This and That from the Scientific World

One of the consequences of writing blogs like this is that one tends to be on the lookout for things to write about. This ends up with a collection of curiosities, some of which can be used, some of which eventually get thrown away, and a few I don’t know what to do about. They tend to be too short to write a blog post, but too interesting, at least to me, to ignore. So here is a “Miscellaneous” post.

COP 27.

They agreed that some will pay the poorer nations for damage so far, although we have yet to see the money. There was NO promise by anyone to reduce emissions, and from my point of view, even worse o promise to investigate which technologies are worth going after. Finally, while at the conference there were a number of electric buses offering free rides, at the end of the conference these buses simply disappeared. Usual service (or lack thereof) resumed.

Fighting!

You may think that humans alone fight by throwing things at each other but you would be wrong. A film has been recorded ( https://doi.org/10.1038/d41586-022-03592-w) of two gloomy octopuses throwing things at each other, including clam shells. Octopuses are generally solitary animals, but in Jervis Bay, Australia, the gloomy octopus lives at very high densities, and it appears they irritate each other. When an object was thrown at another one, the throw was far stronger than when just clearing stuff out of the way and it tended to come from specific tentacles, the throwing ones. Further, octopuses on the receiving end ducked! A particularly interesting tactic was to throw silt over the other octopus. I have no idea what the outcome of these encounters were.

Exoplanets

The star HD 23472 has a mass of about 0.67 times that of our sun, and has a surface temperature of about 4,800 degrees K. Accordingly, it is a mid-range K type star, and it has at least five planets. Some of the properties of these include the semi-major axis a (distance from the star if the orbit is circular), the eccentricity e, the mass relative to Earth (M), the density ρ  and the inclination i. The following table gives some of the figures, taken from the NASA exoplanet archive.

Planet     a              e            M        ρ           i

b           0.116      0.07       8.32      6.15      88.9

c           0.165      0.06       3.41      3.10      89.1

d           0.043      0.07       0.55      7.50      88.0

e           0.068      0.07       0.72      7.50      88.6

f           0.091      0.07       0.77       3.0        88.1

The question then is, what to make of all that? The first thing to notice is all the planets are much closer to the star than Earth is to the sun. Is that significant? Maybe not, because another awkward point is that the inclinations are all approaching 90 degrees. The inclination is the angle the orbital plane of the planet makes with the equatorial plane of the star. Now planets usually lie on the equatorial plane because that was also the plane of the accretion disk, so something has either moved the planets, or moved the star. Moving the planets is most probable, and the reason the inclinations are all very similar is because they are close together, and they will probably be in some gravitational resonance with each other. What we see are two super Earths (b and c), two small planets closest to the star, which are small, but very dense. Technically, they are denser than Mercury in our system. There are also two planets (c and f) with densities a little lower than that of Mars.

The innermost part of the habitable zone of that star is calculated to be at 0.364 AU, the Earth-equivalent (where it gets the same radiation as Earth) at 0.5 AU, and the outer boundary of the habitable zone is at 0.767 AU. All of these planets lie well inside the habitable zone. The authors who characterised these planets (Barros, S. C. C. et al. Astron. Astrophys. 665, A154 (2022).) considered the two inner planets to be Mercury equivalents, presumably based on their densities, which approximate to pure iron. My guess is the densities are over-estimated, as the scope for error is fairly large, but they certainly look like Mercury equivalents that are somewhat bigger than our Mercury

Laughing Gas on Exoplanets

One of the targets of the search for exoplanets is to try and find planets that might carry life. The question is, how can you tell? At present, all we can do is to examine the spectra of atmospheres around the planet, and this is not without its difficulties. The most obvious problem is signal intensity. What we look for is specific signals in the infrared spectrum and these will arise from the vibrations of molecules. This can be done from absorptions if the planet transits across the star’s face or better (because the stellar intensity is less a problem) from starlight that passes through the planet’s atmosphere.

The next problem is to decide on what could signify life. Something like carbon dioxide or methane will be at best ambiguous. Carbon dioxide makes up a huge atmosphere on Venus, but we do not expect life there. Methane comes from anaerobic digestion (life) or geological activity (no life). So, the proposal is to look for laughing gas, better known as nitrous oxide. Nitrous oxide is made by some life forms, and oddly enough, it is a greenhouse gas that is becoming more of a problem from the overuse of agricultural fertilizer, as it is a decomposition product of ammonium nitrate. If nothing else, we might find planets with civilizations fighting climate change!

