Battery duration and usable energy
Preview Version 0.1.0How long a battery runs at a given power, its C-rate, and how much energy it delivers and needs to recharge.
Duration at dispatch power
5.33h
At 75 MW, this battery runs 5.33 hours; it delivers 360.0 MWh and needs 423.5 MWh to recharge.
NLRSelf-checked · The spec's 5.33 h, 0.1875 C-rate, 360 MWh, and 423.5 MWh cases pass. What this means
Self-checked only: no independent check has been run yet · Example values · Review pending Report a problem
How we got this
Method
Duration is energy ÷ power; C-rate is power ÷ energy. Depth of discharge limits the energy delivered, and round-trip efficiency is a loss taken on charging, so charging energy is delivered energy ÷ efficiency. The same convention holds in the workbench's battery screen.
Steps
- Duration at rated power: 400 MWh ÷ 100 MW = 4 h.
- Duration at 75 MW: 400 ÷ 75 = 5.33 h; C-rate 75 ÷ 400 = 0.1875.
- Usable delivered energy: 400 MWh × 90% depth of discharge = 360 MWh.
- Charging energy: 360 MWh ÷ 85% round-trip efficiency = 423.5 MWh, with the losses taken on charging.
Assumptions
- Rated energy is the battery's nameplate energy at its rated power; real duration falls at high power and low temperature.
- Depth of discharge and round-trip efficiency are the values entered; degradation is not modeled.
Sources
- NLR, Annual Technology Baseline (ATB): Utility-Scale Battery Storage, 2025, Definitions of power, energy, duration, and round-trip efficiency
Known limits
- Real duration depends on power level, temperature, and age; these are nameplate figures.
- Auxiliary loads and standby losses are not modeled.