Table 1 Electrical generation analysis of four 200-W PV modules over 1Â year
|  | Optimal tilt angle (°) | Module tilt | Change in efficiency from flat orientation | ||
|---|---|---|---|---|---|
Flat (kWh/year) | Optimal (kWh/year) | Increase (kWh/year) | Percent increase | ||
Minneapolis, MN | 41 | 238 | 297 | 59 | 25 |
Boulder, CO | 38 | 280 | 345 | 65 | 23 |
Phoenix, AZ | 32 | 349 | 404 | 55 | 16 |
Average | Â | Â | Â | 60 | 21 |