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Posts posted by MBobrik

  1. I could go on about you massively underestimating the advantage of interactivity while searching, and the diminishing returns of throwing more people at observing the same visual information, but this is more important, because it deals with end results of your approach.

    However, if we ever do develop the technology to send people beyond Mars, it's pretty likely that robotics, sensors, AI, and communication bandwidth will also have improved. In fact, I'm willing to believe that those areas will advance much faster than interstellar propulsion and manned spaceflight technology, which will make the decision to send people even harder than it is today.

    Sure. AI improved to the point where it can make all the decisions locally, which implies at least human intelligence. So we end up starting an interstellar civilization of not humans but sentient robotic researches, and thinking they will throw some bits of information our way, hoping they won't turn around and start treating us just like any other animal to research. To that I can only say, what's sauce for the goose, it's sauce for the gander. If we shall give up the rest of the universe to the robots, why to hang around and waste oxygen at all, and not replace us with robots down here too ?

  2. I wouldn't be so sure of that. There are multiple teams monitoring a whole slew of camera and sensor feeds transmitted by every camera, over nearly every inch of ground covered by a rover. What do you think they might have missed ?

    Trowing more people at it won't solve the basic problem of inadequacy of passively watching compared to interactively searching.

    If anything, a single driver who is concentrated on driving over the terrain would be less efficient.

    Why single driver ? why just driving by and not stopping to walk and look around ?

    Time delay is no big deal if you're going slow, and neither is bandwidth. Time is one resource that unmanned missions have plenty of. Again, there is no hurry, the rocks aren't going anywhere.

    except that the delay and bandwidth issues get more severe the further you go. Just slowing things down is practical on mars, maybe jupiter. But beyond that ? rocks may wait another billion of years, but the rover has limited life expectancy, and so have the humans operating it. So good luck with that strategy researching the kuiper belt and beyond.

  3. A rover doesn't notice anything. The people driving it do. There is no reason the driver inside an SEV would have more awareness than the driver of a robot, given the appropriate sensors. And there are also things that a robot's sensors might detect (especially if it moves at a slower pace) that a human wouldn't.

    Time delay, bandwidth. You don't notice, nor can you check as many things when you are (for all practical purposes) passively watching video feed as if you are actively moving around in real time, searching.

  4. Construction time is far longer with an nuclear plant however the main problem is lawfare.

    This is exactly the point I was trying to make.

    simple wells is far faster and will give money back pretty fast.

    I was talking about oil shale extraction. Which is almost as far from a simple well as it gets.

  5. I'm sorry, but did you just compare building a bunch of coal-burning boilers with the problem of mining, refining, and using uranium or another nuclear fuel safely? Germany basically had to weld some tanks and buy some coal. That's the extent of this particular infrastructure change. Don't get me wrong, its still massive on scale alone, but converting the other way, from coal to nuclear, is a whole another problem. There's a reason why steam power is early 19th century tech, and nuclear power is second half of the 20th.

    Well, the numbers tell a different story. Coal 2900 $ / kW installed, nuclear $5500 / kW installed. Which is surely bigger, but not that bigger as your description of tech level difference between "1800's coal burning boilers" and "hyperadvanced 1950's high tech" might suggest.

    Return from oil field is within months. Not decades. Completely different time scale.

    Seems unlikely because they got the same EROEI as solar panels. I don't think that oil fields are fast to set up and that short-lived.

  6. Germany is an edge case. Most pollution is produced by China and US. EU follows with notable gap. Politics is a huge factor, but even with the right policy, we cannot switch everyone over in just a few years.

    Germany shows us that a change of infrastructure is economically possible right now. Even though it demonstrated it by changing in exactly the opposite direction of what is needed.

    There is no other reason than political that Germany converts its nukes to coal and not in the other direction, and there is no other reason than political that prevents other countries from changing their infrastructure too.

    Sounds about right. Now consider that life time of a panel is about 20 years. So that is 3 years before it pays for itself.

    Now consider that the same number applies to an oil shale field ( or mine ? ) too. But we are all putting our money there, and nobody is saying that it does not pay out.

  7. So? If there is no substitute that proves more profitable than regular old farming, it would still be the prime method.

    If there isn't any more efficient substitute. However the bar is set very low with natural photosynthesis efficiency and inefficiencies of planting and harvesting on top of that.

