Reducing Electricity Usage in Your Refrigerator

When thinking about battling climate change, did you know that a major electricity consumer in your house is your refrigerator? The International Institute of Refrigeration (yes, there are institutes for just about everything) estimates that about 20% of all electricity used is expended on vapour compression refrigeration. The refrigerator works by compressing a vapour, often some sort of freon, or in industry, with ammonia, and when compressed it gives off heat. When you ship it somewhere else and expand it, the somewhere else gets colder. This is also the principle of the heat pump and various air conditioning units. Compress gas here to add heat from a heat exchanger; ship the gas there and expand it, where it cools a heat exchanger. The compression and expansion of gas moves heat from A to B, hence the name heat pump. Also, the refrigerant gases tend to be powerful greenhouse gases. One kilogram of R410a has the same greenhouse impact as two tonne of carbon dioxide. Refrigerants leak into the atmosphere from faulty equipment or when equipment is not properly disposed of.

It is possible to heat or cool without any gas through the Peltier effect. Basically, when electric current passes between two conductors, heating or cooling effects may be generated. There are commercial solid-state such cooling systems, but they suffer from high cost and poor efficiency, in part because the effect is restricted to the specific junction.

There is an alternative. Some solid state materials can cool when they are subjected to strain, which is generated from an external field, such as  the electric or magnetic fields, or simply pressure. So far most efforts have been focused on the magnetic field, and one material, Mn3SnC apparently gives significant cooling,  but the magnetic field has to be greater than 2 tesla. That means expensive and bulky magnets, and additionally the refrigerator, if it used them, would have to be a “no-go” area for credit cards, and possibly people with a pacemaker. Even aside from direct messing with the pacemaker, losing all those bitcoin just because you wanted a cool beer could lead to medical problems.

However, there has been an advance. Wu et al. (Acta Materiala 237: 118154) have taken the Mn3SnC and coated it with a piezoelectric layer of lead zirconate titanate. Don’t ask me how they come up with these things; I have no idea, but this is certainly interesting. They probably do it by looking through the literature to find materials already known to have certain properties. Thus a piezoelectric effect is where you generate an electric voltage by applying pressure. Such effects are reversible so if you can generate a voltage by applying pressure to something, you can generate pressure by applying a potential difference. Recall that pressure also can generate a cooling effect. Accordingly, by applying an electric field to this coated material a cooling effect was obtained equivalent to that of a 3 tesla magnetic field. When the electric field is removed, the temperature returns to where it was. How useful will this be? Hard to tell right now. The temperature drop when applying a field of 0.8 kV/cm was slightly under 0.6 of a degree Centigrade, which is not a huge change while the voltage is tolerably high. Interestingly, if you apply a magnetic field you also get a temperature change, but in the opposite direction – instead of cooling, it heats. Why that is is unclear.

As you might guess, there is still a significant distance to go before we get to a refrigerator. First, you have to get the cooling into some other fluid that can transport it to where you need it. To do that you have to take the heat out of the cooling fluid, but that will heat up your unit, so you need another fluid to take the heat to where it can be dissipated. We have very roughly the same cycle as our present system except we are not compressing anything but we have two fluids. Except I rather think we will be, because pumping a fluid involves increasing its pressure so it flows. The alternative is to put the material across the rear wall of the refrigerator thus to cool the interior and have the heat dissipated out the back. The problem now is the change of temperature is rather small for the voltage. This is not so much a problem with fluids transporting it, but if the solids transport it, the solids are always heated by the environment so your temperature drop is from the room temperature. Half a degree is not very helpful, although you could increase the electric field. Unfortunately, to get a big enough temperature change you might be into the spark jumping region. Lightning in the kitchen! Finally, do you want the back of your refrigerator to be carrying even a kilovolt electric field? My guess is this effect may remain a curiosity for some length of time.

Economic Consequences of the Ukraine War

My last post mentioned the USSR collapse. One of the longer term consequences has been this Ukraine war. Currently, there have been problems of shelling of the Zaporizhzhia nuclear plant, and this appears to have happened in that our TV news has shown some of the smashed concrete, etc. The net result is the plant has shut down. Each side accuses the other of doing the shelling, but it seems to me that it had to be the Ukrainians. Russia has troops there, and no military command is going to put up with his side shelling his own troops. However, that is far from the total bad news. So far, Ukraine has been terribly lucky, but such luck cannot last indefinitely. There are consequences outside the actual war itself. The following is a summary of some of what was listed in the August edition of Chemistry World.

The Donbas area is Ukraine’s heavy industry area, and this includes the chemical industry. Recently, Russian air strikes at Sieverierodonetsk hit a nitric acid plant, and we saw images of the nitrogen dioxide gas spewing into the atmosphere.

Apparently, in 2017 Ukrainian shelling was around a chemical plant that contained 7 tonne of chlorine. Had a shell hit a critical tank, that would have been rather awkward. Right now, in the eastern Donbas there is a pipeline almost 700 km long that pipes ammonia. There are approximately 1.5 million people in danger from that pipeline should it burst; exactly how many depends on where it is broken. There are also just under  200,000 t of hazardous waste stored in various places. The question now is, with all this mess generated, in addition to demolished buildings and infrastructure, who will pay what to clean it up? It may or may not be fine for Western countries to use their taxes to produce weapons to give to Ukraine, but cleaning up the mess requires the money to go to Ukraine, not armament-making corporations at home.

