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Posts Tagged ‘technology

the tides – a massive potential resource?

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A floating tidal turbine, Orkney islands, as seen on Fully Charged

A recent episode of Fully Charged, the Brit video series on the sources and harnessing of clean energy, took us again to the very windy Orkney Isles at the top of Scotland to have a look at some experimental work being done on generating energy from tidal forces. When you think of it, it seems a no-brainer to harness the energy of the tides. They’re regular, predictable, unceasing, and in some places surely very powerful. Yet I’ve never heard of them being used on an industrial scale.

Of course, I’m still new to this business, so the learning curve continues steep. Tide mills have been used historically here and there, possibly even since Roman times, and tidal barrages have been operating since the sixties, the first and for a long time the largest being the La Rance plant, off the coast of Brittany, generating 240 MW. A slightly bigger one has recently been built in Korea (254 MW).

But tidal barrages – not what they’re testing in the Orkneys – come with serious environmental impact issues. They’re about building a barrage across a bay or estuary with a decent tidal flow. The barrage acts as a kind of adjustable dam, with sluice gates that open and close, and additional pumping when necessary. Turbines generate energy from pressure and height differentials, as in a hydro-electric dam. Research on the environmental impact of these constructions, which can often be major civil engineering projects, has revealed mixed results. Short-term impacts are often devastating, but over time one type of diversity has been replaced by another.

Anyway, what’s happening in the Orkneys is something entirely different. The islanders, the Scottish government and the EU are collaborating through an organisation called EMEC, the European Marine Energy Centre, to test tidal power in the region. They appear to be inviting innovators and technicians to test their projects there. A company called ScotRenewables, for example, has developed low-maintenance floating tidal turbines with retractable legs, one of which is currently being tested in the offshore waters. They’re designed to turn with the ebb and flood tides to maximise their power generation. It’s a 2 MW system, which of course could be duplicated many times over in the fashion of wind turbines, to generate hundreds if not thousands of megawatts. The beauty of the system is its reliability – as the tidal flow can be reliably predicted at least eighteen years into the future, according to the ScotRenewables CEO. This should provide a sense of stability and confidence to downstream suppliers. Also, floating turbines could easily be removed if they’re causing damage, or if they require maintenance. Clearly, the effect on the tidal system would be minimal compared to an estuarine barrage, though there are obvious dangers to marine life getting too close to turbines. The testing of these turbines is coming to an end and they’ve been highly successful so far, though they already have an improved turbine design in the wings, which can be maintained either in situ or in dock. The design can also be scaled down, or up, to suit various sites and conditions.

rotors are on retractable legs, to protect from storms, etc

Other quite different turbine types are being tested in the region, with a lot of government and public support, but I got the slight impression that commercial support for this kind of technology is somewhat lacking. In the Fully Charged video on this subject (to which I owe most of this info), Robert Llewelyn asked the EMEC marketing manager whether she thought tidal or wave energy had the greatest future potential (she opted for wave). My ears pricked up, as wave energy is another newie for me. Duh. Another post, I suppose.

As mentioned though in this video, a lot of the developments in this tidal technology have come from shipbuilding technology, from offshore oil and gas technology, and from maritime technology more generally, as well as modern wind turbine technology, further impressing on me that skills are transferable and that the cheap clean energy revolution won’t be the economic/employment disaster that the fossil fuel dinosaurs predict. It’s a great time for innovation, insight and foresight, and I can only hope that more government and business people in Australia, where I seem to be stuck, can get on board.

fixed underwater tidal turbine being tested off the Orkney Islands

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Written by stewart henderson

October 11, 2017 at 6:27 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

capacitors, supercapacitors and electric vehicles

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from the video ‘what are supercapacitors’

Jacinta: New developments in battery and capacitor technology are enough to make any newbie’s head spin.

Canto: So what’s a supercapacitor? Apart from being a super capacitor?

