Those readers that share my fascination with Science Fiction books know the plot: In the (far) future, humans have solved Nuclear Fusion and with that unlimited energy is then able to fly to the stars.
“The Star Builders” however is not a Science Fiction book but the attempt to analyze the current status of this technology, written by a “serious” Physics researcher.
Nuclear Fusion is the process of “fusing” Atoms together which then releases significant amounts of energy, a process that occurs naturally, however only at a galactic scale within the stars of our universe.
Compared to Nuclear fission, which splits Atoms, fusion in theory should be a lot safer, produces a lot less radioactive waste and the input material is easier to obtain. The big problem so far is that with one exception (hydrogen bomb), current science requires still much more energy input to start a fusion reaction than the resulting energy output.
The book explains well that the biggest issue with regard to the theoretical foundations of Fusion energy is the fact that scientists don’t know that much about how Plasma behaves. Fusion only occurs when molecules are in a Plasma state. Plasma Physics seems to be an extreme complicated area and so far, keeping the Plasma somehow constant is really difficult to achieve. However, for a functioning fusion reactor, controlling the plasma seems to be key.
The key factors that determine fusion are temperature, density and energy confinement. Currently two fusion technologies are looking most promising: Magnetic confinement and inertial confinement. The author also looks at other technologies, even one that is based on a technique used by shrimps (no joke…)
So far, the most efficient fusion reactor produced only 70% of the energy that was put into it, so there is still a long way to go to achieve the required 10x or 100x output hat is required to make this commercial. Another issue will be how to efficiently capture the output and turn it into electricity, but that seems to be a more easily solvable problem.
The book also gives an overview over the many start-up companies that try and claim to turbo charge nuclear fusion development. The author is quite skeptical on most of these, as many are very in-transparent on how their “secret sauce” is working.
Some interesting takeaways:
- Even when (and if) it works, Fusion energy will not be cheap due to the significant technological effort required
- large scale fusion reactors will require significant space and if something goes wrong they will be very difficult to repair (i.e. significant overbuilt required for mitigating down times, adding to cost)
- It most likely not scalable within the time frame required to combat the climate crisis, so relying on nuclear fusion to save the climate is not a strategy
- Many “sensational” stories on “cold fusion” and other breakthroughs etc. are very likely false
As a summary, I found the book really interesting and easy to read, even for a non-science guy like myself. It really gives a great overview over where this technology stands and what to reasonably expect from it.
