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on electrickery, part 2 – the beginnings

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William Gilbert, author of De Magnete, 1600

Canto: So let’s now start at the beginning. What we now call electricity, or even electromagnetism, has been observed and questioned since antiquity. People would’ve wondered about lightning and electrostatic shocks and so forth.

Jacinta: And by an electrostatic shock, you mean the sort we get sometimes when we touch a metal door handle? How does that work, and why do we call it electrostatic?

Canto: Well we could do a whole post on static electricity, and maybe we should, but it happens when electrons – excess electrons if you like – move from your hand to the conductive metal. This is a kind of electrical discharge. For it to have happened you need to have built up electric charge in your body. Static electricity is charge that builds up through contact with clothing, carpet etc. It’s called static because it has nowhere to go unless it comes into contact with a positive conductor.

Jacinta: Yes and it’s more common on dry days, because water molecules in the atmosphere help to dissipate electrons, reducing the charge in your body.

Canto: So the action of your shoes when walking on carpet – and rubber soles are worst for this – creates a transfer of electrons, as does rubbing a plastic rod with wooden cloth. In fact amber, a plastic-like tree resin, was called ‘elektron’ in ancient Greek. It was noticed in those days that jewellery made from amber often stuck to clothing, like a magnet, causing much wonderment no doubt.

Jacinta: But there’s this idea of ‘earthing’, can you explain that?

Canto: It’s not an idea, it’s a thing. It’s also called grounding, though probably earthing is better because it refers to the physical/electrical properties of the Earth. I can’t go into too much detail on this, its complexity is way above my head, but generally earthing an electrical current means dissipating it for safety purposes – though the Earth can also be used as an electrical conductor, if a rather unreliable one. I won’t go any further as I’m sure to get it wrong if I haven’t already.

Jacinta: Okay, so looking at the ‘modern’ history of our understanding of electricity and magnetism, Elizabethan England might be a good place to start. In the 1570s mathematically minded seamen and navigators such as William Borough and Robert Norman were noting certain magnetic properties of the Earth, and Norman worked out a way of measuring magnetic inclination in 1581. That’s the angle made with the horizon, which can be positive or negative depending on position. It all has to do with the Earth’s magnetic field lines, which don’t run parallel to the surface. Norman’s work was a major inspiration for William Gilbert, physician to Elizabeth I and a tireless experimenter, who published De Magnete (On the Magnet – the short title) in 1600. He rightly concluded that the Earth was itself a magnet, and correctly proposed that it had an iron core. He was the first to use the term ‘electric force’, through studying the electrostatic properties of amber.

Canto: Yes, Gilbert’s work was a milestone in modern physics, greatly influencing Kepler and Galileo. He collected under one head just about everything that was known about magnetism at the time, though he considered it a separate phenomenon from electricity. Easier for me to talk in these historical terms than in physics terms, where I get lost in the complexities within a few sentences.

Jacinta: I know the feeling, but here’s a relatively simple explanation of earthing/grounding from a ‘physics stack exchange’ which I hope is accurate:

Grounding a charged rod means neutralizing that rod. If the rod contains excess positive charge, once grounded the electrons from the ground neutralize the positive charge on the rod. If the rod is having an excess of negative charge, the excess charge flows to the ground. So the ground behaves like an infinite reservoir of electrons.

So the ground’s a sink for electrons but also a source of them.

Canto: Okay, so if we go the historical route we should mention a Chinese savant of the 11th century, Shen Kuo, who wrote about magnetism, compasses and navigation. Chinese navigators were regularly using the lodestone in the 12th century. But moving into the European renaissance, the great mathematician and polymath Gerolamo Cardano can’t be passed by. He was one of the era’s true originals, and he wrote about electricity and magnetism in the mid-16th century, describing them as separate entities.

Jacinta: But William Gilbert’s experiments advanced our knowledge much further. He found that heat and moisture negatively affected the ‘electrification’ of materials, of which there were many besides amber. Still, progress in this era, when idle curiosity was frowned upon, was slow, and nothing much else happened in the field until the work of Otto von Guericke and Robert Boyle in the mid-17th century. They were both interested particularly in the properties, electrical and otherwise, of vacuums.

Canto: But the electrical properties of vacuum tubes weren’t really explored until well into the 18th century. Certain practical developments had occurred though. The ‘electrostatic machine’ was first developed, in primitive form, by von Guericke, and improved throughout the 17th and 18th centuries, but they were often seen as little more than a sparky curiosity. There were some theoretical postulations about electrics and non-electrics, including a duel-fluid theory, all of which anticipated the concept of conductors and insulators. Breakthroughs occurred in the 1740s with the invention of the Leyden Jar, and with experiments in electrical signalling. For example, an ingenious experiment of 1746, conducted by Jean-Antoine Nollet, which connected 200 monks by wires to form a 1.6 kilometre circle, showed that the speed of electrical transmission was very high! Experiments in ‘electrotherapy’ were also carried out on plants, with mixed results.

Jacinta: And in the US, from around this time, Benjamin Franklin carried out his experiments with lightning and kites, and he’s generally credited with the idea of positive to negative electrical flow, though theories of what electricity actually is remained vague. But it seems that Franklin’s fame provided impetus to the field. Franklin’s experiments connected lightning and electricity once and for all, though similar work, both experimental and theoretical, was being conducted in France, England and elsewhere.

Canto: Yes, there’s a giant roll-call of eighteenth century researchers and investigators – among them Luigi Galvani, Jean Jallabert, John Canton, Ebenezer Kinnersley, Giovanni Beccaria, Joseph Priestley, Mathias Bose, Franz Aepinus, Henry Cavendish, Charles-Augustin Coulomb and Alessandro Volta, who progressed our understanding of electrical and magnetic phenomena, so that modern concepts like electric potential, charge, capacitance, current and the like, were being formalised by the end of that century.

Jacinta: Yes, for example Coulomb discovered, or published, a very important inverse-square law in 1784, which I don’t have the wherewithal to put here mathematically, but it states that:

The magnitude of the electrostatic force of attraction between two point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.

