Fusion

December 15, 2022

Yesterday’s NY Times Morning feed reported on a recent breakthrough in creating fusion energy.  Earlier this month scientists at the Department of Energy announced they had carried out a fusion reaction that produced more energy than went into it.  This implies humans can tap into the process that powers stars to produce energy on Earth.  Fusion provides a clean source of energy that could replace the polluting fossil fuels and help overcome climate change.  There are still serious barriers but if the remaining challenges can be resolved fusion could produce more energy than any of our current energy technologies.  It is unclear if scientists can reliably replicate the test they achieved.  There are questions if they can do it more efficiently, quicker, and on a scale to make it a viable alternative.  If not, yesterday’s announcement may amount to little more than laboratory science.

When I looked online, I found Fusion power generates electricity by using heat from nuclear fusion reactions.  In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, while releasing energy.  Devices designed to harness this energy are called fusion reactors.  Research into fusion reactors began in the 1940’s, but to date the only successful design to produce positive fusion energy (more power out than in) is the inertial confinement laser-driven fusion machine at the US National Ignition Facility.  The fusion process requires fuel and a confined environment with enough temperature, pressure, and confinement time to create plasma for the fusion to occur.  The blend of these figures results in a power-producing system known as the Lawson criterion.  Hydrogen is the most common fuel in stars, and gravity provides extremely long confinement times that reach the conditions needed for fusion energy production.  Proposed fusion reactors generally use heavy hydrogen isotopes (deuterium and tritium, or a combination) to allow them to reach the Lawson criterion requirements with less extreme conditions.  Most designs aim to heat their fuel to around 100 million degrees, which presents a major challenge in producing a successful design.

Most nuclear fusion experiments have used doughnut-shaped reactors and magnetic fields to trap hydrogen, fuse it, and release energy.  Those experiments have yet to produce more energy than they used.  The Department of Energy’s lab is different.  It fired 192 lasers at a tiny hydrogen pellet to heat the pellet and cause it to implode, fuse into helium, and release a blast of energy.  The lab has been conducting this experiment for years, tweaking how and where the lasers are fired.  These changes paid off on December 5th.  The resulting nuclear fusion produced about 50% more energy than the energy from the lasers.  As exciting as the results are to scientists, they say it will require decades of work before this breakthrough leads to widespread commercial use, if ever.  It is typical for scientific breakthroughs to start in unrealistic lab settings before they are refined for public use.  At the very least, this discovery shows that nuclear fusion can be a source of energy. Now they just need to turn it into a usable technology.

THOUGHTS:  While fusion promises to provide unlimited energy for the future, it is unlikely to be a viable source of energy by the 2035 deadline to eliminate all greenhouse gas emissions in the US from its electricity sector.  This plan relies on a sharp increase in wind and solar energy generation, although it may get a boost from nuclear fusion.  What is clear is that the US, and the world, cannot rely solely on any single power source.  Our reliance on fossil fuel provided a cheap power source that caused us to abandon improvements in other sources, much to our detriment.  Wind, solar, hydro, and geothermal energy all need to continue to be researched and improved.  Then together with fusion we may begin to reverse the climate catastrophe that is on our horizon.  Act for all.  Change is coming and it starts with you.