This Tuesday, the U.S. Department of Energy announced a breakthrough in nuclear fusion technology. Experts have been working on developing a safe, effective way to perform nuclear fusion for 80 years, and a group of scientists in California finally discovered how to harness nuclear fusion in a way that produces more energy than it takes to create.

Nuclear fusion is a process by which two lighter elements combine to form a heavier element. This typically occurs in the Sun and other stars, where two Helium atoms collide at a high speed and combine to form a Hydrogen atom. This is how solar energy is created. On Earth, nuclear fusion is performed by fusing deuterium and tritium. Deuterium can be sourced from the ocean, and tritium from the atmosphere. In order to create nuclear fusion on Earth, scientists must mimic the gravitational force and heat of the Sun, which is no small feat. Fusion on Earth requires extremely high pressures and a temperature of 100 million degrees Celsuis.

Up until Tuesday, it seemed nearly impossible to recreate the power of the Sun on Earth without using much more energy than would be gained from the reaction. However, Tuesday morning at the National Ignition Facility in Lawrence Livermore National Laboratory in California, 192 giant lasers requiring 2.05 megajoules of energy fired at a BB-sized pellet of deuterium and tritium. Fusion occurred, expelling a flood of neutron particles carrying about 3 megajoules of energy. This led to a factor of 1.5 in net energy gain.

What does this mean for clean energy? Arati Prabhakar, the White House science advisor said, “This is such a wonderful example of a possibility realized, a scientific milestone achieved, and a road ahead to the possibilities for clean energy”. According to the United National International Atomic Energy Agency, fusion releases nearly four million times more energy than burning coal or gas. Additionally, there is no risk of a nuclear meltdown at a fusion reactor because any disturbance in a fusion reaction will simply cause the reaction to stop. Achieving net energy gain is a huge milestone for fusion, and though building reactors that can reliably produce a significant amount of energy will not be easy, this demonstrates that it is possible.

The ability to produce energy using nuclear fusion is a monumental step in the right direction for the future of clean energy. Though it may take many decades before the technology is developed enough to build a nuclear fusion power plant, the wait will be well worth it.