PORRITTINC
( LAYTON, UT )
ENERGY DEEP DIVE · BEYOND LITHIUM-ION: IRON-AIR, FLOW BATTERIES AND MORE

Grid-scale
battery
storage.

Four hours of lithium solves the evening ramp. It does not solve a still, cloudy week — and the chemistry that wins at 100 hours is not the chemistry that wins at four.

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The essentials
TOPIC

Duration changes chemistry

Short duration rewards power density; long duration rewards cheap energy storage. Lithium optimizes the first, iron-air and flow the second.

TOPIC

Iron-air

Rusting iron reversibly. Terrible round-trip efficiency, wonderful cost per kilowatt-hour. For multi-day storage that trade is correct.

TOPIC

Flow batteries

Energy in tanks, power at the stack, sized independently. Ideal when duration and power need to scale separately.

4 hr
Lithium sweet spot
100 hr
Iron-air target
DECOUPLED
Flow sizing
$/kWh
Long-duration metric

Go deeper.

Part of the Porritt Inc. energy library. Questions or corrections are welcome.

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