Comment by 1970-01-01

As a big proponent of fusion: we should be spending more money and effort on it. We should be spending more money and effort on fission too. Sustainable energy sources shouldn't be fighting for scraps.

Yes, there are significant issues. Nothing we do not anticipate solving, but still. It will take time and solving these issues in a resource-effective way so that it can actually work as a power plant will be a challenge.

> But fusion often use it's pending development as an argument against fission - a technology we already have and desperately need to adopt now.

If it helps, CEA is also doing a ton of R&D on fission (and batteries, among others). But there, the real issues are mostly political.

Now that we've made it to 2025, 2050 doesn't feel nearly as far away to me.

20 years ago I would have agreed with you. However today we have proof that wind and solar work, are cheap, and are useful. The world doesn't need fusion or fission, other technology is plenty good.

Unless you can do a science fiction thing of turning off the sun, and harvesting the hydrogen in it to power local reactors in earth orbit to provide the energy (light) we need without letting the vast majority escape our solar system unused. Otherwise that big fusion reactor in the sky provides all the energy we need.

> return on the initial investment.

It's not only initial investment. Half of the fusion fuel is tritium, which is one of the most expensive substances on Earth (a google search finds that the price of tritium is about $30k per gram [1]). For comparison, fission reactors need enriched uranium, and that costs only about $4000 per kilogram [2]. People have the idea that fusion produces many times more energy than fission, probably because fusion bombs have a higher yield than fission bombs. This is not true. The most typical fusion reaction involves one deuterium and one tritium and yields 17.5 MeV from a total or 5 nucleons. A fission reaction involves one neutron and one atom of U-235 and yields 190 MeV from 236 nucleons. So fusion yields about 4.3 times more energy per nucleon. That's respectable, but in the popular imagination fusion yields 100 or 1000 times more energy than fission, so the fuel cost can be neglected. Nothing could be further from the truth.

[1] https://www.google.com/search?q=tritium+price

[2] https://www.uxc.com/p/tools/FuelCalculator.aspx

Agreed. I think fusion power would be great, but the sales pitch of 'limitless free power' just isn't true. The thought experiment I use is this: Let's imagine coal is magically free in every way. How does my power bill change? The answer is "barely at all" because the cost of utility electric power is mostly in distribution. We pay around 30c/kWh while the wholesale energy price is more like 2c/kWh.

It'll still make a difference in large scale energy intensive stuff, like desalination, aluminium refining, etc. but the average punter is going to save a lot more by installing solar panels.

We'll never know until (or if it ever comes) but there's reason to believe Fusion could be >50% cheaper than Fission.

That would still be more expensive than Solar and Wind (by 100% or more) - but I am skeptical in the same time frame those sources will be able to take over baseload generation.

It's really comparing apples to oranges.

Plus, it's a very hypothetical future. Anything could happen between now and then.

Even if fusion is an expensive power source, it may still be desirable in areas which aren’t well suited to wind or solar.

There is a certain amount of "who cares about the cost" when it comes to fusion power. Nations will want to build them to lower or eliminate reliance on foreign energy, to address climate change concerns, and as a backup for renewables, and for other non-economic reasons. Many things that governments will want to fund that have nothing to do with directly "how much does the electricity cost?" or "when can we expect a return on investment?"

And the first generation will be expensive. That's how all new technology is.

There's definitely an existential question around if fusion will ever be able to beat renewables plus batteries, but who knows with our energy demands ever increasing at some point renewables may hit a breaking point in land cost.

I'm generally pro-publicly funded research. There is not any direct ROI on say the LHC, but it does fund advanced manufacturing and engineering work that might enable other more practical industrial applications. The ROI might be a century away.

> At the risk of coming off as a nay-sayer, let's say engineering hurtles related to fusion power generation is overcome. How is the presumably high upfront capital costs going to compare with the ROI?

Does money even matter once fusion is attainable?

A Mars mission would benefit humanity, but less directly. The past lunar missions and space program benefited humanity in many ways.

For pure return on investment, I agree with your take.

Provided of course that any future threats to humanity as a single planet civilization don’t materialize. There’s a low and uncertain tail risk ignored in our calculation.

The planet Mars is a gift from God for humanity

I like the idea of the passively-safe, waste-reducing LFTR but it's still a materials science issue at this point, and there's no real solution in sight.

Fission still has this huge stigma about "nuclear=dangerous and bad" which clearly isn't true with the growing number of passively-safe designs... but nobody wants to fund development of those into proper commercial reactors.

Meanwhile, fusion is still different and futuristic enough to have support from governments and the general public.

Yeah but I still think it would be a great scientific achievement and should be pursued.

Fusion has better security properties than fission, so perhaps it will find some use case in the far future.

It’s a common fallacy: “$thing is good, new and exciting, therefore everything else is old and rubbish”. The pattern is very easy to see if we pay attention. It’s very common in tech circles, where people tend to be easily excited about new things.

>Why do you think a result like this would make anyone less skeptical of fusion?

Just 9 days ago: >>Ability to run a device for this long is not the obstacle to success for nuclear fusion.

What an odd take. Do you also consider the list of flight endurance records to be immaterial to aircraft evolution?