Ken Fabian

This study of Solar in Switzerland (in part a response to another study in support of nuclear that claimed PV used more energy than it produced) came up with 7-10 times more energy produced than energy used, in less than ideal Swiss climate. That includes associated equipment, installation etc, not just solar cells. Other studies have come up with higher than that and lower. Currently home solar is heavily advertised in Australia, with 6kW grid tied systems for around AU$4,000 (maybe US$3000) installed. I don't see how it would be possible for manufacturing to support costs that low if EROI is low, even given lower power costs for Chinese manufacturers; manufacturers elsewhere, with high power (as well as other) costs are usually more expensive but not by that much.

I suppose it will happen that - following a cold day - it will be warmer before 9am the next morning than any time over the previous 24hrs but that would be rare and unusual. Maybe you should contact them and ask how (or if) they deal with that should it occur. For climate change purposes - averages and trends - it probably doesn't occur often enough to make much difference but it probably does need to be considered. Maybe it is. That any maximum records would be broken when it occurs will be even less likely - not impossible but possibly so rare that it has never occurred. Do you think temperature records and averages/trends derived from them are invalidated by the choice of a 9am to 9am "day" for record keeping purposes? I don't.

No, the actual maximum and actual minimum temperatures are recorded for each day by thermometers that keep a record of what those were, no matter what time of day they occur and irrespective of when the station keepers report those to the record keeping agency (if not automated). In Australia that agency is the Bureau of Meteorology. If daily maximums are recorded as lower than minimums or vice versa they will have been errors. From the description of a max/min thermometer suitable for weather stations - (my italics) - Rainfall is recorded for each 24 hr period, with a 9am to 9am 24 hr period used in Australia. That was for convenience, so people don't have to do it at midnight. If we were starting now it likely would be automated and could align with a midnight to midnight 24 hrs.

As someone who plays guitar a bit (I play a homemade 1 string box bass too) I appreciate Marc's (Enthalpy) point that it takes time playing instruments to fully appreciate their qualities - and it doesn't come down to any one thing. I had a guitar maker "adjust the intonation" - which involved small changes to the bridge (on the guitar body, that the strings go over) to change the precise active length of each string, compensating for differences between each string (thickness of strings, wound vs unwound). It means the frets line up more precisely to the required notes when you hold the string down. The differences were small but real but I needed to warm up my fingers and play for some time to notice a difference. I suppose the test will be if such chemically treated woods get made into violins and in a century or two we will be able to know... except there is much less highest quality specialist timber than ever before and a lot more instruments are being made; sourcing the same kinds and quality of wood as Strativari used adds another impediment.

I've heard variations of this - treating the wood with rotting fruit was one I'd heard of. Plums if I recall correctly. I've also heard claims that blindfolded violinists prefer the sound of modern instruments and can't tell which is Strativari's. I also wonder what Enthalpy thinks.

I am not sure "Why?" is a valid question - babies with large heads in comparison with other mammals is how humans are when born; it is in our developmental genetics. "How?" might be better - which may answer why the balance between pre-birth and post-birth development shifted during evolution, which simply means those with the bigger heads at birth went on to survive and reproduce but those with smaller heads didn't. It is not just about the baby but the carrying mother; it is safe to assume those with heads too big/mothers too small did not survive. It does not even follow that those with smaller birth size failed because of their smaller birth size; the crucially significant baby born with genetics for smaller births size but capable of growing a big brain may have gotten eaten by a hyena and all human evolution after that was altered forever. Those that were born better able to function more independently at birth and needed less parental care somehow did not go on to thrive - and not necessarily because of any direct relationship; other factors can and will be in play. We can list the advantages and disadvantages and hope we haven't overlooked some but it cannot really give a definitive answer

