a practical fuel cell as singly ionized hydrogen is just a proton and readily passes through a PEM (proton exchange membrane). It is the only element that can do that. The fuel cell is pretty simple and dependable if pure hydrogen can be delivered to it. This can be done by reforming a hydrocarbon fuel, such as methane, in the car, just before the fuel cell instead of at a fixed plant, with the hydrogen then needing to be transported. Using a liquid fuel like alcohol is even better as it is far easier to handle. Two alcohols, methanol and ethanol, can even be reformed in the fuel cell, making it even simpler. Water has to be added and the temperature raised. For methanol, the temperature is modest, about that of an ICE, and one third of the water from the exhaust can be recovered and used, and the reactions are simple and dependable. For ethanol, the temperature needs to be above the boiling point of water, which would be acceptable in a big chemical plant, but not good in a mobile one. Also, the reactions are quite touchy; so the fuel cell would not be reliable. Of the two, methanol is quite practical, ethanol is not.

Methanol can be produced in large quantities from coal, petroleum, or oil shale, or from such things as wood scrap, after all, it is known as wood alcohol. It can even be made from ethanol, so indirectly from grain, switch grass, etc. The overall reaction is C2H5OH + H2O -> 2 CH3OH. If I had it to do over again I might go into chemical engineering instead of physics. Facinating.

Methanol can be distributed by pipeline, if corrosion can be handled, or by tanker, same as ethanol. Trouble is, CO2 is also produced along with the methanol and also in the fuel cell. The zealots will not hear of it. There is no interest in this practical and available means of producing electricty in a car. Instead, the effort will be made to tame hydrogen, an exotic fuel, perhaps for the far future, but not hardly appropriate now.

Batteries
For about a century, pretty well the entire 20th century, the lead - acid battery was about it. It is still around, virtually unchanged. Oh, it is now sealed and the life has improved from about 2-3 years to about 5-6 years, but still, pretty much the same battery. Other than accessories, such as starting the engine, it is not very useful. It has been used in golf carts, but is not up to the needs of an electric car.

In the last decade or so there has been rapid development of others; NiCad (nickel - cadmium), NiMH (nickel - metal hydride), and Liion (lithium ion). The litium battery has about 20 or more times the energy capacity of the lead - acid and can be used for a car. The basic lithium ion still has problems, the main one being a slow charge rate and heat buildup. Both these problems have now been solved, at least well enough to get started. They were caused by use of graphite for the anode. Lithium ions could not attatch readily, only about 1 per 6 carbon atoms, and being the wrong size, they caused stress, producing the heat, which limited the charging rate, and giving a life of only about 1000 charge cycles, about 3-4 years typical use in a car.

Now they have lithium titanate which can be formed into very uniform nano particles, giving much more area to the anode, allowing many more lithium ions to attatch, and they are just the right size to avoid the stess. This leads to a much higher charge rate and a life of over 15,000 cycles, meaning they will outlast a car. The old ones needed about 6 hours to charge, the newer ones about 10 minutes. That is fast enough for a recharge on the road at a fast charge station, and with about 35 kwh (kilowatt hour) capacity, giving a range of about 150 miles, and that makes an all electric practical for over the road. At a typical 8 cents per kilowatt hour, that is about $2.50 worth of electricity per charge, but of course you would need about twice as many as gas tank fill ups, and some overhead, but still a good deal cheaper than a tank of gas.

Electric Cars
Why electric cars? I believe that of all the technology available or even on the horizon, only electric has the potential to give important advancement to cars, and that such advancement is somewhat urgent because of growing problems with energy supply. To repeat something I have pointed out before, the ICE (internal combustion engine) has served well and in some applications, such as aircraft and boats, probably will continue. However, the ICE suffers from a rather narrow efficiency curve, and for automobiles, most of its operation is well off the peak. It takes too long to start and get it ready for use to be able to shut it off while waiting, and start up causes problems with pollution, so it has to keep running, wasting fuel during the frequent waits in city driving. It also cant do regenerative braking, a big plus for electrics in city driving.