This law was an essential first step in the theory of electromagnetism, and it was anticipated by other researchers, including Priestley, Aepinus and Cavendish.

get it?

Canto: And Volta produced the first electric battery, which he demonstrated before Napoleon at the beginning of the 19th century.

Jacinta: And of course this led to further experimentation – almost impossible to trace the different pathways and directions opened up. In England, Humphrey Davy and later Faraday conducted experiments in electrochemistry, and Davy invented the first form of electric light in 1809. Scientists, mathematicians, experimenters and inventors of the early nineteenth century who made valuable contributions include Hans Christian Orsted, Andre-Marie Ampere, Georg Simon Ohm and Joseph Henry, though there were many others. Probably the most important experimenter of the period, in both electricity and magnetism, was Michael Faraday, though his knowledge of mathematics was very limited. It was James Clerk Maxwell, one of the century’s most gifted mathematicians, who was able to use Faraday’s findings into mathematical equations, and more importantly, to conceive of the relationship between electricity, magnetism and light in a profoundly different way, to some extent anticipating the work of Einstein.

Canto: And we should leave it there, because we really hardly know what we’re talking about.

Jacinta: Too right – my reading up on this stuff brings my own ignorance to mind with the force of a very large electrostatic discharge….

now try these..

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Written by stewart henderson

October 22, 2017 at 10:09 am

Why science?

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why is it so?

Ever since I was a kid I was an avid reader. It was my escape from a difficult family situation and a hatred or fear of most of my teachers. I became something of a quiet rebel, rarely reading what I was supposed to read but always trying to bite off more than I could chew in terms of literature, history, and occasionally science. I did find, though, that I could chew almost anything – especially in literature and history. And I loved the taste. Science, though, was different. It certainly didn’t come naturally to me. I didn’t know any science buffs and in fact I had no mentors for any of my reading activities. We did have encyclopaedias, though, and my random reading turned up the likes of Einstein, Newton, Darwin, Pasteur and other Big Names in science. Of course I was more interested in their bios than in the nature of their exotic researches, but in my idealised view they seemed very pure in their quest for greater understanding of the material world. I sometimes wished I could be like them but mostly I just dived into ‘literature’, a more comfortable world in which ordinary lives were anatomised by high-brow authors like Austen, Eliot and James (I had a fetish for 19th century lit in my teens). I took silent pride in my critical understanding of these texts, it surely set me above my classmates, though I remember one day walking home with one of the smartest kids in my class, who regaled me with his exploration of the electronics of a transistor radio he was pulling apart at home. I remember trying to listen, half ashamed of my ignorance, half hoping to change the subject to something I could sound off about.

Later, having dropped out of my much-loathed school, I started hanging out, or trying to, with other school drop-outs in my working-class neighbourhood. I didn’t fit in with them to say the least, but the situation worsened when they began tinkering with or talking about cars, which held no interest for me. I was annoyed and impressed at how articulate they were about carbies, distributors and camshafts, and wondered if I was somehow wasting my life.

Into my twenties, living la vie boheme in punk-fashionable poverty among art students and amateur philosophers, I read and was definitely intrigued by Alan Chalmers’ unlikely best-seller What is this thing called science? It sparked a brief interest in the philosophy of science rather than science itself, but interestingly it was a novel that really set me to reading and trying to get my head around science – a big topic! – on a more or less daily basis. I was about 25 when I read Thomas Mann’s The Magic Mountain, in which Hans Castorp, a young man of about my age at the time, was sent off to an alpine sanatorium to be cured of tuberculosis. Thus began a great intellectual adventure, but it was the scientific explorations that most spoke to me. Wrapped up in his loggia, reading various scientific texts, Castorp took the reader on a wondering tour of the origin of life, and of matter itself, and it struck me that these were the key questions – if you want to understand yourself, you need to understand humanity, and if you want to understand humanity you need to understand life itself, and if you want to understand life, you need to understand the matter that life is organised from, and if you need to understand matter…

I made a decision to inform myself about science in general, via the monthly magazine, Scientific American, where I learned at least something about oncogenes, neutrinos and the coming AIDS epidemic, inter alia. I read my first wholly scientific book, Dawkins’ The Selfish Gene, and, as I was still living la vie boheme, I enjoyed the occasional lively argument with housemates or pub philosophers about the Nature of the Universe and related topics. In the years since I’ve read and half-digested books on astronomy, cosmology, palaeontology and of course the history of science in general. I’ve read The origin of species, Darwin’s Voyage of the Beagle and at least four biographies of Darwin, including the monumental biography by Adrian Desmond and James Moore. I’ve also read a biography of Alfred Russell Wallace, and more recently, Siddhartha Mukherjee’s The Gene, which traces the search for the cause of the random variation essential to the Darwin-Wallace theory. And I still read science magazines like Cosmos on a more or less daily basis.

These readings have afforded me some of the greatest pleasures of my life, which would, I suppose, be enough to justify them. But I should try to answer the why question. Why is science so thrilling? The answer, I hope, is obvious. It isn’t science that’s thrilling, it’s our world. I’m not a science geek, it doesn’t come easily to me. When, for example, a tech-head explains how an electronic circuit works, I have to watch the video many times over, look up terms, refer to related videos, etc, in order to fix it in my head, and then, like most people, I forget the vast majority of what I read, watch or listen to. But what keeps me going is a fascination for the world – and the questions raised. How did the Earth form? Where did the water come from? How is it that matter is electrical, full of charge? How did language evolve? How has our Earth’s atmosphere evolved? How are we related to bananas, fruit flies, australopithecines and bats? How does our microbiome relate to obesity? What can we expect from CRISPR/Cas9 editing technology? What’s the future for autonomous vehicles, brain-controlled drones and new-era smart phones?

