Realistic
Batteries. It's holding back a LOT of things. A lot of technologies are solved, but just require power.
Semi-Realistic
Room Temperature Super-Conductor.
If that can be solved, the power density and efficiencies would just be astronomical....
It would absolutely destroy multi-billion industries overnight.
Way-Out-There-Stuff
If they ever prove out an actual functional EmDrive-like thruster, that would absolutely open up space travel to our species.
Batteries are the big one. Can you imagine how many people (homeowners/renters) will go out and buy a tiny 100W panel knowing that even though it will fill a battery with energy very slowly, they can still bank on it for a week?
Right now we have batteries that can survive about a day, using a modern solar panel system with inverter (~1000€). Imagine when we have batteries that can store weeks of power.
I agree with this. The extreme weather keeps getting significantly worse YOY, and a recent extreme temperature spike in the antarctic has scientists worried that our timeline is a lot shorter than previously estimated, which means significant action needs to be soon.
We are making excellent progress with fusion, especially the recent development to use AI to keep the magnetic fields containing the reaction stable, but how long will it be before we have a material that is strong enough to withstand the heat of a literal miniature sun for the years at a time required to run a plant? Just the energy from the magnetic field is strong enough that they've developed a super efficient was to use those microwaves to bore holes through the earth's crust hundreds of times deeper than ever before. So we have to at least come up with something significantly stronger than the pressurized material 2km deep into the earth's surface.
I am and will remain on the fusion bandwagon, but putting all of our eggs in that basket is a baaaad idea with the current state of things. On that note, that crust-boring technique i mentioned should make geothermal much more viable.
Honestly, I would consider it too late if it ready to build the first commercial plant right now. Building one of those takes a decade or two and building them all over the world takes significantly longer as expertise doesn't pop up out of nowhere in as many people as you want and neither does funding happen for plants all over the world as the first one isn't even finished yet.
There's a massive fusion reactor in the sky that we could easily use by turning the radiation from it into electricity or harnessing the winds that are caused by the temperature differences it creates.
Nuclear fusion still has a long way to go, but to slow climate change (already too late to stop it) we need to act now.
Nuclear power reactors built after the 1970's. New generation (5?, 6?) for baseload. Mox, msr, lead moderated... Renewables can bicker over the transient loads while reactors provide the 'always on, always needed' bulk of power load.
Fuel reprocessing to close the loop would be the grail at this point.
All well and good but at the higher end they're writing applications in JavaScript and electron and using many times more system resources than C or rust, and it will always be cheaper for them to develop in higher level languages (especially when the performance problem can be offloaded on the user's machine instead of their own servers)
It's cheaper for companies to have their developers spend less time developing in higher level languages and just throw more hardware at the problem than spend more money developing in a more difficult language
They aren't concerned with energy or material efficiency, only financial
Only their own specifically. Our economy wants people to only care about themselves. Even though this doesnt make sense as polluting the earth will directly impact you.
This could theoretically be done with stemcell stuff, but it's not there yet. However, when we finally reach the point where we can infinitely regenerate our body cells, we'll become effectively "ammortal"; unable to die due to natural causes (such as illness), but we will still die from other people (for example, a bullet to the head)
Besides that, I think nuclear fusion would be an incredible development if we can finally harness it to power our homes.
Fusion won't be the silver bullet people tout it as for much of the same reasons as fission isn't (mostly politics). No politician wants to spend billions of dollars on something that is going to take a decade to even be functional and another decade to break even. It would get cheaper with scale, but so would fission, we just never let it get there. It also still produces radioactive waste, despite what proponents claim, and it even produces more radioactive waste than a fission reactor by volume. But it isn't as long-lived.
These are the same tired arguments we hear about fission. If your country isn't actively building fission, it's probably not going to build fusion, aside from demonstrations.