The Recent Fusion “Breakthrough”

Published at 19:48 on 14 December 2022

There’s a lot of very bad takes like this out there about the recent so-called “breakthrough” in controlled nuclear fusion.

First, I put “breakthrough” in quotes to emphasize that what’s just been achieved is a lot less impressive than what many have been led to believe by the news stories. “Milestone” would be a much better description for what has been achieved. It’s important, but far from a big breakthrough.

For openers, any claims of “net energy gain” rest on an extremely deceptive definition of what “net energy gain” is. All that has been achieved is a net gain over the output power of the lasers used to initiate the reaction. Those lasers are themselves monstrously inefficient devices; the vast majority of the energy fed into them is wasted as heat.

The upshot of this is that, overall, the fusion reactor that just achieved this supposed “breakthrough” of “net energy gain” actually consumes roughly 100 times as much energy as it produces. (And that’s without even taking all the other energy costs involved in manufacturing and operating the fusion reactor into the picture.)

Next, we come to whoppers like the following claim (source: first link in this entry): “[W]hat if we didn’t have to economize? What could humanity do for ourselves and our planet? … Bring the whole world up to a Western standard of living — and beyond — without worrying about the environmental cost?”

I mean, really now: it’s hardly as if consumption of energy at First World levels is the only unsustainable thing about modern industrial civilization. There’s all the other non-energy natural resources, many of them nonrenewable ones, that are being eaten through at an ever-increasing pace. That’s before one gets to inconvenient matters such as how shifting to fusion to power cars and trucks means shifting to electric vehicles, which are significantly more resource-intensive to manufacture than fossil-fuel powered ones (compare the resource footprint of a lithium battery bank to that of an empty steel fuel tank and it’s not exactly a pretty picture).

Suppose all goes better than planned and we get to actual net energy gain from fusion. That’s going to take a while. Then it will take a while longer for such reactors to make the journey from laboratory curiosity to a practical industrial technology. All the while that goes on, fusion will not be available as an energy source.

Mark my words, if fusion ever does become practical, it will definitely be a huge help. But that’s all it will be: a help. It won’t be a magic bullet. It won’t be a get out of jail free card from having to confront our unsustainable ways and downshift.

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