@Peterkin (re way back) - I included biofuels to be more complete but I'd need to see some cost and land-use effective examples to become enthusiastic. Other biofuels than ethanol for cars would include: biodiesel - mostly waste vegetable oils but can be purpose produced: algal diesel - I struggle to find any working commercial examples but would be pleased to know they exist: bio-gas - I'm sure someone will be doing sewage gas somewhere in place of fossil gas, because they can, but it isn't leaping out as something being done at big scales. None of them stand out. So, not withstanding the role that mass transit and autonomous taxis as well as the part good urban planning and design can play it seems to be between Hydrogen Fuel Cell and Battery EV and EV's are winning. Even if Hydrogen were the better clean transport solution in the long run (it is a question) EV's are the solution we are getting. I think Hydrogen takes a lot more commitment, more planning, more pre-investment and funding - that has not been forthcoming. Whereas most EV charging was and is at home, when garaged - early adopters could tolerate a sparse charging network because you can charge at home but Hydrogen absolutely has to have the fueling stations up front, ie a big pre-investment and commitment. And Hydrogen remains expensive to produce and transport. Even the few cars that are made for Hydrogen are expensive. EV's are closing in on ICE on cost - saving on running costs but suffering for being expensive up front. In a sense we've gotten EV's despite no serious demands that there be low emissions transport - credit to Mr Musk and his Tesla team. That success has emboldened policy makers in the face of climate concerns and given the established auto industry a shock but I suspect battery tech was catching up on the practical EV problem anyway. There were and are too many drivers for battery R&D, but Tesla might have gained us a decade. Or perhaps we got EV's because there were no serious demands for low emissions transport; without the deep commitment the planning and funding and implementation of Hydrogen infrastructure could never happen. Maybe Hydrogen can find a place in the road freight space but I suspect even there battery electric will get there first and will prove hard to beat. The way I see it (when I'm feeling optimism) if Li-Ion and equivalent battery costs can be halved EV's will win on cost across most road transport modes. If battery weight can be halved I think that would seal the deal and open some battery electric air transport possibilities. I think both of those look achievable. There has never been more R&D targeted at better, cheaper batteries than there is now and I suggest the tools of science have never been better fitted for the task. Bill Gates suggested a fivefold increase in clean energy R&D, but I think we've already got that for batteries. Whoever invents the best of possible batteries will get richer than Bill and Elon put together.

An ICE using petro-chem fuel that is 100% energy efficient is still making CO2 emissions. An EV or biofuel car built and running off 100% clean energy doesn't make CO2 emissions. It doesn't have to have 100% energy conversion efficiency to do so, just zero emissions energy; even wasteful energy and inefficient energy use will have zero emissions. Efficiency is a slippery concept; in a world where fossil fuels are abundant, cheap and there is no accountability for climate and other externalised costs (climate, health) the energy conversion efficiencies don't really matter. What people pay matters but not conversion efficiency. Where fuels are expensive conversion efficiency matters more. Where fuels come with externalised costs (climate, health) greater efficiency reduces those costs but only a shift to clean energy can eliminate them.

Big yes, but to me, not so scary. That doesn't mean I would try to pick a spider like that up, although I did once encourage one to walk onto my hand to get it off someone who was freaking out. It did. I stepped outside and it stepped off to the post I offered it as a way off me, all done peacefully, almost politely, without violence on it's part or mine. Frankly I think spiders are not nearly so scary as some people are.

Spiders don't bother me because the ones I mostly encounter are not dangerous. Anyone with a fear of snakes would not like living where I do - although again, they are mostly not dangerous, but some care is needed around them, especially the venomous ones. There are a pair of carpet pythons in our roof space as I type - they come out to sun themselves, snuggling together contentedly between their amorous exploits. Another time we had a female python "in heat" she attracted males from far and wide - I counted 5 different males sniffing about and they were less timid than usual, ignoring people and going places they normally wouldn't. And there were some fights - which were more like arm (neck?) wrestles that seemed quite civilised; no-one gets injured and the loser accepts defeat and moves on. It was a bit alarming but not panic inducing; we had to watch our steps. They aren't aggressive but like any wild animal you have to be careful. Carpet pythons are not usually considered dangerous but they are capable predators always on the lookout for an easy meal; I suspect large ones could target unattended babies or toddlers. I would be a lot less apathetic about their presence if we had little kids here and the snake had ready access. My video of two male pythons arguing over a girl - sorry, the dialogue is a bit... disjointed -

Shining the critical spotlight on the extremist fringe and claiming they are all like that looks like disappointingly normal political pointscoring. A minority of "leftists" were (and are) back to nature/alternative medicine/hippie types. They brought that with them when they identified as Left but it wasn't ever a mainstream Left policy. Most of the anti-vaxxers on the Right are on the fringe; I would like to think they are atypical and the overwhelming majority are pleased to support and use vaccination to prevent disease.

