Previous versions of the Automation Engine had the functionality to export a forecast
How to export a forecast in version 12?
Release: AUTWAB99000-12.2-Automic Workload Automation-Base Edition
The functionality to export a forecast isn't available on 12.0, 12.1 and 12.2. This functionality is included with 12.3 which is tentatively planned for release in June 2019.