The moon, uniquely, has no atmosphere and no magnetic field, meaning the solar wind may have deposited large quantities of Helium-3 in the lunar dust over millions or billions of years. Helium-3 is possibly a viable fuel for fusion energy production at an industrial scale. Current reactors fust Hydrogen-2 with Hydrogen-3. Hydrogen-2 is abundant but Hydrogen-3 is exceedingly rare. If I remember correctly, there are only on the order of 10 kilograms of it currently available on Earth. Helium-3 is possibly a good substitute for Hydrogen-3 in fusion reactions.

Fusion reactions already produce net positive energy in laboratory settings, although it will be some time before this scientific net positive can be turned into an engineering net positive, and even more time still until it becomes an economic net positive.