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Comment by scifibestfi | Hacker News Reader

Let's say they manage to scale this up. What effect would it have on humanity? Climate change is solved. What else?

Climate change has inertia so probably not solved by the time we have industrial scale fusion + would not solve the two other main anthropic activity related problems: biodiversity loss and depletion of natural resources

with unlimited cheap energy you can pull CO2 out of the atmosphere, produce hydrocarbons and pump them back into the wells

I don't know what the math looks like here, but there is waste heat in this, right? We could lower CO2, but "unlimited cheap energy" at the scale required to make a dent in climate change surely gives off a pretty phenomenal amount of heat. I wonder what the equation looks like for the overall effect on the planet.

my understanding of chemistry is poor, but presumably if energy is liberated from combustion, reversing that reaction requires energy

(with some input to kick it off possibly)

regardless, the earth receives 173,000 TW of solar radiation from the sun

we have a way to go yet

better yet... you can kep current hydrocarbon economy factories, vehicles, etc in operation by simply producing fuels from air. Wil be cheap enough. Hydrocarbons are a great, usable source of dense energy.

I really don't think all we need is cheap energy, it's still an economically unproductive thing to do, so you need a govt to tax people and use the $ to perform sequestration.

You need to build out the sequestration plants, maintain and run them, only one of those inputs is cheap energy. You need to move the carbon to a safe storage facility etc.

It's still a huge undertaking, but would be way simpler if we had cheap electricity (which it seems like we will get via solar anyways, carbon sequestration could probably be turned on and off as needed for grid conditions)

> You need to move the carbon to a safe storage facility etc.

fortunately we already have millions of holes we drilled in the ground to get the stuff we burnt originally

Carbon tax + cheap energy = people starting carbon sequestration companies to sell credits to polluters. As long as the tax is high enough we can reach close to zero net emissions.

I agree, but also you really need regulation with teeth around what is a carbon credit. The voluntary market for carbon offsets is pretty sketchy right now.

Cheap energy doesn't need to come from fusion, wind and solar are getting quite cheap, I suspect it'll take a loong time for fusion to get as cheap even after it's wall plug positive.

https://www.lazard.com/perspective/levelized-cost-of-energy-...

28 - 37 $/MWh for solar 26 - 50 $/MWh for wind

This includes the maintenance and operating costs.

Their estimate for maintenance costs of a pre-existing nuclear plant is 29 $/MWh. That means there are cases where it'd make financial sense to shutter a pre-existing plant to build a new solar array (obviously not all cases, the generation profile of nuclear is very nice for base load)

Fusion is 10 years away from being able to generate more energy than it consumes, how far away is it from being able to be cost competitive with solar & wind?

One could, but this is unlikely to actually be done unless there is an economic incentive, which is basically why everyone put the CO2 into the air in the first place despite knowing the consequences.

carbon credits and carbon trading were invented, what, twenty years ago?

Indeed, and look how effective they’ve been.

extremely effective indeed?

(where implemented)

with unlimited clean energy you'd be able to print carbon credits as a result of direct hydrocarbon sequestration

the economic infrastructure already exists today, but the cost structure doesn't work

Isn't the fact that they were not implemented part of the definition of their failure? Since it's supposed to be the backbone of the solution that allows the neoliberal model to continue without significant changes, the fact that it was not adopted is a clear indictment.

no?

my town's anti-dog fouling laws aren't a failure because there exist other towns that permit dog fouling

in terms of contribution to global emissions everything is dominated by Chinese growth

but that doesn't mean that it hasn't curtailed emissions significantly where implemented

That's not the point.

The fundamental appeal of these carbon schemes is that they can permit a theoretical decrease in greenhouse gases while keeping the current economic model alive and well. But despite being greatly amenable to the way things currently are, with few extra efforts or changes needed in comparison to other types of plans for the climate, they were not widely adopted at all.

