For the first time, researchers have created a fusion reaction that resulted in a net energy gain. The Resultsfrom the Lawrence Livermore National Laboratory in California, mark an important step on the very long road towards generating clean energy from nuclear fusion.
“Last week, lo and behold, they shot a bunch of lasers at a pellet of fuel and more energy came out of that fusion ignition than the energy of the lasers that went in,” Arati, director of the Office of Science and Technology Policy of the White House. Prabhakar said on one press conference announcing the achievement in Washington, DC, today. “I just think this is such a great example of what perseverance can really accomplish.”
“A great example of what persistence can really achieve”
Nuclear fusion occurs when atoms collide, “merging” to create a heavier atom, releasing energy in the process. In the sun and other stars, hydrogen nuclei fuse to form helium and generate massive amounts of energy. To achieve nuclear fusion on Earth, humans must heat atoms to enormous temperatures — millions of degrees Celsiusthat’s why it was so difficult to achieve a net energy gain.
In this case at 1:03 a.m. local time on December 5, the national laboratory used 192 powerful laser beams to hit a solid target of hydrogen isotopes only about the size of a peppercorn. They produced 3.15 megajoules of energy, about 50 percent more than the 2.05 megajoules that the lasers used to start the reaction. By doing this and reaching a scientific energy break-even, the researchers achieved what is called “fusion ignition.”
Exploiting nuclear fusion could be revolutionary – giving people an abundant source of energy without the nasty side effects of greenhouse gas emissions or long-term radioactive waste. However, this depends on overcoming huge technical hurdles. After decades of experimentation, today’s announcement represents a small but significant victory over one of those hurdles. But there’s one more long, long way before nuclear fusion can fulfill all clean energy dreams.
The US government funds fusion energy research since the fifties. Around the world, the chase has raised tens of billions of dollars in funding. And late last year, scientists with the Joint European Torus (JET) in the UK generated a record 59 megajoules of energy from nuclear fusion. The big problem is that until now nuclear fusion in a laboratory had not been possible Lake energy than was needed for the reaction to take place.
It is an important milestone, but there are still some important caveats to note. An important point is that the DOE bases this victory solely on the output of the lasers, which are quite inefficient. It takes 300 megajoules of energy from the grid to get it those two megajoules of laser energy. So today’s announcement depends on a narrow definition of ‘net energy gain’.
Lasers aren’t the only way to achieve nuclear fusion. Other efforts, including JET, include a magnetic device called a Tokamak to confine and heat plasma. Whatever the method, we are probably decades away from generating energy in a power plant this way. It will take a lot more money and incremental wins to get there, and today’s announcement is one of them.
“With real investment and real focus, that timeline can get closer,” Kim Budil, director of Lawrence Livermore National Laboratory, said at the news conference. “We were in a position for a very long time where it never got closer, right? Because we needed this first fundamental step. So we are in an excellent position today to understand what it takes to take that next step.”
For starters, scientists need to be able to get back to ignition. “This is one ignition capsule, one time. To realize commercial fusion energy you have to do many things; you have to be able to produce a lot of fusion ignition events per minute,” Budil said. “There are very significant hurdles, not only in science but also in technology.”
One hurdle is that the lasers used in future efforts will need to be much more efficient. The system used in this experiment, called the National Ignition Facility, is the largest, highest-energy laser in the world—larger than three football fields. But it’s still based on technology from the 1980s. Modern lasers are more efficient, and future efforts will likely try to incorporate newer technology into experiments.
“This shows that it is possible. That threshold being crossed allows them to start working on better lasers, more efficient lasers, on better containment pods, etc.” Budil said. “We need the private sector to get involved. It’s really important that an incredible amount of US government dollars have been poured into this breakthrough, but any steps we’ll take to get this to a commercial level will still require public scrutiny and private scrutiny.
