@perestroika - eviltoast
  • 14 Posts
  • 151 Comments
Joined 1 year ago
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Cake day: June 11th, 2023

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  • Why the water isn’t killing the fire?

    Could be anything from sodium to calcium carbide to fluorine. :) Sodium makes hydrogen with water, carbide makes acetylene with water, and flouride just oxidizes water by grabbing hydrogen away from oxygen.

    If the character’s plan is to try fascism next, I think they’re into fairly agressive substances. :P


  • While the article takes no solid position about the benefits and harms of alleviating global warming with solar geoengineering, it does correctly point out that discussion and governance of the subject is lacking.

    Some hypothetical examples:

    Case A:

    • a coastal country experiences increased storm surges, a large percentage of its population stands at risk, it perceives climate change as an existential risk
    • this country decides to engage in solar geoengieering to cool the planet, however its neigbours on higher ground don’t perceive a risk from warming, instead they fear that wind patterns could change and deprive them of rainfall
    • they accuse each other of violating each other’s rights, start a trade dispute and eventually make war

    Case B:

    • lots of people are convinced that efforts to control climate change by reducing carbon output have failed
    • they decide to go for solar geoengineering, but the predicted impact on food production is -10%
    • this affects the poorest of people most adversely, but there is no compensation mechanism
    • cooling the planet succeeds, but results in outbreaks of famine

    Case C:

    • lots of people are convinced that efforts to reduce emissions have failed
    • solar geoengineering allows to cool the planet to pre-industrial levels
    • does incentive to reduce emissions disappear now?
    • if the cooling effect is terminated, extremely fast warming may now happen

    Myself, I perceive this as a last resort. If reasonable measures don’t save the day, this is one of the less reasonable measures that could buy time. I would like people to research this, so that capability would exist. But I would not be easily convinced of the necessity of taking action, as long as alternatives remain.



  • I mean sure, if you’re at such extreme latitudes that you have months of total darkness, then solar will have a problem there. Maybe small modular reactors make sense for those niche applications.

    Currently, solar still makes economic sense, but from April to October. Lots of it was built rather fast, now the adoption is slowing since the grid can’t accept it everywhere.

    Consequently, summer is when oil shale miners rest and prepare for the next season.

    Since the goal is to get rid of mining oil shale, big plans exist to install a lot of wind power. Sadly, this has gone embarrassingly slow, and it cannot cover winter consumption, and there is not enough storage.

    As a result, some companies and building out storage, but only enough to last a few hours.

    …and in the next country southwards, there is a huge gas reservoir that could accept methane, enough to last the whole winter, but nobody has a good enough handle on methanation to renewably produce a considerable quantity and store it there. :o

    With regard to reactors, it seems likely that getting one would take 10 years and the local country here doesn’t even have legislation built out for nuclear power. They’re drafting it. Starting from zero is quite slow.



  • Machinery comes is varying width. I would guess a farmer needs to decide at some point - is the priority using a 10-meter wide tool, or is it OK to settle with a 6-meter tool, or even a smaller one.

    Basing on that, they’ll decide what the clearance between rows of panels should be. From an energy installation viewpoint, the shadow of one row should not cover another row during normal operating conditions. Assuming sun at 30 degrees elevation (“September on latitude 60”), the shadow of a fence that’s 1.2 meters tall will be about 1.75 * 1.2 = 2.1 m long. So from an energy generation viewpoint, one can pack things more densely than makes sense for farming.


  • Since 2021, nearly 4 full years, the world has closed less than 1% of active coal power plants.

    Closing will come later, when alternatives are widely available. What renewable energy does currently - at least here - is forcing those plants temporarily out of the market, especially during summer months and windy weather. The plants will exist and stay ready in case of need for well over a decade, maybe even two - but they will start up ever more rarely.

    Technically, the deal is: we don’t have seasonal energy storage. Short term storage is being built - enough to stabilize the grid for a cold windless hour, then a day, then a week… that’s about as far as one can go with batteries and pumped hydro.

    To really get the goods one has to add seasonal storage or on-demand nuclear generation. The bad news is that technologies for seasonal storage aren’t fully mature yet, while nuclear is expensive and slow to build. There’s electrolysis and methanation, there’s iron reduction, there are flow batteries of various sorts, there’s seasonal thermal storage already (a quarter step in the right direction)…

    …but getting the mixture right takes time. Instead of looking at the number of closed plants, one should look at the sum of emissions. To remain hopeful, the sum should stop growing very soon.


  • Also, costing €623,000 over three years sounds rather expensive for just 100m

    It’s hugely expensive, but I expect most of the cost to be in the wagon that lays panels down and picks them up - and could hopefully service a big stretch of railway (if it works). That kind of systems will cost a pretty big penny.

    I doubt if this project will “fly”, however. A totally horizontal solar panel at ground level is a far cry from producing energy efficiently.






  • The proliferation of a new technology typically doesn’t start from poor people.

    It starts from fanatics first. I built my first EV. It was crap, I cut it apart and sold the metal (environmental footprint: awful). Then I built my second EV. It drove around 10 000 km, but had to be retired due to metal fatigue (enviromental footprint: neutral at best, lesson learned: big).