This all might sound like gaga adolescent optimism, but I’m only cautiously optimistic, or maybe not optimistic at all, just fascinated about what might happen, on the upside and the downside. And I’m endlessly impressed by human ingenuity in discovering new things and using those discoveries in innovative ways. I’m also fascinated, in a less positive way, by the anti-scientific tendencies of conspiracy theorists, religionists, new-agers and those who identify with and seem trapped by ‘heavy culture’. Podcasts such as The Skeptics’ Guide to the Universe, Skeptoid and Australia’s The Skeptic Zone, as well as various science-based blogs like Why Evolution is True and Skeptical Science are fighting a seemingly never-ending fight against the misinformation churned out by passionate supporters of fixed non-evidence-based positions. But spending too much time arguing with such types does your head in, and I prefer trying to accentuate the positive than trying to eliminate the negative.

And on that positive side, exciting things are always happening, whether it’s battery technology, cancer research, exoplanetary discoveries, robotics or brain implants, more developments are occurring than any one person can keep abreast of.

So I’ll end with some positive and reassuring remarks about science. It’s not some esoteric activity to be suspicious of, but neither is it something easily definable. It’s not a search for the truth, it’s more a search for the best, most comprehensive, most consistent and productive explanation for phenomena. I don’t believe there’s such a thing as the scientific method – the methods of Einstein can’t easily be compared with those of Darwin. Methods necessarily differ with the often vast differences between the phenomena under investigation. Conspiracy theories such as the moon landings ‘hoax’ or the climate science ‘fraud’ would require that scientists and their ancillaries are incredibly disciplined, virtually robotic collaborators in sinister plots, rather than normal, questing, competitive, collaborative, inspired and inspiring individuals, struggling desperately to make sense and make breakthroughs. In the field of human health, scientists are faced with explaining the most complex organism we know of – the human body with its often perverse human mind. It’s not at all surprising that pseudo-science and quackery is so common in this field, in which everyone wants to live and thrive as long as possible. But we need to be aware that with such complexity we will encounter many false hopes and only partial solutions. The overall story, though, is positive – we’re living longer and healthier, in statistical terms, than ever before. The past, for the most part, is another country which we might like to briefly visit, but we wouldn’t want to live there. And science is largely to be thanked for that. So, why not science? The alternatives do nothing for me.

The SGU team – science nerds fighting the good fight

Written by stewart henderson

October 7, 2017 at 6:18 am

stand-alone solar: an off-grid solution for Australia’s remote regions (plus a bit of a rant)

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According to this article, Australia is leading the world in per capita uptake of rooftop solar, though currently South Australia is lagging behind, in spite of a lot of clean energy action from our government. The Clean Energy Regulator has recently released figures showing that 23% of Australians have installed rooftop solar in the last ten years, and this take-up is set to continue in spite of the notable lack of encouragement from the feds. South Australia is still making plenty of waves re clean energy, though, as it is continually lowering its record for minimum grid demand, through the use of solar PV. The record set a couple of days ago, interestingly on Sunday afternoon rather than in the middle of the night, was 587MW, almost 200MW less than the previous record set only a week or so before. Clearly this trend is set to continue.

It’s hard for me to get my head around what’s happening re disruptive technologies, microgrids, stand-alone solar, EVs, battery research and the like, not to mention the horribly complex economics around these developments, but the sense of excitement brought about by comprehensive change makes me ever-willing to try. Only this morning I heard a story of six farming households described as being ‘on the fringe of Western Australia’s power network’ who’ve successfully trialled stand-alone solar panels (powered by lithium-ion batteries) on their properties, after years of outages and ‘voltage spikes’*. The panels – and this is the fascinating part – were offered free by Western Power (WA’s government-owned energy utility), who were looking for a cheaper alternative to the cost of replacing ageing infrastructure. The high costs of connecting remote farms to the grid make off-grid power systems a viable alternative, which raises issues about that viability elsewhere given the decreasing costs of solar PV, which can maintain electricity during power outages, as one Ravensthorpe family, part of the trial, discovered in January this year. The region, 500 kilometres south of Perth, experienced heavy rain and flooding which caused power failures, but the solar systems were unaffected. All in all, the trial has ‘exceeded expectations’, according to this ABC report.

All this has exciting implications for the future, but there are immediate problems. Though Western Power would like to sign off on the trial as an overwhelming success, and to apply this solution to other communities in the area (3,000 potential sites have been pinpointed), current regulation prevents this, as it only allows Western Power to distribute energy, not to generate it, as its solar installations are judged as doing. Another instance of regulations not keeping up with changing circumstances and solutions. Western Power has no alternative but to extend the trial period until the legislation catches up (assuming it does). But it would surely be a mistake not to change the law asap:

“You’d be talking about a saving of about $300 million in terms of current cost of investment and cost of ongoing maintenance of distribution line against the cost of the stand-alone power system,” Mr Chalkley [Western Power CEO] said.

Just as a side issue, it’s interesting that our PM Malcolm Turnbull, whose government seems on the whole to be avoiding any mention of clean energy these days, has had solar panels on his harbourside mansion in Point Piper, Sydney, for years. He now has an upgraded 14 kW rooftop solar array and a 14kWh battery storage system installed there, and, according to a recent interview he did on radio 3AW, he doesn’t draw any electricity from the grid, in spite of using a lot of electricity for security as Prime Minister. Solar PV plus battery, I’m learning, equals a distributed solar system. The chief of AEMO (the Australian Energy Market Operator), Audrey Zibelman, recently stated that distributed rooftop solar is on its way to making up 30 to 40% of our energy generation mix, and that it could be used as a resource to replace baseload, as currently provided by coal and gas stations (I shall write about baseload power issues, for my own instruction, in the near future).

Of course Turnbull isn’t exactly spruiking the benefits of renewable energy, having struck a Faustian bargain with his conservative colleagues in order to maintain his prestigious position as PM. We can only hope for a change of government to have any hope of a national approach to the inevitable energy transition, and even then it’ll be a hard road to hoe. Meanwhile, Tony Abbott, Turnbull’s arch-conservative bête noir, continues to represent the dark side. How did this imbecilic creature ever get to be our Prime Minister? Has he ever shown any signs of scientific literacy? Again I would urge extreme vetting of all candidates for political office, here and elsewhere, based on a stringent scientific literacy test. Imagine the political shite that would be flushed down the drain with that one. Abbott, you’ll notice, always talks of climate change and renewable energy in religious terms, as a modern religion. That’s because religion is his principal obsession. He can’t talk about it in scientific terms, because he doesn’t know any. Unfortunately, these politicians are rarely challenged by journalists, and are often free to choose friendly journalists who never challenge their laughable remarks. It’s a bit of a fucked-up system.