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COP 27 – the 27th Cop-out??

Currently, a number of parties have descended on Sharm el-Sheikh for COP 27. This is the 27th “Conference of the Parties” to deal with climate change. Everybody, by now, should be aware that a major contributor to climate change is the increased levels of carbon dioxide in the atmosphere, and we have to reduce emissions. In the previous 26 conferences various pledges were made to reduce such emissions, but what has happened? According to Nature, CO2 emissions are set to reach a record high of 37.5 billion tonne in 2022. So much for a controlled reduction of emissions. In my opinion, the biggest effect from such conferences is the increased emissions due to getting all the participants to them. In this context there are apparently over 600 fossil fuel lobbyists at this conference. So the question then is, why has so little been achieved?

My answer is the politicians took the easy way out: to be seen to be doing something they implemented a carbon trading scheme. This allows money to flow, and the idea was that economics will make people transition to non-fossil-based energy by raising the price of the fossil fuels. To make this look less like a tax, they then allowed the trade of credits, and politicians issued credits to “deserving causes”. There were two reasons why this had to fail: the politicians had the ability to sabotage it by issuing credits to those it favoured, and secondly, there are no alternatives that everyone can switch to. Therein lies the first problem. Price does not alter activity much unless there is an alternative, and in most cases there is no easy alternative.

The second one is that even if you can develop alternatives, there is far too much installed capacity. The economies of just about every country are highly dependent on using fossil fuel. People are not going to discard their present vehicles and join a queue to purchase an electric one. They are still selling new petroleum-powered vehicles, and a lot of energy has been invested in making them. Like it or not, the electricity supply of many countries is dependent on coal-fired generation, and it costs a lot to construct a new plant to generate electricity. No country can afford to throw away their existing generation capacity.

In principle, the solution for electricity is simple: nuclear. So why not? Some say it is dangerous, and there remains the problems of storing wastes. It is true that people died at Chernobyl, but that was an example of crass incompetence. Further, in principle molten salt reactors cannot melt down while they also burn much of the waste. There is still waste that has to be stored somewhere, but the volume is very small in comparison. So why is this not used? Basically, the equipment has not been properly developed, the reason being that reactors were first designed so they could provide the raw material for making bombs. So, when the politicians recognized the problem at the end of the 1980s, what should have happened is that money was invested for developing such technology so that coal-fired power could be laid to rest. Instead, there was a lot of arm-waving and calls for solar and wind power. It is true these generate electricity, and in some cases they do it efficiently, however they cannot handle main load in most countries. Similarly with transport fuels. Alternative technologies for advanced biofuels were developed in the early 1980s, but were never taken to the next stage because the price of crude oil dropped to very low levels and nothing could compete. The net result was that technology was lost, and much had to be relearned. We cannot shut down the world industries and transport, and the politicians have refused to fund the development of alternative fuels.

So, what will happen? We shall continue on the way we are, while taking some trivial steps that make at least some of us, usually politicians, feel good because we are doing something. Unfortunately, greenhouse gas levels are still rising, and consider what is happening at the levels we are at. The Northeast Greenland Ice Stream is melting and the rate of melt is increasing because the protection from the Zachariae Isstrøm glacier that protected the coastal part of the ice stream broke off. Now, warmer seawater is penetrating up to 300 km under the ice stream. Global ocean levels are now predicted to rise up to a meter by the end of the century from the enhanced melting of Greenland ice. More important still is Antarctica. There is far more ice there, and it has been calculated that if the temperatures rose by four degrees Centigrade above pre-industrial levels up to two thirds of that ice could go.

Unfortunately, that is not the worst of the problems. If the climate heats, food becomes more difficult to provide. The most obvious problem is that most of the very best agricultural land is close to sea level, so we lose that. But additionally, there will be regions of greatly increased drought, and others with intense floods. Neither are good for agriculture. Yet there is an even worse problem: as soil gets hotter, it loses carbon and becomes less productive, while winds tend to blow soil away. So, what can we do about this? Unfortunately, it has to be everyone. We have to not only stop venting greenhouse gases into the atmosphere, but we have to work out ways to take it out. Stop and ask yourself, does your local politician understand this? My guess is no. Does your local politician understand what a partial differential equation means? My guess is no.