The system these schemes were designed to save was unable to pick even the lowest-hanging fruit that could have potentially saved it.

So yes, it might work with unlimited clean energy, but if we have that we are already in a different arena altogether with entirely new problems and solutions and where carbon credits are unnecessary anyway.

The fact that the cost-structure doesn't work now is the indictment. Cost structures is how we got into all this mess to begin with. Saying carbon credits work is like saying a healthy lifestyle can prevent obesity. It's of course true on its own, but also fairly useless since the problem is that people are very resistant to adopting such a lifestyle.

> The fact that the cost-structure doesn't work now is the indictment.

given this entire thread is about a hypothetical future where we have unlimited clean energy I'm not sure why this is a problem

The subthread was whether the carbon schemes are effective. They are either ineffective because they do not fix the incentive problem, or effective in a context where they are no longer needed

it's my subthread, and it's explicitly about what I said.

Why, do we have unlimited cheap energy? Or the technology to pull out CO2 from the atmosphere at this scale yet?

IMO this is wishful thinking, and the wrong attitude to solve a problem that is right here right now.

We should focus on reducing emissions, not on hoping that a technology that is not yet proven will be available soon

EDIT: sorry for the tone, I just re-read what I wrote. Anyhow what I wrote still stands: we have no proof that fusion will ever bring unlimited cheap energy, if ever viable.

It poses many problems, from neutron activation of the blanket to energy extraction, problems that we don't know yet how to solve, to solve them in a economically viable AND with neutral carbon footprint... well seems just unfeasible to me (hope to be proven wrong). Therefore I might suggest to pursue more understood ways to mitigate the huge problem we have

Would depletion of natural resources be so much of an issue if we could use fusion to recreate them? (after all, they didn't come into existence by magic...) Biodiversity is a bigger problem given the sheer levels of complexity and our relatively poor understanding of exactly how we depend on the exact make-up of the biosphere. Most likely humanity could survive without it, but it would be a poor sort of existence - our bodies and brains evolved in tandem with the huge diversity of life around us and is optimised to thrive in that context.

Not all natural resources are renewable. Unlimited cheap energy would probably be more harmful to nature in the short term. Unrestricted mining, logging and human expansion.

This is why my primary donations are to bio diversity and endangered animal protection orgs instead of climate change.

My layman understanding tells me depletion of natural resources will be worse if we manage to find a sustainable source of energy.

Little effect I think. Fusion power can do little that fission power can't do already, which is provide "free" power after you look past the cost to build and maintain the plant. The best advantage of fusion power is the public perception is presently better.

Is the safety profile any better? Or is it just public perception?

The lack of major radioactive waste is a plus, only the pipes and stuff inside the core of the reactor will have radioactive elements due to neutron activation. The only waste from it otherwise is helium (and tritium, which is re-used in the reaction later).

isn't helium valuable? seems like a good "waste" to produce

Safe airships for all!

Yeah that's GP's point by the 'only'. It's 'waste' as in a byproduct.

It's part of the reason fusion's so sought after - it doesn't result in anything bad or that has to be carefully sequestered.

(Apart from extraordinary heat I suppose. Perhaps there's an argument the actual reactor would always be a pretty risky place. But any incident isolated at least, worst case a remote industrial building burns down beyond economical repair.)

The temperature is high but the amount of heat is no different than other thermal power plants. The atoms move very fast, but there aren't many of them.

Very little will be produced. Indeed, a fusion reactor may leak more He from its cryo system than it creates.

There are major differences. For one, in case of catastrophic failure, the plasma will dissipate, its temperature will drop and the fusion reaction will stop.

This. The hard part is keeping it going, not getting it to stop.

Also, if I understand correctly, the waste products are a lot less nasty.

> The hard part is keeping it going, not getting it to stop.

I'm rather glad that doesn't apply to the fusion reactor in the sky that we'll be fully dependent on for a while yet.

