10.1 kW electrical at the design flow of 60 L/s and 27.5 m net head, about 64,558 kWh a year (capacity factor 73%). Best-suited turbine: Cross-flow (Banki–Michell). Pays back in about 5 years.
Electrical power at design flow
10.1kW
Cross-flow (Banki–Michell) · overall η 57% water-to-wire
Annual energy
64,558kWh
177 kWh per day on average
Capacity factor
73.3%
6,420 full-load hours
Net head
27.5m
friction + minor loss 2.54 m (8.5%)
Design flow
60L/s
mean 60 L/s · residual 6 L/s
Hydraulic power (net)
16.2kW
gross 17.7 kW = ρgQH
Penstock velocity
1.91m/s
Re 293,849 · f 0.0149
Year-1 value
€9,684
Payback
4 yr 11 mo
capex 45,248 €
LCOE
0.063€/kWh
IRR 21.3%
CO₂ avoided per year
25.8t
Turbine selection (net head, design flow)
| Turbine | Head range (m) | Flow range (m³/s) | Peak η | Min. flow | Fits your site |
|---|---|---|---|---|---|
| Cross-flow (Banki–Michell) | 2–200 | 0.01–10 | 72–80% | 15% | ✓ selected |
| Turgo | 10–300 | 0.002–10 | 78–85% | 15% | ✓ |
| Pelton | 10–1,800 | 0.001–50 | 80–88% | 10% | ✓ |
| Propeller / fixed-blade | 1.5–30 | 0.05–500 | 78–88% | 70% | ✓ |
| Francis | 10–700 | 0.1–1,000 | 84–92% | 40% | — |
| Kaplan (double-regulated) | 1.5–40 | 0.3–1,000 | 84–91% | 20% | — |
| Archimedes screw | 1–10 | 0.1–15 | 75–82% | 20% | — |
Monthly breakdown
| Month | Stream flow (L/s) | Turbine flow (L/s) | Load | Power (kW) | Energy (kWh) |
|---|---|---|---|---|---|
| Jan | 87 | 60 | 100% | 10.1 | 7,107 |
| Feb | 84 | 60 | 100% | 10.1 | 6,419 |
| Mar | 78 | 60 | 100% | 10.1 | 7,107 |
| Apr | 63 | 57 | 95% | 9.63 | 6,586 |
| May | 51 | 45 | 75% | 7.75 | 5,477 |
| Jun | 39 | 33 | 55% | 5.68 | 3,882 |
| Jul | 30 | 24 | 40% | 4.07 | 2,874 |
| Aug | 27 | 21 | 35% | 3.53 | 2,496 |
| Sep | 33 | 27 | 45% | 4.6 | 3,149 |
| Oct | 51 | 45 | 75% | 7.75 | 5,477 |
| Nov | 81 | 60 | 100% | 10.1 | 6,878 |
| Dec | 96 | 60 | 100% | 10.1 | 7,107 |
- Use a long-term mean flow. A single measurement in a wet month will badly overstate output.
- Monthly flow follows a generic “Temperate rain-fed (winter high)” pattern. Real streams vary day to day, so a flow-duration curve from gauging data gives a better estimate.
- Residual flow requirements are set by your water authority (often Q347 or 5–20% of mean flow). Permits, intake works and grid connection usually dominate small-hydro costs.