Scientists have just crossed one of the most important thresholds in the quest for fusion energy. A team at Lawrence Livermore National Laboratory has created the first known fusion reaction with a net energy gain — that is, it produced more energy than it consumed and resulted in ignition. The researchers achieved the feat on December 5th, when they used 192 lasers at the National Ignition Facility to blast a cylinder containing frozen hydrogen surrounded by diamond.
The reaction, which generated a flurry of X-rays, struck a fuel pellet of deuterium and tritium with 2.05 megajoules of energy. That, in turn, led to a wave of neutron particles and 3.15 megajoules of output. That gain was 'only' equivalent to about 1.5lbs of TNT, but that was enough to meet the criteria for fusion ignition.
The development has been a long time coming. The National Ignition Facility started work in 2009, but it wasn't until 2014 that the installation's laser-based fusion technology produced a meaningful volume of energy. Progress accelerated in the past year, however. Lawrence Livermore generated a much larger amount of energy in a test last August, producing an output equivalent to 70 percent of the energy needed to perform the reaction. An attempt in September generated 1.2 megajoules using the 2.05-megajoule blast.
The lab and the Energy Department are quick to caution that "many" advancements are still necessary before fusion reactors are practical enough to power homes. During a presentation, scientists said they needed to improve the number of reactions per minute, simplify the process and otherwise make it easily repeatable. The net energy gain also doesn't include the entire system required to run the laser systems. And of course, the developers need to improve scaling — a reactor would have to power enough households to justify its existence.
The National Ignition Facility also isn't intended as a generator research program. It's using fusion to test and maintain the US nuclear arsenal. Other organizations and companies will need to cooperate on civilian uses.
The Energy Department is in the midst of rebooting a coordinated fusion power effort, however. During the event, officials also noted that a functional plant wasn't as far off as you might think. While they didn't commit to a timeframe, they said it was less than the 50 or 60 years they might have predicted in the past. You might see the first commercial fusion reactor in your lifetime, to put it another way.
The technology could be vital to limiting global warming and otherwise fighting climate change. While renewable energy sources like solar and wind power are more eco-friendly than coal, they don't always meet demand and can require large amounts of land. Solar also isn't as effective in regions where sunlight can be limited. Sufficiently powerful fusion reactors could achieve the dream of clean powerplants that have enough capacity to serve large populations without the radioactive waste of nuclear facilities.