Jacinta: I don’t know but I need to find out fast because supercapacitors are about to be eclipsed by a new technology developed in Great Britain which they estimate as being   ‘between 1,000 and 10,000-times more effective than current supercapacitors’.

Canto: Shite, they’ll have to think of a new name, or downgrade the others to ‘those devices formerly known as supercapacitors’. But then, I’ll believe this new tech when I see it.

Jacinta: Now now, let’s get on board, superdisruptive technology here we come. Current supercapacitors are called such because they can charge and discharge very quickly over large numbers of cycles, but their storage capacity is limited in comparison to batteries…

Canto: Apparently young Elon Musk predicted some time ago that supercapacitors would provide the next major breakthrough in EVs.

Jacinta: Clever he. But these ultra-high-energy density storage devices, these so-much-more-than-super-supercapacitors, could enable an EV to be charged to a 200 kilometre range in just a few seconds.

Canto: So can you give more detail on the technology?

Jacinta: The development is from a UK technology firm, Augmented Optics, and what I’m reading tells me that it’s all about ‘cross-linked gel electrolytes’ with ultra-high capacitance values which can combine with existing electrodes to create supercapacitors with greater energy storage than existing lithium-ion batteries. So if this technology works out, it will transform not only EVs but mobile devices, and really anything you care to mention, over a range of industries. Though everything I’ve read about this dates back to late last year, or reports on developments from then. Anyway, it’s all about the electrolyte material, which is some kind of highly conductive organic polymer.

Canto: Apparently the first supercapacitors were invented back in 1957. They store energy by means of static charge, and I’m not sure what that means…

Jacinta: We’ll have to do a post on static electricity.

Canto: In any case their energy density hasn’t been competitive with the latest batteries until now.

Jacinta: Yes it’s all been about energy density apparently. That’s one of the main reasons why the infernal combustion engine won out over the electric motor in the early days, and now the energy density race is being run between new-age supercapacitors and batteries.

Canto: So how are supercapacitors used today? I’ve heard that they’re useful in conjunction with regenerative braking, and I’ve also heard that there’s a bus that runs entirely on supercapacitors. How does that work?

Jacinta: Well back in early 2013 Mazda introduced a supercapacitor-based regen braking system in its Mazda 6. To quote more or less from this article by the Society of Automotive Engineers (SAE), kinetic energy from deceleration is converted to electricity by the variable-voltage alternator and transmitted to a supercapacitor, from which it flows through a dc-dc converter to 12-V electrical components.

Canto: Oh right, now I get it…

Jacinta: We’ll have to do posts on alternators, direct current and alternating current. As for your bus story, yes, capabuses, as they’re called, are being used in Shanghai. They use supercapacitors, or ultracapacitors as they’re sometimes called, for onboard power storage, and this usage is likely to spread with the continuous move away from fossil fuels and with developments in supercaps, as I’ve heard them called. Of course, this is a hybrid technology, but I think they’ll be going fully electric soon enough.

Canto: Or not soon enough for a lot of us.

Jacinta: Apparently, with China’s dictators imposing stringent emission standards, electric buses, operating on power lines (we call them trams) became more common. Of course electricity may be generated by coal-fired power stations, and that’s a problem, but this fascinating article looking at the famous Melbourne tram network (run mainly on dirty brown coal) shows that with high occupancy rates the greenhouse footprint per person is way lower than for car users and their passengers. But the capabuses don’t use power lines, though they apparently run on tracks and charge regularly at recharge stops along the way. The technology is being adopted elsewhere too of course.

Canto: So let me return again to basics – what’s the difference between a capacitor and and a super-ultra-whatever-capacitor?

Jacinta: I think the difference is just in the capacitance. I’m inferring that because I’m hearing, on these videos, capacitors being talked about in terms of micro-farads (a farad, remember, being a unit of capacitance), whereas supercapacitors have ‘super capacitance’, i.e more energy storage capability. But I’ve just discovered a neat video which really helps in understanding all this, so I’m going to do a breakdown of it. First, it shows a range of supercapacitors, which look very much like batteries, the largest of which has a capacitance, as shown on the label, of 3000 farads. So, more super than your average capacitor. It also says 2.7 V DC, which I’m sure is also highly relevant. We’re first told that they’re often used in the energy recovery system of vehicles, and that they have a lower energy density (10 to 100 times less than the best Li-ion batteries), but they can deliver 10 to 100 times more power than a Li-ion battery.

