[bmitc]

Does anyone have some thoughts on whether fusion will actually help fight climate change?

Of course, fusion is far more clean than coal or gas and less environmentally destructive, aside from the mining of materials required, than say hydro power plants. But from what I can tell, the primary contributor to damaging the climate and environment is consumption, as a process. I currently see no end result where fusion does not drastically increase consumption, which means more use of non-clean materials and processes.

So I guess the question is: will the benefits of fusion offset the increase in consumption?

[gcheong]

Good question. I think people are betting that even with dramatically increased consumption (for example all developing countries reaching developed country levels standard of living) we will eventually reach something resembling a steady-state of population and consumption. I think it's a big bet indeed but I think it needs to be made if nothing else than just to reduce the amount of suffering around the world caused by our current system. At worst, assuming fusion succeeds, we stave off the inevitable for a while longer in the hopes something else comes along to balance the equation.

[sebzim4500]

I don't understand your argument at all. In a world where people can produce power through fusion cheaper than they can through coal or oil, why would use of non-clean materials increase?

[bmitc]

Because it isn't just about power production. People use that power to then go off and do things. The question I'm asking is what does that look like? Because how we do things still requires oil and other destructive acts, for example.

An analogous situation is electric cars. Electric cars, eventually over the lifetime of use (not immediately), save emissions over combustion engine cars. However, building a single mile of road is something like 10x or 100x (I forget the exact multiplier, but it's at least an order of magnitude and maybe greater) the emissions of a car (electric or combustion). So given the idea that electric cars actually bolster if not increase the love and use of cars, then that has a downstream effect of more roads being built and maintained, which is far more polluting than the cars themselves.

So you need to look at things as a system. I'm not arguing for anything but looking to understand things. I think fusion is obviously something we should do. What I'm wondering is how do we get people to realize it isn't a one-stop shop for staving off even more environmental change.

[sebzim4500]

>then that has a downstream effect of more roads being built and maintained, which is far more polluting than the cars themselves.

Surely this is negligable compared to the carbon currently being emitted by ICE cars? The first source I can find says that building and maintaining one lane mile of highway emits 3,500 tons of CO2, whereas the vehicles driving on it will emit 90,000 tons of CO2.

[bmitc]

I shouldn't have included maintained in there because I just meant the emissions for manufacture. The emissions for building an electric car is more than that of a combustion engine car, and building a mile of single lane road dwarfs both of those. So switching to electric cars keeps us building roads and increases emissions at the time manufacture. To get the real story, one needs to consider the use of and maintenance of these things. At some point, there is a crossover point where electric cars have less total emissions than combustion cars. But the use of electric cars will not slow the building, use, and maintenance. If anything, they will increase it because they make buying and owning a car sexy again. Plus, electric cars are far heavier than combustion cars, which will increase road wear. And most analyses don't include battery recycling and disposal as part of an electric cars emissions. So electric cars are probably or even maybe a win in the long term, but the simple act of having electric cars isn't enough.

My point is that one can't simply look at the power production of a car as the sole comparison, and I think that also holds true for power plants. I just haven't seen this analysis for fusion plants. They will be a good thing for sure, but I worry many think it's a silver bullet, and I'd like to understand their affects once they're on the scene.

[sebzim4500]

Why do you keep talking about building a mile of road? There are many more cars in the US than there are miles of road, and the replacement time of roads is at least decades.

[gcheong]

There's more to environmental destruction than just emissions. If we're net zero emissions with something like nuclear energy, and clean energy is ubiquitous and cheap, people are still going to want to do things with the energy and that will potentially dramatically increase consumption of finite resources in general. For example, clean-fueled fishing boats don't matter much if we still fish the oceans to extinction.

[switchbak]

Well sure, but that's a bit of a dead end conclusion.

I think it's still better than belching out coal soot, and with abundant energy we can power other processes to help clean things up. Well - we could, but we'll probably just mine bitcoin with it and zip around in our flying cars :( But unbounded consumption and our awful societal structure is a bit of a different problem compared to how we fuel it.

See Jevons paradox - increased efficiency often leads to increased demand and usage.

[anonuser123456]

The price of oil+nat gas will fall as alternative forms of energy come online. But when the price falls, consumption goes up (demand elasticity).

[alexb_]

If the logic works in this direction, it works in the other direction too - are you saying we should shut down renewable energy so that the price of energy goes up and consumption of it goes down accordingly?

[anonuser123456]

>are you saying we should shut down renewable energy so that the price of energy goes up and consumption of it goes down accordingly?

No. I’m suggesting that once a cost competitive alternative exists at scale for hydrocarbons, we institute Pigouvian taxes (e.g. carbon taxes). This ensures that at the margin, people are incentivized to choose low/zero carbon energy sources.

[sebzim4500]

There is a nonzero cost of extracting hydrocarbons, the price can only fall so far.

[anonuser123456]

There will need to be policy, hopefully in the form of Pigouvian taxes. But before you can get the policy in place you will need a viable source of energy that’s cost competitive with hydrocarbons.

Once we have a viable alternative to hydrocarbons at scale, carbon/methane/ high GWP gases will need to be priced appropriately (e.g. taxed in a way to incentivize reduced consumption).

[jillesvangurp]

I think it's a long term great option that will have to prove itself based on a cost/performance basis in an extremely competitive market.

Therefore, short term the impact is going to be minimal/negligible. There are no plants yet, no approved plans to build any, no validated designs for any, etc. The first few plants are going to be very research/prototype focused and won't produce any impressive amounts of energy relative to what is needed and what is coming online every year in other forms. Best case, we'll see some early adoption in the late 2030's early 2040s with some proof of concept reactors coming online maybe in the next five to ten years already. Several companies are claiming that they are doing that; including Helion. That would be optimistic but it could happen. But I'd be surprised if it hits more than a few percent of global supply before middle of the century. And even that would be a lot.

Getting most coal, gas, and other fossil fuels offline by the 2050s would be the main challenge and a bit of a stretch goal according to some. I think fusion will be too late for to play a major role for that either way. If fusion starts working as advertised, it will likely be the second half of this century. It's main role will be to drive cost down and replace more expensive nuclear reactors.

I'm actually optimistic about the 2050 timeline here mainly because I think the fossil fuel industry is heading for an investment and cost cliff much faster than they are hoping and mainly because that is driven by the pricing of and investment in renewables. They are being to optimistic how long they can remain profitable and too pessimistic about how much further renewables are going to come down in cost. Once they hit that cliff, a lot of remaining supply will be deprecated and taken offline as fast as they can replace it with something vastly cheaper. They'll be bleeding cash all the way. Also, investment is ramping up and shifting from one to the other faster than they hope. So, I take most current projections that seem overly pessimistic and conservative with a grain of salt.

Either way fusion won't be that important for getting rid of fossil fuels. But if it works and is cheap enough there will be a role for it beyond the 2050 timeline.

By then, we should be pretty far done tackling climate change. Mostly via renewables and maybe a bit of nuclear here and there and lots of cheap and scalable storage. There are so many proven battery chemistries and other solutions for this now that I consider that as pretty much guaranteed to happen. A mix of short term, mid term, and long term storage coming online by the tens of twh per year in a few decades. The grid will be very different than it is today with lots of private and de-centralized generation (almost exclusively renewables) and storage, micro grids, etc.

[DennisP]

If Helion actually works, their plan is to build a factory making twenty 50MW reactors each day, shippable by rail. That could replace the world's fossil-based electricity production in six years, and that's just one factory.