[azernik]

100 hours = (kWh/kg) / (kW/kg) - ie capacity divided by the most cost-effective discharge rate.

[ComputerGuru]

I agree but that’s a highly misleading number because there’s a conflation of scenarios. Capacity is one thing, useable capacity at the requested discharge rate is another. You can’t pick and choose which numbers to use.

[azernik]

The combination of duration class and capacity is useful, though. 1MWh of 10-hour storage gives you a very clear idea of usable energy.

[amelius]

What if the discharge rate versus cost plot is mostly flat?

[azernik]

Then typically you'll run it at a higher discharge rate, and has something cheaper with a higher capacity/discharge ratio.