Are We Closer To Genuine Fusion Power?
Are We Closer To Genuine Fusion Power?
Yes and no.
Nuclear fusion has been the holy grail of climate technology since the late 50s. Theoretically, it should be ultra-compact, incredibly powerful, insanely clean and brilliantly safe. It promised to be the energy source of the future and beckon in a new era of near-unlimited planet-friendly energy. But setback after setback means that even after decades and decades of research, this energy source still remains elusive to us. But last year, the National Ignition Facility (NIF) broke a significant fusion milestone and was able to get a net gain in energy from their incredible reactor. Since then, they have struggled to even get close to replicating this monumental achievement. However, NIF recently announced that they have repeated this historic experiment, and it seems they have actually produced even more energy this time. So, does this mean we are closer to a fusion-powered future?
Before we look at this new experiment, let’s first recap what fusion is and what fusion is and how NIF works.
Nuclear fusion is the process that keeps the Sun “burning.” The Sun is made of mostly hydrogen, and at its core, the temperature and pressure are so high that the collisions between hydrogen atoms have enough kinetic energy to overcome the repulsive forces that keep atoms separate. The two hydrogen atoms collide, forming a single, larger helium atom, which is slightly lighter than the two hydrogen atoms, due to the smaller number of gluons in its nucleus. This excess mass is turned into energy and released. As Einstein stated in his famous E=MC² equation, a small amount of mass is equal to a vast amount of energy. This means that a single fusion reaction releases an unholy amount of power through radiation and heat.
Fusion is so potent that fusing 17 tonnes of hydrogen will release enough energy to power the entire US for a year! That equates to only 0.05 grams of hydrogen per US citizen! Even better, helium is the only gas emitted throughout this process. This incredible fuel efficiency and zero carbon emissions make fusion power one of the most eco-friendly energy sources on Earth.
Scientists and engineers have developed several different types of reactors capable of replicating those conditions in the core of the Sun. NIF is unique among these as it is one of the few “inertial confinement” reactors. This means it uses lasers to compress and heat a fuel pellet containing hydrogen to the point where fusion happens.
All of these fusion reactors are incredibly inefficient, as it takes more energy to create the conditions to start fusion than you get back from said fusion. Until very recently, most reactions had a net energy loss of around 80%! Needless to say, this is the monumental problem stifling fusion technology.
But in December 2022, NIF did what many thought wouldn’t happen for a decade or so. They created a net gain in energy! A laser with the power of 2.05 megajoules sparked a fusion reaction that emitted 3.15 megajoules of energy. That is a monumental 54% net energy gain!
This colossal lead happened because NIF found a way to “ignite” the hydrogen plasma. Fusion ignition is when the energy from one fusion event causes another, creating a chain reaction in the plasma. This causes the plasma to self-heat and fuse far more efficiently, leading to far higher energy yields.
However, NIF struggled to replicate this historic experiment. No matter how hard they tried, they couldn’t get the hydrogen to ignite. The reason behind this was something that has plagued fusion development for years. Quite simply, fusion is incredibly sensitive to changes in the initial conditions and the experiment. This is because there is so much energy and chaos within the hydrogen plasma that almost imperceptible changes in the setup can cause massive changes in results. The issue NIF was having is that the tolerances they could build their fuel pellets to is larger than the tolerance needed for creating ignition, meaning it was hit or miss if an experiment would reach ignition.
But, about a week ago, NIF announced that they had successfully repeated the experiment and yet again created a net gain in energy. Rumours spread for days afterwards that they had actually created more energy than last time. Then, the Financial Times announced that the experiment had yielded a result of 3.5 megajoules, which is 11% more than last time.
NIF is still in the process of analysing, writing up and getting the results of this experiment peer reviewed before they announce any profound breakthroughs to the public. I will keep you guys posted if anything interesting pops up from this.
So, does this take us closer to fusion? Yes and no.
It shows that NIF has the ability to replicate ignition. This will allow scientists and engineers to better understand this process, giving them a far better insight into fusion dynamics than we have ever had. This, in turn, should allow them to make NIF and plenty of other fusion reactors far more efficient in the near future. So, in that way, it is a massive leap forward.
But this won’t directly lead to a functional fusion power plant. While the actual reaction had a net gain in energy, the overall machine is still losing significant amounts of energy. This is because NIF’s laser is woefully inefficient at less than 1% efficiency, and energy capture systems (which NIF doesn’t yet use) to turn this fusion energy into electricity are at most around 70% efficient. So despite this breakthrough, we still can’t make a fusion reactor that can actually make useable energy, but even if this weren’t a problem, we would still be miles away from a viable fusion reactor. The lasers at NIF are also fragile and can only be fired a handful of times a year. What’s more, the intricate diamond-coated fuel pellets have a significant manufacturing bottleneck, meaning over a few dozen ones are produced each year that have high enough tolerances to be used in the reactor. As each experiment produces less energy than it takes to charge a Tesla, these limitations would make a NIF-based fusion power plant (with an impossible hypothetical 100% machine efficiency) utterly pointless.
We are still far away from a fusion-powered future. Even NIF engineers admit this, as they have estimated it would take a net gain of 100 times (10,000%) to create a viable fusion reactor. But NIF shows that progress isn’t stifled or stuck in a dead end. We are making consistent baby steps towards this utopian technology. If we keep this pace up, then this holy grail of climate technology could be ours before you know it.
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Sources: FT, The Guardian, IFL Science, Will Lockett, Will Lockett, Business Insider, Pop Sci