It's a lot easier to build passively safe fission power plants than any sort of fusion power plant.

https://en.wikipedia.org/wiki/Passive_nuclear_safety

In case of catastrophic failure, thousands of tons of radioactivated lithium hydroxide burn uncontrollably, the smoke producing drain opener in contact with mucus membranes and lungs.

(Lithium hydride. The resulting caustic vapor is lithium hydroxide.)

Doesn't matter.

Public perception > reality.

Look at hydroelectric. Terrible for ecosystems, decent number of deadly failures over the years, way better perception and less pushback from the public than fission.

Dams are being taken down at an increasing rate as it is recognized that the fisheries they destroyed are far more valuable than anything they produce.

The safety profile is better with fusion, but I think you underestimate how good the safety profile of nuclear is these days. We haven't had any significant incidents since Fukushima, but we upgraded the safety mechanisms of our nuclear plants a lot based on that experience. Nuclear is on a path similar to flight, were we started off with very risky airline travel and got to a point where you are more likely to suffer an accident on the taxi on your way to the airport.

Fission power is already the second safest form of energy production, after hydro.

At least one source saying hydro causes more deaths than fission:

https://www.businessinsider.com/dam-safety-statistics-risk-o...

And the worst power plant accident ever was Banqaio Dam, which killed 26,000 people immediately, and another 150,000 or so in the aftermath.

Don't ignore the fact that uranium reserves would not last 100 years if we used it as our sole power source.

That seems like an estimate on the lower side, but still, in those 100 years we should be able to at least move to thorium, no? Which could last a lot longer.

You should say "current" uranium reserves.

As demand goes up, so does supply, as additional reserves are prospected for and more costly uranium sources become economically viable.

There's not much reason to prove reserves if you won't be able to profitably mine them.

There is enough uranium on Earth for getting all our current power for millions of years. (source: wikipedia)

There just isn't much at current prices, but fuel costs are not significant so prices cam rise.

Linky? It seems preposterous to assume that we will be able to map the energy budget of earthlings over a thousand millennia.

If you're comparing with solar, it seems fair to assume a level of energy usage that could reasonably be supplied by solar. We're not going to cover the planet in solar panels.

With that assumption, fission can last for a very long time if we get uranium from the oceans, and burn it in fast reactors. The oceans hold four billion tons of uranium, and with fast reactors we'd use it a hundred times more efficiently than we do today.

I said "all our current power" and I mentioned my source.

Even with fusion, it's very clear that many politicians are afraid of it simply because of the word “nuclear” in it.

As nuclear fission, nuclear fusion might simply not be used because of that scary word alone.

It's possible that some Western countries will be that silly at first, but China certainly won't. Everybody else will come to their senses before long.

Long term, yes. But much of the climate change problem is decided in the next 25 years. Even if this reactor would work right now, building enough of them in that time frame everywhere, switching all industry and factories to electric, switching all transportation and cars and heating systems in all the houses to electric is very tough.

So it's still very challenging.

Exactly. I’d also add that climate change is a just a symptom of us reaching the natural carrying capacity of Earth for humans, so adding new ways of generating power doesn’t completely eliminate the issue.

Very true. Though an abundance of cheap energy may prove helpful in brute force engineering some other problems out of existence. I'm thinking of recycling and geo-engineering in particular.

Fusion cannot produce cheap energy, in any case.

Fuel cost is a substantial fraction of exactly none of the generation methods in use.

Can you explain what you mean by "the natural carrying capacity of Earth for humans". You framed this like it's something that exists outside of technology.

Peak everything is happening over the next little while.

Direct thermal climate foring is a couple of orders of magnitude out from current energy use.

Classical computing is almost finished.

Many minerals are at the point where extraction takes a rapidly increasing amount of energy per tonne.

Land used for grazing and agriculture is over half of habitable land.

Fishing is wiping out entire ecosystems.

It's time to think about moving earth to a steady state economy.

