an autodidact meets a dilettante…

‘Rise above yourself and grasp the world’ Archimedes – attribution

Posts Tagged ‘technology

is there life on Mars? – encore

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Don’t worry Davey, we’ll find out

The recent announcement about a large lake of water beneath the ice near the south pole of Mars has naturally engendered great excitement among those desperate to find life ‘elsewhere’, and with good reason. Mars, our closest planet, has long been a haven of hope for this sort of thing, but it has also engendered the ‘too good to be true’ response. It’s almost been seen as a lazy conjecture, as if we should expect to work really hard, and over unimaginably long distances, to find this precious and surely extremely rare stuff called life. But in recent decades we’ve managed to discover life surviving and even thriving under the most extreme circumstances in odd nooks and crannies of our own planet, which has widened our view of life’s diversity and tenacity. And the fact that we’ve been discovering new life on our own planet, is a testament to our developing skills and technology in the search for life – because, of course, the life we’re discovering isn’t new at all, what’s new is our technology and our deeper awareness of life’s range and possibilities.

And what we know about life on Earth is all about water. We’re full of the stuff, as are the plants and animals around us, and we now know that our ancestors emerged from the stuff, and we’ve never stopped being dependent on it. So it’s not surprising that the question about life on Mars is also all about water.

In previous centuries it was much speculated that water lay on the surface of Mars, in what appeared to be canals or waterways of some kind. Nowadays what we’ve learned about the atmosphere at Mars’ surface – low temperature and pressure – has rendered the possibility of liquid water increasingly unlikely. However, water below the surface is another matter. Lake Vostok, four kilometres below the surface in Eastern Antarctica, is just the largest of a number of subsurface lakes – at least 400 found under that continent – and they support thousands of living species.

So for some time there’s been a search for subsurface water on Mars. A radar instrument called MARSIS, orbiting the planet on the European Space Agency’s Mars Express, and purpose-built to search for underground water, has been sending out radio waves which are reflective to liquid water but not to ice or rock. A particularly reflective patch near the south pole appears to reveal a layer of water about 1.5 kilometres below the surface. However, MARSIS is limited in the data it can provide. The depth of the water, and what other material is mixed in with it, are not known – though we know that it’s about 20 kilometres across, and the the Italian research team that has published the findings estimates the water to be at least a metre deep, indicating a genuine lake rather than meltwater. It’s expected that the water will contain salts, which lower the freezing point of water, as would pressure from the material above the lake.

There are still many unknowns here, but the various Mars rovers and orbiters are building evidence, for example that Mars was once warmer and wetter, and that even now liquid water can still be found at periods on the surface. What we haven’t found so far is evidence of life. So how can we get this evidence? First, we need to look for life ‘as we know it’, carbon-based life, because that’s very likely the kind of life we’ll find on our nearest neighbour, and because we have no way of knowing how to look for completely alien life.

Mars’ Curiosity rover has already found organic molecules, specifically methane, which may or may not be produced by biological activity beneath the surface. The rover has been sampling the atmosphere and has found methane at varying levels as the seasons have changed. However, it’s generally believed that the thin atmosphere at Mars’ surface would be insufficient to deflect life-harming radiation. The discovery of a specific and more or less substantial body of water below the surface, perhaps sufficiently protected from radiation, provides a target for future researchers to aim at.

The next step would be to obtain samples from the lake, which is easier said than done. It would require some sort of robotic drill to be sent out there and operated remotely, a task beyond current capabilities. Meanwhile, a Chinese probe is set to be flown to Mars in 2020. It will have radar instrumentation similar to MARSIS, but operating at a slightly different frequency. It may confirm the MARSIS findings or discover other underground bodies of water, further piquing our interest in the very real possibility of life on the red planet.

Is it an underground lake? We can’t be entirely sure.

