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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so South Australia can briefly enjoy some fame as having the biggest battery in the world, though I’m sure it’ll be superseded soon enough with all the activity worldwide in the battery and storage field.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.

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Written by stewart henderson

December 9, 2017 at 9:07 pm

an assortment of new technology palaver

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I like the inset pic – very useful for the Chinese

Western Australia lithium mining boom

I’m hearing, better late than never, that lithium carbonate from Western Australia is in big demand. The state already provides most of the world’s lithium for all those batteries used to run smart devices, electric vehicles, and large-scale storage batteries such as South Australia’s Tesla-Neoen thingy at Jamestown (now 80% complete, apparently). Emissions legislation around the world will only add to the demand, with the French and British governments planning to ban the sale of petrol and diesel vehicles by 2040, following similar plans by India and Norway, and the major investments in EVs in China. Australia’s government, of course, is at the other end of the spectrum re EVs, but I’ve no doubt we’ll get there eventually (we’ll have to!). Tesla, Volvo, Nissan, Renault, Volkswagen and Mercedes are all pushing more EVs into the marketplace. So now’s the time, according to Money Boffins Inc, to buy shares in lithium and other battery minerals (I’ve never bought a share in my life). This lithium mining boom has been quite sudden and surprising to many pundits. In January of this year, only one WA mine was producing lithium, but by mid-2018 there will be eight, according to this article. The battery explosion, so to speak, is bringing increased demand for other minerals too, including cobalt, nickel, vanadium and graphite. Australia’s well-positioned to take advantage. Having said that, the amount of lithium we’re talking about is a tiny fraction of what WA exports in iron ore annually, but it’s already proving to be a big boost to the WA economy, and a big provider of jobs.

battery recycling

Of course all of this also poses a problem, as mentioned in my last post, and it’s a problem that the renewable energy sector should be at least ideologically driven to deal with: waste and recycling. Considering the increasing importance of battery technology in our world, and considering the many toxic components of modern batteries, such as nickel, lead acid, cadmium and mercury, it’s yet another disappointment that there’s no national recycling scheme for non-rechargeable batteries. Currently only lead acid batteries can be recycled, and the rest usually end up in landfill or are sent to be recycled overseas. So it’s been left to the industry to develop an Australian Battery Recycling Initiative (ABRI), which has an interesting website where you can learn about global recycling and many other things batterial – including, of course, how to recycle your batteries. Also, an organisation called Clean Up Australia has a useful battery recycling factsheet, which, for my own educational purposes I’m going to recycle here, at least partly. Battery types can be divided into primary, or single-use, and secondary, or rechargeable. The primary batteries generally use zinc and manganese in converting chemical to electrical energy. Rechargeable batteries use a variety of materials, including nickel cadmium, nickel metal hydride and of course lithium ion chemistry. Batteries in general are the most hazardous of waste materials, but there are also environmental impacts from battery production (mining mostly) and distribution (transport and packaging). As mentioned, Australian batteries are sent overseas for recycling – ABRI and other groups are trying to set up local recycling facilities. Currently a whopping 97% of these totally recyclable battery units end up in landfill, and – another depressing factoid – Australia’s e-waste is growing at 3 times the rate of general household waste. So the public is advised to use rechargeable batteries wherever possible, and to take their spent batteries to a proper recycling service (a list is given on the fact sheet). The ABRI website provides a more comprehensive list of drop-of services.

2015 registrations: Australia’s bar would be barely visible on this chart

EVs in Australia – a very long way to go

I recently gave a very brief overview of the depressing electric vehicle situation in Australia. Thinking of buying one? Good luck with that. However, almost all motorists are much richer than I am, so there’s hope for them. They’re Australia’s early adopters of course, so they need all the encouragement we can give them. Journalist Timna Jacks has written an article for the Sydney Morning Herald recently, trying to explain why electric vehicles have hit a dead end in Australia. High import duties, a luxury car tax and a lack of subsidies and infrastructure for electric vehicles aren’t exactly helping the situation. The world’s most popular electric car, the Nissan Leaf, is much more expensive here than in Europe or the US. And so on. So it’s hardly surprising that only 0.1% of all cars sold in Australia in 2015 were electric cars (compared with 23% and rising in EV heaven, aka Norway, 1.4% in France and 0.7% in the US). Of course Australia’s landscape’s more or less the opposite of compact, dense and highly urbanised Europe, and range anxiety might be a perennial excuse here. We have such a long way to go. I expect we’ll have to wait until shame at being the world’s laughing-stock is enough of a motivation.

Adelaide’s Tindo

I’ve been vaguely aware of Adelaide’s ‘green bus’ for some years but, mea culpa, haven’t informed myself in any depth up until now. The bus is called Tindo, which is a Kaurna aboriginal word meaning the sun. Apparently it’s the world’s first and only completely solar powered electric bus, which is quite amazing. The bus has no solar panels itself, but is charged from the solar panels at the Franklin Street bus station in the city centre. It’s been running for over four years now and I’m planning to take a trip on it in the very near future. I was going to say that it’ll be the first time I’ve been on a completely electric vehicle with no internal combustion engine but I was forgetting that I take tram trips almost every day. Silly me. Still, to take a trip on a bus with no noisy engine and no exhaust fumes will be a bit of a thrill for me. Presumably there will be no gear system either, and of course it’ll have regenerative braking – I’m still getting my head around this stuff – so the ride will be much less jerky than usual.

So here are some of the ‘specs’ I’ve learned about Tindo. It has a range of over 200 kilometres (and presumably this is assisted by the fact that its route is fixed and totally urban, so the regen braking system will be charging it up regularly). It uses 11 Swiss-made Zebra battery modules which are based on sodium nickel chloride, a type of molten salt technology. They have higher energy density, they’re lightweight and virtually maintenance free. According to the City of Adelaide website the solar PV system on the roof of the bus station is (or was – the website is annoyingly undated) ‘Adelaide’s largest grid-connected system, generating almost 70,000 kWh of electricity a year’. No connection to the ‘carbon-intensive South Australian electricity grid’ is another plus, though to be fair our grid is far less carbon intensive than Victoria’s which is almost all brown coal. South Australia’s grid runs on around half gas and half renewables, mostly wind. The regen braking, I must remind myself, means that when decelerating the bus uses no energy at all, and the motor electronically converts into an electrical generator, which generates electricity with the continued forward motion of the bus. There are many more specs and other bits of info on this Tindo factsheet.

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

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

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