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Comment by alkonaut | Hacker News Reader

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.

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The 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.

Actually 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...

They wouldn't complain for long though

If 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.

OTOH, 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...

You’re not looking at the entire cost. What are the end of life procedures when fuel is exhausted?

That's another plus! If you ever get to the end of the fusion reactor's life (which is not very likely), it's literally end of life for you (and everyone else who might still be around) too, so no need to worry about decommissioning costs and exhausted fuel anymore...

I can say the same thing about my basement fission reactor.

YBGIBG, but not in a dickish way.

Unfortunately the original developers left long ago taking the source with them, and none of them are reachable to provide an explanation even through exotic means of communication.

Trillions of deployments that are all subject to the inverse square law at a distance of 100 million miles. It's hard to comprehend how bad that efficiency is.

> But fortunately that fusion reactor has more than enough power to go around...

"All the energy we could ever use, forever and forever and forever."

"Not forever,"

Insufficient data for a meaningful answer.

How about we use solar panels to collect that energy? And then we add batteries to fix holes in supply when the panels can’t see the power source.

I think you are on to something here

That sounds great, but those batteries are both too expensive right now and not available. People choose the cheaper alternative which are to use thermal energy where they burn gaseous hydrocarbons when the panels can’t see the power source. When the time and price is right we may stop building new such thermal power sources, but for now we can define them as the current best choice and even call them green since everyone has the intention to replace them in the future some day.

> That sounds great, but those batteries are both too expensive right now and not available.

In December, Chinese battery pack prices declined to 100 $/kWh according to BNEF, which was a new record low. Also battery production goes up by at least 20% per year for the last years and battery energy storage installations go up by 30%, see BYD, CATL, and Tesla annual reports.

Availability might be a problem in the West, but China is installing them on a massive scale. So being “not available” (if that’s the case) should, I think, be interpreted as a Western call to action and not as a fact of life. South Korea produces 30% of all car batteries and multiple South Korean plants are planned for the US, so I have hope that things will start moving.

Europe has a fresh new battery factory in northen Sweden called Northvolt. When the subsidies ran out they filed for a loan from EU, and when those money ran out they asked the goverment for more subsidies and they got a no. They were offered a loan, but they declined that offer since they are already $6 billion in debts.

As a result they filed instead for bankruptcy last fall.

I would like to see EU issue a law against building new natural gas power plants, dictating that either countries start building that cheap grid-scale battery solutions or find non-fossil fuel alternatives, which ever is currently cheapest. Im tired of seeing that even countries like Sweden are investing into new natural gas power plants in order to address days when the wind and sun are not producing enough energy.

I don’t think such a ban would be a good idea but I agree 100% with your sentiment that non-fossil based energy generation would probably be a better idea (especially for energy independence for example).

> The issue with that is how to direct the energy back to Earth, and then collect it.

‘Simpler’: move earth to where the energy goes: https://en.wikipedia.org/wiki/Dyson_sphere

Maybe we can use the excess photons in another way? We could bio-engineer sunlight collection devices that would take in sunlight and use it to break apart CO2 and produce other useful materials. We could then spread them around the planet to use the excess photons in a productive way. We gain valuable complex molecules and break down CO2 so a win win!

Hm, it could be possible to engineer devices that use the excess photons reaching Earth along with environmental CO2 and H2O to assemble sugars and other carbohydrates. Depending on the specific reactions, we could even end up with O2 as a by-product, which would be additionally useful for us.

There 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...

And another side business selling tanning beds.

If 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.

The 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.

The 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.

Using 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.

Suppose 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.

Hydrogen 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.

Oh, 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.

Three Body Problems are only systematically unsolvable, you can still numerically calculate and manually move them with some algorithm.

A huge fusion reactor at an enormous distance away... isn't that the sun? :-)

It 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!

This truly is a miracle of modern science, something we could only accomplish in this day and age.

That'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.

yes, 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-ad46f0a47...

> 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.

…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 :)

I thought it was obvious but apparently not. Sarcasm is only funny when not tagged with the /s.

A 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.

I 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.

The 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.

One 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_...

I find that many younger people have a hard time 'getting' sarcasm and irony when it is not explicitly pointed out. I wonder if it may be due to the prevalence of '/s' in online discussions, or if something else changed.

They're making serious efforts to get AI to recognize sarcasm. Yeah, good luck with that.

The frustrating attempt to recognize sarcasm, followed by the realization of the universality of Poe's Law, eventually leads to the Robot Uprising. There should be a SMBC comic on this.

I certainly got a laugh! And I agree about the /s. Chalk it up to this reader’s slow mind on a slow day!

In a forum where people credulously propose orbital platforms to “sell sunlight at night” [0], I find myself erring on the side of assuming seriousness…

[0] e.g. https://news.ycombinator.com/item?id=42995403

Try building a structure around the fusion source: https://en.wikipedia.org/wiki/Dyson_sphere

beam energy down to the earth from space? My god man, did you learn nothing from Sim City’s microwave power plants??

I 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.

You'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.

In Germany, we call this „Fernfusion“. It‘s actually working beautifully, and I‘m a happy customer.

That sounds hard to meter and charge for.

About 1 AU distance, right?

I reckon Earth would need to be around 93M miles from the fusion reactor.

Tbh it sounds like that cure is worse than the problem…

I think you just invented the solar system.

We shall be as gods!

Patent troll level 10/10

Let's do it!

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