Scientists from the United States have once again demonstrated the energy effectiveness of thermonuclear synthesis, bringing us closer to the dream of limitless energy without carbon dioxide emissions.
Physicists have been attempting to replicate the thermonuclear synthesis that occurs in the sun since the 1950s. However, until recently, no group of scientists had managed to produce more energy from the reaction than was spent on it.
In December, researchers from the Lawrence Livermore federal laboratory in California achieved this milestone for the first time. They have now repeated their success on July 30, surpassing the results of the previous experiment.
Thermonuclear synthesis involves heating two hydrogen isotopes – deuterium and tritium – to extreme temperatures, causing atomic nuclei to merge and releasing helium and a significant amount of energy in the form of neutrons. While thermonuclear power plants may still be decades away from becoming a reality, their potential cannot be ignored. A small glass of hydrogen fuel could theoretically power a house for hundreds of years.
The most studied method of obtaining energy from thermonuclear synthesis is through magnetic confinement. However, the Laurence Livermore laboratory employs an inertial confinement method, directing lasers onto a microscopic fuel capsule.
The achievement of this milestone was hailed by US Energy Minister Jennifer Granholm in December as “one of the most impressive scientific achievements of the 21st century.” The scientific community eagerly awaits more detailed data from the experiment, but it is clear that progress in the development of thermonuclear energy is accelerating.
Preliminary results of the July experiment indicate an energy output of over 3.5 MJ, which is enough to power an iron for an hour. Achieving a net energy gain has long been seen as a critical step towards demonstrating the feasibility of commercial thermonuclear power plants. However, there are still several obstacles to overcome. The increase in energy output is currently only compared to the energy generated by the lasers, not the total energy required to power a system, which is much higher.
Scientists estimate that for commercial synthesis, a reaction must generate 30 to 100 times more energy than the lasers. Additionally, the National Ignition Facility (NIF) where the experiments took place can only perform one shot per day, while a power plant with internal confinement would likely need to perform multiple shots per second. Nevertheless, the improved results at the NIF, achieved “just eight months later” after the initial breakthrough, serve as another indication that progress is accelerating.