References

http://www.abc.net.au/news/science/2018-07-26/vast-liquid-lake-found-under-mars-south-polar-ice-cap/10030264

https://theconversation.com/discovered-a-huge-liquid-water-lake-beneath-the-southern-pole-of-mars-100523

http://www.abc.net.au/news/science/2018-07-26/mars-life-evidence-organic-carbon-methane-liquid-water/10038324

https://www.bbc.com/news/science-environment-44952710

 

Written by stewart henderson

August 11, 2018 at 10:38 pm

more on Australia’s energy woes and solutions

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the SA Tesla Powerpack, again

Canto: So the new Tesla battery is now in its final testing phase, so South Australia can briefly enjoy some fame as having the biggest battery in the world, though I’m sure it’ll be superseded soon enough with all the activity worldwide in the battery and storage field.

Jacinta: Well I don’t think we need to get caught up with having the biggest X in the world, it’s more important that we’re seen as a place for innovation in energy storage and other matters energetic. So, first, there’s the Tesla battery, associated with the Hornsdale wind farm near Jamestown, and there are two other major battery storage systems well underway, one in Whyalla, designed for Whyalla Steel, to reduce their energy costs, and another smaller system next to AGL’s Wattle Point wind farm on Yorke Peninsula.

Canto: Well, given that the federal government likes to mock our Big Battery, can you tell me how the Tesla battery and the other batteries work to improve the state?

Jacinta: It’s a 100MW/129MWh installation, designed to serve two functions. A large portion of its stored power (70MW/39MWh) is for the state government to stabilise the grid in times of outage. Emergency situations. This will obviously be a temporary solution before other, slower reacting infrastructure can be brought into play. The rest is owned by Neoen, Tesla’s partner company and owner of the wind farm. They’ll use it to export at a profit when required – storing at low prices, exporting at higher prices. As to the Whyalla Steel battery, that’s privately owned, but it’s an obvious example, along with the AGL battery, of how energy can be produced and stored cleanly (Whyalla Steel relies on solar and hydro). They point the way forward.

Canto: Okay here’s a horrible question, because I doubt if there’s any quick ‘for dummies’ answer. What’s the difference between megawatts and megawatt-hours?

Jacinta: A megawatt, or a watt, is a measure of power, which is the rate of energy transfer. One watt equals one joule per second, and a megawatt is 1,000,000 watts, or 1,000 kilowatts. A megawatt-hour is one megawatt of power flowing for one hour.

Canto: Mmmm, I’m trying to work out whether I understand that.

Jacinta: Let’s take kilowatts. A kilowatt (KW) is 1,000 times the rate of energy transfer of a watt. In other words, 1000 joules/sec. One KWh is one hour at that rate of energy transfer. So you multiply the 1000 by 3,600, the number of seconds in an hour. That’s a big number, so you can express it in megajoules – the answer is 3.6Mj. One megajoule equals 1,000,000 joules of course.

Canto: Of course. So how is this working for South Australia’s leadership on renewables and shifting the whole country in that direction?

Genex Power site in far north Queensland – Australia’s largest solar farm together with a pumped hydro storage plant

Jacinta: Believe me it’s not all South Australia. There are all sorts of developments happening around the country, mostly non-government stuff, which I suppose our rightist, private enterprise feds would be very happy with. For example there’s the Genex Power solar, hydro and storage project in North Queensland, situated in an old gold mine. Apparently pumped hydro storage is a competitor with, or complementary to, battery storage. Simon Kidston, the Genex manager, argues that many other sites can be repurposed in this way.

Canto: And the cost of wind generation and solar PV is declining at a rate far exceeding expectations, especially those of government, precisely because of private enterprise activity.

Jacinta: Well, mainly because it’s a global market, with far bigger players than Australia. Inputs into renewables from states around the world – India, Mexico, even the Middle East – are causing prices to spiral down.

Canto: And almost as we speak the Tesla gridscale battery has become operational, and we’ve gained a tiny place in history. But what about this National Energy Guarantee from the feds, which everyone seems to be taking a swing at. What’s it all about?

