Modeling Inflow/Outflow methodology?

Modeling Inflow/Outflow methodology?
Hi,

Michigan recently approved an inflow/outflow structure in which instantaneous inflows (usage > generation) and instantaneous outflows (generation > usage) are aggregated separately. At the end of the month, total inflow kWh are billed at the retail rate, while total outflow kWh are credited at an 'outflow' rate.

The previous version of SAM allowed a proxy of this approach under the 'hourly netting' option, which calculated and aggregated hourly inflow and outflows separately. However, the current version appears to only have 'net billing', which based on the help file suggests inflows and outflows are netted against each other over the month, with any excess credited at the sell rate.

for instance, if one has an inflow of 150 kWh and an outflow of 200 kWh, the 'net billing' options appears to credit 50 kWh (200 - 150) at the sell rate. However, the inflow/outflow method would instead charge 150 kWh at the 'buy' rate and credit 200 kWh at the 'sell' rate. These two methods do not produce the same result.

Is there a way to use the current version to model the inflow/outflow process, at least at an hourly resolution?

Thanks,
Kevin

Hi Kevin,

The "Buy all / sell all" metering and billing option should model this type of structure.

We renamed those options in SAM 2018.11.11 to make them more consistent with conventional naming practices as described in Zinamen, O. et al. (2017) Grid-Connected Distributed Generation: Compensation Mechanism Basics. NREL/BR-6A20-68469. ( PDF 861 KB ).

Best regards,
Paul.