Trees for Carbon Capture, and Subsequent Problems

A little over fifty years ago, a 200 page book called The Limits to Growth was published, and the conclusion was that unless something was done, continued economic and population growth would deplete our resources and lead to global economic collapse around 2070. Around 1990, we predicted that greenhouse gases would turn our planet into something we would not like. So, what have we done? In an organized way, not much. One hazard with problem solving is that focusing on one aspect and fixing that often simply shifts it, and sometimes even makes it worse. Currently, we are obsessed with carbon dioxide, but all we appear to be doing is to complacently pat ourselves on the back because we shall be burning somewhat less Russian gas and oil in the future, oblivious to the fact that the substitute is likely to be coal.

One approach to mitigate global warming involves using biomass for carbon capture and storage (See Nature vol 609, p299 – 305). The authors here note that the adverse effects of climate change on crop yields may reduce the capacity of biomass to do this, as well as threaten food security. There are two approaches to overcoming the potential food shortage: increase agricultural land by using marginal land and cutting down forests, or increase nitrogen fertilizer. Now we see what “shifting the problem” means. If we use marginal land, we still have to increase the use of nitrogen fertilizer. This leads to the production of nitrous oxide gas, and these authors show the production of nitrous oxide would be roughly three times as effective as a greenhouse gas as the saving of carbon dioxide in their model. This is serious. All we have done is to generate a worse problem, to say nothing about the damage done to the environment. We have to leave some land for animals and wild plants.

There is a further issue: nitrogen fertiliser is currently made by reacting natural gas to make hydrogen, so for every tonne of fertilizer we will be making something like a tonne of CO2. Much the same happens if we make hydrogen from coal. Rather interestingly for such a paper, the authors concede they may have over-estimated the problems of food shortages on the grounds that new technology and practices may increase yields.

Suppose we make hydrogen by electrolysing water? Ammonia is currently made by heating nitrogen and hydrogen together at 200 times atmospheric pressure. This is by no means optimal, but higher pressures cost a lot more to construct, and there are increasing problems with corrosion, etc. Hydrogen made by electrolysis is also more expensive, in part because electricity is in demand for other purposes, and worse, electricity is also made at least in part by burning fossil fuels, and only a third of the energy is recovered as electricity. When considering a new use, it is important to not that the most adverse in terms of cost and effectiveness must be considered. Even if there are more friendly ways of getting electricity, you get favourable effects by doing nothing and turning off the adverse supply, so that must be assigned to your new use.

There is, however, an alternative in that electricity can directly reduce nitrogen to nitride in the presence of lithium, and if in the presence of a proton-donating substance (technically an acid, but not as you would probably recognize) you directly make ammonia, with no high pressure. So far, this is basically a laboratory curiosity because the yields and yield rates have been just too small, but there was a recent paper in Nature (vol 609, 722 – 727) which claims good increased efficiency. Since the authors write, “We anticipate that these findings will guide the development of a robust, high-performance process for sustainable ammonia production.” They do not feel they are there yet, but it is encouraging that improvements are being made.

Ammonia would be a useful means of carrying hydrogen for transport uses, but nitrogen fertilizer is important for maintaining food production. So can we reduce the nitrous oxide production? Nitrous oxide is a simple decomposition product of ammonium nitrate, which is the usual fertilizer used, but could we use something else, such as urea? Enzymes do convert urea to ammonium nitrate, but slowly, and maybe more nitrogen would end up in the plants. Would it? We don’t know but we could try finding out. The alternative might be to put lime, or even crushed basalt with the fertilizer. The slightly alkaline nature of these materials would react in part with ammonium nitrate and make metal nitrate salts, which would still be good fertilizer, and ammonia, which hopefully could also be used by plants, but now the degradation to nitrous oxide would stop. Would it? We don’t know for sure, but simple chemistry strongly suggests it would. So does it hurt to do then research and find out? Or do we sit on our backsides and eventually wail when we cannot stop the disaster.

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.

