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Posts Tagged ‘energy

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 Short-term impacts are often devastating, but over time one type of diversity has been replaced by another.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

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