Nuclear Fusion Just Took Another Huge Step Forward
But are we any closer to unlocking this utopian energy source?
I have said it before, and I will say it again. Nuclear fusion could be one of the most game-changing technologies ever. The nuclear fusion of just 17 tonnes of hydrogen produces enough energy to power the entire US for a year, all without producing a single gram of carbon dioxide or high-level radioactive waste. There is just one glaring problem. It takes more energy to initiate fusion than we can get out of it. Or at least that has been the case for decades. Back in December 2022, the National Ignition Facility (NIF) broke a significant milestone and created more energy from a fusion reactor than they had put in! Well, these results have now been peer-reviewed, and these papers have shown that NIF hasn’t been resting on its laurels and has taken yet another vast leap forward. So, are we close to bringing our nuclear fusion-powered utopia to fruition?
Let’s start with the big news from these peer review papers.
About a year ago, NIF announced that their 2022 experiment had used a 2.05 megajoule laser to heat and compress a hydrogen fuel pellet enough to not only start nuclear fusion but to reach ignition. That is a lot of jargon, so let me explain.
Nuclear fusion happens when two atoms are pushed together with enough force that they fuse together into a newer, larger atom. This new atom is slightly lighter than the sum of the original atoms, and the leftover mass is converted into a vast amount of energy in the form of heat and radiation and released. In all previous fusion experiments, fusion only happened due to energy put into the hydrogen fuel by the reactor, but not so with this reaction; it reached ignition. This is when the energy released by fusion events causes other fusion events to happen in a kind of ongoing burn. This dramatically increases the efficiency of the reaction, significantly boosts its energy yield, and has been the holy grail of fusion technology.
Thanks to reaching ignition, NIF estimated that they created 3.15 megajoules of energy from the reaction. That is a 54% net gain in energy! For some context here, just a few years earlier, most fusion reactions reached a 50% net energy loss at most.
However, this was only NIF’s initial analysis. This needed to pass peer review to check that no mistakes had been made with NIF’s processes before we can say for absolute certainty that this milestone had been reached. Well, a bunch of peer-reviewed papers on this experiment by researchers not involved in the experiment have recently been published and confirmed NIF’s findings!
But, these papers also announced that NIF had smashed their 2022 breakthrough in mid-2023. This later experiment generated 3.88 megajoules of energy from the same 2.05 megajoule laser. That is a net energy gain of 89.2%!
So, with the amount of energy we can create with fusion on a rapid upward trajectory, the question has to be asked: are we close to fusion energy being a viable energy technology?
Sadly, the answer is no. It still has two huge problems.
Firstly, NIF has a fuelling problem.
Those hydrogen fuel pellets that NIF uses are immensely difficult to produce. They start out as diamonds produced synthetically around a silicon carbide core through chemical vapour deposition, which is expensive and laborious. This produces a minuscule flawless diamond; it has to be flawless; otherwise it creates losses in the experiment, and ignition can’t be reached. But even this isn’t perfect enough, and the diamond has to be polished to near-atom precision perfection. It takes 60 days to produce 20–40 of these diamond pellets, and even then, most of them are thrown out as they don’t meet NIF’s tight tolerances. The handful that make it through this gauntlet are charged by replacing the silicon carbide with hydrogen (the fuel for the reaction) and are then used in the reactor.
But, even that more recent 2023 reaction only produced the equivalent of 0.5 kWh of energy, or enough to power a Model 3 for around 2 miles of driving. In other words, it would take 60 fuel pellets for NIF’s reactor to power an average US home for a day (30 kWh). At the current rate of production, amassing that many pellets would take 2 years!
So, a fuelling bottleneck is rendering this reactor far from viable. What’s more, there is no real way to solve this issue in a way which can unlock the wide-scale use of fusion power.
But there is also another problem. Efficiency.
You see, the figures NIF states are for the energy put into and emitted by the hydrogen, not the energy put into the machine and the amount of useful energy extracted. Which is a significant problem. The laser NIF uses is only 1% efficient, and while NIF doesn’t have any energy-capturing systems, the best we currently have are only around 70% efficient. This means that reaching an overall break-even between the energy going in the machine and useful energy coming out of the machine would require the fusion reaction to reach a net energy gain of 14,285%. Needless to say, we are well off that figure.
So, yes, these results are taking us closer to unlocking nuclear fusion. However, they are baby steps. There are still some utterly gargantuan engineering and scientific challenges to overcome before we get there. But we are taking these baby steps rapidly, so don’t give up on this world-changing technology just yet.
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