Solve California's NEM3 Complexity with Lunar AI
2025-03-17 | lunarenergy.com
Overview
The 2023 shift to NEM3 in California turned residential batteries into money-saving machines — but NEM3's complex rate plans require advanced software to capture those savings. Lunar AI is Lunar's proprietary forecasting and optimization software, comes standard with every Lunar System, and can be activated as a mode in the Lunar App.
With 850 million hours of battery control experience on more than 100,000 batteries, Lunar AI automatically navigates NEM3's complexity — also known as the Net Billing Tariff (NBT) or Solar Billing Plan (SBP).
The Challenge: Complex Import & Export Rates
Under NEM2, maximizing utility bill savings was straightforward — solar exports were credited at relatively high, stable rates. Under NEM3, export rates bear no relation to import rates, and there are different export rates for each hour of each month of each year. That's 288 different export rates per year, and those rates change every year.
For example, PG&E export rates for customers with 2025 interconnection applications range from near $0/kWh midday in spring to over $1.03/kWh on August weekday evenings. Peak export rates are also projected to grow year over year through 2027–2028.
A simplistic self-consumption strategy ignores the opportunity during late summer afternoons/evenings when customers can receive large credits for exported energy. Managing rates manually requires significant effort from installers and customers — and export rates change every year.
Lunar AI: Making the Complex Simple
Lunar AI continuously optimizes for all the key variables: solar generation forecasts, customer energy consumption patterns, battery state of charge, and current hourly import and export rates.
Real-world example: On September 30, Lunar AI exported to the grid at a high rate starting at 7pm (PG&E export rate ~$4/kWh). The following day in October it exported much less — because Lunar AI knew the rate had dropped significantly. No manual intervention was needed.
Lunar AI also automatically accounts for: backup reserve maintenance, storm/outage preparation (Outage Watch), EV usage prediction, and Virtual Power Plant (VPP) participation.
The Value of Forecasting
Lunar's machine learning algorithms predict solar generation (including shading, cloud cover) and home energy consumption patterns. This allows the system to:
Prioritize filling the battery from solar on high-consumption days
Import cheap grid energy when rates are low
Hold battery charge for discharge during peak export/import rate windows
Avoid expensive evening import rates by discharging stored solar
Getting Started
Installers can activate Lunar AI at the end of commissioning. Customers can also select Lunar AI in the Lunar App once they have PTO. Set the correct rate plan in the Lunar App or Gridshare, and after a couple of weeks of learning the home's energy patterns, Lunar AI begins optimizing automatically.
References
PG&E Export Rates: https://www.pge.com/eecvalues | SCE Export Rates: https://www.sce.com/business/generating-your-own-power/solar-billing-plan | SDG&E Export Rates: https://www.sdge.com/solar/solar-billing-plan/export-pricing