The separation of the Donbas has led to many mines being closed, and these have filled with water. This has allowed mercury and sulphuric acid to be leached and then enter the water table. During 2019, a survey of industrial waste was made, and Ukraine apparently stores over 5.4 billion t of industrial waste, about half of which is in the Donbas. Ukraine has presumably inherited a certain amount, together with some of the attitudes, from the old Soviet Union. From experience, their attitude to environmental protection was not their strong point. I recall  one very warm sunny morning going for a walk around Tashkent. I turned a corner and saw rather a lot of rusty buildings, and also, unbelievably, a cloud. How could water droplets form during such a warm dry climate? The answer was fairly clear when I got closer. One slight whiff, and I knew what it was: the building was emitting hydrogen chloride into the atmosphere and the hydrochloric acid droplets were the reason for the rust.

Meanwhile, some more glum news. We all know that the sanctions in response to the Ukraine war has led to a gas shortage. What most people will not realize is what this is doing to the chemical industry. The problem for the chemical industry is that unlike most other industries, other than the very sophisticated, the chemical industry is extremely entangled and interlinked. A given company may make a very large amount of chemical A, which is then sold as a raw material to a number of other companies, who in turn may do the same thing. There are many different factories dependent on the same raw chemical and the material in a given chemical available to the public may have gone through several different steps in several different factories.

An important raw mixture is synthesis gas, which is a mix of carbon monoxide and hydrogen. The hydrogen may be separated and used in steps to make a variety of chemicals, such as ammonia, the base chemical for just about all nitrogen fertilizer, as well as a number of other uses. The synthesis gas is made by heating a mixture of methane gas and water. Further, almost all chemical processing requires heat, and by far the bulk of the heat is produced by burning gas. In Europe, the German government is asking people to cut back on gas usage. Domestic heating can survive simply by lowering the temperature, although how far down one is prepared to go during winter is another question. However, the chemical industry is not so easily handled. Many factories use multiple streams, and it is a simple matter to shut down such a stream, but you cannot easily reduce the amounts going through a stream because the reactions are highly dependent on pressure, and the plant is in a delicate balance between amount processed and heat generated.  A production unit is really only designed to operate one way, and that is continuously with a specific production rate. If you close it down, it may take a week to get it started again, to get the temperature gradients right. One possibility is the complete shutdown of the BASF plant at Ludwigshafen, the biggest chemical complex in the world. The German chemical industry uses about 135 TWhr of gas, or about 15% of the total in the country. The price of such gas has risen by up to a factor of eight since Russia was sanctioned, and more price rises are likely. That means companies have to try to pass on costs, but if they face international competition, that may not be possible. This war has consequences far beyond Ukraine.

Gorbachev: A Man for What Season?

Mikhail Sergeyevich Gorbachev is dead, and the eulogies are flowing thick and fast, but mainly from those outside Russia. He may well have the record for the most praise for someone who made the worst botch-up of the job he was appointed to do. He is praised in the West for dismantling the Soviet Union, but that was the last thing he was trying to do. He believed that liberalizing the economy would improve the lot of Russians. After he was deposed and the USSR fell, the GDP of Russia almost halved, and only too much that was left fled the country in the hands of a few oligarchs. You see comments by Bill Browder on how bad Putin is, but he made a billion dollars from the ignorance of the ordinary Russian and according to Russia, he never paid a cent in tax to Russia. Quite simply, Gorbachev gave the country that hated Russia (the US) what it wanted and completely failed Russia. He had a dream, but he never checked to see whether it was realistic, and he never had a workable plan to implement it.

Gorbachev’s early important jobs related to agriculture. The Soviet Union should have been a major food exporter, but in the 1970s, in part because of poor weather, it had to import grain. Gorbachev was supposed to do something about this, and his response was to blame central decision-making. That may well have been a factor, but it was not the required answer. I visited the USSR in the early 1980s, and in a drive through the countryside of Uzbekistan the problem was easy to see. There were huge areas of the steppe that had been ploughed, and then, nothing. Not even harrowed to at least make it look as if something was being done. But in small “oases” there was extremely intense productivity. Those in the collective were given very small areas of land for themselves to use, and basically they concentrated on that. This was where almost all the local food came from, a tiny percentage of the total land. Now, if I could see this in a short visit which was really more as a tourist (I was getting over jet lag and enjoying a weekend before heading to Moscow for what I went there for) surely Gorbachev could have found this out if he wanted to.