A Plan to Counter Global Warming Must be Possible to Implement

Politicians seem to think that once there is a solution to the problem in theory, the problem is solved so they stop thinking about it. Let us look at a reality. We know we have a problem with global warming and we have to stop burning fossil fuels. The transport sector is a big problem, but electric vehicles will do the trick, and in theory that might be true, but as I have pointed out in previous posts there is this troublesome matter of raw materials. Now the International Energy Agency has brought a little unpleasantness to the table. They have reported that global battery and minerals supply chains need to expand ten-fold to meet the critical needs of 2030 if the plan is to at least maintain schedule. If we take the average size of a major producer as a “standard mine” according to the IEA we need 50 more such lithium mines, 60 more nickel mines, and 17 more cobalt mines operating fully by 2030. Generally speaking, a new mine needs about ten years between starting a feasibility study and serious production. See a problem here? Because of the costs and exposure, you need feasibility studies to ensure that there is sufficient ore where you can’t see, that there is an economic way of processing the ore, and you must have a clear plan on what to do with what to do with minerals you do not want, with materials like arsenates or other undesirables also being present. You also have to build new roads, pipe in water, provide electricity, and do a number of other things to make the mine work that are not directly part of the mine. This does not mean you cannot mine, but it does mean it won’t be quite as easy as some might have you think. We now want our mines not to be environmental disasters. The IEA report notes that ten years, and then adds several more years to get production up to capacity.

The environmental issues are not to be considered as irrelevant. Thus the major deposits of lithium tend to be around the Andes, typically in rather dry areas. Then lithium is obtained by pumping down water, dissolving the salts, then bringing them up and evaporating the brine. Once most of the lithium is obtained, something has to be done with the salty residue, and of course the process needs a lot of water. The very limited water already in some locations is badly needed by the local population and their farms. The salt residues would poison agriculture.

If we consider nickel, one possible method to get more from poorer ores is high-pressure acid leaching. The process uses acid at high temperatures and pressure and end up with nickel at a grade suitable for batteries. But nickel often occurs as a sulphide, which means as a byproduct you get hydrogen sulphide, and a number of other effluents that have to be treated. Additionally, the process requires a lot of heat, which means burning coal or oil. The alternative source to the sulphide deposits, as advocated by the IEA, is laterite, a clayish material that also contains a lot of iron and aluminium oxides. These metals could also be obtained, but at a cost. The estimate of getting nickel by this process is to double the cost of the nickel.

The reason can be seen from the nature of the laterite (https://researchrepository.murdoch.edu.au/id/eprint/4340/1/nickel_laterite_processing.pdf), which is a usually a weathered rock. At the top you have well weathered rock, more a clay, and is red limonite. The iron oxide content (the cause of the red colour) is over 50% while the nickel content is usually less than 0.8% and the cobalt less than 0.1%. Below that is yellow limonite, where the nickel and cobalt oxides double their concentration. Below that we get saprolite/serpentine/garnierite (like serpentine but with enhanced nickel concentration). These can have up to 3% nickel, mainly due to the garnierite, but the serpentine family are silicates, where the ferrous such as in olivine has been removed. The leaching of a serpentine is very difficult simply because silicates are very resistant. Try boiling your average piece of basalt in acid. There are other approaches and for those interested, the link above shows them. However, the main point is that much of the material does not contain nickel. Do y9ou simply dump it, or produce iron at a very much higher cost than usual?

However, the major problems for each are they are all rather energy intensive, and the whole point of this is to reduce greenhouse emissions. The acid leach is very corrosive, and hence maintenance is expensive, while the effluents are troublesome for disposal. The disposal of the magnesium sulphate at sea is harmless, but the other materials with it may not be. Further, if the ore is somewhere like the interior of Australia, even finding water will be difficult.

Of course all these negatives can be overcome, with effort, if we are prepared to pay the price. Now, look around and ask yourself how much effort is going into establishing all those mines that are required? What are the governments doing? The short answer, as far as I can tell, is not much. They leave it to private industry. But private industry will be concerned that their balance sheets can only stand so much speculative expansion. My guess is that 2030 objectives will not be fulfilled.

Will We Do Anything To Stop Global Warming?

