I have a question about Step ten: Add sensitivity variables in the homer help, what is scaled annual average and what is it`s difference between annual average which HOMER automatically calculate after we add wind monthly average?
Using the scaled annual average input box for a HOMER variable allows you to adjust the size of an annual average input (load, wind speed, etc.) while not changing the way that variable changes on an hourly, daily or monthly scale.
If you have imported a wind resource file that contains 8760 data points (one for each hour of the year), HOMER calculates the daily average wind resource in m/s. In the case of the HOMER Getting Started guide this annual average is 4.5 m/s. If you imported this wind resource data from a site that is not the site you are simulating in HOMER then the wind resource at your site is likely to be quite different to the wind resource data you imported. If the two sites are close enough you can assume that the wind at your site will follow the same pattern as the data you imported, but it may be 10%-20% higher or lower. This is where you use the scaled annual average.
Scaling the annual average up or down will change the absolute value of each of the 8760 data points, but it will not change the relative shape or pattern of the data. Therefore you can use sensitivities in the scaled annual average box to see what the impact on you system would be if the wind resource were a bit higher or a bit lower without having to import or create the wind resource file all over again.