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Archive for the ‘energy’ Category

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 Short-term impacts are often devastating, but over time one type of diversity has been replaced by another.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

On electrickery, part 1 – the discovery of electrons

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Canto: This could be the first of a thousand-odd parts, because speaking for myself it will take me several lifetimes to get my head around this stuff, which is as basic as can be. Matter and charge and why is it so and all that.

Jacinta: so let’s start at random and go in any direction we like.

Canto: Great plan. Do you know what a cathode ray is?

Jacinta: No. I’ve heard of cathodes and anodes, which are positive and negative terminals of batteries and such, but I can’t recall which is which.

Canto: Don’t panic, Positive is Anode, Negative ICathode. Though I’ve read somewhere that the reverse can sometimes be true. The essential thing is they’re polar opposites.

Jacinta: Good, so a cathode ray is some kind of negative ray? Of electrons?

Canto: A cathode ray is defined as a beam of electrons emitted from the cathode of a high-vacuum tube.

Jacinta: That’s a pretty shitty definition, why would a tube, vacuum or otherwise, have a cathode in it? And what kind of tube? Rubber, plastic, cardboard?

Canto: Well let’s not get too picky. I’m talking about a cathode ray tube. It’s a sealed tube, obviously, made of glass, and evacuated as far as possible. Sciencey types have been playing around with vacuums since the mid seventeenth century – basically since the vacuum pump was invented in 1654, and electrical experiments in the nineteenth century, with vacuum tubes fitted with cathodes and anodes, led to the discovery of the electron by J J Thomson in 1897.

Jacinta: So what do you mean by a beam of electrons and how is it emitted, and can you give more detail on the cathode, and is there an anode involved? Are there such things as anode rays?

Canto: I’ll get there. Early experiments found that electrostatic sparks travelled further through a near vacuum than through normal air, which raised the question of whether you could get a ‘charge’, or a current, to travel between two relatively distant points in an airless tube. That’s to say, between a cathode and an anode, or two electrodes of opposite polarity. The cathode is of a conducting material such as copper, and yes there’s an anode at the other end – I’m talking about the early forms, because in modern times it starts to get very complicated. Faraday in the 1830s noted a light arc could be created between the two electrodes, and later Heinrich Geissler, who invented a better vacuum, was able to get the whole tube to glow – an early form of ‘neon light’. They used an induction coil, an early form of transformer, to create high voltages. They’re still used in ignition systems today, as part of the infernal combustion engine

Jacinta: So do you want to explain what a transformer is in more detail? I’ve certainly heard of them. They ‘create high voltages’ you say. Qu’est-ce que ça veux dire?

Canto: Do you want me to explain an induction coil, a transformer, or both?

Jacinta: Well, since we’re talking about the 19th century, explain an induction coil.

Canto: Search for it on google images. It consists of a magnetic iron core, round which are wound two coils of insulated copper, a primary and secondary winding. The primary is of coarse wire, wound round a few times. The secondary is of much finer wire, wound many many more times. Now as I’ve said, it’s basically a transformer, and I don’t know what a transformer is, but I’m hoping to find out soon. Its purpose is to ‘produce high-voltage pulses from a low-voltage direct current (DC) supply’, according to Wikipedia.

Jacinta: All of this’ll come clear in the end, right?

Canto: I’m hoping so. When a current – presumably from that low-volage DC supply – is passed through the primary, a magnetic field is created.

Jacinta: Ahh, electromagnetism…

Canto: And since the secondary shares the core, the magnetic field is also shared. Here’s how Wikipedia describes it, and I think we’ll need to do further reading or video-watching to get it clear in our heads:

The primary behaves as an inductor, storing energy in the associated magnetic field. When the primary current is suddenly interrupted, the magnetic field rapidly collapses. This causes a high voltage pulse to be developed across the secondary terminals through electromagnetic induction. Because of the large number of turns in the secondary coil, the secondary voltage pulse is typically many thousands of volts. This voltage is often sufficient to cause an electric spark, to jump across an air gap (G) separating the secondary’s output terminals. For this reason, induction coils were called spark coils.

