US scientists have conducted the first-ever nuclear fusion experiment to achieve a net energy gain, paving the way for “clean energy that could revolutionize the world”.
During a landmark news conference at Lawrence Livermore National Laboratory in California, officials revealed a successful fusion experiment last week.
If it happened: ‘Amazing’ scientific breakthrough could create unlimited energy
It is the result of “60 years of global research, development, engineering and experimentation” and could eventually become the backbone of commercial power generation.
Such an outcome would accelerate the world’s transition to renewable energy and help fight climate change.
U.S. Energy Secretary Jennifer Granholm said the breakthrough “will go down in history.”
“It’s one of the most impressive scientific feats of the 21st century,” she added.
How was the experiment carried out?
The experiment involved firing 192 high-powered laser beams at a capsule containing the elements deuterium and tritium, heating it to temperatures in excess of 3 million degrees Celsius – briefly simulating conditions in a star.
It’s “been done hundreds of times,” says Dr. Marvin Adams, but has never succeeded in producing more energy than it expends.
“For the first time, they designed the experiment so that the fusion fuel stays hot enough, dense enough, round enough, and ignited long enough that it produces more energy than can be deposited with a laser,” he said.
“The input is about 2 megajoules, the output is about 3 megajoules—add 1.5, and it takes less time to generate energy than it takes light to travel an inch.”
As he quips, it’s “a little bit quicker”.
Uses a high-powered laser, focused on a “peppercorn-sized” target
While the target is smaller than a pea, the lasers — part of the so-called NIF system — are powerful enough to deliver more energy than the entire power grid that sustains the entire United States.
It is “the size of three football fields and can deliver more than 2 million joules of energy, with a peak power of 500 trillion watts,” said lead engineer Jean-Michel Di Nicola.
“In a very short amount of time, a nanosecond, it overwhelms the entire U.S. electrical grid,” he said.
NIF system has 192 lasers
How long does the process take to produce usable energy?
After the press conference everyone was discussing how long the process would take to generate energy we could actually use.
Dr. Kim Budil, director of Lawrence Livermore National Laboratory, admits it will take “probably decades”.
President Joe Biden has said he wants commercial fusion reactors to be in place within 10 years, and officials have acknowledged that the private sector must play an important role in accelerating the transition from laboratory experiments to commercial electricity production.
Other fusion projects will also play a role – scientists in California cite work by a team in Oxfordshire that earlier this year Generate approximately 11 megawatts of energy using their JET machines.
This far exceeds the energy generated in the NIF experiment, but — crucially — no net energy gain was achieved.
A major scientific milestone—but lasers require enormous power
When Dr. Marv Adams held up the cylindrical target containing the “peppercorn-sized” fusion fuel pellets, he confirmed that they had achieved the “ignition” of the fusion reaction.
He also revealed that the scientists put about 2MJ of energy into their fusion reaction and released about 3MJ of energy.
This is evidence of the “energy gain” that this announcement refers to.
It’s a major scientific milestone: Proving that the fusion reaction itself can generate more energy than you put it into it.
But they have to use 300MJ of electricity to power the laser.
So from an energy production standpoint, they still need to put more than 99% of the electricity in the whole machine.
Gianluca Gregori, a professor at the University of Oxford who is an expert on the lasers used in the lab, stresses that the energy generated is less than that required to power a wall plug.
“While this is not yet an economically viable power plant, the path ahead is clearer,” he added.
Jeremy Chittenden, professor of plasma physics at Imperial College London, said scientists “will need to find a way to reproduce the same effect more often and cheaper”.
If they do, it will be an important shot in the arm in the world’s push for renewable energy.