6 ms·
If we do the fusion in zero g then we have solved the confinement issue. The problem is creating conditions for fusion in zero g. The simplest way would probabl
by alkonaut 2y ago
If we do the fusion in zero g then we have solved the confinement issue. The problem is creating conditions for fusion in zero g. The simplest way would probably be aggregating enough material to a single spot that gravity itself creates conditions for fusion. But then the power plant becomes too energetic for earth so it has to be at an enormous distance away to be safe. And with that of course you have the problem of transmitting the power back to earth. But I think photons could be gathered at a safe distance from this fusion, to harvest it without having to be so close.
- AnthonyMouse 2y agoIf you only have one of them then the photons would only be available on that side of the earth at any given time and the other side wouldn't have power, but two of them would confuse the animals and disrupt everyone's circadian rhythm and then you'd have to deal with the three-body problem. Even the reactor-facing side would also have issues with the photons not getting through when it's cloudy.
- alkonaut 2y agoThe photons will also create heat and that heat can be used for useful work at any time, even when there are no photons hitting that side of the earth. For example it will evaporate water which will later condense into rivers, where you can put turbines. So it's a kind of fusion power, but less direct. Pure science fiction, of course.
- AnthonyMouse 2y agoThe energy density of gravity-based storage is very low, so it could work in places where you have mountainous terrain and a lot of cheap land, but what do you do after the sites suitable for it are already in use? To make that work you'd need a scalable storage technology with a low enough cost per kWh of capacity to economically scale to multiple TWh of storage in case it's cloudy for an extended period of time. For example, if you could make batteries at a price of $115/kWh, the cost for enough capacity to sustain the US power grid for a week would be around 24 trillion dollars, and that's just for the batteries and not any of the associated electronics or the land or the photon collectors themselves. It seems like to make your plan work you'd need a scalable storage technology with a significantly lower cost per kWh of capacity.
- pfdietz 2y agoUsing batteries for week-long storage is a bad idea. Lower efficiency, but lower capex, storage technologies like hydrogen would be better for that. Optimized combinations of batteries and longer term storage typically comes out to maybe 12 hours of batteries, sometimes less. We wouldn't need the hydrogen until the last few percent of the grid goes renewable; until then natural gas would be fine.
- AnthonyMouse 2y agoSuppose you have a 65% renewable grid which is then 35% natural gas, but it's dark and the batteries are empty. Being able to generate 35% of the load from natural gas still leaves you needing to make up the other 65% from somewhere. This is obviously worse if the grid is 95% renewable and 5% natural gas, but it's the same problem. To use hydrogen for that you'd need close to a TW of hydrogen fuel cells, and storage tanks to hold enough hydrogen to run the whole grid for a week, and enough hydrogen production equipment to refill those tanks in a reasonable amount of time if you had to use them, none of which gets used but once every year and a half. That might still be cheaper than a week's worth of lithium batteries but it's still not cheap when it's something you have to pay for on top of the generating equipment and batteries needed to run the grid on a normal day. And it still leaves you in a bad way if you had enough hydrogen for 7 days but the clouds persisted for 9.
- pfdietz 2y agoOh, and one other thing: a grid that is 35% natural gas doesn't mean you only have turbine capacity for 35% of the grid demand, it means that of the total energy put onto the grid, 35% is from natural gas. The peak NG could supply could be much greater. A 65%/35% renewable/natural gas grid probably doesn't need any storage at all.
- pfdietz 2y agoHydrogen would be burned in turbines, not fuel cells. A simple cycle turbine powerplant might cost $0.60/W. Remember, the goal here is minimizing capex, not maximizing efficiency. Backing up the entire grid with such turbines is a small cost compared to powering that grid with, say, nuclear ($10/W). A once-through steam cycle with steam generated by hydrogen-oxygen combustion heating additional water (save the oxygen from electrolysis also) might have even lower capex. The combustion would occur with water injection in a kind of rocket-like combustor, no heat exchangers needed. This is potentially cheaper because it avoids spending 50+% of the output of the turbine on the compressor. Hydrogen, like natural gas, is extremely storable, very cheaply, in underground storage formations. Nations typically store months worth of natural gas, and the volume could be greatly extended. Europe for example has the geology to store millions of GWh of hydrogen, and that's not even touching the salt formations under the Mediterranean.
- corimaith 2y agoThree Body Problems are only systematically unsolvable, you can still numerically calculate and manually move them with some algorithm.
- mock-possum 2y agobeam energy down to the earth from space? My god man, did you learn nothing from Sim City’s microwave power plants??
- alkonaut 2y agoI did some back of the envelope calculations for this and it turns out that almost all life will eventually evolve to have reasonable protection against it. Except in Australia.
- alwa 2y ago…is this an elaborate joke about solar power? And by extension, virtually all the energy that’s accumulated on the earth over the eons? It took me a minute :)
- alkonaut 2y agoI thought it was obvious but apparently not. Sarcasm is only funny when not tagged with the /s.
- spiderfarmer 2y agoA majority of the people on HN think there is an explicit no-humor policy. Judging by the fact that a lot of people here are genuinely confused when they come across something really funny, I can see why they try to pretend humor can’t insightful, useful or informative. It saves them from embarrassment.