Jacinta: Okay, so much for an induction coil, to which we shall no doubt return, as well as to inductors and electromagnetic radiation. Let’s go back to the cathode ray tube and the discovery of the electron.

Canto: No, I need to continue this, as I’m hoping it’ll help us when we come to explaining transformers. Maybe. A key component of the induction coil was/is the interruptor. To have the coil functioning continuously, you have to repeatedly connect and disconnect the DC current. So a magnetically activated device called an interruptor or a break is mounted beside the iron core. It has an armature mechanism which is attracted by the increasing magnetic field created by the DC current. It moves towards the core, disconnecting the current, the magnetic field collapses, creating a spark, and the armature springs back to its original position. The current is reconnected and the process is repeated, cycling through many times per second.

A Crookes tube showing green fluorescence. The shadow of the metal cross on the glass showed that electrons travelled in straight lines

Jacinta: Right so now I’ll take us back to the cathode ray tube, starting with the Crookes tube, developed around 1870. When we’re talking about cathode rays, they’re just electron beams. But they certainly didn’t know that in the 1870s. The Crookes tube, simply a partially evacuated glass tube with cathode and anode at either end, was what Rontgen used to discover X-rays.

Canto: What are X-rays?

Jacinta: Electromagnetic radiation within a specific range of wavelengths. So the Crookes tube was an instrument for exploring the properties of these cathode rays. They applied a high DC voltage to the tube, via an induction coil, which ionised the small amount of air left in the tube – that’s to say it accelerated the motions of the small number of ions and free electrons, creating greater ionisation.

x-rays and the electromagnetic spectrum, taken from an article on the Chandra X-ray observatory

Canto: A rapid multiplication effect called a Townsend discharge.

Jacinta: An effect which can be analysed mathematically. The first ionisation event produces an ion pair, accelerating the positive ion towards the cathode and the freed electron toward the anode. Given a sufficiently strong electric field, the electron will have enough energy to free another electron in the next collision. The  two freed electrons will in turn free electrons, and so on, with the collisions and freed electrons growing exponentially, though the growth has a limit, called the Raether limit. But all of that was worked out much later. In the days of Crookes tubes, atoms were the smallest particles known, though they really only hypothesised, particularly through the work of the chemist John Dalton in the early nineteenth century. And of course they were thought to be indivisible, as the name implies.

Canto: We had no way of ‘seeing’ atoms in those days, and cathode rays themselves were invisible. What experimenters saw was a fluorescence, because many of the highly energised electrons, though aiming for the anode, would fly past, strike the back of the glass tube, where they excited orbital electrons to glow at higher energies. Experimenters were able to enhance this fluorescence through, for example, painting the inside walls of the tube with zinc sulphide.

Jacinta: So the point is, though electrical experiments had been carried out since the days of Benjamin Franklin in the mid-eighteenth century, and before, nobody knew how an electric current was transmitted. Without going into much detail, some thought they were carried by particles (like radiant atoms), others thought they were waves. J J Thomson, an outstanding theoretical and mathematical physicist, who had already done significant work on the particulate nature of matter, turned his attention to cathode rays and found that their velocity indicated a much lighter ‘element’ than the lightest element known, hydrogen. He also found that their velocity was uniform with respect to the current applied to them, regardless of the (atomic) nature of the gas being ionised. His experiments suggested that these ‘corpuscles’, as they were initially called, were 1000 times lighter than  hydrogen atoms. His work was clearly very important in the development of atomic theory – which in large measure he initiated – and he developed his own ‘plum pudding’ theory of atomic structure.

Canto: So that was all very interesting – next time we’ll have a look at electricity from another angle, shall we?

 

Written by stewart henderson

October 1, 2017 at 8:14 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

electric vehicles in Australia, a sad indictment

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Toyota Prius

I must say, as a lay person with very little previous understanding of how batteries, photovoltaics or even electricity works, I’m finding the ‘Fully Charged’ and other online videos quite addictive, if incomprehensible in parts, though one thing that’s easy enough to comprehend is that transitional, disruptive technologies that dispense with fossil fuels are being taken up worldwide at an accelerating rate, and that Australia is falling way behind in this, especially at a governmental level, with South Australia being something of an exception. Of course the variation everywhere is enormous – for example, currently, 42% of all new cars sold today in Norway are fully electric – not just hybrids. This compares to about 2% in Britain, according to Fully Charged, and I’d suspect that the percentage is even lower in Oz.