Meanwhile the ‘green religionists’, such as the Chinese and Indian governments, and the German and Scandinavian governments, and Elon Musk and those who invest in his companies, and the researchers and scientists who continue to improve solar PV, wind turbine and battery technology, including flow batteries, supercapacitors and so much more, are improving their developments and disrupting traditional ways of providing energy, and will continue to do so, in spite of name-calling from the fringes (to whom they’re largely deaf, due to the huge level of support from their supporters). It really is an exciting time not to be a dinosaur.

 

Written by stewart henderson

September 20, 2017 at 9:32 pm

what are capacitors?

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the shapes and sizes of capacitors – a screenshot taken from the youtube vid – What are Capacitors? – Electronics Basics 11

Jacinta: We’re embarking on the clearly impossible task of learning about every aspect of clean (and sometimes dirty because nothing’s 100% clean or efficient) technology – batteries, photovoltaics, turbines, kilo/megawatt-hours, glass electrolytes, powerwalls, inverters, regen, generators, airfoils, planetary gear sets, step-up transformers, nacelles AND capacitors.

Canto; Enough to last us a lifetime at our slow pace. So what, in the name of green fundamentalism, is a capacitor?

Jacinta: Well I’ve checked this out with Madam Youtube…

Canto: Professor Google’s co-dependent…

Jacinta: And in one sense it’s simple, or at least it sounds simple. Capacitors store electric charge, and the capacitance of a capacitor relates to how much charge it can hold.

Canto: So how does it do that, and what’s the purpose of storing electric charge?

Jacinta: Okay now you’re complicating matters, but basic to all capacitors are two separated pieces of conducting material, usually metal. Connected to a battery, they store charge…

Canto: Which is a kind of potential energy, right?

Jacinta: Umm, I think so. So take your battery with its positive and negative terminals. Attach one of the bits of conducting material (metal) to the positive terminal and you’ll get a flow of negatively-charged electrons to that terminal, because of ye olde law of attraction. This somehow means that electrons are repelled from the negative terminal  (which we’ve hooked up to the other bit of metal in the capacitor). So because the first strip of metal has lost electrons it has become positively charged, and the other bit of metal, having gained electrons, has an equal and opposite charge. So each piece of metal has the same magnitude of charge, measured in coulombs. This is regardless of the size and shape of the different metal bits.

Canto: But this process reaches a limit, though, yes? A kind of saturation point…

Jacinta: Well there comes a point where, yes, the accumulated charge just sits there. This is because there comes a kind of point of equilibrium between the positive battery terminal and the now positively charged strip of metal. The electrons are now caught between the attractive positive terminal and the positive strip.

Canto: Torn between two lovers, I know that foolish feeling.

Jacinta: So now if you remove the battery, so breaking the circuit, that accumulated charge will continue to sit there, because there’s nowhere to go.

Canto: And of course that accumulated or stored charge, or capacitance, is different for different capacitors.

Jacinta: And here’s where it gets really complicated, like you know, maths and formulae and equations. C = Q/V, capacitance equals the charge stored by the capacitor over the voltage across the capacitor. That charge (Q), in coulombs, is measured on one side of the capacitor, because the charges actually cancel each other out if you measure both sides, making a net charge of zero. So far, so uncomplicated, but try and get the following. When a capacitor stores charge it will create a voltage, which is essentially a difference in electric potential between the two metal strips. Now apparently (and you’ll have to take my word for this) electric potential is high near positive charges and low near negative charges. So if you bring these two differently charged strips into close proximity, that’s when you get a difference in electric potential – a voltage. If you allow a battery to fully charge up a capacitor, then the voltage across it (between the two strips) will be the same as the voltage in the battery. The capacitance, Q/V, coulombs per volt, is measured in farads, after Micky Faraday, the 19th century electrical wizz. I’m quoting this more or less verbatim from the Khan Academy video on capacitors, and I’m almost finished, but here comes the toughest bit, maths! Say you have a capacitor with a capacitance of 3 farads, and it’s connected to a nine volt battery, the charge stored will be 27 coulombs (3 = 27/9). 3 farads equals 27 coulombs of charge divided by nine volts, or 27 coulombs of charge is 3 farads times 9 volts. Or, if a 2 farad capacitor stores a charge of 6 coulombs, then the voltage across the capacitor will be 3 volts.

Canto: Actually, that’s not so difficult to follow, the maths is the easiest part for me… it’s more the concepts that get me, the very fact that matter has these electrical properties…

Jacinta: Okay here’s the last point made, more or less verbatim, on the Khan Academy video, something worth pondering:

You might think that as more charge gets stored on a capacitor, the capacitance must go up, but the value of the capacitance stays the same because as the charge increases, the voltage across that capacitor increases, which causes the ratio to stay the same. The only way to change the capacitance of a capacitor is to alter the physical characteristics of that capacitor (like making the pieces of metal bigger, or changing the distance between them).

Canto: Okay so to give an example, a capacitor might be connected to an 8 volt battery, but its capacitance is, say, 3 farads. It will be fully charged at 24 coulombs over 8 volts. The charge increases with the voltage, which has a maximum of 8. The ratio remains the same. Yet somehow I still don’t get it. So I’m going to have a look at another video to see if it helps. It uses the example of two metal plates. They start out as electrically neutral. You can’t force extra negativity, in the form of electrons, into one of these plates, because like charges repel, and they’ll be forced out again. But, according to the video, if you place another plate near the first, ‘as electrons accumulate in the first metal plate, they will repel the electrons in the second metal plate’, to which I want to respond, ‘but electrons aren’t accumulating, they’re being repelled’. But let’s just go with the electron flow. So the second metal plate becomes depleted of electrons and is positively charged. This means that it will attract the negatively charged first metal plate. According to the video, this makes it possible for the first plate to have more negative than positive particles, which I think has something to do with the fact that the electrons can’t jump from the first plate to the second, to create an equilibrium.