- lanstin 2y agoI mostly read HN news for the laughs, although the odd technical insights posted by those that know is fun too. I don't know why I post, somethings just to dissipate negative emotions, sometimes to share a favorite anecdote. Sometimes to joke, maybe,? Although those are more likely to be closed without posting.
- mrguyorama 2y agoThe problem is that there are numerous people on HN that spew these insane takes fully sincerely A Modest Proposal is a lot less funny when you have people who really do believe we should eat babies to solve the Irish problem.
- ahazred8ta 2y agoOne teacher handed out sour patch kids gummy babies and had the students read A Modest Proposal. Really drove the point home. It was epic. https://old.reddit.com/r/Teachers/comments/1hz41n1/a_modest_proposal/m6owy4f/ https://old.reddit.com/r/Teachers/comments/1hz41n1/a_modest_...
- hghid 2y agoThere may also be a side business selling skin products to protect people who may be exposed to the radiation from this new reactor. Possibly people may even choose to vacation in areas of elevated radation, as it is likely to be warmer. Interesting...
- robertlagrant 2y agoAnd another side business selling tanning beds.
- deleted 2y ago[deleted]
- nkrisc 2y agoThe issue with that is how to direct the energy back to Earth, and then collect it. If you can’t direct it and it radiates in all directions then only a tiny fraction of the produced photons will reach Earth. Then you need to collect those photons in order to do useful work, otherwise they will just heat the earth. If the distance needed to remain safe is greater or less than geosynchronous orbit, you’ll need collectors all over the Earth as they won’t have constant line of sight towards the source and experience a “nighttime” of sorts. There is also the issue of atmospheric effects, such as high densities of moisture, absorbing or scattering the photons, reducing the efficiency of the collectors. So it could work, but the effective maximum capacity will always be quite limited and the overall process highly inefficient relative to the total fusion energy produced.
- rob74 2y agoActually you don't want the transmission process to be 100% efficient. If you really captured all the fusion energy transmitted (or even just the small part of it reaching Earth), all sorts of people would complain, trust me! But fortunately that fusion reactor has more than enough power to go around...
- _Algernon_ 2y agoThey wouldn't complain for long though
- nkrisc 2y agoIf only it were smaller and closer. We could make it smaller by using a force other than gravity to compress the matter. Perhaps a very strong magnetic field? If it was strong enough you’d only need a fraction of the matter.
- rob74 2y agoOTOH, the concept proposed by OP is already implemented and has been working reliably for billions of years with trillions of successful deployments, while this newfangled technology you are proposing still has to be demonstrated to work...
- fransje26 2y ago> If we do the fusion in zero g then we have solved the confinement issue. If me move the reactor close enough to the center of the earth, eventually we can get to zero g. We then also solved the confinement problem.
- UltraSane 2y agoThat sounds hard to meter and charge for.
- nxpnsv 2y agoTbh it sounds like that cure is worse than the problem…
- watt 2y agoTry building a structure around the fusion source: https://en.wikipedia.org/wiki/Dyson_sphere https://en.wikipedia.org/wiki/Dyson_sphere
- ManuelKiessling 2y agoIn Germany, we call this „Fernfusion“. It‘s actually working beautifully, and I‘m a happy customer.
- verisimi 2y agoLet's do it!
- palata 2y agoA huge fusion reactor at an enormous distance away... isn't that the sun? :-)
- PhunkyPhil 2y agoIt looks like ultimate goal of this is creating a self-sustaining fusion reactor approximately 1AU away from earth (for safety) and using photovoltaic arrays to absorb the energy... Ingenious!
- ZeWaka 2y agoThis truly is a miracle of modern science, something we could only accomplish in this day and age.
- iamgopal 2y agoThat's what OP was implying. Energy (..and its derivative global warming ) is just infrastructure and finance problem now onwards. Balancing grid, Moving power from sunshine area to non-sunshine area, storing some power at night, handling fluctuation all are more or less solved problem. Fusion is just research subject ( ..or for may be powering colony on mars ? ). ..... saying that, I hope our collective curiosity for fusion will take us to new inventions and space opportunities.
- FilosofumRex 2y agoyes, exactly, no need for any fusion reactors in space. Collect space solar energy and beam it back to earth via microwave radiation. Space solar is an old idea and the Soviets/Russians have worked on it since the 70's; and nowadays, like most other Russian inventions the Chinese are commercializing it. https://www.ft.com/content/2d43ed21-9f9d-4e90-a18b-ad46f0a4760d https://www.ft.com/content/2d43ed21-9f9d-4e90-a18b-ad46f0a47...
- dghughes 2y agoYou'd have to stick it in a lagrange point 1.5M km away though since just in orbit is not true zero G. Microwave energy transfer should work. That's what I like about the Helion fusion reactor design they don't use steam to power generators it's direct power no water or steam.
- moomin 2y agoI think you just invented the solar system.
- Fruitmaniac 2y agoI reckon Earth would need to be around 93M miles from the fusion reactor.
- peterlada 2y agoAbout 1 AU distance, right?