There’s so much to find out about and write about in this field it’s hard to know where to start, so I’m going to limit myself in this post to electric cars and the situation in Australia.

First, as very much a lower middle class individual I want to know about cost, both upfront and ongoing. Now as you may be aware, Australia has basically given up on making its own cars, but we do have some imports worth considering, though we don’t get subsidies for buying them as they do in many other countries, nor do we have that much in the way of supportive infrastructure. Cars range in price from the Tesla Model X SUV, starting from $165,000 (forget it, I hate SUVs anyway), down to the Toyota Prius C and the Honda Jazz, both hybrids, starting at around $23,000. There’s also a ludicrously expensive BMW plug-in hybrid available, as well as the Nissan Leaf, the biggest selling electric car worldwide by a massive margin according to Fully Charged, but probably permanently outside of my price range at $51,000 or so.

I could only afford a bottom of the range hybrid vehicle, so how do hybrids work, and can you run your hybrid mostly on electricity? It seems that for this I would want a (more expensive) plug-in hybrid, as this passage from the Union of Concerned Scientists (USA) points out:

The most advanced hybrids have larger batteries and can recharge their batteries from an outlet, allowing them to drive extended distances on electricity before switching to [petrol] or diesel. Known as “plug-in hybrids,” these cars can offer much-improved environmental performance and increased fuel savings by substituting grid electricity for [petrol].

I could go on about the plug-ins but there’s not much point because there aren’t any available here within my price range. Really, only the Prius, the Honda Jazz and a Toyota Camry Hybrid (just discovered) are possibilities for me. Looking at reviews of the Prius, I find a number of people think it’s ugly but I don’t see it, and I’ve always considered myself a person of taste and discernment, like everyone else. They do tend to agree that it’s very fuel efficient, though lacking in oomph. Fuck oomph, I say. I’m the sort who drives cars reluctantly, and prefers a nice gentle cycle around the suburbs. Extremely fuel efficient, breezy and cheap. I’m indifferent to racing cars and all that shite.

Nissan Leaf

I note that the Prius  has regenerative braking – what the Fully Charged folks call ‘regen’. In fact this is a feature of all EVs and hybrids. I have no idea wtf it is, so I’ll explore it here. The Union of Concerned Scientists again:

Regenerative braking converts some of the energy lost during braking into usable electricity, stored in the batteries.

Regenerative braking” is another fuel-saving feature. Conventional cars rely entirely on friction brakes to slow down, dissipating the vehicle’s kinetic energy as heat. Regenerative braking allows some of that energy to be captured, turned into electricity, and stored in the batteries. This stored electricity can later be used to run the motor and accelerate the vehicle.

Of course, this doesn’t tell us how the energy is captured and stored, but more of that later. Regenerative braking doesn’t bring the car to a stop by itself, or lock the wheels, so it must be used in conjunction with frictional braking.  This requires drivers to be aware of both braking systems and how they’re combined – sometimes problematic in certain scenarios.

The V useful site How Stuff Works has a full-on post on regen, which I’ll inadequately summarise here. Regen (in cars) is actually celebrating its fiftieth birthday this year, having been first introduced in the Amitron, a car produced by American Motors in 1967. It never went into full-scale production. In conventional braking, the brake pads apply pressure to the brake rotors to the slow the vehicle down. That expends a lot of energy (imagine a large vehicle moving at high speed), not only between the pads and the rotor, but between the wheels and the road. However, regen is a different system altogether. When you hit the brake pedal of an EV (with hand or foot), this system puts the electric motor into reverse, slowing the wheels. By running backwards the motor acts somehow as a generator of electricity, which is then fed into the EV batteries. Here’s how HSW puts it:

One of the more interesting properties of an electric motor is that, when it’s run in one direction, it converts electrical energy into mechanical energy that can be used to perform work (such as turning the wheels of a car), but when the motor is run in the opposite direction, a properly designed motor becomes an electric generator, converting mechanical energy into electrical energy.