Part of my life has been devoted as a consultant to fixing problems, and my first rule of fixing a problem has always been, first examine the problem in intense detail and understand it. To examine it, you actually have to go and look at it yourself. Reading a report is no good unless there is a recommendation to fix it, because if whoever wrote the report does not know how to fix it, perforce (s)he does not understand it. This is probably a major failing of leaders everywhere, but it was much worse in the USSR. If the leader cannot take the time off to look at it, he should delegate to someone who can. At this time fixing agriculture was Gorbachev’s main job; he was the delegated man, and at this point he failed. The USSR kept importing food, which also was a drain on foreign currency. One could argue that the system prevented success, but Gorbachev had Yuri Andropov as a friend, and if he could persuade Andropov, almost certainly what he recommended would be done. The simple answer is the farmers had to have an incentive to increase the communal yield. That introduces the most significant problem in economics: how to properly reward people. Something needed to be tried, such as giving small groups of farmers (since they had to maintain some part of communism) the right to take shares of the yield from a block of the commune land.

When Gorbachev became effectively the leader of the USSR, he had learned nothing from his agrarian program, and while he recognized industry needed a better output and productivity, he still relied on central planning, while ignoring implementation. A plan that might work is only of use if there is a working procedure to make it work. For his plans to work, first he had to remove the many layers of bureaucrats between the major decision and implementation. His first move was to remove the “old guard”. This was a clear mistake as a first move. They knew someone younger was needed, which was why they put him there. Many should have been potential allies. His replacements included people like Yeltsin, who ended up doing everything he could to subvert Gorbachev. Gorbachev was not a good judge of character, and completely failed the next step: if you want to run a central system the top priority is to find someone who gets things done. They are seldom people who play the political game making fine speeches praising Lenin. Gorbachev tried to introduce some sort of limited private enterprise and market economics, but because of the layer of incompetents under him and his demand that central planning be retained, that did not work.

The next major blunder was “glasnost”; giving the people the right to complain. There was too much to complain about. Freedom to criticize is all very well, but if the criticisms are going to be well-grounded and nobody is fixing them, the society fragments. Gorbachev apparently thought that if the people knew about all the problems they would rally behind his efforts to fix them. That was ridiculous. The noisiest dissidents are the least constructive. He needed fixers in place before allowing people to shout out what needed fixing. After all, a lot was obvious. Again, I recall going into a building in the old USSR that was supposed to be where you bought things. The shelves were empty. Fixing food production and providing a range of consumable goods should have been the first priority. If everyone had more to purchase, and higher incomes from the increased productivity, now open criticism would be harmless.

Gorbachev made an impression on Western leaders. The nuclear disarmament treaty was an achievement, but when it came to the reunification of Germany and the USSR giving the Warsaw Pact countries their independence from Moscow control, Gorbachev badly needed to ensure that NATO did not march East. Given that he was offering a lot, he needed a signed treaty ensuring the “neutral zone”. He could have obtained that from the Eastern countries, although he probably also needed the US to agree, but for some reason he made no effort at all, which eventually brings us to the current Ukraine conflict. He was to permit some of the republics to leave the USSR, but he made no effort to settle the legal conditions of doing so, which later led to the Georgian and now Ukrainian problems. The USSR owned all the factories, etc, in the breakaway republics, but these ended up in the hands of a very few oligarchs.  Gorbachev had great ideas, but was seemingly uninterested in the details of achieving them, or of ensuring decisions were not undermined by others. The end result was the rule of Yeltsin, and the impoverishment of a very large fraction of the population, the transfer of virtually all of Russia’s industrial and resource assets into the hands of a few oligarchs, the almost halving of the nation’s GDP, and all this really followed from Gorbachev’s inept governance. Gorbachev seemed to think people would rally behind to get the best outcome. That is delusional. They follow incentives or they fly off in different directions. He failed to provide incentives or control where things went. He achieved nothing of substance for those who depended on him. He is popular with those who took advantage of him.

Nuclear War is Not Good

Yes, well that is sort of obvious, but how not good? Ukraine has brought the scenario of a nuclear war to the forefront, which raises the question, what would the outcome be? You may have heard estimates from military hawks that apart from those killed due to the blasts and those who got excessively irradiated, all would be well. Americans tend to be more hawkish because the blasts would be “over there”, although if the enemy were Russia, Russia should be able to bring it to America. There is an article in Nature (579, pp 485 – 487) that paints a worse picture. In the worst case, they estimate deaths of up to 5 billion, and none of these are due to the actual blasts or the radiation; they are additional extras. The problem lies in the food supply.

Suppose there was a war between India and Pakistan. Each fires nuclear weapons, first against military targets, then against cities. Tens of millions die in the blasts. However, there is a band of soot that rises into the air, and temperatures drop. Crop yields drop dramatically from California to China, and affect dozens of countries. Because of the limited food yields, more than a billion people will suffer from food shortages. The question then is, how valid are these sort of predictions?

Nuclear winter was first studied during the cold war. The first efforts described how such smoke would drop the planet into a deep freeze, lasting for months, even in summer. Later studies argued this effect was overdone and it would not end up with such a horrific chill, and unfortunately that has encouraged some politicians who are less mathematically inclined and cannot realize that “less than a horrific chill” can still be bad.

India and Pakistan each have around 150 nuclear warheads, so a study in the US looked into what would happen in which the countries set off 100 Hiroshima-sized bombs. The direct casualties would be about 21 million people. But if we look at how volcanic eruptions cool the planet, and how soot goes into the atmosphere following major forest fires, modelling can predict the outcome. A India-Pakistan war would put 5 million tonne of soot into the atmosphere, while a US Russian war would loft 150 million tonne. The first war would lower global temperatures by a little more than 1 degree C           , but the second would lower it by 10 degrees C, temperatures not seen since the last Ice Age. One problem that may not be appreciated is that sunlight would heat the soot, and by heating the adjacent air, it causes it to rise, and therefore persist longer.

