Comparison of Storage Technology Options
Flow Batteries: electrolyte is stored in a external container and circulates trough the battery cell stack.
Advantages: Unlimited electrical capacity.
Limited by electrolyte reservoir
Disadvantages: Limited useful life --> 3-5 years
Advanced Batteries: lithium-ion, polymerion, nickel metal hybrid and sodium sulfur type.
Advantages: use less space
Disadvantages: expensive for large applications
Super Capacitors: Electronic device which have the characteristics of capacitors and electrochemical batteries except there is no chemical reaction.
Advantages: Virtually unlimited cycle life, low impedance, rapid charging, simple charge methods
Disadvantages: Linear discharge, voltage prevents use of the full energy spectrum, low energy density, cells have low voltages, high self-discharge.
Super Conducting Magnetic Energy Storage: Energy stored in the magnetic field created by the flow of direct current in a coil of superconducting material that has been cryogenically cooled.
Advantages: Power is available almost instantaneously, high power output for a brief period, no loss of power, no moving parts.
Disadvantages: Energy content is small and short-lived, cryogenics cold temperature technology can be challenging.
Pumped Hydro: Water pumped from a lower reservoir uphill then flow downhill to through turbines.
Advantages: Readily available and widely used in high power applications, lower cost of power, frequency regulation on the grid, and reserve capability.
Disadvantages: Spends years in regulatory and environmental review, can only be implemented in areas with hills.
Compressed Air: Compressed Air Energy Storage (CAES), air storage during off-peak hours and released to combustion turbine when necessairy.
Advantages: Conserves some natural gas by using low-cost, heated compressed air to power turbines and create off-peak electricity.
Disadvantages: Low efficiency, for every kWh of energy going in, only 0.5 kWh energy can be taken out.
Flywheels: A cylinder that spins at a very high speed, storing kinetic energy.
Advantages: Charge and discharge rapidly, affected little by temperature, take up relatively little space, long life span, lower maintenance.
Disadvantages: Power loss faster than for batteries.