Encountering spiders without previous experience of them probably does trigger significant alarm - encountering most animal species without experience of them would do that and modern lifestyles tend to limit such encounters. When they go on to encounter a kind of animal they believe to be potentially dangerous the fear and aversion is probably reinforced. Tangentially I read a book on dog training that claimed whether dogs take to some activities like swimming can depend on the age they are when they are first introduced to them; there probably are age ranges where negative encounters can imprint long running aversion but at other ages will tolerate the new and unusual. I think that familiarity breeds... apathy; they are around and they don't attack anyone so people living around them can get quite casual about them. There are only a very few species of spider in Australia that are genuinely dangerous. Perhaps if the spiders you first encounter are these ones, you might not develop any arachnophobia -

I think most of it is learned, that without observing the aversion in others in combination with being warned to avoid them or kill them because they are dangerous most children would not develop that response. I did learn that response but have mostly gotten over it with attempts to put reason ahead of learned fear responses. That is distinct from personal experience of painful bites and stings, which can make a big impression especially when young. I avoid bee hives and paper wasp nests- they hurt - and won't make pets of them but I suspect many beekeepers quite like their bees. The only bite from a spider I got that I am aware of was (lots of stings and itches have been mysteries) was from an Australian Huntsman spider that had hidden in the sleeve of a raincoat; it drew blood but must not have used venom. No sting or reaction; they do have venom and it can be painful (I've read) but not usually dangerous unless there is unusual sensitivity or allergy. It made me wary of poking my hands through sleeves of my raincoat for a time but hasn't caused a fear of Huntsman spiders. Because only some spiders are dangerous to humans but most people will not know which are and which are not, the warnings - and the subsequent fear of them - is applied across the board. In a similar way to some Muslims being terrorists has resulted in many people who have little first hand experience of them being suspicious and fearful of all Muslims.

Getting a view of space would have to wait until instruments that can deal with other bands than visible - or aircraft/rockets to lift instruments or observers above the cloud layer - but I don't know to what extent such technology would be dependent on astronomy. Seems like we should be able to do those things without an understanding of what is out there and still get there in the end. I don't think being unable to see the stars would prevent a sense of wonder or curiosity - and I seriously doubt the evolution of those traits was ever dependent on it; they evolved and developed and got naturally selected for other, more prosaic, down to Earth reasons.

There is the question - what if there were no stars at all. That would leave us without a Sun. What if there was only one star - the Sun; that would leave Earth without the elements that came from other stars. But I think the question may be about if they exist but could not be seen and whether we could feel similar awe and wonder for other objects. It seems obvious to me that we can... because humans do feel that about other things than the night sky and celestial objects; the vast oceans, their reaches, their mysterious depths. Mountain ranges, giant forest trees. Caves and deep underground. Volcanoes. Living things. I recently watched visualisations of biomolecular processes - mitosis, DNA replication, transcription, the kinetochore - wow! I have to say I had only limited interest in stars as a child; shooting stars, sure and the first visible stars after sunset (for making wishes, which I quickly realised weren't coming true). There was the "saucepan" - Orion's Belt and other stars, because it looked like a join the dot drawing of a saucepan with a handle and the Southern Cross, that is on Australia's (and other nation's) flags, that we were told could help give a guide to the direction South. But they were all kinda static and not that exciting; the wonder has come from other people getting all passionate about them and learning what is out there.

I do think major growth of nuclear energy in the absence of opposition would have resulted in more accidents as well as nuclear weapons proliferation and potentially incidents of use of them; those were and remain real, not imaginary issues and those concerns gained a deal of mainstream tolerance and support for anti-nuclear activism. The drive to build reactors that cannot melt down came in part as response to safety concerns raised mostly by activists. I also suspect the desire of major powers to limit weapons proliferation was a significant factor (after cost and difficulty) in why that major uptake did not happen - the attraction of nuclear weapons was and remains a significant factor in the decisions of many nations to adopt nuclear and there were efforts to limit that, with nuclear energy growth a casualty. In Australia's case - where I live - I suspect it was the decision to NOT develop an Australian nuclear weapons capability that meant we abandoned nuclear energy ambitions and that choice would likely have been urged on us by powers like the US and UK, to keep a lid on WMD's. On the basis of energy costs it was never a good deal - especially not for a nation that floats on deep beds of coal... in an absence of climate considerations. The energy industry in Australia may not have opposed nuclear but it had no good reason to develop it, until global warming... and then the energy industry chose climate science denial, not nuclear. Climate concerns would probably have been delayed but not eliminated by large scale take-up of nuclear energy. From producers and transport and industrial users of fossil fuels there would still have been strong opposition to climate accountability so we could have ended up with the same kind of conflicted politics we have been seeing, but without the illusion that people who like fossil fuels and people who like nuclear - united in their dislike of anti-nuclear and environmental activism - are on the same page.

