System shutdown hours per annum can be found in Audit Wizard, step 3 'create site & energy profile'.
It's purpose is to omit or exclude hours from annual hours calculations. An example of this would be a period of non operation or shutdown during the year where maintenance may be carried out. Such periods of non operation or shutdown would influence annual hours calculations. Because such events would not be recorded by audit loggers during an audit, the audit wizard field provides a location to manually enter such events.