Jacinta: This was announced a little over a month ago, as a rejection of our chief scientist’s Clean Energy Target. Note how the Feds again avoid using such terms as ‘clean’ and ‘renewable’ when it talks or presents energy policy. Anyway, it may or may not be a good thing – there’s a summary of what some experts are saying about it online, but most are saying it’s short on detail. It’s meant to guarantee a reliable stream of energy/electricity from retailers, never mind how the energy is generated – so the government can say it’s neither advocating nor poo-pooing renewables, it’s getting out of the way and letting retailers, some of whom are also generators, deliver the energy from whatever source they like, or can.

Canto: So they’re putting the onus on retailers. How so?

Jacinta: The Feds are saying retailers will have to make a certain amount of dispatchable power available, but there is one ridiculously modest stipulation – greenhouse emissions from the sector must be reduced by 26% by 2030. The sector can and must do much better than that. The electricity sector makes up about a third of emissions, and considering the slow movement on EVs and on emissions reductions generally, we’re unlikely to hold up our end of the Paris Agreement, considering the progressively increasing targets.

Canto: But that’s where they leave it up to the private sector. To go much further than their modest target. They would argue that they’re more interested in energy security.

Jacinta: They have a responsibility for providing security but not for reducing emissions? But it’s governments that signed up to Paris, not private enterprises. The experts are pointing this out with regard to other sectors. More government-driven vehicle emission standards, environmental building regulations, energy efficient industries and so forth.

Canto: And the Feds actually still have a renewable energy agency (ARENA), in spite of the former Abbott government’s attempt to scrap it, and a plan was announced last month to set up a ‘demand response’ trial, involving ARENA, AEMO (the energy market operator) and various retailers and other entities. This is about providing temporary supply during peak periods – do you have any more detail?

Jacinta: There’s a gloss on the demand response concept on a Feds website:

From Texas to Taiwan, demand response is commonly used overseas to avoid unplanned or involuntary outages, ease electricity price spikes and provide grid support services. In other countries, up to 15 per cent of peak demand is met with demand response.

Canto: So what exactly does it have to do with renewables?

Jacinta: Well get ready for a long story. It’s called demand response because it focuses on the play of demand rather than supply. It’s also called demand management, a better name I think. It’s partly about educating people about energy not being a finite commodity available at all times in equal measure…

Canto: Sounds like it’s more about energy conservation than about the type of energy being consumed.

Jacinta: That’s true. So on extreme temperature days, hot or cold – but mostly hot days in Australia – electricity demand can jump by 50% or so. To cope with these occasional demand surges we’ve traditionally built expensive gas-based generators that lie idle for most of the year. For reasons I’m not quite able to fathom, at such extreme demand times the ‘spot price’ for wholesale electricity goes through the roof – or more accurately it hits the ceiling, set by the National Energy Market at $14,000 per MWh. That’s just a bit more than the usual wholesale price, about $100/MWh. Demand management is an attempt to have agreements with large commercial/industrial users to reduce usage at certain times, or the agreements could be with energy retailers who then do deals with customers. Of course, bonuses could be handed out to compliant customers. The details of how this offsets peak demand usage and pricing are still a bit of a mystery to me, however.

Written by stewart henderson

December 9, 2017 at 9:07 pm

battery technology and the cobalt problem

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The battery in my iPhone 6+ is described as a lithium polymer, or Li-ion polymer battery. I’m trying to find out if it contains cobalt. Why? Because cobalt is a problem.

According to this Techcrunch article, most of the world’s cobalt is currently sourced from Africa, especially the Congo, one of the world’s poorest countries. Child labour is regularly used in the mines there, under pain of beatings and other forms of coercion. The battery industry uses about 42% of global cobalt production, and the rest is used in a range of essential military-industrial applications.

Incidentally, this article from teardown.com blog goes deep inside the iPhone 6+ battery, showing that it uses lithium cobalt oxide (LiCoO2) for the cathode.

I can think of three possible ways out of this problem. 1. Stop sourcing cobalt from the Congo, or anywhere else that has exploitative labour practices. 2. Reform those labour practices, to improve the lives of the workers and provide them with a fairer share of the tech revolution profits. 3. Find an alternative to cobalt for batteries and other applications.

