Hi,
I don't believe it can be set within the script as I believe that would somewhat defeat the point of the Execution Policy. Depending on your environment it can be set using the Set-ExecutionPolicy command, set by group policy or set manually.
I do some bits with Task Scheduler to run automation script and I address it by setting it at the command line so a script can be run using:
Powershell.exe -NonInteractive -WindowStyle Hidden -NoProfile -ExecutionPolicy Bypass -File C:\Scripts\MyScript.ps1
How are you planning to execute the scripts when you move to full automation?