I wonder if you have some material that I can read more about subject or some explanation as to why we should add the noise.

As for why you should add noise, the reason is that electrical loads tend to be noisy.  The electrical load from my house is not the same every day, so if I assumed that every day’s load profile was equal to the average load profile, I would seriously underestimate the peak load.  If you combined the electrical load of all the houses in my neighbourhood, some smoothing would occur so the aggregate load would be less noisy than my own house’s load, but the data would still show lots of noise.

The best explanation we have written on how HOMER adds noise is the help file article that you can find by looking up ‘noise in load data’ in the index of the Help system.  The process goes like this:

1.       For each day, HOMER draws a random number from a normal distribution with mean of zero and standard deviation equal to the daily noise value.  That’s the ‘daily perturbation factor’.

2.       For each hour, HOMER draws  another random number from a normal distribution with mean of zero and standard deviation equal to the hourly noise value.  That’s the ‘hourly perturbation factor’.

3.       For each hour, HOMER multiplies the unperturbed load value by (one plus the daily perturbation factor for that day plus the hourly perturbation factor for that hour).

The graphs in that help file article illustrate the effects of this process.