What AC output should be expected for a 4KW PV system in southern California?

Re: What AC output should be expected for a 4KW PV system in southern California?

Welcome to the Forum Jeff.

You can use various programs to estimate the output of solar power systems. A very simple one that I like to use is called PV Watts. It has data for ~20 years of solar irradiance for various locations around the US and World.

Plug in a few assumptions, and away it goes. A 4kW solar array, fixed mount, tilted to latitude in Los Angeles CA, with 0.77 derating (solar panels lose power when hot, and a bit of losses in wiring+GT inverter gives you):

"Station Identification"
"City:","Los_Angeles"
"State:","California"
"Lat (deg N):", 33.93
"Long (deg W):", 118.40
"Elev (m): ", 32
"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 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/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, 6.06, 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

So, on average (+/- 10% is very common from year to year) you would get around 398 to 582 kWH per month.

Or, 5,879 kWH per year for 365 days per year:

• 5,879 kWH per year/365 Days per year = 16.1 kWH per day

There is also a Output Hourly Performance button (each 24 hour period is a "representative" average day) and put it into a spread sheet.

It is interesting to change tilt, try 1 and 2 axis trackers, etc...

-Bill