Nuclear fusion, the energy that powers the sun, has held the promise of clean, unlimited energy for nearly a century. Ever since we understood the basic principles governing this powerful energy source, we have envisioned it as the ultimate solution to our energy problems. However, replicating the heart of a star on Earth has proven to be a monumental challenge, and the question remains: when will fusion power generation become a reality?
The theory is elegant in its simplicity: under immense pressures and temperatures, the nuclei of light atoms, such as hydrogen, fuse to form heavier nuclei, releasing enormous amounts of energy in the process. The sun, a gigantic ball of incandescent gas, achieves this thanks to its immense mass and the resulting gravitational force, which compresses hydrogen to extreme densities and temperatures – more than 15 million degrees Celsius – forcing the nuclei to collide and fuse. The result is solar radiation that bathes our planet from almost 150 million kilometres away.
Replicating these conditions on Earth is a Herculean task. It requires creating a controlled environment where temperatures and pressures similar to those in the solar core can be achieved, confining the resulting plasma – an ionised gas at extreme temperatures – and, crucially, extracting the energy released efficiently.
For decades, scientists have worked tirelessly to overcome these obstacles, with important advances but still without reaching the long-awaited goal of ignition, the point at which the energy produced by fusion exceeds the energy needed to start and maintain the reaction. A few months ago this was achieved but only for a few thousandths of a second
Traditional methods have focused on magnetic confinement, using powerful magnets to contain super-hot plasma within a toroidal reactor, such as the Tokamak. Despite major investments and technological advances, ignition has remained elusive. Major milestones have been achieved, such as generating significant amounts of fusion energy over short periods of time, but sustainability and scalability remain major challenges. One cannot help but recall the optimistic predictions of half a century ago, which heralded fusion energy as an imminent reality. History reminds us of the complexity of this challenge and the need for caution in our expectations.
However, the landscape appears to be changing. Advances in materials technology, supercomputing, and understanding plasma physics are opening up new possibilities. Investment in fusion research and development remains robust, driven by the promise of a clean, safe, and virtually inexhaustible energy source. The urgency of the climate crisis and the need to diversify our energy sources add new impetus to the quest for fusion.
Against this backdrop, new ideas and approaches are emerging. One company exploring an alternative path is OpenStar, which is betting on a different magnetic confinement concept, using a magnetic dipole at the centre of the reactor. While this idea is not new and has already been explored in the past without success in generating net energy, technological advances may provide a second chance for this approach. The history of science is full of examples of ideas that, initially dismissed, re-emerge with renewed vigour thanks to new tools and perspectives.
The quest for fusion energy is a testament to human perseverance and our ability to meet major scientific and technological challenges. While the exact date for the arrival of commercial fusion energy remains uncertain, continued investment in research, the emergence of new ideas and the growing urgency of the energy transition give us reason for optimism. Perhaps, in a few decades, fusion will cease to be a promise and become a reality that transforms our world.
However, it is crucial not to lose sight of the present. As we pursue the dream of fusion, we must focus on the sustainable energy solutions already within our reach. Energy efficiency, renewable energy, and electrification of our energy systems are crucial steps we can take today to mitigate climate change and build a cleaner, safer energy future.
Public policy and social pressure must focus on accelerating the transition to these proven and available technologies, while continuing to support research into promising technologies like nuclear fusion. But let us not forget that the energy of the future is built today with the means we have.
Let us hope so.
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