The oceans tell a different story. Global cooling would affect the oceans’ acidity, and the pH would soar upwards (making it more alkaline). The model also suggested that would make it harder to form aragonite, making life difficult for shellfish. Currently, the shellfish are in the same danger from too much acidity; depending on aragonite is a bad option! The biggest danger would come regions that are home to coral reefs. There are some places that cannot win. However, there is worse to come: possibly a “Nuclear Niño”, which is described as a “turbo-charged El Niño”. In the case of a Russia/US war, the trade winds would reverse direction and water would pool in the eastern pacific ocean. Droughts and heavy rain would plague different parts of the world for up to seven years.

One unfortunate effect is that this is modelled. Immediately, another group from Los Alamos carried out different calculations and came to less of a disastrous result. The difference depends in part on how they simulate the amount of fuel, and how that is converted to smoke. Soot comes from partial combustion, and what happens where in a nuclear blast is difficult to calculate.

The effects on food production could be dramatic. Even following the small India-Pakistan war, grain production could drop by approximately 12% and soya bean production by 17%. The worst effects would come from the mid-latitudes such as the US Midwest and Ukraine. The trade in food would dry up because each country would be struggling to feed itself. A major war would be devastating, for other reasons as well. It is all very well to say your region might survive the climate change, and somewhere like Australia might grow more grain if it gets adequate water, as at present it is the heat that is the biggest problem. But if the war also took out industrial production and oil production and distribution, now what? Tractors are not very helpful if you cannot purchase diesel. A return to the old ways of harvesting? Even if you could find one, how many people know how to use a scythe? How do you plough? Leaving the problem of knowing where to find a plough that a horse could pull, and the problem of how to set it up, where do you find the horses? It really would not be easy.

Burying Carbon Dioxide, or Burying Cash?

In the last post, I expressed my doubt about the supply of metals for electric batteries. There is an alternative to giving up things that produce CO2 and that is to trap and sequester CO2. The idea is that for power stations the flu gases have the CO2 removed and pumped underground. That raises the question, how realistic is this? Chemistry World has an article that casts doubt, in my mind, that this can work. First, the size of the problem. One company aims to install 70 such plants, each capable of sequestering 1 million t of CO2. If these are actually realized, we almost reach 0.2% of what is required. Oops. Basically, we need to remove at least 1 billion t/a to stand still. This problem is large. There is also the problem of how we do it.

The simplest way is to pass the flu gases through amine solvents, with monoethanolamine the most common absorbent used. Leaving aside the problem of getting enough amine, which requires a major expansion of the chemical manufacturing industry, what happens is the amine absorbs CO2 and makes the amine carbonate, and the CO2 is recovered by heating the carbonate and regenerating the amine. However, the regeneration will never be perfect and there are losses. Leaving aside finding the raw materials actually synthesizing the amine takes about 0.8 MWh of energy, the inevitable losses mean we need up to 240 MWh every year to run a million tonne plant. We then need heat to decompose the amine carbonate, and that requires about 1 MWh per tonne of CO2 absorbed. Finally, we need a little less than 0.12 MWh per tonne of CO2 to compress it, transport it and inject it into the ground. If we wanted to inject 1 billion t of CO2, we need to generate something like 840 TWh of electricity. That is a lot of electricity.

We can do a little better with things called metal organic frameworks (MOFs).These can be made with a high surface energy to absorb CO2 and since they do not form strong chemical bonds the CO2 can be recovered at temperatures in the vicinity of  80 – 100 degrees C, which opens the possibility of using waste heat from power stations. That lowers the energy cost quite a bit. Without the waste heat the energy requirement is still significant, about half that of the amines. The comes the sting – the waste heat approach still leaves about 60% of what was absorbed, so it is not clear the waste heat has saved much. The addition of an extra step is also very expensive.

The CO2 content of effluent gases is between 4 – 15%; for ordinary air it is 0.04%, which makes it very much more difficult to capture. One proposal is to capture CO2 by bubbling air through a solution of potassium hydroxide, and then evaporating off the water and heating the potassium carbonate to decomposition temperature, which happens to be about 1200 degrees C. One might have thought that calcium oxide might be easier, which pyrolyses about 600 degrees C, but what do I know? This pyrolysis takes about 2.4 MWh per tonne of CO2, and if implemented, this pyrolysis route that absorbs CO2 from the air would require about 1.53 TWh of electricity per year for sequestering 1 million t of CO2.

When you need terawatt hours of electricity to run a plant capable of sequestering one million tonne of CO2, and you need to sequester a billion t, it becomes clear that this is going to take an awful lot of energy. That costs a lot money. In the UK, electricity costs between £35 – 65 per MWh, and we have been talking in terms of a million times that per plant. Who pays? Note this scheme has NO income stream; it sells nothing, so we have to assume it will be charged to the taxpayer. Lucky taxpayer!

