Modeling California's NEM 3.0 in Aurora

What is in the NEM3 / Net Billing Tariff:

While NEM 3.0 is not finalized, Aurora is closely monitoring the proceedings and this guide is based on the latest structures to this plan proposed on December 13th, 2021. The below guidelines would affect any interconnection applications submitted after May 27th, 2022 if the current proposal is passed. 

• Residential customers are required to enroll in Electrification Rates. The currently allowed rates are:

  • PG&E: EV2-A
  • SCE: TOU-D-PRIME
  • SDG&E: EV-TOU-5
  • We expect more rates to be allowed by the CPUC in the future
  • Commercial and CARE customers can keep any TOU rate.

What has changed with NEM 3.0 and how to model it with Aurora

Overview

• Behind-the-meter operation is the same as normal. However, excess energy is no longer compensated at retail rate (less non-bypassable charges); instead, the compensation rate is based on the most recent Avoided Cost Calculator and has a different rate for each hour.
  • Aurora does not currently support export rates that vary hourly. However, we find that you can approximate the ACC export rates using a percentage reduction.
    • For residential customers:
      • PG&E: Export Rate with an 80% reduction
      • SCE: Export Rate with a 75% reduction
      • SDG&E: Export Rate with an 80% reduction.

CARE rates still need this reduction, but should be closer to 65% since the CARE volumetric rates are roughly half of non-CARE volumetric rates.

• • The export rate is only fixed for 5 years, however, there’s no strong indication that future iterations of the ACC will be better or worse for solar.
  • It is important to note that this is an approximation as an exact rate would be extremely difficult to set up, you would need to create a distinct period for each month-hour, for weekdays and weekends - a total of 576 individual period types.
• There is now a fixed “Grid Participation Charge”, at $8/kW CEC-AC/month.
  • You will have to add this manually to the fixed charge section.
  • The CEC AC rating is the product of the module’s PTC rating and the inverter efficiency. You can approximate this as 90% of the STC rating, so the monthly fee is approximated as $7.20/kW STC per month.
  • Minimum charges are removed and can be set to $0/month.
  • CARE rates ignore the Grid Participation Charge.
• True-up period is still annual, and the true-up month is based on the expected PTO of the system.
• Market Transition Credit:
  • There is a $/kW CEC-AC/month credit that lasts for 10 years, and you can approximate this as a PBI in the incentives section.