Wednesday, December 14, 2022

Be cynical about fusion claims

nuclear fusion "breakthrough" this week seems to have attracted an awful lot of media attention.

But actually it wasn't that much of a breakthrough (unless you are a nuclear fusion scientist). This is a big deal for scientists because is a kind of proof of concept: for a brief moment in time, scientists at Lawrence Livermore National Laboratory in California succeeded in generating a nuclear fusion reaction that produced more power than it used - 3.15 megajoules out for 2.05 megajoules in - at least if you don't take into account the 300 megajoules required to produce the lasers that produced the reaction in the first place. 

So yes, after several decades of experimentation and untold billions of dollars of investment, a fusion experiment finally managed to produce a net power gain, sort of. The 1.1 megajoules net gain is about enough to boil a tea kettle a couple of times.

Forgive me for being less than "super excited", but the fusion power program has been holding press conferences for decades now to celebrate even the tiniest of advances. And it is still a long way from anything of any practical use, as even the Laboratory directors admit. "This is a science achievement, not a practical one", said one. "There are many, many steps that would have to be made in order to get to an inertial fusion as an energy source", said another. Some argue that we will never get to the stage where basically "unlimited fusion" power is commercially available, nor should we even be trying, for a variety of different reasons.

Bear in mind, this is not actually a renewable energy technology, (see here for a quick primer on how nuclear fusion works) although it is more or less carbon neutral (depending on the electricity source employed). And, in the meantime, solar, wind and hydro power move from strength to strength, and are already highly cost effective, and other renewable sources like geothermal, tidal and wave power, as well as battery technology, are also making good progress. Plus, fusion involves temperatures many times those in the core of the sun, and pressures billions of times that normally experienced on earth; so, while it is a physicists wet dream, it is not something to be entered into lightly.

So, expect a whole load more dramatic press releases from the public relations whizzes in the fusion industry. And expect many more billions of dollars to be spent, and many more years to pass, before we get anything close to a practical source of power. And expect a lot more cynicism from me.

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