PG&E does not currently offer an option to pay these charges on a monthly basis, but upon receipt of your monthly statement you can pay ahead, resulting in a credit on your account. PG&E recommends this practice to avoid a large bill at the end of your True-Up period.
Each month your billing statement will have a section titled "Your Net Energy Metering Account Summary" on the first page. If you would like to pay the Net Energy Metering charges monthly, please add the amount listed under Additional NEM Charges Due at True Up to the Total Amount Due.
Once you start to send in the payments preparing for your true-up, please keep in mind they will not be applied to your Net Energy Metering charges but will still be reflected on your PG&E statement. At the end of your 12-month Net Energy Metering billing cycle, any remaining credits accrued from your payments will be applied to any solar charges.