For the first time, a nuclear fusion experiment has produced more energy than was consumed in the process. After the rumors of recent days, the official announcement came on Tuesday 12 December. Jennifer Granholm, US Secretary of Energy, said at a press conference in Washington that the experiment was able to replicate “some conditions found only in stars and the sun”. A novelty that “brings us one significant step closer to the possibility of having zero-carbon energy that feeds our society”, she added.
The one obtained by the Lawrence Livermore National Laboratory, a US government laboratory in California, is an historic result in no uncertain terms, which brings humanity closer – even if enormous obstacles remain – to a technology that promises abundant, stable, carbon-free electricity and also low in radioactive waste. Scientists have been chasing it since the 1950s, amid more failures than celebrations.
Nuclear fusion is the reaction that powers the Sun and other stars. Compared to fission, the process that takes place in the power plant reactors working in the world, it works in the opposite way: instead of breaking the nuclei of heavy atoms, it generates energy by joining light nuclei. Furthermore, smelting waste has low radioactivity and decays more rapidly than traditional waste.
On paper, in short, nuclear fusion is practically perfect: it does not emit CO2 like coal and gas, it does not depend on the weather like solar and wind power and it does not produce as much waste as fission. According to the most enthusiastic celebrators, it will have a revolutionary impact and will allow millions of people around the world to be lifted out of energy poverty: a “small sun” will be enough to meet the needs of an entire nation.
In reality, however, things are different. First of all, fusion is complicated to keep stable for long periods, given the very high temperatures (millions of degrees Celsius) required by the process of uniting the nuclei. And it is also difficult to obtain a “net energy gain”, i.e. an amount of energy greater than that consumed by the machinery that triggers the reaction. Before Lawrence Livermore National Laboratory, no one had done it. The structure instead obtained 2.5 megajoules of energy against the 2.1 megajoules spent, according to provisional data reported by the Financial Timesone hundred and twenty percent more.
Despite the extraordinary goal achieved in the United States, favored by substantial public and private investments, nuclear fusion is still far from commercial use. And it will hardly be established for at least a few decades. Although the obstacle of the “net energy gain”in fact, many other engineering and economic challenges remain: scientific discovery alone is not enough; the procedure must be taken out of the experimental phase and made more efficient, less expensive and replicable.
As the Washington Post writes, to recreate the conditions of the successful experiment on a large scale – during which one of the largest lasers in the world was used to “bombard” hydrogen isotopes – will require enormous resources. It will then be necessary to build better equipment, capable of withstanding the stresses induced by the reaction without breaking. And it will be necessary to build machinery capable of converting the energy of fusion into electricity suitable for being fed into the grid.
In short, before being able to assert itself as a stable process for the generation of electricity, nuclear fusion will need a whole series of technologies to be perfected or still to be invented. It is therefore very unlikely that it will contribute to the climate agenda between now and the next thirty years. After all, the technologies useful for the immediate reduction of emissions – renewablesthe batteries, synthetic fuelscarbon capture, nuclear fission – are already available and proven, or are at a more advanced stage of development.
The result of the Lawrence Livermore National Laboratory is extremely important, but it will not change the near future of energy. Nuclear fusion research doesn’t have to stop, though. Because in the long term, from 2050 onwards, when many countries should have already reached carbon neutrality, fusion could be a fundamental ally for the profound decarbonization of human civilization.