Well, a whole lot of things would need to have been different and not just absence of anti-nuclear activism, which I think has been amongst the least of nuclear's problems. I suspect nuclear technology itself would have to have been different - more like the still yet to be achieved mass manufactured, ultra-safe, foolproof, tamper-proof, ultra-reliable, low maintenance modular power plant. And cheaper than coal or gas or oil. I am not sure it is going to provide much illumination to run through possible alternative histories: the impacts of no protesters and subsequently more relaxed shit happens approach to accidents and to nuclear weapons proliferation: when or even if global warming concerns sufficient to demand action on transport and industry and land use emissions would have reached critical mass: whether the development of wind and solar, EV's and batteries - successful, useful, working technologies now - would have been proceeded anyway or been delayed. We have to start from where we are and nuclear is still yet to achieve its promise, despite at the time of the emergence of mainstream global warming concerns nuclear standing alone as credible replacement for fossil fuels. The way I see it mainstream politics balked at emerging evidence of global warming from the world's number one waste product - CO2 - and nuclear energy has been a casualty of an unfortunate failure to show leadership. Enviro types got worked up about it - to be expected - but I don't really think they expected to get handed the podium in "you care so much, tell us how you'll fix it" style. They distrusted nuclear and preferred alternative, clean energy technologies - solar and wind mostly, which didn't work, mostly. Which mainstream politicians still funded in what I suspect was a cynical mix of empty gesture politics and give em enough rope. Fortunately others besides enviro protester types took up the challenges of climate change and clean energy - scientists, engineers, entrepreneurs - and they made solar and wind and batteries and EV's and etc cost effective despite the doubts and the derision and fossil fuels getting the biggest energy subsidy of all, the enduring amnesty on externalised climate and health costs. Unfortunately when large parts of mainstream politics fled the field on climate and clean energy they took most of the existing support for nuclear solutions with them; if there is no climate problem there is no need. As I see it most of the latent support for nuclear energy as principle clean energy option has been rendered ineffectual, behind a Wall of Denial. Climate science denial has no redeeming features - it's proponents appear to have no compunction about nuclear as collateral damage in the fight to prevent fossil fuels being accountable for climate change. Not strength of opposition but weakness of support meant the nuclear industry was unable to take full advantage of the unparalleled opportunity it has to save the world from global warming. In the world we have now nuclear energy faces the problem that when the Conservative Right's Wall of Denial comes down and Right politics commits to clean energy for real... those voters can no longer be presumed to support nuclear over renewables; just as wind and solar was opposed on the basis of cost back when they got started with Doubt, Deny, Delay politicking, they could oppose nuclear now... on the basis of cost.

Without any evidence people who make medicines and study viruses and develop policies to reduce and eliminate harm from infectious diseases are accused of deliberately making and releasing serious viral sicknesses. All the virologists and immunologists and other health experts are either incompetent or in on it? I went to school with someone who's ambition was medical research - never cheated on tests and never had to and would have been appalled at the idea of making diseases so some companies and shareholders make money. Frankly I think anonymous pseudo-experts casually passing around such toxic accusations is appalling - and the evidence of that is in our faces.

Energy efficient homes help but I don't have a problem with growing AC use, just with any growth of fossil fuel consumption to run them. And heat pump (including AC) technologies are amongst our most efficient. Building an abundance of clean energy helps whether homes are efficient or not - and that shift to clean energy is already happening, just not quickly enough. Similarly for Electric Vehicles; they are not a solution without a shift to clean energy sources to both build them and run them. It is not enough that people who care enough to voluntarily reduce their carbon footprint at personal cost, we need solutions that will work equally well with people who are extravagantly wasteful and don't care, ie our primary sources of energy all need to be shifted to very low/zero emissions so that everything flowing from that, including manufacturing and running AC and EV's, is very low/zero emissions. There will be real limits on overall economic prosperity but I don't see the shift to zero emissions as a primary limiting factor; on the contrary, failure to adopt clean energy will be a major factor that hurts our continuing prosperity as climate impacts become more pronounced.