    I bought my third EV on a crashed vehicle auction. New front axle, stretching the frame back to correct dimensions… I drive it every day, but it’s a crap car that I’d not recommend to my worst enemy. :) Environmental footprint: positive, I can produce fuel for myself from April to October. But if the same vehicle would be used by someone who doesn’t produce (or buy) renewable power, the footprint would be less positive.

    Anticipating the demise of my factory-made electric microcar, I am however building another EV. Again the footprint is negative, but I need information about how to easily manufacture one, and obtaining information has a cost in resources. :(

    Meanwhile, of course, truly rich folks buy fancy and electronics-laden self-driving EVs which some then proceed to crash or mishandle due to lack of clue. People are like that and it will stick out in statistics.

    IMHO: if they hadn’t bought an EV, they’d have bought another kind of status symbol and would have used it even more wastefully. What matters more is what the average person can and will do. And how do we influence the auto makers to produce less resource-intensive vehicles?


  • I have a solar panel that died. A piece or plywood flung by a storm went right through it, leaving a 30 cm “wound”.

    Well, to be honest, it’s alive, just weaker - the panel remains suitable for pumping water on the field during muddy season. I wouldn’t take a good panel to such a bad place, but this panel, I have no worries about.

    As for what happens when they really, really die - they get disassembled. The aluminum frame gets taken off and goes into metal recycling. Junction boxes go to where plastic goes - not a nice place. The glass and doped silicon go into a crushing mill, after which they get separated. The glass is easy to recycle, but the doped silicon is difficult to refine again to such a purity, so it likely won’t become a solar panel. But it’s a very small fraction of the panel’s mass.


  • Looking at the beatiful show, I cannot avoid thinking: “each of them a potential weapon”.

    So in fair weather, when communication is smooth and all navigation systems are working, it’s entirely feasible to coordinate a swarm of 10 000. Wow. :)

    Soon enough, they will be coordinating each other in the presence of electronic warfare, and swarms of 100+ fly already, so 1000 is the next step. Anyone doing air defense is probably designing energy weapons (lasers, masers, etc) at a pace approaching madness, besides making ever-cheaper drones.

    As for the environmental footprint - if each drone withstands 10 performances, they will probably save resources. :)




  • instead of powering the heat pump from the wall, the heat pump can be connected directly to a PV

    I have no experience with this exact combination. I know that “batteryless” inverters exist, but most of them are on-grid inverters. In that scenario, all that matters is monitoring your production: if you don’t want grid energy, you only run your system when your PV produces enough.

    Another type of batteryless inverters are “pump inverters”. Farmers seem to like them for pumping water from wells into water towers. A pump inverter can be configured to run at 50 Hz (or 60 Hz for North Americans) and 230…240 V (or 110 V for North Americans) alright, but it is not designed to power electronic devices, but dumb agricultural motors. There is considerable risk involved with powering a heat pump from a pump inverter, unless you find an exceptionally simple and dumb heat pump with very limited or resilient steering electronics.

    Efficiency losses are small anyway, but mostly happen during battery storage or when voltage needs to rise or drop considerably (e.g. a transition of 700 -> 24 V or 24 -> 240 V would cause a small efficiency loss).

    I’ve heard that a PV can directly power a compressor

    This seems unlikely as the compressor would have to be a brushed DC motor. That kind of motors don’t last long, they wear out their brushes. Long-lasting motors are brushless, and those generally cannot be run on DC power. For example, a “brushless DC” motor is essentially a three-phased AC motor, just its controller (full of smartness and MOSFET transistors) accepts DC input.

    If you have a good technical overview of your heat pump system, maybe you can locate a point where regulated DC can be fed into the system, but that would be hacking. Alternatively, maybe a niche market already exists for DC-powered heat pumps, e.g. for caravans, trucks or ships? But on niche markets, prices typically aren’t good for you. :(


  • Relays: my use for truck relays is switching on heaters in my thermal storage water tank. Not big ones, though - I use relays rated for 24V and 40A of current. Since they are old, I have applied a safety margin and only let 25 A flow through them, so each of them handles 24 x 25 = 600 W.

    As for using DC appliances: benefits do exist. If a household has a low voltage DC battery bank (some do, some don’t) then dropping the battery voltage a few times to power car parts comes with a smaller efficiency loss. In my household, DC appliances are used for lighting, communications, computing, cooling food, pumping water and soldering electronics. The rest goes via AC. I think a car air conditioner could cool some small storage room decently. With big living rooms, it would have difficulty since it’s a small device.


  • it would (as far as i understand with high school chemistry) be strictly more efficient to electrolyse rust directly

    I’m not a chemist either, but I do know a bit of chemistry.

    Typically, you need a solution of NaOH (sodium hydroxide) to directly reduce iron oxide in an electrolysis cell. If your iron oxide contains impurities, those may react with NaOH and ruin the fun. Also, if you have exposure to CO2, your NaOH will gradually degrade, producing NaHCO3 and losing potency.

    My impression: wet electrolysis is great for making high purity iron, but it would be hard to make it work for energy storage.