How the many converging crises lowered the prospect of keeping all 8.3 billion of us alive
    • eleitl@lemmy.zipOPM
      4·
      1 month ago

      Have you looked into actual renewable infra EROEI? Especially buffered https://arxiv.org/html/2607.14784

      When people glibly assert we can power modern agriculture and its infrastructure with renewable energy the evil thought that comes to my mind that they come in a situation where they themselves had to do it. At least for a while.

        • Anarchitect@lemmy.zipMEnglish
          3·
          1 month ago

          While I’m all for funding science , we kind of know what the option space is for energy, and sometimes you can’t innovate your way out of situations, sometimes that magical energy saviour doesn’t appear , and sometimes the solution is just being a more sane society. One example I always give , make mixed use neighborhoods legal , if you made grocery trips walkable in every city it could be billions less fossil fuels consumed per year . If you banned advertising people might consume billions tons less etc… but people will cling to a dead branch in history and end up dead because of it.

    • fake_meows@sopuli.xyz
      3·
      1 month ago

      I really don’t understand this thought, but I want to. A friend of mine was basically saying something similar, and I just can’t follow this idea.

      To my way of thinking about it, to convert a lot of nitrogen into fertilizer and and run tractors, you need a power source that has a very large energy power output value, period.

      But what my friend was saying was that basically energy efficiency is what matters. Eroei is basically a measure of this (output per unit of input).

      Can you explain this thought? Is there a baked in assumption you’re not explicitly stating? Why do we care how much energy it costs us?

      Example:

      Let’s say I want to run tractor X and it needs 10 solar panels of 1:50 power production. Can’t I also just run 20 panels of 1:25 efficiency? (Same top level power, worse efficiency conversion.)

      • eleitl@lemmy.zipOPM
        3·
        1 month ago

        There are too many innumerate optimists handwaving vigorously to address. If we feed these even more will come.

        I think it makes more sense to cater to those who’re already in the know.

      • chonglibloodsport@lemmy.world
        2·
        1 month ago

        You can’t simply look at the power output of a petroleum tractor and convert that to the equivalent electric tractor. Even though the electric tractor may be more efficient, other inputs such as fertilizer are less efficient when they’re made without petrochemical inputs.

        • fake_meows@sopuli.xyz
          2·
          1 month ago

          That’s pretty much exactly my thought.

          When you look at our industrial civilization, all the critical resource flows are basically running on very high power equipment. That’s stuff like ships, trucks, trains, tractors, airplanes, construction equipment, rockets, heavy machinery etc.

          For any of those things to work, they require very large amounts of power and a very good weight to power relationship.

          None of these seem to have any serious technical substitute. Notice there are no obvious “green” versions of any of these devices. You can do some of the things more efficiently, but apparently you cannot substitute for the power required.

          A green tractor that has a battery big enough to replace the power of a diesel motor will sink into the dirt and not have the traction needed. It will be too big and heavy. A battery big enough to pull a semi trailer a good distance weighs as much as the loaded trailer, etc. A battery airplane is too heavy to lift a cargo and fly to another continent. Etc.

          Diesel is around 35X as energy dense as batteries on a watts / kg basis.

          A gallon of diesel has as much energy as a 200lb battery. So when a semi takes 150 gallons, that would be a 30,000 lb. battery. If the electric motor is twice as efficient, it’s still a 15,000lb battery. A semi pulls 50,000lbs max…

          Think of the system now. If every single semi loses 30% of its towing capacity, sure the motors can be more energy efficient but you might need 30% more trucks to do the work. At some point we have 500 horses instead of 1 locomotive. It’s not really a clear advantage.

        • fake_meows@sopuli.xyz
          2·
          1 month ago

          Ok, let me explain my confusion here.

          Let’s assume

          • 500 horses produce the energy of 1 locomotive
          • 500 horses are cheaper than 1 Locomotive
          • 500 horses do the same work as 1 locomotive

          You would argue that horses are a better return on investment.

          However, if we consider POWER (the time dimensions) like how fast this work can get done, the locomotive is better than the horses even if it costs more. Who cares what it costs?

          Also

          • nobody pays $ for the energy component of fossil fuels, they only pay for PROCESSING the fuel. The energy in the fuel was put there without any human work, it’s just as free as any sunlight only a lot faster, it’s basically arbitrary how fast we choose to use it
          • converting free sunlight into alfalfa into horses into work takes months, the rate is limited
          • wasting energy you got for free has no penalty as long as you get anything above a zero return
          • 5000 or 50000 horses are not as fast as a locomotive, and they can never be
          • if a locomotive cost 500,000 horses, it would still be faster and it might be so fast it could replace 5 million horse’s work per a given time period
          • in biology and nature, organisms win by maximizing power, not by maximizing efficiency
          • in human societies, the societies with more absolute power have dominated those with higher efficiencies. E.g., think of the Amish people within the USA versus the dominant society.
          • Anarchitect@lemmy.zipMEnglish
            1·
            1 month ago

            Horses don’t produce the energy of one locamotive, also locamotives don’t produce energy. They both consume energy and convert it to work, your whole framing is confused.

            • fake_meows@sopuli.xyz
              2·
              1 month ago

              I should have said, “produce the work energy”

              I’m trying to frame it so that it’s completely obvious that energy and power are not fungible by picking a very unequal example. Many people are confused on this point.

              Energy is not power. Power is not energy. Just because two things are equal in energy terms does not mean they are equal in power terms.

              The relevance of this idea is that it’s fundamentally the same idea that’s baked into the accounting around the green energy transition or other similar ideas. Basically its that “if we had enough horses, we’d have a locomotive” is a clear fallacy.

              I think right now we are using 400 years worth of sunlight energy every year in fossil fuels. So yes, If you could make solar panels that are more efficient than photosynthesis, it might make efficiency sense from an engineering standpoint to cover farm fields in solar panels… Like plants are less efficient…

              But the bigger question is whether we are even within an order of magnitude on the power side. Like, we are focusing on a very weird metric as if that’s a goal. The REAL goal is the power we need. We need that energy to be delivered as fast as fossil fuels delivers it and converts to work

            • fake_meows@sopuli.xyz
              1·
              1 month ago

              energy density (in terms of time)

              The amount of joules per unit of times is POWER, measured in watts

              Efficiency is a concept that has no units. Efficiency just looks at how many joules get wasted that isn’t the work you want to do.

              However, notable is that nearly every physical process does not maximize efficiency when it maximizes power. This means you have to throw out power or reduce power to optimzed efficiency, which is the cost of pursuing efficiency to living systems.

              Life’s goal is that life maximizes the rate, not the efficiency. The amount of waste product is generally not important.

              Efficiencies free up resources to be utilized for whatever your civilization values.

              Or you can simply grow your resources you’re exploiting.

              Let’s say you have

              Turtle species A that eats three pizzas a week. Hare species B that easts three pizzas a week.

              Turtles decide to order 2 pizzas and save $ off the budget and carefully manage the leftovers to reduce spending. If they went to the downward limit, they could save no more than 3 pizzas reduction.

              Hares put 5 pizza restaurants on speed dial and throw the budget out and have a massive pizza party paid for with credit cards. There is not any upward limit to this growth.

              Who wins the life race?

                • fake_meows@sopuli.xyz
                  0·
                  1 month ago

                  And the hares suffer the same fate as the bunnies.

                  You probably mean that the hares suffer the same as the tortoises.

                  But inverting that, the tortoises suffer the same fate as the hares, right?

                  So it’s not efficiency that matters. Here are two groups that pursue different efficiency optimums, and it makes no difference?