Climate change not solved. This is another in our long series of silver bullets.

Greenhouse gases retain heat. Sea level temperature is a function of ambient heat due to sunlight and other heat sources, minus the rate at which it dissipates into outer space, mediated by the insulation effect of the atmosphere.

Projects that try to reduce the carbon intensity of energy are focused on changing the denominator in the equation. The current aim of these projects is to produce a cheap and plentiful energy source, via a heat engine. What they are actually chasing, whether they admit it to themselves or not, is a cheap and plentiful heat source. If they succeed they change both the numerator and the denominator, which ends up partially cancelling each other.

Wind and solar are different because they tap into an existing heat engine, instead of trying to build a new one.

What we as a people need is a fusion plant that costs less per KWH than a fossil fuel power plant with tariffs to account for the cost of the carbon dioxide, but still about as expensive as a fossil fuel plant where the carbon is free. If we actually got a fusion plant that was 10x more cost efficient then we'll just introduce the concept of heat pollution to the conversation, swapping out the villain in the story but keeping the same outcome.

Are you saying the heat output of a fusion generator would be so great that it would impact climate change?

If you give people a generator that produces "cheap and plentiful energy"? Absolutely. Total world power dissipation increases as fast as they can build the plants. If we never produce another molecule of CO2 again we might be okay in that situation, but things like that don't change overnight.

edit: conclusion

edit again: I'm extrapolating from https://en.wikipedia.org/wiki/Jevons_paradox but didn't remember what it was called

Hardly. The amount of energy trapped by the atmosphere is vastly greater than the heat capacity we would wish to be able to produce, and the corollary - the amount of energy irradiated by the earth into space is vastly greater than amount of heat we wish to produce.

And it was balanced, so it doesn’t matter if it’s fifty terrawatts or fifty million. What matters is:

> The growth in Earth's energy imbalance from satellite and in situ measurements (2005-2019). A rate of +1.0 W/m2 summed over the planet's surface equates to a continuous heat uptake of about 500 terawatts (~0.3% of the incident solar radiation).[2][35]

https://en.wikipedia.org/wiki/Earth's_energy_budget

I found a chart that says we’re producing about 25,000 TWh per year of power now, or 2.9 TW continuous to put it in the same units. But what is the efficiency of those plants? 35%? That’s 8.3 TW of heat, which is already 1.6% of our budget surplus. If we dogleg our energy production while thinking it virtue signaling, that quickly becomes 5% of a number that is slowly cooking us. That brings doomsday in by years.

We can’t endlessly dump heat into the atmosphere any more than we can continuously dump mercury into the oceans.

In your equation above. The sun produces so much more ambient heat I imagine everything else is a rounding error. I highly doubt any number of fusion plants would affect global temperature.

Please check my math here https://news.ycombinator.com/item?id=32760914

I’m getting 1.6% of our heat surplus at present power production rates, and I’m saying what if we triple our power production because it’s cheap and clean now?

Wind doesn’t increase this number. Nor does hydro. Solar only does if the albedo is lower than ambient. Tidal… I wouldn’t even know where to start calculating that. Heat engines increase it by something like 300% of the power that gets to your light switch.

Still negligible.

Fusion and fission are bad ideas on their own merits, regardless of heat they might produce.

Rough order of magnitude calculation, the Earth receives about 1000W/m^2, that's 6370km^2 * pi * 1000W/M2 ~ 1e17W, and according to Wikipedia the global energy use of humanity is 7050 millions tons of oil equivalent per year so 7050 * 11.63TWh / 1year ~ 1e13W. So we have about 4 orders of magnitude of difference here. Does the human heat output make any difference? Probably not.

Adding some invented constraints on to the problem of nuclear fusion is the most bikesheddy thing I've ever read.

What invented constraints? We've been chasing nuclear fusion since long before we really cared about greenhouse gas emissions. We want 'cheap and plentiful power'. Greenhouse gas intensity is a recent addition to the set of goals. It doesn't replace the existing motives, and to claim otherwise is greenwashing.

