Solar economics depend on when power is used, what exports earn and which charges remain. Net metering is a starting question, not a complete model.
Self-consumption and exports
Onsite use can offset purchased energy subject to the tariff. Export compensation follows separate rules and may differ from import prices. Demand and fixed charges may remain even with substantial annual generation.
Obtain the tariff for the customer class, meter arrangement, installation date and system size. A statewide label cannot establish a commercial project's economics.
California's net billing example
The California PUC states that eligible customers applying for interconnection from April 15, 2023 take net billing service. Export value changes by hour and usually differs from retail import prices. Existing systems and specialized meter arrangements require their applicable rules.
Storage can shift use or exports. It is not universally mandatory or automatically profitable. Do not apply California's framework to Illinois or another state.
Use an interval model
- Gather interval use and seasonal occupancy.
- Estimate production from a site-specific design.
- Calculate onsite consumption and exports by interval.
- Apply actual import and export schedules.
- Model demand using utility rules.
- Include financing, maintenance, insurance and service fees.
Show sensitivity to occupancy, production and compensation. Annual kWh alone can hide weak alignment with building demand.
Define the storage purpose
Specify energy shifting, demand management, backup or a combination. Include usable capacity, power, efficiency, degradation and reserved backup charge. The same stored energy cannot serve competing purposes simultaneously.
Backup operation requires appropriate transfer and islanding design. A grid-connected solar array alone does not establish outage capability.
Confirm owner and tenant rights
Identify equipment ownership, benefiting meter, payer and lease allocation. Confirm roof rights, lender consent, access, lease duration and removal obligations.
Keep incentives separate
Check current tax and utility rules for actual dates and ownership. Carry a base case without unapproved benefits. Review the incentive verification guide before relying on old timelines.
Sources and scope
- ENERGY STAR: building benchmarking
- DOE: energy management information systems
- DOE: re-tuning existing buildings
- DOE: islanding a microgrid
- CPUC: net energy metering and net billing
- IRS: wind and solar construction timing
Reviewed October 12, 2026. Confirm effective tariffs, program rules and signed terms for the actual account. Hypothetical examples are planning calculations, not current offers or client results.
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