One small-scale effort in Iceland offers a suggested route. It is not clear how they capture the CO2, but then they dissolve it in water and inject that into basalt, where the carbonic acid reacts with the olivine-type structures to make carbonates, where it is fixed indefinitely. That suggests that provided the concentration of CO2 is high enough, using pressure to dissolve it in water might be sufficient. That would dramatically lower the costs. Of course, the alternative is to crush the basalt and spread it in farmland, instead of lime. My preferred option to remove CO2 from the air is to grow plants. They work for free at the low concentrations. Further, if we select seaweed, we get the added benefit of improving the ecology for marine life. But that requires us to do something with the plants, or the seaweed. Which means more thinking and research. The benefit, though, is the scheme could at least earn revenue. The alternatives are to bankrupt the world or find some other way of solving this problem.

Limits to Growth

A little over fifty years ago, the Systems Dynamics group at MIT produced a 200-page book called The Limits to Growth. Their message was, continued economic and population growth would deplete Earth’s resources and lead to global economic collapse by 2070. At the time, this was considered heresy. The journal Nature was scathing (See vol 236, pp 47 – 49, 1972). How could the foundations of industrial civilization, such as coal mining, steel-making, oil production, crop spraying, cause lasting damage? It was accepted that such industries caused pollution, but such effects were considered to be only temporary. At the time computer modelling was looked down upon. This is understandable; at the time computers were quite primitive compared with now, and big computers were only available to the major organizations. I recall four years before that someone doing a chemical bond calculation and coming back from the computer with what looked like a couple of kg of printout. His problem was that his program only produced two answers, depending on what he changed in the code. The answers were zero or infinity. As I remarked, the truth would be somewhere in between.

It is unlikely that any other computer model has made a bigger impact. There are still debates, but it is now clear that our activities have made irreversible environmental effects. As I have also noted in a previous post, there is also significant resource depletion. The elements have not gone anywhere, but that does not help if they are so diluted with other material that we cannot use them. Of course, it is arguable we could with unlimited energy, but we do not have that. The sun effectively produces unlimited energy, but it is too far away; here all it delivers is approximately 1360 W/m^2 at the top of the atmosphere, which is reduced to somewhere between 1000 – 1150 W/m^2 on a surface at right angles to the radiation at the surface. These numbers have to be divided by three for a 24-hr day, assuming no clouds.

The obvious problem for people is economic growth. Some people assume that economic growth can continue if we adopt technology much faster, particularly employing more renewable energy. Others argue we have to abandon the idea of growth. Was living as per we did in, say, 2016 that bad? One problem is that politicians need votes, and to get them they want to raise GDP. Thus if there is a choice of what to do, politicians will go for that which produces the most jobs. Excessive spending on the military increases jobs; corresponding spending on healthcare does not, but which is the more useful?

One analysis (Rockström et al. 2009, Nature 461: 472 – 475) argued there were boundaries. If we stayed within these the planet would adjust and correct our behaviour, but as we approached those boundaries (i.e. too much of something is being emitted) the planet may respond in a non-linear and often in an abrupt way. Most of these thresholds depend on one, or sometimes more, variables. They suggest ten such processes have such boundaries, three of which, biodiversity loss, climate change, the nitrogen cycle, are already exceeded, while a fourth, the phosphorus cycle is close to the breaking point and a fifth, ocean acidification is troublesome. Two more, chemical pollution and atmospheric aerosol loading were not quantified. Three, fresh water use, land use, and ozone depletion are considered to be under control.

The last time the poles were essentially ice-free the CO2 levels were approximately 450 ppm. As can be seen from my last post, exceeding that seems inevitable without drastic action. For biodiversity, extinctions are currently about 100 – 1000 times greater than natural. Biodiversity is very important to maintain the resilience of the system. The production of nitrogen fertilizer and the cultivation of legumes convert around 120 million t/a of nitrogen, which is more than the combined efforts of all Earth’s terrestrial processes. This ends up as pollution, it erodes resilience of some of the plant life, and it sends nitrous oxide into the atmosphere, and this makes a major contribution to greenhouse forcing. Excess nitrogen fertiliser leads to turbid waterways, lakes, etc, and sometimes pronounced algal blooms. About 20 Mt of phosphorus is mined each year, and about half of this finds its way into oceans. This is around eight times the natural erosion rate. When critical levels of phosphate enter the oceans, large scale anoxic events occur, which can lead to mass extinctions of marine life. The authors conclude that as long as we do not exceed the thresholds, we can pursue long-term economic and social development. Our problem is, we are crossing some.

Energy Sustainability

Sustainability is the buzzword. Our society must use solar energy, lithium-ion batteries, etc to save the planet, at least that is what they say. But have they done their sums?. Lost in this debate is the fact that many of the technologies use relatively difficult to obtain elements. In a previous post I argued that battery technology was in trouble because there is a shortage of cobalt, required to make the cathode work for a reasonable number of cycles. Others argue that we could obtain sufficient elements. But if we are going to be sustainable, we have to be sustainable for an indefinite length of time, and mining is not sustainable; you can only dig up the ore once. Of course, there are plenty of elements left. There is more gold in the sea than has ever been mined; the problem is that it is too dilute. Similarly, most elements are present in a lump of basalt; just not much of anything useful and it is extremely difficult to get it out. The original copper mines of Cyprus, where even lumps of copper could occasionally be found, are all worked out, at least to the extent that mining is no longer profitable there.