This one:

> What we as a people need is a fusion plant that costs less per KWH than a fossil fuel power plant with tariffs to account for the cost of the carbon dioxide, but still about as expensive as a fossil fuel plant where the carbon is free

That the fusion plant can't be too expensive, or too cheap.

Heat pollution from power generation is a non-problem. We will run out of raw materials to build power plants out of long before this happens. This is what happens when people don't run the numbers.

Cheap energy means lower costs of manufacturing therefore lower prices for consumer goods, thus increasing quality of life.

There is no reason a priori to assume fusion power will be cheap. On the contrary, everything we know about it now suggests the opposite.

At least in North America, things tend to maximize corporate profits rather than maximize quality of life.

They are aligned, at least for those things where consumers are the purchaser.

Everyday goods becoming cheaper have significantly increased the quality of life of Americans. That trend will continue as energy becomes more abundant. Corporations can't monopolize profits on goods that are perfectly competitive.

What has decreased the quality of life, which offsets the above slightly and makes it appear as thought things aren't improving much, is goods that require domestic labor, such as education, whose price has outstripped CPI, and goods that have artificial regulatory capture which cause their price to be artificially high, such as insulin, and demerit goods such as opioids which detract from the utility of the customer.

Profits tend toward 0 in competitive markets.

Question is, how much will the kWh cost, all costs considered. And how much time does it take to build.

With the knowledge that comes out of building fusion power plants the next thing to build is fusion rockets.

https://en.wikipedia.org/wiki/Project_Daedalus

Not to be confused with USS Daedalus

https://stargate.fandom.com/wiki/Daedalus

Idk. If you want a steady stream of energy enough to power a small house, you can achieve that for $20k today with a big enough solar panel and a PowerWall. Fusion has to be cheap as well as effective.

> What effect would it have on humanity? Climate change is solved.

Not really. It'll just be another tool for the fossil fuel lobby to use to misdirect attention from what will make them irrelevant forever (reduction and sunlight).

Even if the reactor part is free and 100% reliable. Getting heat out of a 100 million degree chamber that is spewing neutrons everywhere and turning it into electricity is much much harder and more expensive than collecting some photons and building a train.

As the fossil fuel industry becomes obsolete, it would be wise to rebrand themselves into carbon removal and lobby for high payouts of carbon credits.

https://www.economist.com/the-world-if/2020/07/04/what-if-ca... (not sure how to overcome the paywall)

Archive gets around their paywall: https://archive.ph/Q9b6b

Pretty interesting article.

None.

We already have proven basically unlimited electric energy in the form of PV panels (and batteries if you need it stored). So far, that tech has not solved climate change at all, because actually building enough of these things is something that people need to be willing to pay for.

Terraforming, space exploration. On the compute side, running extremely fine grained simulations.

Each dollar diverted to this from building out renewables brings climate disaster, global civilization collapse, and billions starving, incrementally nearer.

There is no reason we can't do both.

Dollars are fungible. A dollar spent on X is manifestly not spent on Y, except by accident.

The money could come from somewhere else like say military budgets.

It might solve the greenhouse side of climate change, but you can't run away from thermodynamics. All electricity generated eventually turns into heat. Earth can only radiate so much heat into space in a given time period. If you generate more heat than Earth is capable of radiating, the planet warms. Don't start thinking that "free energy" from fusion reactors means that we can generate infinite power (as nice as that would be). It just means that the new negative externality would be heat itself.

The numbers say otherwise.

If we generated enough spare power to run lots of carbon capture equipment, and removed enough carbon, the planet would cool.

There are fantastic reasons to abandon fusion, and even better reasons to accelerate build-out of renewables, but that is not one of them.

Jevon’s paradox implies we’d have a brief respite, chronologically speaking, before having to tackle something like heat shedding.

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