There are some handy parameters that can be used to estimate the power or revenue generation of a PV system. Often people will take the kW of the system and multiply it by the expected parameter to get expected value such as kW hours per year or dollars per year. These numbers are relatively easy to calculate. Ideally people are using the most realistic values possible if they want to estimate their expected outcome.
An example is, how many kilowatt hours should I generate from my 5 kW system on my roof?
First, here are my parameters for our 4.9 kW DC system [5 kW string inverter]:
| Variables |
kW |
Dollars |
| Mean [4.9 kW] |
15.81 |
$12.68 |
| Per [1 kW] |
3.23 |
$2.59 |
| Min [4.9 kW] |
0.05 |
$0.04 |
| Max [4.9 kW] |
35.13 |
$28.17 |
In this case, applying my parameters to a hypothetical 5 kW DC system, we could estimate mean daily kW production over the year to be 5 kW * 3.23 kW per kW = 16.15 kW per day. Multiply that your FIT contract price and this would be your daily income averaged over the year.
You can use the values above to estimate your highest and lowest income as $28.17 / 4.9 * your DC kW.
Oh, and you can see that you'll have some bad days too - $0.04 / 4.9 kW will give you $0.01/kW on dark snowy, snow-covered panel days.