Canto: You’ll be explaining that?

Jacinta: Yes, later. Another big difference is in charge-recharge cycles. A good rechargeable battery may manage a thousand charge and recharge cycles, while a supercap can be good for a million. And the narrator even gives a reason, which excites me – it’s because they function by the movement of ions rather than by chemical reactions as batteries do. I’ve seen that in the videos on capacitors, described in our earlier post. A capacitor has to be hooked up to a battery – a power source. So then he uses an analogy to show the difference between power and energy, and I’m hoping it’ll provide me with a long-lasting lightbulb moment. His analogy is a bucket with a hole. The amount of water the bucket can hold – the size of the bucket if you like – equates to the bucket’s energy capacity. The size of the hole determines the amount of power it can release. So with this in mind, a supercar is like a small bucket with a big hole, while a battery is more like a big bucket with a small hole.

Canto: So the key to a supercap is that it can provide a lot of power quickly, by discharging, then it has to be recharged. That might explain their use in those capabuses – I think.

Jacinta: Yes, for regenerative braking, for cordless power tools and for flash cameras, and also for brief peak power supplies. Now I’ve jumped to another video, which inter alia shows how a supercapacitor coin cell is made – I’m quite excited about all this new info I’m assimilating. A parallel plate capacitor is separated by a non-conducting dielectric, and its capacitance is directly proportional to the surface area of the plates and inversely proportional to the distance between them. Its longer life is largely due to the fact that no chemical reaction occurs between the two plates. Supercapacitors have an electrolyte between the plates rather than a dielectric…

Canto: What’s the difference?

Jacinta: A dielectric is an insulating material that causes polarisation in an electric field, but let’s not go into that now. Back to supercapacitors and the first video. It describes one containing two identical carbon-based high surface area electrodes with a paper-based separator between. They’re connected to aluminium current collectors on each side. Between the electrodes, positive and negative ions float in an electrolyte solution. That’s when the cell isn’t charged. In a fully charged cell, the ions attach to the positively and negatively charged electrodes (or terminals) according to the law of attraction. So, our video takes us through the steps of the charge-storage process. First we connect our positive and negative terminals to an energy source. At the negative electrode an electrical field is generated and the electrode becomes negatively charged, attracting positive ions and repelling negative ones. Simultaneously, the opposite is happening at the positive electrode. In each case the ‘counter-ions’ are said to adsorb to the surface of the electrode…

Canto: Adsorption is the adherence of ions – or atoms or molecules – to a surface.

Jacinta: So now there’s a strong electrical field which holds together the electrons from the electrode and the positive ions from the electrolyte. That’s basically where the potential energy is being stored. So now we come to the discharge part, where we remove electrons through the external surface, at the electrode-electrolyte interface we would have an excess of positive ions, therefore a positive ion is repelled in order to return the interface to a state of charge neutrality – that is, the negative charge and the positive charge are balanced. So to summarise from the video, supercapacitors aren’t a substitute for batteries. They’re suited to different applications, applications requiring high power, with moderate to low energy requirements (in cranes and lifts, for example). They can also be used as voltage support for high-energy devices, such as fuel cells and batteries.

Canto: What’s a fuel cell? Will we do a post on that?

Jacinta: Probably. The video mentions that Honda has used a bank of ultra capacitors in their FCX fuel-cell vehicle to protect the fuel cell (whatever that is) from rapid voltage fluctuations. The reliability of supercapacitors makes them particularly useful in applications that are described as maintenance-free, such as space travel and wind turbines. Mazda also uses them to capture waste energy in their i-Eloop energy recovery system as used on the Mazda 6 and the Mazda 3, which sounds like something worth investigating.