There is an interesting review on climate change (Matthews & Wynes, 2022, Science 376: 1404 – 1409). One point that comes up early is how did this sneak up on us? If you look at the graph on global temperatures, you will see that the summers in the 1940s were unusually hot, and the winters in the 1960 – 1980 period were unusually cool, with the net result that people living between 1940 – 1985 could be excused for thinking in terms of extremes instead of averages that the climate was fairly stable. As you will recall, at 1990 there was a major conference on climate change, and by 1992 goals were set to reduce emissions. It is just after this that temperatures have really started rising. In other words, once we “promised” to do something about it, we didn’t. At 1960 the CO2 levels in the atmosphere were about 320 ppm; by 1990 the CO2 levels were about 365 ppm, and at 2022 they are about 420 ppm. The levels of CO2 emissions have accelerated following the treaty in which much of the world undertook to reduce them. Therein lies out first problem. We are not reducing emissions; we are increasing them, even though we promised to do the opposite. (There was a small reduction in 2019-2020 as a result of the Covid lockdowns, but that has passed.) In short, our political promises are also based on hot air.

The current warming rate is approximately a quarter of a degree Centigrade per decade, which means that since we are now about 1.25 degrees warmer than the set 1850 baseline, we shall hit the 1.5 degrees warming somewhere just after 2030. Since that was the 1990 target not to be exceeded, failure seems inevitable. According to the models, to hold the temperature to 1.5 degrees C above our baseline we must not emit more than 360 Gt (billion tonne) of CO2. The IPCC considers we shall emit somewhere between 400 -650 Gt of CO2 before we get carbon neutral (and that assumes all governments actually follow up on their stated plans.) What we see is that current national targets are simply inadequate, always assuming they are kept. Unfortunately, there is a second problem: there are other greenhouse gases and some are persistent. The agricultural sector emits nitrous oxide, while industry emits a range of materials like sulphur hexafluoride, which may not be there in great quantity but it is reputedly 22,800 times more effective at trapping infrared radiation than CO2, and it stays in the atmosphere for approximately 3,200 years. These minor components cannot be ignored, and annual production is estimated at about 10,000 t/a. It is mainly used in electrical equipment, from whence it leaks.

Current infrastructure, such as electricity generators, industrial plant, ships, aircraft and land transport vehicles all have predictable lifetimes and emissions. These exceed that required to pass the 1.5 degree C barrier already unless some other mitigation occurs. Thus, the power stations already built will emit 846 Gt CO2, which is over twice our allowance. People are not going to abandon their cars. Another very important form of inertia is socio-political. To achieve the target, most fossil fuel has to stay in the ground, but politicians keep encouraging the development of new extraction. The average voter is also unhappy to see major tax increases to fund things that will strongly and adversely affect his way of life.

One way out might be carbon capture. The idea of absorbing CO2 from the atmosphere and burying it may seem attractive, but how is it done, at what cost in terms of money and energy required to do it, and who pays for it? Planting trees is a more acceptable concept. In New Zealand there is quite a bit of land that was logged by the early settlers, but has turned out to be rather indifferent farm land. The problem with knowing whether this is a potential solution or not is that it is impossible to know how much of such land can be planted, given that a lot is privately owned. However, planting trees is realistically something that could help, even if it does not solve the problem.

The article seems to feel that the solution must include actions such as lifestyle changes (carless days, reduced speed limits, reduced travel, a reduction of meat eating). My feeling is this would be a very difficult sell in a democracy, and it is not exactly encouraging to persuade some to purchase electric vehicles then be told they cannot use them. The article cites the need for urgency, and ignores the fact that we have had thirty years where governments have essentially ignored the problem. Even worse, the general public will not be impressed to find they are required to do something that adversely affects their lifestyle, only to find that a number of other countries have no interest in subjecting their citizens to such restrictions. The problem is no country can stop this disaster from happening; we all have to participate. But that does not mean we all have to give up our lifestyles, just to ensure that politicians can get away with their inability to get things done. In my opinion, society has to make changes, but they do not have to give up a reasonable lifestyle. We merely need to use our heads for something better than holding up a hat. And to show that we probably won’t succeed, the US Supreme Court has made another 6:3 ruling that appears to inhibit the US Federal Government from forcing certain states to reduce emissions. We shall cook. Yes, this might be a constitutional technicality that Congress could clear up easily, but who expects the current Congress to do anything helpful for civilization?