I still don’t get it. Anyway, apparently this type of braking system works best in city conditions where you’re stopping and going all the time. The whole system requires complex electronic circuitry which decides when to switch to reverse, and which of the two braking systems to use at any particular time. The best system does this automatically. In a review of a Smart Electric Drive car (I don’t know what that means – is ‘Smart’ a brand name? – is an electric drive different from an electric car??) on Fully Charged, the test driver described its radar-based regen, which connects with the GPS to anticipate, say, a long downhill part of the journey, and in consequence to adjust the regen for maximum efficiency. Ultimately, all this will be handled effectively in fully autonomous vehicles. Can’t wait to borrow one!

Smart Electric Drive, a cute two-seater

I’m still learning all this geeky stuff – never thought I’d be spending an arvo watching cars being test driven and  reviewed.  But these are EVs – don’t I sound the expert – and so the new technologies and their implications for the environment and our future make them much more interesting than the noise and gas-guzzling stink and the macho idiocy I’ve always associated with the infernal combustion engine.

What I have learned, apart from the importance of battery size (in kwh), people’s obsession with range and charge speed, and a little about charging devices, is that there’s real movement in Europe and Britain towards EVs, not to mention storage technology and microgrids and other clean energy developments, which makes me all the more frustrated to live in a country, so naturally endowed to take advantage of clean energy, whose federal government is asleep at the wheel on these matters, when it’s not being defensively scornful about all things renewable. Hopefully I’ll be able to report on positive local initiatives in this area in future, in spite of government inertia.

 

Written by stewart henderson

August 15, 2017 at 9:51 am

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

the SA government’s six-point plan for energy security, in the face of a carping Federal government

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South Australian Premier Jay Weatherill, right, with SA Energy Minister Tom Koutsantonis

The South Australian government has a plan for energy, which you can take a look at here. And if you’re too lazy to click through, I’ll summarise:

  1. Battery storage and renewable technology fund: Now touted as the world’s largest battery, this will be a storage facility for wind and solar energy, and if it works, it will surely be a major breakthrough, global in its implications. The financing of the battery (if we have to pay for it!) will come from a new renewable energy fund.
  2. New state-owned gas power plant: This will be a 250 MW capacity gas powered facility designed initially for emergency use, and treated as a future strategic asset when (and if) greater energy stability is achieved at the national level. In the interim the state government will (try to?) work with transmission and distribution companies to provide 200 MW of extra generation in times of peak demand.
  3. Local powers over the national market: The government will legislate for strong new state powers for its Energy Minister as a last-resort measure to enable action in South Australia’s best interests when in conflict with the national market. In addition, all new electricity-generation projects above 5 MW will be assessed as to their input into the state electricity system and its security.
  4. New generation for more competition: The SA Government will use its own electricity contract (for powering schools, hospitals and government services) to tender for more new power generators, increasing competition in the market and putting downward pressure on prices.
  5. South Australian gas incentives: Government incentives will be given for locally-sourced gas development (we have vast untapped resources in the Cooper Basin apparently) so that we can replace all that dirty brown coal from Victoria.
  6. Energy Security Target: This new target, modelled by Frontier Economics, will be designed to encourage new investments in cleaner energy, to increase competition and put downward pressure on prices. The SA government will continue to advocate for an Emissions Intensity Scheme (EIS), contra the Federal government. It’s expected that the Energy Security Target will morph into an EIS over time – depending largely on supportive national policy. Such a scheme is widely supported by industry and climate science.