  8. You still need to pump hundreds or thousands of tons of air through your system to extract tons of CO2. And that's expensive, both in term of energy and money.
    Why not use the plants themselves? Farm them in massive amounts, then process the biomass harvest into fuel. Why bother with inventing the industrial processes when one can make something else make it for him?

    The reason is that plant efficiency really sucks. 2-4 %

    - - - Updated - - -

    Now we run into the classic 'Food vs Fuel' problem. This would have solidified the position of the crude oil industry, since it needs less space than energy crops for the same net energy output.

    Or nuclear. Or solar in desert areas. Or wind turbines.

  9. There's a difference between 'chemically possible' and 'can be mass produced at an industrial scale'. For example, it's relatively straightforward to produce the oxidizer O2F2;

    True, I should be more specific. We are talking about something that plants do safely in their bodies at massive scale. So, methinks, it can be done at industrial scale too.

  10. Actually that land use doesn't sound that bad for powering the entire world - 24.4 million hectares = 244,000 sq km is smaller than Nevada and only a tiny fraction of the world's land.

    Look at his numbers. 165 GWh / year = cca 20 MW plant. There are already over 350 MW power plants that use the space and resources far more efficiently.

  11. I know what Fischer Tropsch is, I went to college where I studied those things.

    Yes, that particular technology does exist, but the viability of it (in terms of money, net energy gain and carbon footprint) depends heavily on every key of the whole production cycle and the actual way of usage.

    First, in my post I merely pointed out that, fischer tropsch is able to produce an adequate kerosene substitute. I was not talking about efficiency yet.

    Second, efficiency is a solvable problem. magnemoe above put even a concrete number - current technology would give us $120/barrel, which is not much higher than current oil prices. And I was talking about a hypothetical situation where all fossil fuels are completely banned, so competing with them would be a non-issue.

    Yes, and that means it can not be base load power. It can be intermediate to peak load source.

    We are talking past each other here. I was talking about producing synthetic kerosene for kerolox using rockets. It has per se no relation to power grid whatsoever. No base, intermediate or peak. It could happily dump out synthetic kerosene even completely disconnected from the grid. So why you are talking about grid load, like ... at all ?

    Well yeah, if you use a crapload of copper to make 1 m thick rods as cables and you don't care about coronal discharge, you could transmit a lot more, but is that viable?


    "HVDC requires less conductor per unit distance than an AC line, as there is no need to support three phases and there is no skin effect."

    " Due to the space charge formed around the conductors, an HVDC system may have about half the loss per unit length of a high voltage AC system carrying the same amount of power."

    Give me a few examples of such compounds.

    Uh, ethanolamine ?

    I'm talking about industrial processes, and you're sticking to semantics.

    If it is chemically possible then it can be made even at industrial scale, methinks.

  12. Long term, sure. But short term? We don't have operational mines in the state they need to be to produce required quantities of nuclear fuels.

    Do you know what the short term looks like for example in Germany ? Following Fukushima they are shutting down nukes and cranking out coal power plants and opening new coal mines like there were no tomorrow. All that building and mining effort could go into nuclear, instead of coal. As I said. It's all politics, and ultimately (patho)psychology.

    No, in the eighties, and even well into the 90's, solar panels flat out took more power to make than they could produce in their life time. Solar panels of 90s were effectively means of exporting pollution to China. Solar panels with net positive output are a very new thing. And yes, it still takes several years for them to produce power that went into manufacturing. Run the numbers yourself if you'd like. In some parts of Europe it can take up to a decade. It's better in sunnier parts of the world, but it's still years.

    From what I see, EROEI of photovoltaics is 6.9 which is comparable to oil from tar sands.

  13. We don't have infrastructure or readily available fuels for nuclear.

    Except that we have. Or could have. The only thing that is preventing us from doing so, is radiation phobia of large segments of the population.

    It takes several years for a single panel to generate enough electricity to cover energy used in production.

    That was true in the eighties. Current solar panels are far more effective. Not to mention the fact that all big solar power plants don't use photovoltaic.

  14. And that's the right approach for many problems, but there is very little CO2 in air, and lots of air, so you need a massive collecting area to do anything meaningful, and a cheap way to concentrate the CO2.

    Air is not like light, you don't need a fixed area. You can let a large volume blow through a small extracting apparatus.

    Capturing CO2 straight out of the exhaust of power plants and other big emitters is also an option, and here, big centralized works.

    When fossil fuels are banned there wont' be any CO2 producing power plants.

