some clarifications with SAM's metering/billing

Hello SAM, 

A few questions on metering/billing

1. Net energy metering: what is roll over net excess compensation to future bills? I don't see any difference choosing this or not. Wouldn't excess kWh roll over to future months for end of the year accounting anyways?
2. Net energy metering  with $ credits is very similar to net billing. Are the differences:
   1. Net energy metering with $ credits: there is a true up period, is if utility owes anything $ credit, the customer does not get paid until the end of the true up period, whereas in net billing, customer gets paid (if there is excess generation) at the end of each billing period.
   2. Net billing also allows for sub-hourly sell/buy rates
   3. Anything else?
3. Net billing with carryover to next month is nearly identical to net energy metering with $ credits, except it allows for sub-hourly sell/rate, is this correct?

Best Regards,
Arman
 

Hi Arman,

These inputs are described in the "Metering and Billing Definitions" section of the "Electricity Rates" Help topic: samrepo.nrelcloud.org/help/electricity_rates.htm .

When you check Roll over net excess compensation to future bills, SAM credits the month that follows the month you choose for Month for end of true-up period with excess kWh generated in the end of true-up month. If you do not check the roll-over option, SAM applies those kWh to the end of true-up period month.

For net energy metering, SAM calculates excess generation based on the total generation and total load over the month. For net billing, SAM calculates excess generation in each time step.

For net energy metering with $ credits, the $ credit earned in a given month is applied to the following month. For net billing, the credit is applied to the current month's bill, and may cause the bill to be negative, i.e., treated as a payment to the system owner.

Best regards,
Paul.

Thanks Paul, this is really helpful! 

Best,
Arman