It’s an ambitious plan perhaps but it’s definitely a plan, and definitely actionable. The battery storage part is of course generating a lot of energy already, both positive and negative, as pioneering projects tend to do. I’m very much looking forward to December’s unveiling. Interestingly, in this article from April this year, SA Premier Jay Weatherill claimed 90 expressions of interest had been received for building the battery. Looks like they never stood a chance against the mighty Musk. In the same article, Weatherill announced that the expression of interest process had closed for the building of SA’s gas power plant, point two of the six-point plan. Thirty-one companies from around the world have vied for the project, apparently. And as to point three, the new powers legislation was expected to pass through parliament on April 26. Weatherill issued a press release on the legislation in late March. Thanks to parliamentary tracking, I’ve found that the bill – called the Bill to Amend the Emergency Management (Electricity Supply Emergencies) Act – was passed into law by the SA Governor on May 9.

Meanwhile, two regional projects, one in the Riverland and another in the north of SA, are well underway. A private company called Lyon Group is building a $1 billion battery and solar farm at Morgan, and another smaller facility, named Kingfisher, in the north. In this March 30 article by Chris Harmsen, a spokesperson for Lyon Group said the Riverland project, Australia’s largest solar farm, was 100% equity financed (I don’t know what that means – I’ll read this later) and would be under construction within months. It will provide 300MW of storage capacity. The 120 MW Kingfisher project will begin construction in September next year. Then there’s AGL’s 210MW gas-fired power station on Torrens Island, mentioned previously. It’s worth noting that AGL’s Managing Director Andy Vesey spoke of the positive investment climate created by the SA government’s energy plans.

So I think it’s fair to say that in SA we’re putting a lot of energy into energy. Meanwhile, the Federal Energy minister, Josh Frydenberg, never speaks positively about SA’s plans. Presumably this is because SA’s government is on the other side of the political divide. You can’t say anything positive about your political enemies because they might stop being your enemies, and then what would you do? The identity crisis would be intolerable.

I’ve written about macho adversarial systems in politics, law and industrial relations before. Frydenberg, as the Federal Minister, must be well aware of SA’s six-point plan (found with a couple of mouse-clicks), and of the plans and schemes of all the other state governments, otherwise he’d be massively derelict in his duty. Yet he’s pretty well entirely dismissive of the Tesla-Neoen deal, and describes the other SA initiatives, pathetically, as ‘an admission of failure’. It seems almost a rule with the current Feds that you don’t mention renewable, clean energy positively and you don’t mention the SA government’s initiatives in the energy field except negatively. Take for example Frydenberg’s reaction to recent news that the Feds are consulting with the car industry on reducing fuel emissions. He brought up the ‘carbon tax’ debacle (a reference to the former Gillard government’s 2012 carbon pricing scheme, repealed by the Abbott government in 2014), declaring that there would never be another one, as if the attempt to reduce vehicle emissions – carbon emissions – had nothing to do with carbon and its reduction, which was what the carbon pricing scheme was all about. This is the artificiality of adversarial systems – where two parties pretend to be further apart than they really are, so that they can engage in the apparently congenial activity of trading insults and holier-than-thou tirades. It’s so depressing. Frydenberg was at pains to point out that the government’s interest in reducing fuel emissions was purely to benefit family economies. It would’ve taken nothing but a bit of honesty and integrity to also say that reduced emissions would be environmentally beneficial. But this apparently would be a step too far.

In my next post I hope to get my head around battery storage technology, and lithium-ion batteries.

References/links

https://ussromantics.com/2017/07/14/whats-weatherills-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/

https://ussromantics.com/2011/06/25/adversarial-approaches-do-we-need-them-or-do-we-need-to-get-over-them/

http://ourenergyplan.sa.gov.au/

http://www.abc.net.au/news/2017-04-13/sa-gas-fire-power-station-gains-international-interest/8442578

https://www.premier.sa.gov.au/index.php/jay-weatherill-news-releases/7263-new-legislation-puts-power-back-in-south-australians-hands

http://www.abc.net.au/news/2017-04-13/sa-gas-fire-power-station-gains-international-interest/8442578

https://www.parliament.sa.gov.au/Legislation/BillsMotions/SALT/Pages/default.aspx?SaltPageTypeId=2&SaltRecordTypeId=0&SaltRecordId=4096&SaltBillSection=0

http://www.abc.net.au/news/2017-03-30/new-solar-project-announced-for-sa-riverland/8400952

http://www.investopedia.com/terms/e/equityfinancing.asp

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

 

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