  15. I think what he meant is that big, localized chemical plants are not the right way to tackle the problem. And until we can have mass produce cheap and small fischer process devices, and handle the logistics of collecting all the "waste", it will be much easier to use biomass.

    The reason why we do "big, centralized" anything is economies of scale. And there is generally nothing wrong doing things that way, as long as it is the more efficient way.

  16. Again, the cellulose thing would require some serious calculations with variables and data we simply don't know here, so it's mostly speculation.


    But it isn't kerosene. It might seems like nitpicking, but details matter for engine performance.

    There is quite extensive research on tuning fisher tropsch to the desired product properties. Producing synthetic kerosene substitute is completely within capability of current technologies. Feel free to check it on the internet.

    good thing that driving fuel synthesis does not place the same demands on the source as power grid base load.


    Fuel synthesis, as opposed to base power gird load, which is constant, and the power supply has to keep up, can be stopped/ started/reduced depending on current power supply.

    HVDC won't work. We're talking about much larger distances.

    There is no upper distance limit for HVDC.

    CO2 is almost on the bottom of the energy well in our world and compounds that would harvest it are alkalis.

    There are many compounds that bind to CO2 almost reversibly, and can thus suck it out of air and release it in concentrated form to fischer tropsch input feed. So the energy cost of this step is not big compared to other steps in the process.

    We can't rely on chemical processes to salvage that gas. Plants should do it.

    Believe it or not, plants work internally by chemical processes ;)

  17. Processing cellulose to kerosene is impossible because cellulose is a compound, and kerosene is a highly complex mixture.

    Wrong. Any organic material can be partially pyrolyzed and then converted to hydrocarbon mixture via fischer tropsch.

    I don't say it is the most efficient, or even acceptably efficient route, but you can do it. And, if there will be no other carbon inputs it has to be CO2 neutral by definition.

    Solar power plants can not be base load sources and therefore can not be something very helpful.

    good thing that driving fuel synthesis does not place the same demands on the source as power grid base load.

    Basically all densely populated, and therefore the largest energy consumers are far away from deserts.

    HVDC, or convert it to fuels on site. Your choice.

    Where's the energy for chemically scrubbing CO2? We're talking about enormous energy requirements that would in the end produce net gain of CO2.

    We are talking about small fraction of the overall energy flow through the system.

    Solar electric and nuclear fission are absolutely uncomparable sources. The first one is valuable in certain regions of Earth for addition to the grid, and nuclear fission is energy extremely dense, reliable and rich source you can put wherever you want. It is absolutely the best source we have on Earth at this moment.

    That is my opinion too, but some people want to avoid the n*** word at all cost. So I say doesn't matter. If you think you can go without it, just go on, your choice. The only restriction is zero fossil carbon.

  18. Good point, though isn't that only on short timescales? On longer time scales forests do pull co2 out of the air, after all that is where coal come from?

    There are definite carbon sinks in the nature, though they are very slow acting. Peat bogs, carbon rich sediment burial ... unfortunately, the classic forest, nor agriculture, is not one of them.

  19. I was being serious when I created it, we as humans have a very hard century ahead of us and we are going to have to make decisions and changes on various things.

    Then we should start with the most significant things first. And space launches are ridiculously insignificant compared to other CO2 sources.

  20. Well I meant that you could plant a forest, that entirely offsets you co2 emissions and get the kerosene as per usual, which is presumably the most efficient method, from fossil carbon.

    Forest, after a short growth period becomes more or less carbon neutral. Reaching equilibrium and stuff. So to offset a steady influx of fossil carbon you would have to convert more and more of land to forest, restricting agriculture, and ultimately running out of places where forest can grow at all. But I ultimately wouldn't care how the CO2 neutrality would be achieved, so if someone wished to temporarily keep up launch rate by converting more and more area to forest, it would be his choice.

  21. What... Like wood? :D


    But more seriously... Why not just plant a forrest?

    Plant a forest and then process its cellulose to kerosene, or cover a desert area with solar power plants, scrub the CO2 from air chemically and then synthesize kerosene. Or replace solar with nuclear. Your choice. But no fossil carbon ;)

  22. But those "majority" have terrible lives, I say less people, better lives.

    I say more CO2 neutral energy sources and no need to reduce us to rural India quality of life nor reduce the population.

    Oh, and if I were really draconian, I would not ban kerosene fuel, I would just make mandatory that all carbon in it comes from captured CO2 from the atmosphere.