Fusion & Grid Storage

Storage and firm generation are partners, not substitutes; fusion covers the long-duration gaps that batteries alone cannot.

Energy storage — batteries, pumped hydro, and emerging long-duration systems — is essential to a clean grid. Storage shifts energy in time: it captures surplus renewable output and releases it later. But storage does not create energy; it moves it. Over long low-renewable periods, stored energy is depleted and must be refilled from generation. Firm clean generation and storage work best together.

Duration is the dividing line

Lithium batteries are excellent at hours-scale shifting — charging midday, discharging in the evening. Covering multi-day weather systems or seasonal swings requires storing enormous quantities of energy, which is difficult and land- and material-intensive to do everywhere. Firm generation sidesteps this by simply continuing to produce, so the storage fleet only has to cover shorter cycles.

A complementary system

With firm clean generation in the mix, storage is used for what it does best — smoothing short cycles and providing fast response — while generation carries the sustained load. This reduces the total storage the system must build. Fusion is designed to be that continuous clean generator, reducing reliance on very large long-duration storage buildouts.

• Storage shifts energy in time; it does not generate it.
• Batteries excel at hours; long gaps need generation or vast storage.
• Firm clean generation lets storage focus on short-cycle smoothing.
• Fusion aims to be the continuous clean generator that pairs with storage.

Design-and-simulation framing. The Kronos machines are today design and simulation studies: the breeder (Hyperion) and the burner (Aegis / MetroVolt). No hardware net-gain has been demonstrated. Breeder construction is planned to begin Q2 2027, with first-of-a-kind (FOAK) first tritium targeted around 2030. Comparisons on this page are qualitative and use only public, defensible figures; nothing here is a performance guarantee.

Storage and firm generation are allies. The most efficient clean grid uses both, each doing the job it is suited for.