Neither ITER, nor fusion in general, are our best shots for clean sustainable energy. They are at best very long shots, and at worst complete wastes of effort.

What's your option?

If you say solar or wind, I'll tell you not without solid state physics experiments to multiply battery capacity by at least 10x. (Not impossible, but as much pie in the sky as fusion.) Or a global electric network. Or space solar with concomitant energy sending infrastructure.

Nuclear is good for maybe 300 years. (And not exclusive with other sources.) Hydro, geothermal are nice where we can have them.

Anything else, we don't even know where to start.

Solar and wind. Your comment about batteries is bizarre. Batteries don't need higher capacity for stationary storage, they need to be cheap. That is not "pie in the sky" and is certainly a much easier engineering problem than fusion. And batteries are not what you'd use for long term storage; that would be hydrogen (which can be stored underground for less than the equivalent of $1/kWh of storage capacity.)

Given reasonable projections of where renewables, batteries, and electrolysers will be in 10 years, one will be able to synthesize artificial baseload sources at a lower cost than nuclear fission, anywhere in the world (in some places much less). And fusion will have a very hard time being competitive even with fission.

Yes. Also for grid- level storage space and weight are not at a premium - so cheap, comparatively in efficient solutions like sodium-ion batteries or redox flow systems is where the field is moving to.

These are really expensive on a scale needed for powering current world with solar and there's nothing to suggest we'll stop there.

I'm not sure you understand the scale involved. We're talking billions tons sodium. Millions tons aluminum and steel.

Hence the 10x.

Let's see... producing 1 kg of sodium metal uses about 10 kWh of electrical energy. 1 TWh would produce 100,000 tonnes of sodium. A billion tonnes of sodium would involve 10,000 TWh. World primary energy consumption is below 20 TW, so you're proposing batteries capable of storing hundreds of hours of world energy demand. This is a gross overestimate -- batteries would be used diurnal leveling, with perhaps 12 hours of storage needed, and that just for the grid. Industrial power demand in a renewable world would likely be more dispatchable, and any demand for thermal energy would use bulk thermal storage, not chemical batteries.

If you meant sodium compounds, not sodium metal, note that annual world production of sodium chloride is about 200 million tonnes.

Oh, and about "millions of tons of aluminum and steel": 2019 world steel production was 1.89 BILLION tonnes. Aluminum production in 2018, 60 million tonnes. The world economy is very large. An energy infrastructure capable of powering that economy will also be large, be it renewable, nuclear, or unicorn power.

Yes. It's not impossible. Just really damn hard to pull off.

Sodium chloride is useful for many things beside batteries, if we were to use that as the source. Say, sulphur as well, other traces too.

10x batteries make this a no brainer and super easy to implement, and economical. Heck, 3x batteries even.

You need to make and place enough panels too, doable but needs a lot of political will. And will of course take some time as well.

I think we shouldn't put the cart before the horse though. Fix the immediate problem with a few smaller nuclear plants and work real hard on our own pace to replace them with renewables. If fusion comes in the meantime, great. In the meantime, we can use the spare resources to remove other sources of GHG vent. (Say optimize transportation.)

See the other branch on how I view fusion. I see DD or enhanced DT fusion as endgame and mostly a space technology. (Fusion engines would be rather nice. Think 50x better ion engines, the technology is related.) Few hundred years of work.

> Yes. It's not impossible. Just really damn hard to pull off.

Yes, any global energy system will be extremely expensive. Trillions of dollars worth of expensive. That it is a lot of work is not a showstopper.

I don't see nuclear being part of that solution, though. Why waste money on something that is demonstrably inferior? It had its chance. We don't need to invest in losers.

Fusion is not an endgame. Fusion is bullshit. It's Rube Goldberg on stilts. From an engineering point of view, it's pretty much the opposite of attractive. Keep It Simple, Stupid is not just a slogan.

DT fusion makes no sense in space. The energy comes out as neutrons, which get turned to heat. You can make heat with fission in space much more easily, and with much less reactor mass, than you can with fusion. The notion that fusion is somehow good for space comes from science fiction more than anything. It's a trope, not a good idea.

> Fusion is bullshit.

Especially because the Tritium fuel problem is not solved, and nobody has the faintest idea how to solve it. The materials needed to breed Tritium in something different from the Sun (or thermonuclear weapons) just do not exist for now.

At this point fusion is an elaborate high energy physics stimulus package.

Max we are looking at 1000 TWh, that's two days of global energy demand. Rule of thumb we need 300gm of sodium per kWh. That's 3 billion metric tons. Which is a lot - but for the entire global energy demand it's peanuts

> Batteries don't need higher capacity for stationary storage, they need to be cheap.

Not only cheap, but also sustainable.

Coal is plenty cheap.

Why do you need increased storage density for grid level storage?

Because we don't have enough batteries. Lithium as a minable element is too limited to have enough without increased capacity. (If lithium fusion were ever available, we'd run out in 2000 years or so. Batteries take more.)

Even redox batteries are, as you need rather pure salts. Even pump storage, cheapest option, would require tons of concrete, which means we'd have serious lime shortage. (Once we run out of natural mountains to use.) Plastics cannot be used as they're either not strong enough or require too much fossil fuels.

Any of these problems can be attacked, and they're all about as easy and solvable. Prediction would give about 40 years until that battery capacity is reached. Fusion could be there just as soon.

This is not to say we should stop developing renewables, but we need 100% clean power yesterday. Or rather 20 years ago. Currently the only open path is nuclear with enough other renewables (expected 25%-33% is doable depending on location).

We're talking gigawatthours of battery capacity installed and running per city. Even if you have everyone an electric car with best available batteries, that would maybe come close. (And the network would have to be heavily as adapted. I've accounted for battery wear and manufacturing with recycling of said batteries.)

Top end sodium-sulphur batteries would work too, in equivalent amount. (They do like 250 kWh per bank. Car lithium-ion do ~120 kWh, but you probably want to drive them in the morning.) Mind you the renewables to power them won't materialize overnight either. You get to pay energy and material to make them and modify the grid to adapt to them.

Since we're late as all hell, the only way right now is to nuclear. We can decommission it in 50 years easily enough as needed.

We had the technology to go full renewable since 80s...

We don't have enough lithium for DT fusion then, either. If we assume fusion reactors have a wall loading of 1 MW/m^2, and assume 50 cm of LiPb in the blanket, then fusion reactors capable of supply (as heat) 10 TW would need the 6Li from 80 million tonnes of lithium. Current Li reserves are a fraction of this.

That ARC reactor design, if extended to world energy demand, would require 100x known beryllium resources.

Yes. Fusion is not short game and should not be treated as one. Not funded like it either.

It will be very useful when we get to space, for example, unless we figure out something better. Much fewer problems with it than with nuclear up there. (Especially with getting fuel.)

Why would it be useful when we get to space? When we get to space, we'll be 1 AU from the Sun. At that distance, solar is vastly superior to fusion. And DT fusion will always be inferior to fission in space.