Firstly, it is possible to run and email bills from PNPSCADA, however those bills are obviously not checked so should not be considered as a final bill.
This is for cases where the bills are emailed to a person to check the bills before giving to the end user.
Steps:
1) select the Meter Account
2) go to Edit->Meter Account
3) click 'show more options' at the bottom
4) Switch on 'Attempt to run Bill Automatically, alternatively send Bill Error notification'.
5) Switch on 'Send Bill as Pdf file attachment on notification when a New Bill is available'
6) select the login that you want to receive the emails
7) Go to Edit->Login Account and make sure the email address is filled in.
8) Next go to Edit->Login Notifications
9) Enable 'Meter Account' and also the email option.

This will now email your bill to you at the start of the month.

The bill will only run if the meter has valid data.
To disable all invalidations, select the Meter in the Meter Account and go to Edit->Meter Event Setup and make sure there are no ticks under the 'Invalidates' column.
Again this defeats the purpose of having a smart meter in the first place as all events will be silenced.

If you need to run the bill for a different date like the 15th, go back to Edit->Meter Account and where it says 'Billing Period' change it to say 'monthly:+14  00:00'.
This will now run the bill on the 15th of every month.
+14 means 14 days after the first, so the 15th.
Also note there are 2 spaces in front of the time, so 'monthly:+14{space}{space}00:00'

Also this assumes your server's email settings has been configured under Tools->Communication Network->Email Settings