Belief in Science

I recently read something from a libertarian who accused people who “believe in science” as followers of a religion. The first point was, how can you so believe when you find well-credentialled scientists on both sides of an issue? The writer claimed that certain people may prefer people do not know this, but dissenting experts exist on many scientific questions that some pronounce as settled by a consensus. It claims credentialled maverick are often maligned as having been corrupted by industry, while scientists who view the established position are pure and incorruptible. So what do you think of that?

One comment lies in “well-credentialled” and “both sides of the issue”. By the time I started science in earnest, so to speak, Sir Richard Doll had produced a study showing heavy smoking greatly increased the risk of lung cancer. At the time, epidemiology was a “fringe” part of medicine but the statistics showed the truth. Naturally, there were people who questioned it, but I recall a review that showed that cigarette smoke contained a large number of chemicals that could be called carcinogens. One, 3,4-benzopyrene, was so active it guaranteed a cancer if a smear was applied to a certain strain of mice. Yes, they were particularly susceptible, but the point was obvious. Cigarette smoke contains a number of carcinogenic chemicals. Yet for years papers were produced that showed cigarette smoke was “harmless” and something else must be doing it. These were published in fringe journals and while the authors had credentials, they were being paid by the tobacco industry. So much for “both sides of the issue”.

A major criticism that comes to my mind is that the author does not understand what he is talking about. Science is not a collection of facts; it is a methodology for attempting to obtain the truth. Like any other activity, it does not always work well, but in principle you do not accept a statement based on the reputation of the speaker; that is the logic fallacy ad verecundiam. Unfortunately, what actually happens is so many are just plain lazy so they do not seek to check but rather accept it. Of course, if it is not important to you the consensus usually makes a lot of sense because you have not examined the details. Further, you accept it because you are only marginally interested. If someone says that a vaccine has passed a clinical trial in which x thousand people took part, there were no adverse effects and the vaccine worked, I take their word. The alternative is to check everything yourself, but you know that a procedure is in place where independent people have checked the statements, so I accept they are true. Science works by recording what we know and building on it. If there was a huge conspiracy to hide some real problems with a vaccine, the conspirators would eventually be found out, and an extended length of time would be spent in a rather uncomfortable cell.

Another criticism was that the “truth” comes down from a set of anointed scientists, and dissenters can be ignored because they are outside the group that matters. There is an element of truth in this. The anointed always get funding, and they get to peer review other funding applications. Dissent from the anointed means it is far more difficult to get funding. Further, the number of citations and publications you get means more funding. This leads to gaming the system, but such gaming cannot work with a dissenter. Sometimes, up to fifty scientists may agree to be authors on a number of papers (If you have fifty, they should produce fifty times the output of one.) But nobody counts the degree of share, and worse, they can keep citing all the papers within the set when one is being written, so automatically the number of citations jumps. Nobody notices they are self-citations or looks to see if they are relevant. That may seem unfair to others, but with money at stake, scientists also do what they can. This funding anomaly does lead to a group consensus.

Another example lies in climate change. Whether there is consensus is irrelevant; the question is, is there a definitive observation? I concede that initially I was suspicious, largely because there was a lot of modelling but not many facts. The theory was known, but the models ignored too many variables, and nothing seemed to have happened to the climate. The theory suggested there was an effect, but at first there was not much evidence for it. Then the evidence of warmer times started to come, but against that is climate has always changed. What was needed was a definitive set of measurements, and eventually they came (Lyman, J. M. and 7 others, 2010. Nature 465: 334-337.) What this showed was between 1993 and 2008 there was been an increase in the heat power delivered to the oceans of 0.64 w.m-2. That may not seem to be much, but multiply that across the area of oceans and you will see the planet is getting a very substantial net power input over a long period of time. We are cooking ourselves, but like the proverbial frog, we seem not to notice enough to do much about it.