Jacinta: They’re kind of attracted by absence. That’s what they must mean by electric potential. It’s very romantic, really. But what you’ve failed to notice, is that a force is being continually applied, to counteract the repulsion of electrons from the first plate. If the force no longer applies then, yes, you won’t get that net negative charge in the first plate, and the consequent equal and opposite charge in the second. My question, though, is how can the capacitance increase by bringing the plates closer together? I can see how it can be changed by the size of the conducting material – more electrons, more electric potential. I suppose reducing the distance will increase the repulsive force…

Canto: Yes, let’s assume so. Any, a capacitor, which stores far less charge than a similarly-dimensioned battery can be used, I think, to briefly maintain power to, say, a LED bulb when it is disconnected from the battery. The capacitor, connected to the bulb will discharge its energy ‘across’ the bulb until it achieves equilibrium, which happens quite quickly, and the bulb will fade out. If the capacitor is connected to a number of batteries to achieve a higher voltage, the fully charged capacitor will take longer to discharge, keeping the light on for longer. If the metal plates are larger, the capacitor will take longer to charge up, and longer to discharge across the LED bulb. Finally, our second video (from a series of physics videos made by Eugene Khutoryansky) shows that you can place a piece of ‘special material’ between the two plates. This material contains molecules that change their orientation according to the charges on the plates. They exert a force which attracts more electrons to the negative plate, and repel them from the positive plate, which has the same effect as increasing the area of the plates – more charge for the same applied voltage.

Jacinta: An increase in capacitance.

Canto: Yes, and as you’ve surmised, bringing the two plates closer together increases the capacitance by attracting more electrons to the negatively charged plate and repelling them from the positively charged one – again, more charge for the same voltage.

Jacinta: So you can increase capacitance with a combo of the three – increased size, closer proximity, and that ‘special material’. Now, one advantage of capacitors over batteries is that they can charge up and discharge very quickly. Another is that they can endure many charge-discharge cycles. However they’re much less energy dense than batteries, and can only store a fraction of the energy of a same-sized battery. So the two energy sources have different uses.

Canto: Mmmm, and we’ll devote the next post to the uses to which capacitors can be put in electronics, and EVs and such.

 

Written by stewart henderson

August 28, 2017 at 6:27 pm

on the explosion of battery research – part two, a bitsy presentation

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This EV battery managed to run for 1200 kilometres on a single charge at an average of around 51 mph

Ok, in order to make myself fractionally knowledgable about this sort of stuff I find myself watching videos made by motor-mouthed super-geeks who regularly do blokes-and-sheds experiments with wires and circuits and volt-makers and resistors and things that go spark in the night, and I feel I’m taking a peek at an alternative universe that I’m not sure whether to wish I was born into, but I’ll try anyway to report on it all without sounding too swamped or stupefied by the detail.

However, before I go on, I must say that, since my interest in this stuff stems ultimately from my interest in developing cleaner as well as more efficient energy, and replacing fossil fuel as a principal energy source, I want to voice my suspicions about the Australian federal government’s attitude towards clean and renewable energy. This morning I heard Scott Morrison, our nation’s Treasurer, repeating the same deliberately misleading comments made recently by Josh Frydenberg (the nation’s energy minister, for Christ’s sake) about the Tesla battery, which is designed to provide back-up power as part of a six-point SA government plan which the feds are well aware of but are unwilling to say anything positive about – or anything at all. Morrison, Frydenberg and that other trail-blazing intellectual, Barnaby Joyce, our Deputy Prime Minister, have all been totally derisory of the planned battery, and their pointlessly negative comments have thrown the spotlight on something I’ve not sufficiently noticed before. This government, since the election of just over a year ago, has not had anything positive to say about clean energy. In fact it has never said anything at all on the subject, by deliberate policy I suspect. We know that our PM isn’t as stupid on clean energy as his ministers, but he’s obviously constrained by his conservative colleagues. It’s as if, like those mythical ostriches, they’re hoping the whole world of renewables will go away if they pay no attention to it.

Anyway, rather than be demoralised by these unfortunates, let’s explore the world of solutions.

As a tribute to those can-do, DIY geeky types I need to share a great video which proves you can run an electric vehicle on a single charge for well over 1000ks – theirs made it to 1200ks – 748 miles in that dear old US currency – averaging around 51 mph. It’s well worth a watch, though with all the interest there are no doubt other claimants to the record distance for a single charge. Anyway, you can’t help but admire these guys. Tesla, as the video shows, are still trying to make it to 1000ks, but that’s on a regular, commercial basis of course.

In this video, basically an interview with battery researcher and materials scientist Professor Peter Bruce at Oxford University, the subject was batteries as storage systems. These are the batteries you find in your smart phones and other devices, and in electric vehicles (EVs). They’ll also be important in the renewable energy future, for grid storage. You can pump electricity into these batteries and, through a chemical process that I’m still trying to get my head around, you can store it for later use. As Prof Bruce points out, the lithium-ion battery revolutionised the field by more or less doubling the energy density of batteries and making much recent portable electronics technology possible. This energy density feature is key – the Li-ion batteries can store more energy per unit mass and volume. Of course energy density isn’t the only variable they’re working on. Speed of charge, length of time (and/or amount of activity) between charging, number of discharge-recharge cycles per battery, safety and cost are all vitally important, but when we look at EVs and grid storage you’re looking at much larger scale batteries that can’t be simply upgraded or replaced every few months. So Bruce sees this as an advantage, in that recycling and re-using will be more of a feature of the new electrified age. Also, as very much a  scientist, Bruce is interested in how the rather sudden focus on battery storage reveals gaps in our knowledge which we didn’t really know we had – and this is how knowledge often progresses, when we find we have an urgent problem to solve and we need to look at the basics, the underlying mechanisms. For example, the key to Li-ion batteries is the lithium compound used, and whether you can get more lithium ions out of particular compounds, and/or get them to move more quickly between the electrodes to discharge and recharge the battery. This requires analysis and understanding at the fundamental, atomistic level. Also, current Li-ion batteries for portable devices generally use cobalt in the compound, which is too expensive for large-scale batteries. Iron, manganese and silicates are being looked at as cheaper alternatives. This is all new research – and he makes no mention of the work done by Goodenough, Braga et al.