I didn’t say there were easy solutions haha. Anyway, let’s examine them.

An online Fortune article from March this year, which by the way confirms that cobalt is indeed used in iPhone and iPad batteries, reported that Apple has responded to investigative articles by Washington Post and Sky News by no longer buying cobalt from companies that employ child labour. Of course, even if we take Apple at its word – and considering that the Congo provides 60% of the world’s cobalt, and other African sources may have similar problems, how else will Apple be able to source cobalt cheaply? – the problem of Congolese child labour remains. The Washington Post report focused on a Chinese company, Zhejiang Huayou Cobalt Company, which purchases a large percentage of Congolese cobalt. It seems highly unlikely that such a company will be as affected by public or media pressure as Apple. However, there are some positive signs. A report in the Financial Times from a year ago, entitled ‘China moves to quell child labour claims in Congo cobalt mines’, says that China has launched a ‘Responsible Cobalt Initiative’ to improve supply chain governance and transparency. Whether this means applying solution 1 or solution 2 to the problem is unclear, but presumably it’s solution 2, and it really is a serious initiative, put forward by the Chinese Chamber of Commerce for Metals, Minerals and Chemicals Importers and Exporters, backed by the OECD and involving a number of international tech companies. Of course we’ll have to wait for reports on how this initiative is faring, and on whether these companies are concerned to improve the lives of cobalt miners or simply to ban the under-age ones while still paying very little to the remainder. Continued scrutiny is obviously necessary.

Of course, solution 3 would be of most interest to tech-heads (though presumably the effect on the Congolese economy would be terrible). According to this marketing article, there isn’t too much cobalt available, and the demand for it is increasing sharply. One problem is that cobalt isn’t generally mined on its own as ‘primary cobalt’ but as a byproduct of copper or nickel, and both of these metals are experiencing a worldwide price plunge, with many mines suspending activities. Also the current supply chain for cobalt is being dominated by Chinese companies. This could have a stifling effect especially on the EV revolution. Governments in advanced countries around the world – though not in Australia – are mandating the adoption of electric vehicles and the phasing out of fossil-fuel-based road transport. The batteries for these vehicles all contain cobalt.

In the TechCrunch article mentioned above, journalist Sebastien Gandon examines the Tesla situation. The company has a target of 500,000 vehicles a year by 2018, with cobalt sourced exclusively from North America. On the face of it, this seems unrealistic. Canada and the US together produce about 4% of the world’s cobalt supply, and  acccording to Gandon the maths just doesn’t add up, to say the least. For a start, the mining companies Tesla is looking to rely on are not even operational as yet.

However, there are a few more promising signs. The Tesla model S has been using high energy density nickel-cobalt-aluminium-based (NCA) battery cells, which have a lower cobalt content than the nickel-manganese-cobalt (NMC) batteries of most other companies. There is also the possibility of adopting lithium-iron-phosphate (LFP) chemistry, or lithium-manganese-oxide (LMO), neither of which use cobalt, though their lower energy density is a problem. In any case, battery technology is going through a highly intensive phase at present, as I’ve already reported, and a move away from cobalt has become a distinct possibility. Nickel is currently being looked at, but results so far have been disappointing. There are certainly other options in the offing, and cobalt itself, which unlike oil is completely recyclable, could still be viable with greater focus. It isn’t so much that it is scarce, it’s more that, in the past, it hasn’t been a primary focus, but mining it as a primary source will require substantial upfront costs, and substantial time delays.

So, all in all, it’s a problematic future, at least in the short term, for vehicles and technologies using cobalt-based battery systems. We can only wait and see what comes out of it.

Written by stewart henderson

October 28, 2017 at 12:55 pm

on electrickery, part 2 – the beginnings

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William Gilbert, author of De Magnete, 1600

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

get it?

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

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

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

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

now try these..

Written by stewart henderson

October 22, 2017 at 10:09 am

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

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