In order to calculate the load factor, simpy paste your load profile - measured power or current values with time stamp of measurement - into the text area and hit the 'Run' button. Alternatively, load it from a CSV file.
The load profile should have the following format (Time stamp, Power):
YYYY-MM-DD HH:MM:SS, S
2015-02-09 01:40:00, 402.2
An example load profile can be downloaded here.