Flow Duration → Annual Energy Yield
Converts a flow‑duration style dataset into annual energy output for a hydropower plant. Enter net head, rated discharge and efficiency, then provide flows with % of year.
Inputs
Flow‑duration style data
Enter a few representative flow classes. Each row represents a flow Q that occurs for a percentage of the year (e.g. 12%). Internally we assume this flow is roughly constant over that share of the year.
| # | Flow Q m³/s |
% of year |
|---|
Summary
Enter net head, rated discharge, efficiency and some flow‑duration data, then click Compute energy to see installed capacity, annual energy and capacity factor.
Tip: You can approximate a flow‑duration curve by grouping similar flows into a few bands (e.g. 0–10 m³/s, 10–20 m³/s, etc.) and using the % of time for each band.
Profile, table & exports
Energy contribution by flow class
Bars show how much each flow class contributes to annual energy (MWh/year). Rated discharge limits turbine flow; any excess is treated as spill.
| Flow Q | % of year | Hours/yr | Turbine Qused | Spill Q | Power used | Energy used |
|---|---|---|---|---|---|---|
| No results yet. Enter data and click Compute energy. | ||||||
Theory (brief)
- Instantaneous power for a unit: \( P = \rho g Q H \eta \). Internally computed in kW using SI units (Q in m³/s, H in m, g = 9.81 m/s², ρ = 1000 kg/m³).
- For each flow class \( i \) with discharge \( Q_i \) and share of the year \( f_i \):
- Hours per year: \( t_i = f_i \times 8760 \).
- Effective turbine flow: \( Q_{i,used} = \min(Q_i, Q_r) \).
- Spill flow: \( Q_{i,spill} = \max(0, Q_i - Q_r) \).
- Power: \( P_i = \rho g H Q_{i,used} \eta \).
- Energy: \( E_i = P_i \, t_i \).
- Total annual energy: \( E_{year} = \sum_i E_i \) (reported in MWh and GWh).
- Installed capacity: \( P_{inst} = \rho g H Q_r \eta \).
- Capacity factor: \( CF = \dfrac{E_{year}}{P_{inst} \times 8760} \).