The answer is to recycle, right? Well, according to an article [Charpentier Poncelet, A. et al. Nature Sustain. https://doi.org/10.1038/s41893-022- 00895-8 (2022)] there are troubles. The problem is that even if we recycle, every time we do something we lose some of the metal. Losses here refer to material emitted into the environment, stored in waste-disposal facilities, or diluted in material where the specific characteristics of the elements are no longer required. The authors define a lifetime as the average duration of their use, from mining through to being entirely lost. As with any such definition-dependent study, there will be some points where you disagree.

The first loss for many elements lies in the production state. Quite often it is only economical to obtain one or two elements, and the remaining minor components of the ore disappear in slag. These losses are mainly important for specialty elements. Production losses account for 30% of rare earth metals, 50% for cobalt, 70% for indium, and greater than 95% for arsenic, gallium, germanium, hafnium, selenium and tellurium. So most of those elements critical for certain electronic and photo-electric effects are simply thrown out. We are a wasteful lot.

Manufacturing and use incur very few losses. There are some, but because materials are purified ready for use, pieces that are not immediately used can be remelted and used. There are exceptions. 80% of barium is lost through use; it is used in drilling muds.

The largest losses come from the waste management and recycling stage. Metals undergoing multiple life cycles are still lost this way; it just takes longer to lose them. Recycling losses occur when the metal accumulates in a dust (zinc) or slag(e.g. chromium or vanadium), or get lost in another stream, thus copper is prone to dissolve in an iron stream. Longest lifetimes occur for non-ferrous metals (8 to 76 years) precious metals (4 to 192 years), and ferrous metals (8 to 154 years). The longest lifetimes are for gold and iron.

Now for the problem areas. Lithium has a life-cycle use of 7 years, then it is all gone. But lithium-ion batteries last about this long, which suggests that as yet (if these data are correct) there is very little real recycling of lithium. Elements like gallium and tellurium last less than a year, while indium manages a year. Before you protest that most of the indium goes into swipeable mobile phone screens and mobile phones last longer than a year, at least for some of us, remember that losses occur through being discarded at the mining stage, where the miner/processor can’t be bothered. Of the fifteen metals most lost during mining/processing, thirteen are critical for sustainable energy, such as cobalt (lithium-ion batteries), neodymium (permanent magnets), indium, gallium, germanium, selenium and tellurium (solar cells) and scandium (solid oxide fuel cells). If we look at the recycled content of “new material” lithium is less than 1% as is indium. Gallium and tellurium are seemingly not recycled. Why are they not recycled? Metals that are recycled tend to be like iron, aluminium, the precious metals and copper. It is reasonably easy to find uses for them where purity is not critical. Recycling and purifying most of the others requires technical skill and significant investment. If we think of lithium-ion batteries, the lithium reacts with water, and if it starts burning it is unlikely to be put out. Some items may have over a dozen elements, and some are highly toxic, and not to be in the hands of the amateur. What we see happening is that the “easy” metals are recycled by organizations that are really low-technology organizations. It is not an area attractive to the highly skilled because the economic risk/return is just not worth it, while the less-skilled simply cannot do it safely.

Banana-skin Science

Every now and again we find something that looks weird, but just maybe there is something in it. And while reading it, one wonders, how on Earth did they come up with this? The paper in question was Silva et. al. 2022. Chemical Science 13: 1774. What they did was to take dried biomass powder and exposed it to a flash of 14.5 ms duration from a high-power xenon flash lamp. That type of chemistry was first developed to study the very short-lived intermediates generated in photochemistry, when light excites the molecule to a high energy state, where it can decay through unusual rearrangements. This type of study has been going on since the 1960s and equipment has steadily been improving and being made more powerful. However, it is most unusual to find it used for something that ordinary heat would do far more cheaply. Anyway, 1 kg of such dried powder generated about 100 litres of hydrogen and 330 g of biochar. So, what else was weird? The biomass was dried banana skin! Ecuador, sit up and take notice. But before you do, note that flash xenon lamps are not going to be an exceptionally economical way of providing heat. That is the point; this very expensive source of light was actually merely providing heat.

There are three ways of doing pyrolysis. In the previous post I pointed out that if you took cellulose and eliminated all the oxygen in the form of water, you were left with carbon. If you eliminate the oxygen as carbon monoxide you are left with hydrogen. If you eliminate it as carbon dioxide you get hydrogen and hydrocarbon. In practice what you get depends on how you do it. Slow pyrolysis at moderate heat mainly makes charcoal and water, with some gas. It may come as a surprise to some but ordinary charcoal is not carbon; it is about 1/3 oxygen, some minor bits and pieces such as nitrogen, phosphorus, potassium, and sulphur, and the rest carbon.

