In a decade, the international fusion experiment ITER will start operating in the south of France. This historic experiment will generate up to 500 megawatts of fusion power and provide a proof of principle for fusion energy. Fusion has the potential to provide a large fraction of our energy for millions of years. Professor Steven Cowley describes the scientific progress in fusion — from Sir Arthur Stanley Eddington’s prophetic predictions in 1920 to the remarkable results that have lead to ITER. He outlines the challenging problems that must be solved to make fusion power a commercial option, and explains the worldwide efforts to find their solution.

Professor Steven Cowley became Director of the United Kingdom Atomic Energy Authority’s Culham Laboratory in September 2008 and Chief Executive of the UK Atomic Energy Authority in November 2009.