An aircraft engine can cruise at about 80% - 90% of maximum power, or where ever its best efficiency is, but an automobile is almost always running at 20% or less because it needs to produce lots of power to accelerate and pull hills.

Far more power than is needed for cruise. There is no good way around this. There are V8s that lock the valves on one bank to become a 4 cylinder for cruise (GM Cadillac), but they still have to lug around all that weight, and they are complex, meaning reduced reliability. There are small ICEs with an electric boost (Toyoda Prius), with all sorts of extra weight and complexity. There are other kluges, none satisfactory. All ICEs are complex and have a lot of machined parts, meaning expense, lowered reliablilty, lubrication, wear. The electric motor is near ideal. Only one moving part, the rotor, only 2 wearing parts, the bearings, ability to start immediately, so able to stop while waiting, and a broad efficiency curve, giving high efficiency at just about any speed. They generally don't need a transmission or differiential, saving a lot more machined parts that need lubricating and that wear out. Regenerative braking recovers energy when stopping, which is frequent in city driving where most driving is done.

Their big problem has always been the supply of electricity. A long extention cord..... The lead - acid battery just wasn't up to it, but the lithium titanate battery is. We finally have a practical battery for a simple, reliable, inherently cheap and efficient car. I want one.

I think all the technical details are there. All that is left is implementation. Now I don't accuse the big car companies of being either too stupid to notice or too contrary to give us these neat cars, but I do think they will drag their feet as long as possible. Consider the billions of dollars worth of investment they have in tooling, training, and plants to turn out the conventional car with a conventional ICE. They do not want to jepordize this investment with a sizable change. They can make more money tinkering and adding all those gee-gaws so common in SUVs. Look at the recent car show in Detroit. Just more of the same really, and emphasizing styling. Oh there were concept cars and talk of such things as hydrogen, hybrids, electrics, etc., but I think it obvious they really would rather just stick with what they know. At least until the competition forces them to reluctantly change, and they think hopefully that will be years as the large companies competing with them will also be reluctant.

Chevrolet keeps talking about the Volt, showing it, and assuring everyone it is about ready to go as soon as a better battery is available. Surely they have heard of the lithium titanate battery, but probably hope you haven't. They will keep dangling it until a competitor appears, and it takes a lot of investment to start up auto production, so as long as the other big guys are content to wait, so can they.

Unfortunately for them, there are other ways. A start up called Phoenix has tapped into several things out there. They have made arrangements with a South Korean auto maker to import cars without drive trains, and with a consortium to supply 35 kwh lithium titanate batteries, and with several other suppliers for motor and controls, and about all they have to do is put them together and roll them out the door. At first they are targeting fleet users of pickups and vans and expecting about 100 miles range, but a small sedan could get up to 150.

Note that this would work well for a taxi fleet as all that would be needed would be a fast recharge station. A taxi cab running low could pull in and in 10 minutes be back on the street. Fuel costs cut to about 20%, no pollution. For a city like New York where most of your downtown traffic is taxis, that could make a heck of a difference in air quality.

For a commuter, this would be a heck of a car. Rarely would you be limited by range during the week and overnight charge in the garage would be practical, even up to the 150 miles though that would maybe need 220 volts such as for a dryer. A two voltage charger could be provided, probably built in, and for about 70 miles a day you could get by on a standard 110 volt 15 amp outlet.

