Fusion: Why we’re closer (and why fusion matters)

Earlier this week, according to the BBC, scientists at the National Ignition Facility (NIF) in California have overcome one of the major barriers to achieving fusion power generation through the process of Inertial Confinement Fusion (ICF) (this was particularly exciting to me having done an independent study on ICF as part of an energy conversion course in university).

Inertial confinement, which was previously thought to be the less feasible of two approaches to generating fusion power (the other being magnetic confinement), relies on the application of high powered energy, delivered in the form of several coordinated laser pulses, to a fuel target (typically hydrogen isotopes that can fuse to form helium and release valence energy in the process).

Fusion energy is particularly exciting because of the vast energy payload that can be delivered relative to the quantity of fuel used, and the fact that the fuel can be derived from a hydrogen isotope (deuterium) which is found in abundance in ocean water (deuterium constitutes approximately 1/6500th of the world’s ocean water). It is also exciting in that the byproduct of a successful reaction is helium which is less harmful than the nitrogen-oxides (NOx) and sulfur-oxides (SOx) that commonly result from the burning of fossil fuels.

Fusion energy is particularly difficult to achieve because it requires the positively-charged nuclei of two hydrogen atoms to fuse, and to do so these nuclei must overcome the electromagnetic repulsion that exists between them. Through the application of enough energy, the nuclei can be accelerated to extremely high speeds such that, upon colliding, the strong nuclear force within the atoms dominates allowing this fusion to occur. A side effect which has previously proved to be an obstacle for scientists is that applying such large quantities of energy creates plasma, which the BBC article above appropriately refers to as “a roiling soup of charged particles.” The concern has been that the plasma would absorb the majority of the laser’s energy, limiting the amount of energy that could be successfully delivered to the fuel target in a uniform fashion. The energy must be delivered uniformly so that the fuel – a spherical pellet – has nowhere to go but towards its own centre, thus condensing it and creating the conditions to achieve ignition of the reaction.

Recent results have shown that the plasma does not significantly affect the target’s ability to absorb the incident laser energy, and could actually be manipulated to improve uniformity of the fuel compression. The NiF hit their target with 669kJ of energy in approximately 10 billionths of a second, which upon scaling is equivalent to boiling the contents of “50 Olympic-sized swimming pools in one second.” Calculations suggest that the NiF can achieve ignition with 1.2MJ, with spokesperson Dr. Glenzer saying “it’s going to happen this year”.

So why does fusion matter?

If controllable fusion power can realistically be achieved it could stand to change our energy infrastructure dramatically. This is an opportunity for a seemingly endless supply of energy, without the burdensome greenhouse gas emissions produced by conventional power plants.

At a glance, the origins of many serious problems can be directly associated with energy resources. Desalination, for example, is a promising means of providing potable water to coastal developing nations, but this is a very energy-intensive process. If the cost and abundance of energy are no longer a factor, it would be much more feasible to implement large boiling facilities that feed from a fusion grid.

Where droughts are the cause of famine, artificial climates that are conducive to plant growth could be created, or water could be pumped to and from previously unthinkable distances. Perhaps the Sahara desert could be slowly re-cultivated in this fashion.

Conflict and war have historically resulting from the struggle to control resources, as exemplified today in areas such as the Persian Gulf. But, where a cheaper alternative is economically viable, there would be a diminished need for oil.

The simplifications above do little justice to the complexity of these issues, but serve to show the significance of a clean, powerful energy with an abundant fuel supply from more than just a technological perspective (though it is fascinating to conceive our scientists recreating the same energy source as the stars right here on our lonely planet).

Where policy occasionally stumbles, it is good to know that technology continues to progress. And while technology is not the panacea for environmental change, it can certainly help. Energy is a big piece of the environmental puzzle – if we can crack the fusion problem, the other pieces may just start to fall into place.