If you do very fast pyrolysis, called ablative pyrolysis, you can get almost all liquids and gas. I once saw this done in a lab in Colorado where a tautly held (like a hacksaw blade) electrically heated hot wire cut through wood like butter, the wire continually moving so the uncondensed liquids (which most would call smoke) and gas were swept out. There was essentially no sign of “burnt wood”, and no black. The basic idea of ablative pyrolysis is you fire wood dust or small chips at a plate at an appropriate angle to the path so the wood sweeps across it and the gas is swept away by the gas stream (which can be recycled gas) propelling the wood. Now the paper I referenced above claimed much faster pyrolysis, but got much more charcoal. The question is, why? The simple answer, in my opinion, is nothing was sweeping the product away so it hung around and got charred.

The products varied depending on the power from the lamp, which depended on the applied voltage. At what I assume was maximum voltage the major products were (apart from carbon) hydrogen and carbon monoxide. 100 litres of hydrogen, and a bit more carbon monoxide were formed, which is a good synthesis gas mix. There were also 10 litres of methane, and about 40 litres of carbon dioxide that would have to be scrubbed out. The biomass had to be reduced to 20 μm size and placed on a surface as a layer 50 μm thick. My personal view is that is near impossible to scale this up to useful sizes. It uses light as an energy source, which is difficult to generate so almost certainly the process is a net energy consumer. In short, this so-called “breakthrough” could have been carried out to give better yields of whatever was required far more cheaply by people a hundred years ago.

Perhaps the idea of using light, however, is not so retrograde. The trick would be to devise apparatus that with pyrolyse wood ablatively (or not if you want charcoal) using light focused by large mirrors. The source, the sun, is free until it hits the mirrors. Most of us will have ignited paper with a magnifying glass. Keep the oxygen out and just maybe you have something that will make chemical intermediates that you can call “green”.

The Case for Hydrogen in Transport

In the last post I looked at the problem of generating electricity, and found that one of the problems is demand smoothing One approach to this is to look at the transport problem, the other major energy demand system. Currently we fill our tanks with petroleum derived products, and everything is set for that. However, battery-powered cars would remove the need for petrol, and if they were charged overnight, they would help this smoothing problem. The biggest single problem is that this cannot be done because there is not enough of some of the necessary elements to make it work. Poorer quality batteries could be made, but there is another possibility: the fuel cell.

The idea is simple. When electricity is not in high demand, the surplus is used to electrolyse water to hydrogen and oxygen. The hydrogen is stored, and when introduced to a fuel cell it burns to make water while generating electricity. Superficially, this is ideal, but there are problems. One is similar to the battery – the electrodes tend to be made of platinum, and platinum is neither cheap nor common. However, new electrodes may solve this problem. Platinum has the advantage that it is very unreactive, but the periodic servicing of the cell and the replacing of electrodes is realistic, and of course recycling can be carried out because unlike the battery, it would be possible to merely recycle the electrodes. (We could also use pressurised hydrogen in an internal combustion engine, with serious redesign, but the efficiency is simply too low.)

One major problem is storing the hydrogen. If we store it as a gas, very high pressures are needed to get a realistic mass to volume ratio, and hydrogen embrittles metals, so the tanks, etc., may need servicing as well. We could store it as a liquid, but the boiling point is -259 oC. Carting this stuff around would be a challenge, and to make matters worse, hydrogen occurs in two forms, ortho and para, which arise because the nuclear spins can be either aligned or not. Because the molecule is so small there is an energy difference between these, and the equilibrium ratio is different at liquid temperatures to room temperatures. The mix will slowly re-equilibrate at the low temperature, give off heat, boil off some hydrogen, and increase the pressure. This is less of a problem if you have a major user, because surplus pressure is relieved when hydrogen is drawn off for use, and if there is a good flow-through, no problem. It may be a problem if hydrogen is being shipped around.

The obvious alternative is not to ship it around, but ship the electricity instead. In such a scenario for smaller users, such as cars, the hydrogen is generated at the service station, stored under pressure, and more is generated to maintain the pressure. That would require a rather large tank, but it is doable. Toyota apparently think the problem can be overcome because they are now marketing the Mirai, a car powered by hydrogen fuel cells. Again, the take-up may be limited to fleet operators, who send the vehicles out of central sites. Apparently, the range is 500 km and it uses 4.6 kg of hydrogen. Hydrogen is the smallest atom so low weight is easy, except the vehicle will have a lot of weight and volume tied up with the gas pressurized storage. The question then is, how many fuel stations will have this very large hydrogen storage? If you are running a vehicle fleet or buses around the city, then your staff can refill as well, which gets them to and from work, but the vehicle will not be much use for holidays unless there are a lot of such stations.

Another possible use is in aircraft, but I don’t see that, except maybe small short-haul flights driven by electric motors with propellors. Hydrogen would burn well enough, but the secret of hydrocarbons for aircraft is they have a good energy density and they store the liquids in the wings. The tanks required to hold hydrogen would add so much weight to the wings they might fall off. If the main hull is used, where do the passengers and freight go? Another possibility is to power ships. Now you would have to use liquid hydrogen, which would require extremely powerful refrigeration. That is unlikely to be economic compared with nuclear propulsion that we have now.

