• jatone@lemmy.dbzer0.com
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    4 hours ago

    moar energy! there will never not be an application for energy production. specifically fusion has the benefit of being highly dense large scale production. which makes it attractive on a number of levels.

    • skibidi@lemmy.world
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      4 hours ago

      Economical energy production, sure, not any energy production. There is a reason we no longer burn wood to heat public baths.

      I realize the science marketing of fusion over the past 60 years has been ‘unlimited free energy’, but that isn’t quite accurate.

      Fusion (well, at least protium/deuterium) would be ‘unlimited’ in the sense that the fuel needed is essentially inexhaustible. Tens of thousands of years of worldwide energy demand in the top few inches of the ocean.

      However that ‘free’ part is the killer; fusion is very expensive per unit of energy output. For one, protium/deuterium fusion is incredibly ‘innefficient’, most of the energy is released as high-energy neutrons which generates radioactive waste, damages the containment vessel, and has a low conversion efficiency to electricity. More exotic forms of fusion ameliorate this downside to a degree, but require rarer fuels (hurting the ‘unlimited’ value proposition) and require more extreme conditions to sustain, further increasing the per-unit cost of energy.

      Think of it this way, a fusion plant has an embodied cost of the energy required to make all the stuff that comprises the plant, let’s call that C. It also has an operating cost, in both human effort and energy input, let’s call that O. Lastly it has a lifetime, let’s call that L. Finally, it has an average energy output, let’s call that E.

      For fusion to make economical sense, the following statement must be true:

      (E-O)*L - C > 0.

      In other words, it isn’t sufficient that the reaction returns more energy than it requires to sustainT, it must also return enough excess energy that it ‘pays’ for the humans to maintain the plant, maintanence for the plant, and the initial building of the plant (at a minimum). If the above statement exactly equals zero, then the plant doesn’t actually given any usable energy - it only pays for itself.

      This is hardly the most sophisticated analysis, I encourage you to look more into the economics of fusion if you are interested, but it gets to the heart of the matter. Fusion can be free, unlimited, and economically worthless all at the same time.

      • humanspiral@lemmy.ca
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        2 hours ago

        The nuclear industry likes to say that its uranium costs of energy are under 2c/kwh. There are operations costs, unpaid security and insurance. The biggest cost factor of nuclear is, with Vogtle as latest example, capital costs of over $15/watt and 10+ year construction phase. This is completely unbankable, and requires taxpayer advances + subsidies, Even if you hope that construction time financing is included in the $15/w, 5000 revenue hours/year needs to pay 6c/kwh to pay for capital costs at 0% interest rates/ROI over 50 years. With 8% ROI, an extra 24c/kwh in revenue is needed. You only get your revenue hours if all other cheaper energy is suppressed.

        Fusion will have higher capital costs than fission. The 2c/kwh “fuel cost” is irrelevant to the cost of energy from the plant.

        • skibidi@lemmy.world
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          57 minutes ago

          Yes, of course, there is financing and everything else. I was getting a bit deeper:

          If you have to spend 100 joules building a power plant, it better give back more than 100 joules during its lifetime - otherwise it was never worth it to build. That isn’t strictly true, there are special purposes, but certainly as a grid-scale energy deployment you would need - at a bare minimum - for each plant to pay for itself in terms of energy investment.

          The dollars follow from that physical reality.

          The first hurdle for fusion to clear is that the reaction outputs more energy than it needs to sustained. This would be a great academic success, and not much more.

          The second hurdle is that it outputs enough energy such that it exceeds the sustainment energy even after accounting for capture losses (e.g. from neutrons, turbine efficiency, etc.) and production efficiencies (lasers need more energy input than they impart to the reaction chamber, magnets need cooling, etc.).

          The third hurdle is that over the lifetime of a plant, it produces enough excess energy to build itself and pay the embodied costs of all maintenance and operations work. If the reaction is technically energy positive, but you need to replace the containment vessel every 48 hours due to neutron embrittlement, then the plant better be productive enough to pay for refining all that extra steel.

          The fourth hurdle is then that it produces more excess energy per unit of invested energy than any other form of power generation - at which point we’d never build solar panels again.

          These final hurdles are in no way guaranteed to be cleared. Artificial fusion needs to be orders of magnitude denser than natural fusion (Stars) to make any sense… a fusion power plant the size of Earth’s moon, with the same power density as the Sun, could only power around 1 million US homes.

          • humanspiral@lemmy.ca
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            32 minutes ago

            a fusion power plant the size of Earth’s moon, with the same power density as the Sun, could only power around 1 million US homes.

            Capital costs alone are prohibitive.

            TIL/google ai:

            The power density of the sun at its core is about 276.5 watts per cubic meter ((W/m^{3})). This is similar to the power density of a compost pile, but lower than the power density of an adult human’s metabolism.

            ok. wow. But solar energy reaching earth can be converted to electricity by commercial PV at 250w/m^2. Even in US installed at under $1/watt with 50 years of useful output, and under 2c/kwh unamortized energy costs. That seems like the actual bar to pass, which is impossible for fusion or fission.

      • jatone@lemmy.dbzer0.com
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        3 hours ago

        oh boy another economics dweeb who thinks they know what theyre on about. those were a lot of words for a false premise. There is no doubt that fusion can produce more energy than it costs to maintain. we have literal empirical examples of this occurring in nature. You forgetting a significant factor in your analysis: time.

        The problem with fusion isnt the science behind its energy production. its the engineering behind the design of plants, unfortunately for fusion it suffers from being fairly unique in that its a high radiation, high heat domain which makes the engineering incredibly difficult to get funded and there isnt anything else comparable to piggy back off of. That’s currently your C value and those costs are one time. solar and wind also suffered from this for decades. fortunately those tech could piggy back off discovers in other domains.

        The cost of fusion plants and the energy production they’ll eventually unlock will disappear soon as we figure out the containment issues, and we’re getting close. the reason you’re hearing about fusion more and more is because we had a break through in 2010 on superconductors allowing for stronger containment fields.

        We’ve probably spent less than 500 billion globally on fusion research over the entire lifetime of the field. the ‘C’ value is actually remarkably low economically speaking for the return we’ll get.

        • skibidi@lemmy.world
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          2 hours ago

          I encourage you to seriously engage with the topic and not just read and regurgitate platitudes from popsci articles.

          Solar and wind are nothing like fusion.

          Educate yourself, but first maybe pause and spend a second to think that perhaps you aren’t the smartest person in the room and you shouldn’t begin a discussion by speaking down to someone.

          When everything hard looks easy, it is a sign you don’t understand it as well as you think you do.

          Just some advice for you as you grow up.

          • jatone@lemmy.dbzer0.com
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            1 hour ago

            Oh child, you’re the one who walked into this conversation with a grade school take. Ive worked on software for these systems before i retired from the industry last year.

            I never said solar and wind were anything like fusion beyond they’re all used to generate power and varying ranges of energy density per area. But I’m certainly better grounded than you in both the economics and ongoing challenges with fusion.

            If you want people to take you seriously maybe don’t start the conversation with a grade school take on the situation and you wont be dismissed.