I am not so interested in whether bioreactors and biofuels can work on the moon or Mars as whether it can help meet our near term and critical requirements for abundant clean energy here on Earth - but any technology to be used in space will have to be developed and proven on Earth first, so that isn't a conflict of interest. The advantage of PV is you just expose it to sunlight and it makes electricity. No moving parts, can be plug and play, is low cost and exceptionally reliable, and likewise for associated equipment. Available solar area isn't usually the limiting constraint, so energy yield per m2 is not a deal breaker; by all measures the yield from PV in most places is very good right now. There are biofuel successes but they tend to rely on the natural advantages of being on Earth - crops that grow readily in existing soils with natural rainfall, open ponds for algae cultures, availability of power and other supply. The concentrator type and other closed bioreactors are not as efficient and effective as claimed; the first link noted that getting tubular bioreactors from energy negative to energy positive is an ongoing challenge. Just the energy requirement for keeping the fluids well mixed seems to be a major hurdle. Failure to be energy positive is a big problem here on Earth, but would be a bigger problem on Mars. That doesn't sound like something that will make 5 times the energy production than PV to me. PV is demonstrably energy positive but biofuels from tubular bioreactors are not, which makes the claims of superior energy delivery look wrong. Not clear what nutrients would be required but sources will be essential. It doesn't look like any kind of plug and play kind of technology, but would need constant attention, ie farming. It is also not clear what the steps and requirements are between biomass or ethanol gain in a ferment fluid and usable fuels ie dry burnable biomass, diesel grade oil or distilled ethanol of purity suited to fuel cells but they will be there - at a cost to overall efficiency and energy output. In space you will need the Oxygen if you burn anything or use fuel cells; it may be from CO2 recycled, possibly by bioreactor, but in a closed system it will add yet more associated equipment and energy use. I like the enthusiasm for biofuels but it is a long way from being a replacement - let alone clearly superior replacement -for PV. Not on Earth, not in space.

I think people are making it more complicated than it needs to be. I think the "solution" to surviving past the death of the sun is developing the capability to make and sustain self supporting artificial habitats, using just the raw materials from asteroids, comets and similar that will give homo sapiens (and/or later homo speciations) the means. I suspect if we succeed in inhabiting anywhere off Earth it will be because we have are capable of most of that, but initially with the advantage of solar power. To be self sufficient without solar power - to have reliable fusion energy I suppose - looks like an important threshold to cross. A whole lot of technological capabilities are needed that we don't have and I think maintaining a healthy, wealthy Earth will determine if we get the opportunities to develop them. If we can be self sustaining with those kinds of primordial space resources... it's more than just a big solar system. It has a Kuiper Belt. Before we even get started on the Oort. The Oort of the next door stars after that?

Not any kind of expert here but I note that bread and booze are yeast based and whilst they can be interchangeable the bread yeasts are selected for high CO2 production, so bread rises, whilst brewer's yeast is selected for alcohol production as well as some CO2 for the fizz. Even so, some bacterial fermentation appears to be involved as well. Mostly they are considered a problem - including by turning alcohol into vinegar. Yoghurt is bacterial and whilst it produces CO2 the cultures used don't appear great for making alcohol, so maybe not so good for making booze. Some bacteria do make alcohol but I am not aware of any beverages that are primarily fermented with bacteria. Kombucha is apparently a combination of both yeasts and bacteria. Some fermented foods make do with natural bacteria and yeasts, without adding any specific starter.

If it is lasting centuries to millennia in soil it has to be resisting chemical compounding that consumes carbon. Activated carbon filters chemically combine with organic compounds by adsorption (making a film over the surface). My understanding is any reactivity is confined to the surface and becomes self limiting, which leaves the carbon beneath unchanged. Charcoal is activated by grinding it finely to make more surface area, for adsorption, which creates a protective barrier for the internal material - fine ground because it resists compounding once an adsorptive film is formed.

True, yet in the form of charcoal in soil it is quite stable and resistant to microbial breakdown. In boreal forest soils that can be hundreds to thousands of years. I doubt it lasts so long in tropical conditions but I only did a brief lookaround for relevant info. From "Charcoal ecology: Its function as a hub for plant succession and soil nutrient cycling in boreal forests" Sounds like it is more like a catalyst than a chemical "feedstock" in soil; it promotes biogeochemical processes without being used up. Porous, high surface area and adsorptive ie attracts and holds surface coatings of other materials and microorganisms. It's role appears very significant and complex, including promoting nutrient mineralisation .

Incomplete combustion leaves an abundance of charcoal and partially burned materials. Fires will reduce the amount of leaf and other organic material but increase the amount of charcoal in soils - so the premise that it is lost due to fires is actually the reverse of what happens in practice. Intense fires can eliminate most charcoal and burn with little carbon residue but that is localised. Charcoal has beneficial effects in soil, providing a framework that microorganisms take advantage of.