Fusion power: a short-term blessing or long-term curse for the environment?

I’ve been listening to some science podcasts lately about the advancements in fusion reactor research. Closer, closer. But still no cigar.

But the cigar would be so big. Virtually unlimited energy from these little manmade ‘stars’. Low cost, energy with… well, waste management? A lot depends on the winning tech design. But it would be a different problem than burning ancient carbon dumps.

With cheap, unlimited energy through fusion, we would undoubtedly have a great incentive to eliminate fossil fuels for power forever, in terms of climate change action. But my question is this: if electrical power is made cheaper with fusion, will efforts to conserve its use lose appeal, and perhaps more critically… will ‘unlimited’ electrical energy through fusion actually create even greater waste atmospheric heating because… well, thermodynamics?

It’s more of a behavioural question. If human activity becomes more dependent on increasing energy-use density (in terms of kilowatts/year/person), my bet is that even if we manage to severely reduce emissions with fusion technology, we will be unable to resist or control our lust for increasing our power demands and end up dumping even more thermal radiation into the world which we thought we were saving with this tech.

Or is that a problem for those infamous ‘future generations’ to worry about?

Can humanity be trusted to manage ‘unlimited energy’ responsibly?


“There are no solutions. There are only trade-offs.” ― Thomas Sowell


I know too little on Nuclear stuff. I scored a D in O’level physics. Current Nuclear plants have been a source of problems. Using Fission. There is one man-made isotope of a substance which is said to be very problematic. Fusion is new technology which status is unknown. Probably trying to secure capital funding through mass media. There are always some ventures going on, virtualcoins, spaceflights and stuff like that. Some are gimmicks.
Perpetual motion machines are hoaxes which have some examples in history of science. I do not have the knowledge to call something a hoax, because I know too little, but sometimes we have to watch out for some variants of it.

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I absolutely agree. This has been exactly my thinking for decades. More than technological progress, we badly need a cultural evolution which still seems so very far away. In the words of the late great Edward O Wilson: “We have created a Star Wars civilization, with Stone Age emotions, medieval institutions, and godlike technology. We thrash about. We are terribly confused by the mere fact of our existence, and a danger to ourselves and to the rest of life.” No other comment is necessary.


There are two different types of “heating” that have to be distinguished. The one you get from increase energy use, regardless of the source, is application of more heat into the environment. The other is alteration of the environment such that it retains a larger proportion of the heat that enters it. Burning fossil fuels heats the atmosphere in both these ways, while fusion would only heat the atmosphere in the former way. The increase in energy usage with fusion would have to be very great indeed, by order of magnitude, for the transition you discuss to result in more heating than sticking with our current energy mix. There are several quantitative analyses of this question easily found online. Additionally, burning fossil fuels has other disastrous effect, such as ocean acidification, which would be lessened by moving to fusions.


About the increased waste heat if we have cheap fusion electricity, my gut reaction is that a lot of it might radiate into space without a high concentration of greenhouse gases to trap it? But I am not a physicist so I have no idea.

I’ve personally been more worried about what we do with that extra energy. We could move mountains, desalinate and pump huge amounts of water, and completely transform the earth’s surface, which I think would hurt biodiversity.

Honestly, I think that’s a problem with a lot of green technologies that isn’t talked about enough. Cheap solar and wind and hyper efficient EVs might also cause us to use more energy and drive more if we don’t limit ourselves. I do think renewables and electrification are great, but they won’t help with problems like habitat loss, resource overextraction, and waste. They might even make those issues worse if not implemented wisely.

This article on Jevon’s Paradox has really changed my perspective: https://www.newyorker.com/magazine/2010/12/20/the-efficiency-dilemma. And the website lowtechmagazine.com has also influenced me a lot.

I feel like it’s human nature to pursue new technologies and exploit them, which has the unfortunate side effect of damaging our planet. I agree with you and @lynkos that we need to learn how to use technology more responsibly, rather than expect the newest technology to magically fix the problems of the previous technology.

Sorry for my rambling thoughts…


Current nuclear plants are the best energy source we use now, cleaner than what is considered “green” energy.


Agreed. The current “green” political mentality is what is holding us back. It’s time for a purge.

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To my knowledge, the issue right now is that we don’t have fusion reactors that are efficient enough to be viable. You have to pump in a lot of energy to get the fusion reaction going and to keep it contained, and right now that energy is more than what the reactor produces (Energy that most likely isn’t coming from clean sources). Even though fusion puts out a lot of energy, you really do have to essentially heat the reaction to the temperature of the interior of the sun to get it started. On the plus side, there’s no waste byproduct like with nuclear fission. All the atoms you put in are basically broken down to their subatomic components, and the only things that come out are EM radiation (including heat) and your fusion product (for hydrogen fusion, that means helium, which we need badly. There is a shortage, especially of helium-3. The supply is strictly controlled entirely by govt. entities, though the US did recently sell off the remainder of its strategic helium reserve). Additionally with the temperatures reached by fusion reactors, you can break down just about any toxic substance you care to mention. A fusion incinerator could even break down PFAS, the so-called ‘forever chemicals’. We are VERY limited in the things we can achieve by the amount of power we can generate. Hopefully someone will come up with a viable, self-sustaining reactor design in the not too distant future.