Now what would you do if you want to hit the road? Well, two things come to mind. First, provide fast charge stations. This would require greater electric supply at the filling station as 35 kwh in 10 minutes (1/6 hour) would require nearly 200 kw or about a fifth of a megawatt. That is substation power, but could be provided. Providing the power would be a problem, particularly the peaking. To give some idea of what a fifth of a megawatt amounts to, the max power supplied to a new house, typically 200 amp service, amounts to about 25 kilowatts. You need the maximum power for 8 houses to recharge one car, though you only need it for 10 minutes. These could be installed in truck stops first and within a year could be clear across the state, then pop up increasingly all over the place at other stations. Second, put a methanol fuel cell and fuel tank and a bit of plumbing and controls in the car, adding a bit of expense, but then whenever you wanted to hit the road all you would have to do is fill the tank. Your first 150 miles could be on battery, then contine on fuel cell. Of course methanol pumps would have to be installed at stations, probably in place of the E85 pumps now.

It should probably be pointed out that more energy will be needed on the grid and this means more major transmission lines. More are needed anyway if wind energy ever becomes available at an important level as it will mainly be obtained in out of the way places like North Dakota, but used elsewhere in big cities. Naturally this will be expensive. Now there is a stimulus package that would give us something useful. Unfortunately, it is an election year, so lots of votes to buy, so we will be out 150 billion or so with nothing to show for it but more debt.

I hope this gives some idea of possibilities. Wouldn't it be loverly! Now if we can just get people to calm down over CO2.

One further note. I have not found anyone expressing interest in a riding lawn mower, but it should be obvious a battery powered electric riding lawn mower would be the cats meow. You would not even have to have a fast charge battery, the old slow ones would be fine. If it should run down, it is in the yard and can be reached with an extension cord. I want one of those too.
Three more thoughts. First, in defense of Chevrolet, they need to get it about right at the start. They do not want to roll out a few million Volts and have serious battery problems. Even with the fast charge batteries, they need to be pretty sure they will indeed last 15,000 charge cycles in almost all cases. It is one things to demonstrate that in the shop, it is another for them to last in actual use, being jolted for years and exposed to high and low temperatures. Note that a singe cell failing can ruin a battery. The probability of a lead - acid cell failing is small and with only 6, still quite small that one of them in a battery will fail. The battery will be replaced in maybe 5 years anyway and for maybe $50, so that is good enough. To get the power and energy needed, a lithium battery to power the car will have to have maybe hundreds of cells. They are going to have to be very reliable, or some mechanism built in, such as the shorting shunts for serial Christmas tree lights to keep the string working if one fails.

Also note that the Volt, if equipped with a fast charge battery, will maybe be a better choice than a Phoenix. You can run the first 40 on grid only, after that, gasoline until fast recharge stations become available, then more and more use them and cut gasoline more and more. You would still have the gasoline option for long trips when you don't want to stop. You could get a fast charge every time you stopped for rest room or to grab a bite to eat and cut your expense. Only 3 minutes for a 40 mile charge. This is a lot more flexible that the Phoenix, the gasoline is already available and methanol isn't yet. A bigger battery, say 80 - 100 miles would probably be in order. The Volt could always be equipped with a fuel cell once methanol was available.

Secondly, size and cost. These are not dinky little batteries you can pick up with one hand, and they will probably cost thousands of dollars. Production and competition will quickily bring down the cost, but initially, these inherently simple and cheap cars are going to be a bit expensive because of the batteries.

Third. If you really want to reduce CO2 rather than just redistribute weath, then rather than have the government mandate a reduction and levy fines if not met, consider the chemistry involved here. For an ICE, gasoline can be represented by octane, C8H18. Note there is 45% as much carbon and therefore CO2 as hydrogen. For methanol (for a fuel cell) methanol + water, CH3OH + H2O, note there is only one carbon atom for 6 hydrogen, so only 17%. Much less already, and since the fuel cell is much more efficient than the ICE, probably no more than say 4% - 5% as much CO2 per mile. Of course there would be some more CO2 while producing the methanol, and alternatively, if energy from wind or nuclear was available, running on all electric could get down to 0. It isn't quite that simple, but gives you the idea.

It could be 10 years, it could be 20, but I would bet in about 2 years we are going to see some interesting things on the highway.