# Degradation and Plant Construction Schedule

Large power plants are not constructed and commissioned at one point in time, but come on line on a Block-by-Block basis. Therefore, different sections of the plant will start contributing energy staggered in time as each comes on line, and accounting for energization times lasts until the last section is energized and the full capacity of the plant is realized.

In addition, the long term power plant production reduces continuously over time due to environmental exposure, component aging, and accrued module defects. Three mutually-exclusive models are supported, and can be selected by the user on simulation setup:

### Figure 38. List of Degradation Models

### Figure 39. The 3 Degradation Models at 0.5% per year Rate for 4 years. The Linear AC and DC Degradation Follow the Same Line.

# DC Linear

Linear DC degradation function reduces the DC power input to the inverter as a linear function of time by the specified rate from the user.

## Inputs

## Outputs

## Algorithm

1.) Loop for all simulation steps for each Block

a.) The continuous-time function in hours is as follows:

b.) Find the system power due to energization time and degradation for time *t*.

# AC Linear

This function will reduce the AC power output as a linear function of time.

## Inputs

## Outputs

## Algorithm

1.) Loop for all simulation steps for each Block.

a.) The continuous-time function in hours is as follows:

b.) Find the system power due to energization time and degradation for time *t*.

# AC Stepped

This function will reduce the AC power output as a stepped function of time. The AC output of the block is reduced by the linear annual degradation rate at a discrete point in time.

## Inputs

## Outputs

## Algorithm

1.) Loop for all simulation steps for each Block

a.) The discrete-time function in hours is as follows:

b.) Find the system power due to energization time and degradation for time *t*.