This estimator converts storage energy associated with a offshore wind project into hours of support at a selected discharge power. It accounts for an energy reserve and discharge efficiency.
Use it to screen whether a proposed battery or other storage resource can cover a target firming interval. Actual dispatch duration can differ when power varies or operational constraints apply.
Use the storage system’s nominal energy rating in MWh.
Enter the constant MW output the storage must support.
Use a discharge-side efficiency appropriate to the technology.
Exclude energy that must remain unavailable for normal dispatch.
Use the usable MWh and hours to test the coverage target.
Storage duration (hours) = Energy capacity × (1 − Reserve fraction) × Discharge efficiency ÷ Discharge power
This is a constant-power energy balance. It does not model changing dispatch, auxiliary loads, degradation, or minimum operating limits beyond the entered reserve.
The main result expresses continuous discharge duration at the selected power. Use the supporting values to confirm that the scale and assumptions are internally consistent.
Results are planning estimates based on constant inputs and do not replace site-specific engineering, operational, or financial analysis.
A storage system has 800 MWh nominal energy, a 200 MW discharge target, 90% discharge efficiency, and a 10% reserve.
Usable delivered energy = 800 × (1 − 0.10) × 0.90 = 648 MWh. Duration = 648 ÷ 200 = 3.24 hours.
The system can support the selected output for approximately 3.24 hours under these assumptions.
It represents continuous discharge duration at the selected power. It reflects only the values entered and should be interpreted within the stated assumptions.
Use one consistent basis. Do not apply a loss, availability, or cost adjustment twice if it is already embedded in another input.
Use 8,784 hours when the measured period is a full leap year and the calculator includes a period-hours field. For planning estimates, 8,760 hours is the conventional annual basis.
Resource variation, curtailment, downtime, equipment degradation, grid constraints, and measurement boundaries can all change realized results.
Yes, if the inputs use matching definitions and periods. For investment or engineering decisions, compare the underlying assumptions as well as the headline result.