Wow, that’s quite a conclusion to jump to. I’ll point out that solar (a leading ‘green’ energy source), is, in fact a form of fusion power. It’s just coming from much farther away and most of it can’t be harnessed because it’s not radiating toward Earth. However, if we want to harness fusion power (in all parts of the EM spectrum) we’re going to need technologies that arise from solar power research. I agree that there should not be such a stigma against fission power. However, there are also many places where fission just isn’t viable or isn’t safe enough despite all our efforts to make it so (The Fukushima plant springs to mind). Shouldn’t we try to find a better alternative to carbon-generating plants that work for these places, too?


if we want to harness fusion power (in all parts of the EM spectrum) we’re going to need technologies that arise from solar power research

Why? The way fusion reactors would work is by direct heat exchange, like any other kind of thermal power generation. The whole reason we have so many issues with solar power generation is that the sun is too far away to effectively heat substances, although simple thermal methods like a Stirling engine or CSP are still way more efficient than photovoltaic. There would be no reason to use any kind of solar panel when the heat source is right next to the user (not to mention the fact that they wouldn’t be able to withstand the sheer amount of power being pumped into them).

A few things here.

  • It’s not unlimited energy, not by a long shot.
  • Energy use in and of itself is not a bad thing, it’s what and how that energy is used and how it’s acquired that are the issues.
  • Even as we become more energy efficient our total consumption for energy continues to rise, and that is a need that is not going away, no matter how efficient each piece of our technology is, and it’s a need that is going to be met one way or another, regardless of the cost or impact it has.
  • Fusion power is an extremely clean power source, much more so than the majority of ‘renewables’ (this is actually true of nuclear - fission - as well, but there is a lot of fear and misinformation about it that clouds the discussion).
  • Most ‘renewable’ energy production methods are extremely high impact when done at scale. While the power source may be renewable and ‘green’, the production, installation, and ongoing replacement of the systems necessary to harvest energy from most renewable sources is anything but renewable or sustainable, although they are all better than fossil fuels in almost all ways.

Fusion power has the potential to be literally a life saver and ecosystem saver, if it is used in a responsible way, and if we ever get past the, “fusion power is 10/20/40 years away” cycle that we have been in since the 1950s.


That’s a terrific summation, right there. Great quote! Thank you.

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If we have cheap, green energy, why should we care about conserving it? As other commenters have pointed out, the thermal heating issue seems to be minimal vs fossil fuels. And a future of energy abundance is a lot more attractive than the gloomy anti-growth demands of the more Puritanical type of environmentalists.

We have had an earlier hoax discussion - seeding fungal mycelium - the relevant scientist refuted their ‘facts’ and got embroiled in a nasty situation. They didn’t want facts, to get in the way of their money making scam.

We have nuclear Koeberg IN Cape Town. Currently embroiled in extending its life by another 20 years. While losing the skilled workers and scientists. The big boss has taken his expertise to Canada.

And the much vaunted pebble bed reactor has gone very quiet.

PV panels, EV car, and trying to live on a small footprint here

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Really, and this sounds horrible, but humans have a long history of solving one problem only to create worse ones. Green solutions always make me cringe because they seem to lead to accelerated habitat loss (or have impacts like bird blenders) or other issues. They are green because they are better for humans and not necessarily for other creatures. After all, there is no problem that we can’t make worse especially once government gets involved.

I have to admit that I still cherish hopes for fusion energy as maybe having less overall impact than other sources of energy. But there is no stopping humans from using up whatever energy they can get and still needing more. It’s like a law or something. Like that one about always filling up all available space…

Despite my cynicism I somehow manage to stumble forward and hope we will find actual solutions. Maybe it’s just the fact that we are at least trying. After all, it takes hope to do things like buy 70 acres of cutover swamp, enroll it in a conservation/reforestation program, plant over 30,000 trees, and stumble around it every day to fret over the trees and plan for more. Shockingly, my husband and I lost our minds and did that. I am sure we’re not the only ones crazy enough to do things like this so there are small flashes of hope out there…

And maybe fusion really will work out and not cause a host of other problems.



do you have an iNat project for your rehab? A link?

Why wouldn’t you try to capture all the radiant energy you can? Sure, you can do a lot with just the heat that’s put out, but there’s a significant amount of power in other parts of the spectrum, too. Are you just going to let it escape? Material limitations are a good point, but then again, we had to solve that to some extent in order to build a reactor in the first place. It might take some significant R&D but you could certain make a PV system that’s more robust than what we use now. You could also try to capture that radiation for other applications besides power generation as well.

I’m surprised nobody has mentioned energy storage yet. One of the big problems with solar, is that despite its ability to create power during daytime, it doesn’t do much at night (at least photovoltaic, concentrated solar is different).

In my area, this has resulted in utility companies introducing time-of-use rates, where energy is least expensive when nobody is home and more expensive in the evenings, when people run their air conditioners. This is “the market” solution to incentivize more energy storage on the grid and to discourage people from using as much energy. Since most people in my area work away from home during the day and are home at night, I’m sleptical about this solution.

With nuclear and fusion (hopefully one day), the power plant can make enough heat energy to supply as much load as needed. There’s no need to store excess generation because the plant can run all day and night.

With government incentives, maybe the low-cost, excess generation could be used for carbon capture for example?


That quote could hardly be more wrong. Taken at face value, it shows a very poor grasp of human history. Star Wars is science fiction.

To properly understand our current problems, you need only look at a graph of human population growth since the beginning of the Industrial Revolution. From 1700-1900 this roughly doubled every century from about 500m to 2bn, and then almost quadrupled again in the 20th century to around 8bn. None of this growth is due to “god-like” technology. It’s mostly just the consequence of relatively simple public health measures (like sanitation and personal hygiene) that have massively increased our abiliity to control infectious diseases.

We are now living in age where, for the first time in human history, the birth-rate significantly exceeds the death-rate every single year. Needless to say, the “technology” used to produce most of those extra babies hasn’t changed much in the last hundred thousand years. We have simply become victims of our own (very recent) success.

Here’s another science fiction scenario: try to imagine what the world would look like today if we had all the same technology, but there were somehow still only 500m people living on the planet…