References (videos can be accessed from the links above)

http://www.hybridcars.com/supercapacitor-breakthrough-allows-electric-vehicle-charging-in-seconds/

https://en.wikipedia.org/wiki/Supercapacitor

http://www.power-technology.com/features/featureelectric-vehicles-putting-the-super-in-supercapacitor-5714209/

http://articles.sae.org/11845/

https://www.ptua.org.au/myths/tram-emissions/

http://www.europlat.org/capabus-the-finest-advancement-for-electric-buses.htm

Written by stewart henderson

September 5, 2017 at 10:08 am

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

reveries of a solitary wa*ker: wa*k 3

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my new Dino-lite Basic, and some coriander roots, under low magnification

my new Dino-lite Basic, and some coriander roots, under low magnification

coriander roots

Having finished reading the big Darwin book I’m letting the influence of his character and world percolate through me, for example on my way home from work the other day, walking by the city river, I got the idea of taking pics of the bird species hanging by the riverside with my mobile phone – murray magpie, mallard, eurasian coot, black swan, masked lapwing, Australian pelican, Australian magpie, dusky moorhen, Australian white ibis and little pied cormorant. It really brightened my day, though the photos were pretty crappy, but I looked up the species when I got home (this is where the internet really comes into its own) and learned so much about habitats, male-female differences (the male murray magpie, or magpie-lark, has a white ‘eyebrow’ and a black throat) and such. Fun, and now I’m thinking about a good camera for bird-watching. I’ve also, on something of an impulse, bought a digital microscope, on its way from the USA. No idea as yet what to use it for.

Stephen-Hawking-AI-2

At a recent meetup group I had a stimulating discussion, or rather listened in on one, about the end of humanity, the various possibilities for our impending doom, the principal one being artificial intelligence. The idea is that so many things that humans are engaged in are barely in control, and that the best option for the survival of a species isn’t constant change and development, but stasis, as with trilobites perhaps, or some types of bacteria.  Since this appears not to be an option for us, some think that we’re hurtling, with all our good intentions, not towards the singularity, but towards extinction. Anthropogenic global warming, mass species extinction, human-induced epidemics, out-of-control artificial intelligence, or a combination of these might cause this event, but it was the view of one conversationalist that AI would be our undoing, and possibly quite soon. It might lead to a gradual transhumanism, which we won’t recognise until it’s too late. One of the key figures mentioned in analysis of humanity’s possibly grim future was Nick Bostrum, whose name has come to my attention from time to time. Wikipedia tells me he’s a philosopher based at Oxford, and the director of its Future of Humanity Institute. So, a person and an institute I should be conversant with for my solutions ok blog. I should probably link to it there, and it’ll mean a lot more reading and study, groan. Meanwhile, one of the arguments I heard the other night was that this could explain why we don’t find complex life out there looking for us, with their super-clever antimatter rockets and super light-speed travel techniques, because complexity of that sort beats an inevitable path to destruction. Highly-developed life-forms like us and our superiors burn with brief intensity then snuff themselves out. For us, this might be sooner than later. Hmmmm. In any case, existential risk is something I’ll have to pay more attention to in the future, if we have one.

p16om5i0se1fk61ca91qpv1urm1j30_79928

The other day I was listening to the amusing Answer Me This podcast when the name Marky Mark came up – apparently an actor, for he was chosen to star in Peter Jackson’s film The Lovely Bones. Not being too keyed in on popular culture, I’d never heard of Marky Mark (or The Lovely Bones for that matter) so I looked him up. It turned out that this was an early moniker for the actor Mark Wahlberg – whose name I’d heard of, but that was about it. Having now seen some photos of him, I don’t think I’ve seen him in anything, and I had no idea that in his early life as Marky Mark he was a notorious rapper and petty crim. But interestingly, I read that Wahlberg was now seeking a government pardon for the crimes he was convicted of as a teenager – including a few bashings of Asian-looking people. One of these incidents resulted in the victim having permanent eye damage. I don’t automatically trust too many internet sites, but the story appears to be that Marky, as a probably drug-fuelled and undoubtedly peer-influenced teen, indulged in some pretty nasty behaviour, spiced with language about ‘gooks and ‘slopes’, but he did have potential – don’t we all – and with the help of mentors he turned his life around to become, eventually, a Hollywood ‘star’. He did receive punishment for some of his crimes – and I read that he was tried as an adult for at least one of them – probably the one in which a victim lost an eye, or part of one….