In any case it’s fascinating how new problems lead to new solutions. The two most touted and developed forms of renewable energy – solar and wind – both have this major problem of intermittence. In the meantime, battery storage, for portable devices and EVs, has become a big thing, and now new developments are heating up the materials science field in an electrifying way, which will in turn hot up the EV and clean energy markets.

The video ended by neatly connecting with the geeky DIY video in showing how dumped, abandoned laptop batteries and other batteries had plenty of capacity left in them – more than 60% in many cases, which is more than useful for energy storage, so they were being harvested by PhD students for use in small-scale energy storage systems for developing countries. Great for LED lighting, which requires little power. The students were using an algorithm to get each battery in the system to discharge at different rates (since they all had different capacities or charge left in them) so they could get maximum capacity out of the system as a whole. I think I actually understood that!

Okay – something very exciting! The video mentioned above is the first I’ve seen of a British series called ‘Fully Charged’, all about batteries, EVs and renewable energy. I plan to watch the series for my education and for the thrill of it all. But imagine my surprise when I started watching this one, still part of the series, made here in Adelaide! I won’t go into the content of that video, which was about flow batteries which can store solar energy rather than transferring it to the grid. I need to bone up more on that technology before commenting, and it’s probably a bit pricey for the likes of me anyway. What was immediately interesting to me was how quickly he (Robert Llewellyn, the narrator/interviewer) cottoned on to our federal government’s extreme negativity regarding renewables. Glad to have that back-up! I note too, by the way, that Australia has no direct incentives to buy EVs, of which there are few in the country – again all due to our troglodyte government. It’s frankly embarrassing.

So, there’s so much happening with battery technology and its applications that I might need to take some time off to absorb all the videos and docos and blogs and podcasts and development plans and government directives and projects and whatnot that are coming out all the time from the usual and some quite unusual places, not to mention our own local South Australian activities and the naysayers buzzing around them. Then again I may be moved to charge forward and report on some half-digested new development or announcement tomorrow, who knows….

References

They’re all in the links above, and I highly recommend the British ‘Fully Charged’ videos produced by Robert Llewellyn and Johnny Smith, and the USA ‘jehugarcia’ videos, which, like the Brit ones but in a different way, are a lot of fun as well as educational.

 

Written by stewart henderson

August 1, 2017 at 9:26 pm

on the explosion of battery research – part one, some basic electrical concepts, and something about solid state batteries…

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just another type of battery technology not mentioned in this post

Okay I was going to write about gas prices in my next post but I’ve been side-tracked by the subject of batteries. Truth to tell, I’ve become mildly addicted to battery videos. So much seems to be happening in this field that it’s definitely affecting my neurotransmission.

Last post, I gave a brief overview of how lithium ion batteries work in general, and I made mention of the variety of materials used. What I’ve been learning over the past few days is that there’s an explosion of research into these materials as teams around the world compete to develop the next generation of batteries, sometimes called super-batteries just for added exhilaration. The key factors in the hunt for improvements are energy density (more energy for less volume), safety and cost.

To take an example, in this video describing one company’s production of lithium-ion batteries for electric and hybrid vehicles, four elements are mentioned – lithium, for the anode, a metallic oxide for the cathode, a dry solid polymer electrolyte and a metallic current collector. This is confusing. In other videos the current collectors are made from two different metals but there’s no mention of this here. Also in other videos, such as this one, the anode is made from layered graphite and the cathode is made from a lithium-based metallic oxide. More importantly, I was shocked to hear of the electrolyte material as I thought that solid electrolytes were still at the experimental stage. I’m on a steep and jagged learning curve. Fact is, I’ve had a mental block about electricity since high school science classes, and when I watch geeky home-made videos talking of volts, amps and watts I have no trouble thinking of Alessandro Volta, James Watt and André-Marie Ampère, but I have no idea of what these units actually measure. So I’m going to begin by explaining some basic concepts for my own sake.

Amps

Metals are different from other materials in that electrons, those negatively-charged sub-atomic particles that buzz around the nucleus, are able to move between atoms. The best metals in this regard, such as copper, are described as conductors. However, like-charged electrons repel each other so if you apply a force which pushes electrons in a particular direction, they will displace other electrons, creating a near-lightspeed flow which we call an electrical current. An amp is simply a measure of electron flow in a current, 1 ampere being 6.24 x 10¹8 (that’s the power of eighteen) per second. Two amps is twice that, and so on. This useful video provides info on a spectrum of currents, from the tiny ones in our mobile phone antennae to the very powerful ones in bolts of lightning. We use batteries to create this above-mentioned force. Connecting a battery to, say, a copper wire attached to a light bulb causes the current to flow to the bulb – a transfer of energy. Inserting a switch cuts off and reconnects the circuit. Fuses work in a similar way. Fuses are rated at a particular ampage, and if the current is too high, the fuse will melt, breaking the circuit. The battery’s negative electrode, or anode, drives the current, repelling electrons and creating a cascade effect through the wire, though I’m still not sure how that happens (perhaps I’ll find out when I look at voltage or something).

Volts

So, yes, volts are what push electrons around in an electric current. So a voltage source, such as a battery or an adjustable power supply, as in this video, produces a measurable force which applied to a conductor creates a current measurable in amps. The video also points out that voltage can be used as a signal, representing data – a whole other realm of technology. So to understand how voltage does what it does, we need to know what it is. It’s the product of a chemical reaction inside the battery, and it’s defined technically as a difference in electrical potential energy, per unit of charge, between two points. Potential energy is defined as ‘the potential to do work’, and that’s what a battery has. Energy – the ability to do work – is a scientific concept, which we measure in joules. A battery has electrical potential energy, as result of the chemical reactions going on inside it (or the potential chemical reactions? I’m not sure). A unit of charge is called a coulomb. One amp of current is equal to one coulomb of charge flowing per second. This is where it starts to get like electrickery for me, so I’ll quote directly from the video:

When we talk about electrical potential energy per unit of charge, we mean that a certain number of joules of energy are being transferred for every unit of charge that flows.

