U.S. Officials Celebrate Milestone in Fusion, Source of Abundant Clean Energy

U.S. officials hailed a milestone for fusion energy research Tuesday, even as they acknowledged fusion power plants harnessing the power of the sun to supply abundant clean energy may remain decades away at best.

A Dec. 5 fusion experiment at the Department of Energy's Lawrence Livermore National Laboratory in California released more energy than it applied to start the reaction, according to the researchers.

Livermore's 192 high-powered lasers helped to heat plasma inside a targeted fuel capsule the size of a pencil eraser to 150 million degrees Celsius, 10 times the temperature of the sun, for a tiny fraction of a second. As a result, the fuel released more energy than it absorbed, producing a "scientific energy breakeven," also known as fusion ignition.

"America has achieved a tremendous scientific breakthrough," Energy Secretary Jennifer Granholm said at a packed Washington, D.C. press conference with the Livermore scientists.

But Livermore's experiment didn't come close to generating more energy that it consumed, because the lasers it briefly fires operate at less than 1% efficiency, meaning they use more than 100 times the energy they produce.

Each firing, known as a test shot, must be planned like a space launch, while the commercial fusion plant of the future will need to fuse hydrogen isotopes constantly on a scale that's orders of magnitude greater than achieved Dec. 5 at Livermore's National Ignition Facility (NIF), a 10-story building the size of three football fields.

The NIF was completed in 2009 at a cost of $3.5 billion. Its primary purpose is to conduct experiments ensuring the reliability of U.S. nuclear weapons in the absence of nuclear tests.

"There are very significant hurdles, not just in science but in technology," in the way of commercialization of fusion energy, said Livermore Director Kim Budil. "With concerted effort and investments, a few decades of research on the underlying technologies could put us in a position to build a power plant."

Such a plant would also need to convert the fusion energy released into electricity. Gas power plants currently have conversion efficiency ratios of about 45%, while nuclear power plants net about a third of the fission energy released.

Still, the success unveiled Tuesday validates a scientific project beset by years of unexpected reverses and unsubstantiated claims. It also promotes the Biden Administration's aim of "developing a bold vision for commercial fusion energy." The private sector invested $2.5 billion in fusion technology last year, the White House noted in March.

The administration is counting on fusion ignition to promote support and funding for research that clearly isn't cheap. "We have taken the first tentative steps toward a clean energy source that could revolutionize the world," said Jill Hruby, the Energy Department's undersecretary for nuclear security.

Investment promoters are likely to stress the technology's promise as well. Meanwhile, fusion power is likely to remain a research cost rather than a source of profits for the foreseeable future.