Energy Storage Catalog

The right store depends on how long you need to hold energy: a lithium battery for hours (~90% round-trip), a hot water tank or sand battery for days of heat, pumped hydro for seasons, and money or skills for decades. This catalog compares every option by energy density, leak rate, round-trip efficiency and cost.

Key storage types

• Electrochemical — lithium-ion, lead-acid, flow batteries.
• Mechanical — pumped hydro, flywheels, compressed air.
• Thermal — molten salt, ice, hot water tanks, sand batteries.
• Chemical — hydrogen, ammonia, hydrocarbons.
• Monetary — savings, bonds, equities, real estate, Bitcoin.
• Skills & relationships — the highest-density, lowest-leak storage humans have access to.