So apparently, with a 1.5 volt battery (and I note that’s your standard AA and AAA batteries), for every coulomb of charge that flows, 1.5 joules of energy are transferred. That is, 1.5 joules of chemical energy are being converted to electrical potential energy (I’m writing this but I don’t really get it). This is called ‘voltage’. So for every coulomb’s worth of electrons flowing, 1.5 joules of energy are produced and carried to the light bulb (or whatever), in that case producing light and heat. So the key is, one volt equals one joule per coulomb, four volts equals 4 joules per coulomb… Now, it’s a multiplication thing. In the adjustable power supply shown in the video, one volt (or joule per coulomb) produced 1.8 amps of current (1.8 coulombs per second). For every coulomb, a joule of energy is transferred, so in this case 1 x 1.8 joules of energy are being transferred every second. If the voltage is pushed up to two (2 joules per coulomb), it produces around 2 amps of current, so that’s 2 x 2 joules per second. Get it? So a 1.5 volt battery indicates that there’s a difference in electrical potential energy of 1.5 volts between the negative and positive terminals of the battery.

Watts

A watt is a unit of power, and it’s measured in joules per second. One watt equals one joule per second. So in the previous example, if 2 volts of pressure creates 2 amps of current, the result is that four watts of power are produced (voltage x current = power). So to produce a certain quantity of power, you can vary the voltage and the current, as long as the multiplied result is the same. For example, highly efficient LED lighting can draw more power from less voltage, and produces more light per watt (incandescent bulbs waste more energy in heat).

Ohms and Ohm’s law

The flow of electrons, the current, through a wire, may sometimes be too much to power a device safely, so we need a way to control the flow. We use resistors for this. In fact everything, including highly conductive copper, has resistance. The atoms in the copper vibrate slightly, hindering the flow and producing heat. Metals just happen to have less resistance than other materials. Resistance is measured in ohms (Ω). Less than one Ω would be a very low resistance. A mega-ohm (1 million Ω) would mean a very poor conductor. Using resistors with particular resistance values allows you to control the current flow. The mathematical relations between resistance, voltage and current are expressed in Ohm’s law, V = I x R, or R = V/I, or I = V/R (I being the current in amps). Thus, if you have a voltage (V) of 10, and you want to limit the current (I) to 10 milli-amps (10mA, or .01A), you would require a value for R of 1,000Ω. You can, of course, buy resistors of various values if you want to experiment with electrical circuitry, or for other reasons.

That’s enough about electricity in general for now, though I intend to continue to educate myself little by little on this vital subject. Let’s return now to the lithium-ion battery, which has so revolutionised modern technology. Its co-inventor, John Goodenough, in his nineties, has led a team which has apparently produced a new battery that is a great improvement on ole dendrite-ridden lithium-ion shite. These dendrites appear when the Li-ion batteries are charged too quickly. They’re strandy things that make their way through the liquid electrolyte and can cause a short-circuit. Goodenough has been working with Helena Braga, who has developed a solid glass electrolyte which has eliminated the dendrite problem. Further, they’ve replaced or at least modified the lithium metal oxide and the porous carbon electrodes with readily available sodium, and apparently they’re using much the same material for the cathode as the anode, which doesn’t make sense to many experts. Yet apparently it works, due to the use of glass, and only needs to be scaled up by industry, according to Braga. It promises to be cheaper, safer, faster-charging, more temperature-resistant and more energy dense than anything that has gone before. We’ll have to wait a while, though, to see what peer reviewers think, and how industry responds.

Now, I’ve just heard something about super-capacitors, which I suppose I’ll have to follow up on. And I’m betting there’re more surprises lurking in labs around the world…

 

 

Written by stewart henderson

July 29, 2017 at 4:00 pm

What’s Weatherill’s plan for South Australia, and why do we have the highest power prices in the world? Oh, and I should mention Elon Musk here – might get me more hits

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just a superhero pic to rope people in

I’ve written a few pieces on our electricity system here in SA, but I don’t really feel any wiser about it. Still, I’ll keep having a go.

We’ve become briefly famous because billionaire geek hero Elon Musk has promised to build a ginormous battery here. After we had our major blackout last September (for which we were again briefly famous), Musk tweeted or otherwise communicated that his Tesla company might be able to solve SA’s power problems. This brought on a few local geek-gasms, but we quickly forgot (or I did), not realising that our good government was working quietly behind the scenes to get Musk to commit to something real. In March this year, Musk was asked to submit a tender for the 100MW capacity battery, which is expected to be operational by the summer. He has recently won the tender, and has committed to constructing the battery in 100 days, at a cost of $50 million. If he’s unsuccessful within the time limit, we’ll get it for free.

There are many many South Australians who are very skeptical of this project, and the federal government is saying that the comparatively small capacity of the battery system will have minimal impact on the state’s ‘self-imposed’ problems. And yet – I’d be the first to say that I’m quite illiterate about this stuff, but if SA Premier Jay Weatherill’s claim is true that ‘battery storage is the future of our national energy market’, and if Musk’s company can build this facility quickly, then it’s surely possible that many batteries could be built like the one envisaged by Musk, each one bigger and cheaper than the last. Or have I just entered cloud cuckoo land? Isn’t that how technology tends to work?

