Last month, I attended the MIT Technology Review’s Climate Tech conference in Boston. This was a phenomenal conference with top-notch speakers and awesome climate people. Stay tuned for the 2023 conference!
One of the incredible speakers was Anne White, Head of Nuclear Science and Engineering at MIT. Her presentation about fusion filled me with excitement.
I was amazed to hear about the scientific advances researchers were making in fusion. And not only researchers. Many private companies (at least +30) worldwide are working to commercialize fusion.
Anne painted a future where fusion energy might be much closer than we think. The momentum of fusion power is growing.
🌟 The momentum for star power
Several factors are contributing to the growing momentum around fusion.
1. Recent technological breakthroughs
While humanity has never got a net gain from a fusion reactor, we might be approaching the magical Q=1 moment (getting as much energy out of the fusion reactor as we put in).
We have an increasing number of private companies working to commercialize fusion. There are now +30 fusion startups, if not +50. As we will learn later, it is exciting how many different approaches these startups are taking toward fusion!
Note: I find it interesting that most fusion startups are located in the US. Being a European, this is a bit sad, but unfortunately, not surprising to me.
In a fusion reaction, two lighter nuclei merge into a heavier nucleus. As a result, a lot of energy is released.
Below is a picture of two hydrogen isotopes, deuterium and tritium, fusing together into helium. These hydrogen isotopes are among the most commonly used fusion fuel. [What are isotopes?]
For two nuclei to fuse, they need a lot of energy to overcome the force keeping them away from each other (the electromagnetic force).
In the Sun and other stars, where fusion reactions take place, energy is no problem. The Sun has a temperature of 15 million °C at its core and has a huge gravitational force due to its mass (333,000x of the Earth), sustaining the fusion reactions.
⚡ Fusion energy
To harness fusion power on Earth, we must create controllable Sun-like conditions here.
As noted in the previous section, two nuclei need a lot of energy to overcome the repelling electromagnetic force and fuse together. This is achieved by heating the atoms (usually hydrogen isotopes), giving them a lot of kinetic energy.
The plasma density must be right to achieve a suitable fusion reaction rate. The density depends on the approach to fusion (e.g., magnetic confinement, inertial confinement. Read more below!).
The particles of the plasma (electrons and positively charged nuclei) must be kept close to each other for the fusion reactions to occur. Again, depending on the approach to fusion, the confinement time differs.
⚙️ Approaches to fusion
We can achieve these three conditions via a variety of fusion technologies.
It is incredible to see how many different approaches startups take. Below you can see a graph of approaches fusion companies pursue.
The two most common general approaches for fusion are magnetic confinement and inertial confinement.
Magnetic confinement uses magnetic fields to confine the plasma inside the reactor.