Credit: Pixabay/CC0 Public Domain Over the past five years, private-sector funding for fusion energy has exploded. The total invested is approaching US$10 billion (A$15 billion), from a combination of venture capital, deep-tech investors, energy corporations and sovereign governments. Most of the companies involved (and the cash) are in the United States, though activity is also increasing in China and Europe. Why has this happened? There are several drive