The real problem is not so much how do you power a ship, or anything else for that matter, but rather what do you do with the current fleet? There are approximately 1.4 billion motor vehicles in the world and they run on oil. Let us say that in a hundred years everyone will use fuel cell-driven cars, say. What do we do in the meantime? Here, the cheapest new electric car costs about three times the cost of the cheapest petrol driven car. Trade vans and larger vehicles can come down to about 1.5 times the price, in part due to tax differences. But you may have noticed that government debt has become somewhat large of late, due to the printing of large amounts of money that governments have promptly spent. That sort of encouragement will probably be limited in the future, particularly as a consequence of shortages arising from sanctions. In terms of cost, I rather think that many people will be hanging on to their petrol-powered vehicles, even if the price of fuel increases, because the difference in the price of fuel is still a few tens of dollars a week tops, whereas discarding the vehicle and buying a new electric one involves tens of thousands of dollars, and with the current general price increases, most people will not have those spare dollars to throw away. Accordingly, in my opinion we should focus some attention on finding an alternative to fossil fuels to power our heritage fleet.

The IPCC Orders Action

The Intergovernmental Panel on Climate Change has produced Part 3 of a report, and with only about 2900 pages, that has one stark message: we need aggressive action to curb greenhouse gas emission AND we need aggressive action to absorb CO2 from the atmosphere, and the action must start now, not some indefinite time in the future. As I recall, this problem was highlighted thirty years ago, and in that thirty years, emissions have increased. There was not even a hint of a reduction. To give some idea of how seriously some take this matter, Germany closed down its nuclear power plants, and now it threatens not to use Russian gas, but instead burn lignite. We cannot do much worse than that can we?

Maybe we can, and maybe we are. According to an article by Lawrence et al. (Front. For. Glob. Change https://doi.org/10.3389/ffgc.2022.756115 (2022) tropical rain forests not only secrete carbon and take it out of circulation, saving around 0.5 of a degree C, but they also physically cool the planet by a further 0.5 degrees C. What the trees do is to emit much humidity from their leaves, with the result that they cool themselves (similar to sweating) and this humidity creates clouds, which reflect sunlight back to space. This is the sort of a geo-engineering proposal often made, but the trees do it for free. So, what are we doing? Why, cutting down the rain forests. Apparently a third has been removed, and another third has been heavily logged so it is not as functional as it should be. We are supposed to be trying to hold the temperatures to an increase of no more than 1.5 degrees C, we are nearly there already, so do we really need another degree of heating added in for no good reason?

According to the IPCC, carbon emissions will have to decline rapidly after 2025, halve by 2030, and hit “net zero” by the early 2050s. Given current efforts, a warming of 3 degrees is forecast. Emissions from existing and planned projects already exceed the allowable carbon budget. But even going to zero emissions will not suffice in the short term. Nations also need to extract carbon dioxide from the atmosphere.

So, what can we do? First, consider the problem. For our electricity, which has a little under 750 GW global capacity, wind power provides a little over 6%; solar provides a little over 2%, hydropower about 16%, nuclear about 10%. For fuels, earth consumes about 3.8 trillion cubic meters of natural gas, 35.4 billion barrels of oil, and 8.5 billion t of coal a year. Why we have a problem should be clear. Currently, about 2/3 of our electricity comes from burning fossil fuel. Worse, you don’t build a coal-fired power station today and turn it off tomorrow. Wind turbines need solid support. Making a tonne of cement produces roughly 800 kg of CO2, making a tonne of steel releases 1.85 t of CO2; combined they sum to about 16% of the world’s CO2 production. Wind power might be “green” but look at the CO2 emitted making and installing the equipment. Solar is free, but the demand for electricity is when solar is weak or non-existent, so massive storage is required, and that gets expensive, both in terms of money and in CO2 emissions for making the batteries. The point is, all new infrastructure is going to involve a lot of CO2 emissions before any energy is generated.

Transport is a particularly difficult problem. I think it is a common problem, but where I live the cities expanded significantly after WW 2, and they expanded with the automobile in mind. The net result is it is most people get around by car. Most people have access to a car, and that is petrol driven. The electric vehicle that might replace the petrol-driven car costs (here, at least) over twice that of the petrol driven car and you cannot really convert them. The reason is the electric vehicle needs a huge mass of batteries to have a useful driving range. Further, as I pointed out in a previous post, we cannot have everyone driving electric cars because we do not have the cobalt to make the batteries, and we still need ships and aircraft, which use a rather small fraction of the oil cut. We have to do something with the rest of the fuel cut. You may have noticed that large electricity production above and how so much comes from fossil fuels. Transport uses about 25% of the total energy production. That means to convert transport to electricity, we need to expand electricity generation by about another 250 GW. That is easy to write down, but just think of all the CO2 emitted by making the concrete and steel to build the power stations. Our current wind power would have to expand by a factor of 5.5 and we have to hope there are no still days. Of course, you may legitimately argue that if we charged batteries at night that would even the base load and you do not need all the additional installation. That is true, except green electricity generation  usually is not optimal for base loads.

My view is it cannot be done the way the enthusiasts want it done. We shall never get everybody to cooperate sufficiently to achieve the necessary reductions because society simply cannot afford it. We need a different approach, and in some  later posts, I shall try to offer some suggestions.