The German company behind the venture, Proxima Fusion, has raised 411 million euros for the project through a new share issue. The issue values Proxima Fusion at 2.4 billion euros.
In addition to Google, the German energy group RWE is among the investors.
Proxima Fusion hopes to have a fusion facility ready for operation in the 2030s.
Germany began phasing out its nuclear power - using traditional fission as an energy source - after the Fukushima disaster in Japan in 2011 and closed its last reactor three years ago.
Fusion is the energy process that takes place in the sun. But so far, no one has managed to harness it for stable electricity production here on Earth.
