A colossal fusion project that could transform the energy industry just hit a big milestone

This picture, from October 2016, shows construction work on the ITER facility in the south of France.
Anne-Christine Poujoulat | AFP | Getty Images

A vast project to prove that fusion power is sustainable and can be generated on a commercial scale is now 50 percent complete, it has been announced.

The International Thermonuclear Experimental Reactor (ITER) is based in the south of France and described by those working on it as "the most complex science project in human history." ITER members include the European Union, the U.S., Russia, China and India.

The project will use hydrogen fusion, controlled by "superconducting magnets," to generate heat energy. This heat is planned to be used in commercial facilities to drive turbines and produce electricity.

According to the World Nuclear Association, fusion power "offers the prospect of an almost inexhaustible source of energy for future generations." The team behind the ITER project said that fusion energy is carbon free, environmentally sustainable and more powerful than fossil fuels.

The first stage of ITER operating as a functional machine, known as First Plasma, is slated to commence in December 2025. ITER scientists have predicted that fusion plants will subsequently come online as early as 2040.

"The stakes are very high for ITER," Bernard Bigot, director-general of ITER, said in a statement.

"When we prove that fusion is a viable energy source, it will eventually replace burning fossil fuels, which are non-renewable and non-sustainable. Fusion will be complementary with wind, solar and other renewable energies."