One final comment. I wrote a chapter on climate change in my first ebook, which was about how to form theories, and which not only included the reasons why we should recognize the effect is real, but also I listed some previous technologies that could go some way towards reducing our dependencies on fossil fuels. These were all published or recorded in various archives, and one of the interesting things about this is that none of the recommended technologies have been proposed to be used. It is almost as if work done in the 1970-80s might as well not have been carried out. So what seemed to be “state of the art” then is now forgotten. There are problems in dealing with scientific issues and getting value from them, but group consensus is only temporary, and anything that can be forgotten probably will be. You don’t get science funding resurrecting the wheel, but you get somewhere. The question is, do we really want to get somewhere?

Biofuels to Power Transport

No sooner do I post something than someone says something to contradict the post. In this case, immediately after the last post, an airline came out and said it would be zero carbon by some time in the not-too-distant future. They talked about, amongst other things, hydrogen. There is no doubt hydrogen could power an aircraft, as it also powers rockets that go into space. That is liquid hydrogen, and once the craft takes off, it burns for a matter of minutes. I still think it would be very risky for aircraft to try to hold the pressures that could be generated for hours. If you do contain it, the extra weight and volume occupied would make such travel extremely expensive, while sitting above a tank of hydrogen is risky.

Hydrocarbons make by far the best aircraft fuel, and one alternative source of them is from biomass. I should caution that I have been working in this area of scientific research on and off for decades (more off than on because of the need to earn money.) With that caveat, I ask you to consider the following:

C6H12O6  ->  2 CO2 +2H2O + “C4H8”

That is idealized, but the message is a molecule of glucose (from water plus cellulose) can give two molecules each of CO2 and water, plus two thirds of the starting carbon as a hydrocarbon, which would be useful as a fuel. If you were to add enough hydrogen to convert the CO2 to a fuel you get more fuel. Actually, you do not need much hydrogen because we usually get quite a few aromatics, thus if we took two “C4H8” and make xylene or ethyl benzene (both products that are made in simple liquefactions) these total C8H10, which gives us a surplus of three H2 molecules. The point here is that in each of these cases we could imagine the energy coming from solar, but if you use biomass, much of the energy is collected for you by nature. Of course, if you take the oxygen out as water you are left with carbon. In practice there are a lot of options, and what you get tends to depend on how you do it. Biomass also contains lignin, which is a phenolic material. This is much richer in hydrocarbon material, but also it is much harder to remove the oxygen.

In my opinion, there are four basic approaches to making hydrocarbon fuels from biomass. The first, which everyone refers to, is pyrolysis. You heat the biomass, you get a lot of charcoal, but you also get liquids. These still tend to have a lot of oxygen in them, and I do not approve of this because the yields of anything useful are too low unless you want to make charcoal, or carbon, say for metal refining, steel making, electrodes for batteries, etc. There is an exception to that statement, but that needs a further post.

The second is to gasify the biomass, preferably by forcing oxygen into it and partially burning it. This gives you what chemists call synthesis gas, and you can make fuels through a further process called the Fischer-Tropsch process. Germany used that during the war, and Sasol in South Africa Sasol, but in both cases coal was the source of carbon. Biomass would work, and in the 1970s Union Carbide built such a gasifier, but that came to nothing when the oil price collapsed.

The third is high-pressure hydrogenation. The biomass is slurried in oil and heated to something over 400 degrees Centigrade in then presence of a nickel catalyst and hydrogen. A good quality oil is obtained, and in the 1980s there was a proposal to use the refuse of the town of Worcester, Mass. to operate a 50 t/d plant. Again, this came to nothing when the price of oil slumped.

The fourth is hydrothermal liquefaction. Again, what you get depends on what you put in but basically there are two main fractions from woody biomass: hydrocarbons and phenolics. The phenolics (which includes aromatic ethers) need to be hydrogenated, but the hydrocarbons are directly usable, with distillation. The petrol fraction is a high octane, and the heavier hydrocarbons qualify as very high-quality jet fuel. If you use microalgae or animal residues, you also end up with a high cetane diesel cut, and nitrogenous chemicals. Of particular interest from the point of view of jet fuel, in New Zealand they once planted Pinus Radiata which grew very quickly, and had up to 15% terpene content, most of which would make excellent jet fuel, but to improve the quality of the wood, they bred the terpenes more or less out of the trees.

The point of this is that growing biomass could help remove carbon dioxide from the atmosphere and make the fuels needed to keep a realistic number of heritage cars on the road and power long-distance air transport, while being carbon neutral. This needs plenty of engineering development, but in the long run it may be a lot cheaper than just throwing everything we have away and then finding we can’t replace it because there are shortages of elements.

