PVWatts is a performance calculator for grid connected solar power systems developed by NREL (National Renewable Energy Lab) to help non-solar expert conduct estimates for grid-connected solar photovoltaic systems within the USA. The calculator uses hourly Typical Meteorological Year weather data to forecast how many kilowatt hours (kWh) you will generate on a monthly or annual basis.
You can enter parameters such as fixed mounted solar panels, solar panels on a tracker and even the azimuth to properly forecast different solar power system setups. Both version 1 and 2 of the calculator are provided for free on the PVWatts Website. I ran a estimate of how a 4.0 kilowatt (kW) solar power system would perform in Los Angeles using version 1 of the PVWatts calculator. Check out my assumptions and system performance:
| Station Identification | |
| City: | Los_Angeles |
| State: | CA |
| Latitude: | 33.93° N |
| Longitude: | 118.40° W |
| Elevation: | 32 m |
| PV System Specifications | |
| DC Rating: | 4.0 kW |
| DC to AC Derate Factor: | 0.770 |
| AC Rating: | 3.1 kW |
| Array Type: | Fixed Tilt |
| Array Tilt: | 33.9° |
| Array Azimuth: | 180.0° |
| Energy Specifications | |
| Cost of Electricity: | 12.5 ¢/kWh |
| Results | |||
Month | Solar Radiation (kWh/m2/day) | AC Energy (kWh) | Energy Value ($) |
| 1 | 4.44 | 401 | 50.12 |
| 2 | 5.35 | 441 | 55.12 |
| 3 | 5.62 | 506 | 63.25 |
| 4 | 6.05 | 522 | 65.25 |
| 5 | 6.19 | 548 | 68.50 |
| 6 | 6.17 | 526 | 65.75 |
| 7 | 6.48 | 567 | 70.88 |
| 8 | 6.68 | 582 | 72.75 |
| 9 | 5.78 | 487 | 60.88 |
| 10 | 5.43 | 480 | 60.00 |
| 11 | 4.84 | 420 | 52.50 |
| 12 | 4.46 | 398 | 49.75 |
| Year | 5.63 | 5879 | 734.88 |
Whats the performance of a 4.0kW system in your neck of the woods? go ahead feel free to post and discuss your results here.
