Storage
How energy is kept in reserve beyond Earth. Batteries, fuel cells, flywheels, and other buffers that bridge generation and demand.
Batteries
Lithium-ion cells dominate short-duration storage on spacecraft and rovers. State-of-the-art space-qualified packs deliver roughly 200 Wh/kg, with laboratory chemistries targeting 300 Wh/kg. The lunar night, lasting up to 354 hours, exposes the limits of battery-only architectures for large surface outposts.
Regenerative fuel cells
Regenerative fuel cells store energy as compressed hydrogen and oxygen, then recombine them in a fuel cell to produce power. The mass advantage over batteries grows with storage duration, but round-trip efficiency, water management, and moving-part reliability remain active research areas.
Mechanical and thermal storage
Flywheels store energy as rotational inertia and can serve dual duty as momentum wheels. Thermal storage absorbs waste heat or solar heat to buffer temperature swings and can shift power demand away from peak loads. The daily analysis stream covers advances in each approach.