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.

“Green” Electricity

Before thinking about how to replace fossil fuels for electricity, we need to look at how the power demand varies through the day. Not unexpectedly, this varies depending on where you live, but if you take various parts of the US as an example of industrialized usage, there is a baseline that involves minimal usage at about 0500 hrs, and that baseline varies by up to 30% seasonally. The difference between day and night can vary by up to 60%, the biggest variation is in hot summer and is due to the use of air conditioning. This means there is a huge difference between peak demand and minimum demand, which in turn means that difference has to be supplied by generation that can be turned on and off. The big thermal plants do not turn on and off easily. You can run the plant without producing electricity, but now you are simply burning fuel for no purpose.

The most responsive generators are the gas turbine and hydroelectricity. Hydro is an obvious “green” source for load smoothing; you simply shut the gate, save water, and stop generating, but most suitable hydro sites are already used. Wind power is also useful; you simply let wind pass if you do not want power, but it runs into trouble when you need power and there is no wind. Solar means you charge batteries during the day and used the power later, but in a previous post I showed it is impossible to make enough batteries to power our vehicle fleet, so how do we make an even greater supply of batteries? A further alternative is to run your base load near maximum usage, and use the surplus to make something like hydrogen when it is not needed. More on hydrogen in a later post.

The “inconvenient truth” for some is the only general major base load provider to replace coal and gas for electricity generation is nuclear. Unfortunately, nuclear has a bad press. Other downsides include, currently, it is too expensive. Most people think it is too dangerous and it is too likely to leak radiation. Actually, the smoke from coal combustion also is cancer inducing to lungs, while in the US there are around 13,000 premature deaths per year due to coal, and 23,000 annually in Europe. Coal is nowhere nearly as safe as people think. So far, nuclear power has a death rate of 0.07 deaths per terawatt-hour of electricity, or about 1 death per 14 years. That figure is enhanced substantially due to stupidity at Chernobyl. Fukushima has 1 death attributed to it, although there are claims that the stresses of it on those who had to move caused a further 2,200. Up to 2004 (18 years later) 78 died from Chernobyl. This is not good, but it is avoidable.

Current reserves of uranium total 5.3 million tonne, about a third of which are in Australia. However, only about 36,000 t of that is U235, which is what is fissile, and has to be enriched. The depleted uranium waste from the enrichment process goes into armour-piercing military rounds. What happens in most nuclear power stations is the enriched uranium rods generate heat, then have to be taken away to be reprocessed, which involves removing the plutonium for weapons. A long time ago, when I was at school, we had a visiting energy expert who told us that in the future the world would develop breeder reactors, and the enriched uranium would produce more fuel in the form of plutonium than it consumed in making electricity, The need to feed the military complex means that did not happen.

What is possible is a new generation of reactor, based on the fuel being dissolved in molten salt. The reactor is now at thermal equilibrium so it is impossible to have a melt-down – there is nothing to melt. The one catch is the issue of corrosion. That can undoubtedly be dealt with, but we have yet to learn the real long-term issues. China is currently testing one demonstration plant, and it is designed to simply provide the boiling pressurized water to run an existing power plant. The idea is simply the coal-firing is removed, this heat source is plugged in and everything else continues working. As the U238 gets converted to plutonium, it also fissions and generates heat to make electricity. What the surplus neutrons in the reactor do is also to burn “hot” isotopes, so the waste disposal problems are far less. Finally, once going, it can also take thorium as a fuel, and there is far more thorium in the world. Simple fission could keep us going for centuries.

Arguably, nuclear is not “green”. My argument is we either use it or not, but it alone has any chance of providing the levels of electricity we need and replace fossil fuel burning.

Ultimately, fusion power would solve all our energy problems. There is only one problem with it: we do not know how to make it work. There is also one general problem. To change our ways, we shall have to spend a very large amount of money, and basically replace about two thirds of our existing electricity generating infrastructure. The alternative is to do nothing and then rebuild all our major coastal cities when the ice sheets collapse. That is also expensive. We have a choice, but unfortunately our politicians seem to want to do nothing and leave the problem for our grandchildren.