I mention all this because it’s a case that raises a number of fascinating and important ethical issues. Firstly, there’s the tendency, most prevalent in the US but increasingly here too, to try juveniles as adults when they commit serious crimes, as if their ability to be fully responsible for their actions is in direct proportion to the damage they do. This smacks of a slide down the slippery slope of retributive justice – people have been really really hurt so the perp has to be really really punished, no matter that she’s eleven years old. While I have some sympathy for that attitude, and I’ll elaborate on that later, we have to accept that teenagers and children are different and that there are good, scientifically verified reasons for granting them diminished responsibility in a graded way from earliest childhood to the latest teens. The law is always a bit of a bludgeon of course, rarely taking full account of individual developmental and psychological peculiarities, which is one of the problems of ‘equality before the law’, but there’s no doubt that we generally do stupid things as teenagers and school kids, often under peer pressure, things we’d never do as mature adults. I myself got into trouble with the law for stealing, together with four or five of my friends, at the age of fourteen. We’d been egging each other on, and we perpetrated a lot more than we were charged with, but it all came crashing to a halt when we got caught. None of us were nasty brutish types, and it’s unlikely that any of us have reoffended.

Marky’s offending was rather brutish though, with serious consequences for a least one victim. His desire for a pardon is apparently driven by the fact that he’s disqualified at the moment from getting an Oscar or other accolades because of his past. Unlike me he has a permanent criminal record presumably due to being tried as an adult. He’s written a letter to government authorities wanting recognition for being an entirely different person than the one who committed those acts. Marky now does charitable work on the side like many other Hollywood stars – which is fine and dandy especially as they’re significantly overpaid for what they do and would have good reason to consider themselves bloody lucky to be in their position – but as online critics have pointed out, he’s never apologised or made reparations to his permanently-scarred victim. It goes without saying that this soul has also had a change of life since being bashed with a two-by-four all those years ago. Not much work for a one eyed Asian in Hollywood, methinks.

So this is the dilemma. Why doesn’t Marky Mark face up to the damage he did by trying to help the one person whose life he changed irreparably as an oafish teenager? That would seem to be an obvious move. And that brings me back to the treatment of serious crimes committed by persons of diminished responsibility. The reason we seek to impose harsher penalties, and for that reason to attribute greater responsibility to the young perpetrator, is because of the consequences of the crime. We believe someone has to pay for all that damage, and if not the perp, then who? It’s a really vexed question, but imposing an extremely harsh penalty on an adolescent for an extreme crime doesn’t really help, especially when the penalty, such as a prison term, will tend to harden the adolescent and make him more resentful, angry, and subject to bad influence, than he was before.

Unfortunately, we don’t live in a very forgiving society, a society which immediately seeks to help adolescents who’ve gone off the rails to the extent that Marky Mark presumably did – and I should make it clear here that I’m just using him as an example, and I’ve no idea if the facts of his case are exactly as, or even close to, what I’ve reported (I got it off the internet after all). As part of that help, he should’ve been made to face the living consequences of the damage he had done, the suffering and change he had wrought in the lives of others. But that of course would require a massive change in our system of crime and punishment. For adolescent crime though, I think it would work well, and to be fair, it does operate to some extent in some juvenile court systems, conferencing between perpetrators and victims and their families, though there isn’t enough of it, I suspect.

Written by stewart henderson

April 23, 2015 at 9:11 am