In any case, the battery storage facility is designed to bring greater stability to the state’s power network, not to replace the system, so the comparisons made by Federal Energy Minister Josh Frydenberg are misleading, probably deliberately so. Frydenberg well knows, for example, that SA’s government has been working on other solutions too, effectively seeking to becoming independent of the eastern states in respect of its power system. In March, at the same time as he presented plans for Australia’s largest battery, Weatherill announced that a taxpayer-funded 250MW gas-fired power plant would be built. More recently, AGL, the State’s largest power producer and retailer, has announced  plans to build a 210MW gas-fired generator on Torrens Island, upgrading its already-existing system. AGL’s plan is to use reciprocating engines, which executive general manager Doug Jackson has identified as best suited to the SA market because of their ‘flexible efficient and cost-effective synchronous generation capability’. I heartily agree. It’s noteworthy that the AGL plan was co-presented by its managing director Andy Vesey and the SA Premier. They were at pains to point out that the government plans and the AGL plan were not in competition. So it does seem that the state government has made significant strides in ensuring our energy security, in spite of much carping from the Feds as well as local critics – check out some of the very nasty naysaying in the comments section of local journalist Nick Harmsen’s articles on the subject (much of it about the use of lithium ion batteries, which I might blog about later).

It’s also interesting that Harmsen himself, in an article written four months ago, cast serious doubt on the Tesla project going ahead, because, as far as he knew, tenders were already closed on the battery storage or ‘dispatchable renewables’ plan, and there were already a number of viable options on the table. So either the Tesla offer, when it came (and maybe it got in under the deadline unbeknown to Harmsen), was way more impressive than others, or the Tesla-Musk brand has bedazzled Weatherill and his cronies. It’s probably a combo of the two. Whatever, this news is something of a blow to local rivals. What is fascinating, though is how much energetic rivalry, or competition, there actually is in the storage and dispatchables field, in spite of the general negativity of the Federal government. It seems our centrist PM Malcolm Turnbull is at odds with his own government about this.

So enough about the Tesla-Neoen deal, and associated issues, which are mounting too fast for me to keep up with right now. I want to focus on pricing for the rest of this piece, because I have no understanding of why SA is now paying the world’s highest domestic electricity prices, as the media keeps telling us.

According to this Sydney Morning Herald article from nearly two years ago, which of course I can’t vouch for, Australia’s electricity bills are made up of three components: wholesale and retail prices, based on supply and demand (39% of cost); the cost of poles and wires (53%); and the cost of environmental policies (8%). The trio can be simplified as market, network and environmental costs. Market and network costs vary from state to state. The biggest cost, the poles and wires, is borne by all Australian consumers (at least all on the grid), as a result of a massive $45 billion upgrade between 2009 and 2014, due to expectations of a continuing rise in demand. Instead there’s been a fall, partly due to domestic solar but in large measure because of much tighter and more environmental building standards nationwide as part of the building boom. The SMH article concludes, a little unexpectedly, that the continuing rise in prices can only be due to retail price hikes, at least in the eastern states, because supply is steady and network costs, though high, are also steady.

A more recent article (December 2016) argues that a rising wholesale price, due to the closure of coal-fired power stations in SA and Victoria and higher gas prices, is largely responsible. Retail prices are higher now than when the carbon tax was in place in 2013.

This even recenter article from late March announces an inquiry by the Australian Competition and Consumer Commission (ACCC) into retail pricing of electricity, which unfortunately won’t be completed till June 30 2018, given its comprehensive nature. It also contains this telling titbit:

A report from the Grattan Institute released earlier in March found a decade of competition in the market had failed to deliver better deals for customers, with profit margins on electricity bills much higher than for many other industries.

However, another article published in March, and focusing on SA’s power prices in particular (it’s written by former SA essential services commissioner Richard Blandy), takes an opposing view:

Retailing costs are unlikely to be a source of rapidly rising electricity prices because they represent a small proportion of final prices to consumers and there is a high level of competition in this part of the electricity supply chain. Energy Watch shows that there are seven electricity retailers selling electricity to small businesses, and 12 electricity retailers selling electricity to households. Therefore, price rises at the retail level are likely to be cost-based.

Blandy’s article, which looks at transmission and distribution pricing, load shedding and the very complex issue of wholesale pricing and the National Energy Market (NEM), needs at least another blog post to do justice to. I’m thinking that I’ll have to read and write a lot more to make sense of it all.

Finally, the most recentest article of only a couple of weeks ago quotes Bruce Mountain, director of Carbon and Energy Markets, as saying that it’s not about renewables (SA isn’t much above the other states re pricing), it’s about weak government control over retailers (could there be collusion?). Meanwhile, politicians obfuscate, argue and try to score points about a costly energy system that’s failing Australian consumers.

I’ll be concentrating a lot on this multifaceted topic – energy sources, storage, batteries, pricing, markets, investment and the like, in the near future. It exercises me and I want to educate myself further about it. Next, I’ll make an effort to find out more about, and analyse, the South Australian government’s six-point plan for our energy future.

References and more reading for masochists

http://www.abc.net.au/news/2017-03-10/tesla-boss-elon-musk-pledges-to-fix-sas-electricity-woes/8344084

http://www.adelaidenow.com.au/business/sa-government-announces-who-will-build-100mw-giant-battery-as-part-of-its-energy-security-plan/news-story/9f83072547f41f4f5556477942168dd9

http://www.smh.com.au/business/sunday-explainer-why-is-electricity-so-expensive-20150925-gjvdrj.html

http://www.skynews.com.au/business/business/market/2017/03/27/accc-to-find-out-why-power-prices-are-so-high.html

http://www.adelaidenow.com.au/news/south-australia/south-australia-will-have-highest-power-prices-in-the-world-after-july-1-increases/news-story/876f9f6cefce23c62395085c6fe0fd9f

http://indaily.com.au/news/business/analysis/2017/03/07/why-sas-power-prices-are-so-high-and-the-huge-risks-of-potential-fixes/

http://www.theaustralian.com.au/opinion/columnists/graham-richardson/jay-weatherill-must-come-clean-on-elon-musks-battery-deal/news-story/f471b33ebdf140a71b41e0b0bea7894f

http://www.news.com.au/technology/environment/climate-change/why-higher-electricity-prices-are-inevitable/news-story/042712e35c08bf798ed993d13ee573ea

Written by stewart henderson

July 14, 2017 at 10:55 am