The following guide provides information on how the estimated new utility bill (ENUB) is obtained in Solargraf.

Where to find the estimated new utility bill

New utility bill is the estimated new bill that homeowner would pay for the provided consumption and installing the PV or PV + ESS in the design. Find the new utility bill on Web-quote or PDF in the Overview section and Performance analysis section.

How is the value calculated

The estimated new utility bill is computed based on several design and grid considerations. It considers the following data inputs:

• Hourly consumption profile
• Hourly production profile
• Hourly battery charge/discharge profile
• Tariff data – fixed charge, minimum bill, usage charges, demand charges
• Grid properties – grid connection type, credit rollover mechanism, billing period

Step 1: Measure grid import/export at each hour

Grid import/export = consumption – production + battery charge – battery discharge

Step 2: Identify the grid properties and appropriately compute and offset usage charges with credits from previous hours.

Net metering/Net metering (retail rate with fixed reduction): Identify the net grid imports/exports for each Time of use window, compute the $ value of net imports and exports. Calculate the usage charges by adding $ amounts in the billing period.

NEM 3/Net billing: Calculate the import/export charges ($) at each hour based on the kWh import/export. Calculate the net bill by adding the $ amounts in the billing period.

Gross Feed-in tariff: New utility bill will be same as old utility bill as all the production is valued at a different sell rate

Step 3: Compute the demand charges applicable for each time of use window in the billing period. Sum up the demand charges in the billing period

Step 4: Add fixed charges, demand charges, and usage charges for the billing period

Step 5: Calculate the minimum of the minimum bill and the value computed in step 4

New utility bill = Minimum of (minimum bill, fixed charge + usage charge + demand charge)