Two start-ups working to commercialize fusion energy made headlines last week. Helion Energy announced that its Polaris prototype fusion energy machine recently demonstrated measurable deuterium-tritium fusion and achieved a plasma temperature of 150 million degrees Celsius (MºC). Newcomer Inertia Enterprises announced that it has raised $450 million in its Series A fundraising round.

Helion Energy, based in Everett, Wash., today announced an agreement to use its first fusion power plant to provide electricity to Microsoft. Constellation, which operates 21 commercial nuclear reactors in the United States, will serve as the power marketer and will manage transmission for the project.