Earlier in August, the Lawrence Livermore National Laboratory in California said it had repeated its controlled nuclear fusion reaction experiment, achieving higher energy yield than during the laboratory's original feat last December. Back then, scientists from the United States became the first to conduct a controlled fusion experiment that produced more energy from fusion than the laser energy used to drive it.
Such developments have excited proponents of fusion, who hope to one day produce nearly limitless, carbon-free energy and displace fossil fuels as well as other traditional energy sources. However, this remains an elusive goal at the moment, since fusion happens at inordinately high temperatures and pressures that are extremely hard to control.
"In the recent experiment, the fusion energy is very small. It can heat roughly a cup of water. To produce a power plant (i.e. to produce hundreds of megawatts of power per hour) one would need to have many fusion explosions per second. Now, one has no idea how to produce laser pulses at the required rate," Jean Barrette, professor emeritus with McGill University's Department of Physics in Canada, said.
Barette concluded that "one would need at least 30 years of research to approach the necessary performance, and it is not clear at all if it is possible."
When asked which of the main approaches to controlled-fusion energy — inertial confinement or magnetic confinement — is more viable from a technical and economic standpoint, the expert replied that there was no way to determine this, as both methods have a long way to go before reaching a final positive result.
The magnetic confinement approach is embodied in the International Thermonuclear Experimental Reactor (ITER) project, which has been in development since the late 1980s, with actual construction launched in 2010.
Nevertheless, while ITER is closer to being a working power plant, it is still unclear whether the project will be economically viable, Barrette said. At the same time, the inertial confinement model used by the US Lawrence Livermore National Laboratory is "further away but may be progressing faster, at least for a while," the expert added.
"Note [that] today one only talks about the Livermore Inertial Confinement Result and ITER as the only two options. This is not quite the total picture," Barrette said, citing reports about other approaches, some of which are quite old.
In a similar vein, George Tynan, chair of the Department of Mechanical and Aerospace Engineering at the University of California, San Diego, thinks that while both methods allow making conditions for net energy production from controlled nuclear fusion, it is currently unknown which of them will become technologically viable and lucrative. He also noted that "both approaches have clear challenges that the world research community is working hard to resolve."
Challenges Ahead
Apart from the nuclear fusion technology itself, there are still other technological challenges that have to be resolved before it becomes a widespread and profitable energy source.
"Aside from producing the conditions within the fusion fuel — the so-called plasma — necessary to produce a significant energy gain, we must also demonstrate the ability to continuously produce such energy gains for an extended period of time, must learn how to generate a sufficient amount of tritium [a hydrogen isotope used as fuel] to maintain the fusion reactor's operation," Tynan, who is also a professor of engineering science, explained.
The scientist also added that it is necessary to "develop and demonstrate materials that can withstand the extreme conditions that will be found in a fusion reactor."
In addition, the expert drew attention to the need for an entirely new and technologically complex supply chain that would allow the fusion energy industry to compete in the global energy market. He also noted that there had been an increase in both government and private efforts related to fusion energy in recent years, which, in his opinion, will accelerate research and development in the area.
"But it also creates the temptation to raise barriers to full discussion of solutions to the challenge of fusion energy development. In the face of these developments, it is essential that we recognize that fusion energy development is a highly complex endeavor that will require the best ideas from the entire world's physics and engineering research community," Tynan noted.
Barrette, for his part, stressed the need for a device that could conduct fusion on a smaller scale than is available today. This is where various non-mainstream approaches to nuclear fusion could potentially help to achieve a breakthrough, the physicist stressed.
Fusion and Cooperation
When asked if the current developments would launch a full-scale race between countries for leadership in nuclear fusion technology, both experts suggested that it is more likely to foster cooperation rather than competition on account that this technology could benefit the whole world.
"I expect some competition between countries but nothing comparable to the atomic bomb race. It is now a pure financial competition. Each large country will invest in the field to make sure that have some leadership position, but in the end there will be a lot of collaboration since the energy problem is a world problem," Barrette said.
This sentiment was echoed by Tynan, who also emphasized the role of scientific cooperation between the United States and Soviet-led blocs that took place at the height of the Cold War, which helped, among other things, to achieve breakthroughs in arms control and other areas.
"In the face of the challenge of decarbonizing the world's energy system, the need for an energy technology with the characteristics of fusion energy, and the significant scientific and engineering challenges remaining to be solved to realize fusion's promise, it is my hope that the field will continue to benefit from a similar level of cooperation and openness," Tynan stated.
He also noted in an interview with Sputnik that "fusion research presents an opportunity to try to strengthen the sort of scientific and technological cooperation that can benefit all the humankind even in these challenging times."