How Are Hourly Export Credits Calculated Under California NEM 3.0? (2026 Guide)

Rooftop solar panel installation in California offers major utility savings, but understanding how those savings are calculated has become incredibly complex in 2026. If you have recently researched going solar in the Golden State, you have likely encountered the term Net Billing Tariff, commonly known as NEM 3.0.

Under this new regulatory framework, the simple one-to-one retail net metering of the past has been completely eliminated. Instead, California homeowners are now compensated for their excess solar power through a highly variable mechanism known as hourly export credits. These credits determine exactly how much money your utility provider—whether that is PG&E, SCE, or SDG&E—will credit your bill when your panels send surplus electricity back to the grid.

Understanding how hourly export credits are calculated under the California Net Billing Tariff is critical for anyone looking to maximize their return on investment. This comprehensive 2026 homeowner guide breaks down the complex mathematics of the Avoided Cost Calculator, explores the exact value of your solar power during different times of the year, and provides actionable strategies to protect your savings.

Overview of the Net Billing Tariff (NEM 3.0)

Before diving into the mathematics of hourly export credits, it is important to understand the broader context of the Net Billing Tariff (NBT), which went into effect for all new solar customers in California after April 14, 2023. Historically, under NEM 2.0, if you paid 30 cents per kilowatt-hour (kWh) to pull electricity from the grid, the utility paid you roughly the exact same 30 cents when you exported excess solar power back to them.

This simple retail-rate compensation effectively allowed the grid to act as a giant, free battery for homeowners. However, utility companies successfully lobbied the California Public Utilities Commission (CPUC) to change this, arguing that paying retail rates for solar energy was unsustainable and unfairly shifted infrastructure costs to non-solar ratepayers.

The result was the Net Billing Tariff. Under NEM 3.0, the value of your exported solar power is decoupled entirely from retail electricity rates. Instead of receiving a flat credit, your compensation is now based on wholesale energy values that fluctuate radically depending on the exact hour of the day, the day of the week, and the month of the year.

The Avoided Cost Calculator (ACC) Explained

At the very heart of the hourly export credit calculation is a complex econometric model known as the Avoided Cost Calculator (ACC). Developed by the CPUC, the ACC is the definitive mathematical framework that determines exactly how much your exported solar power is worth at any given moment.

What is the Avoided Cost?

The fundamental premise of the Avoided Cost Calculator is straightforward: utility companies should only pay you what it would have cost them to generate or procure that same amount of electricity themselves. When your solar panels push power onto the grid at noon, the utility avoids having to buy power from a natural gas power plant or a massive solar farm.

Therefore, your hourly export credit is directly tied to this "avoided cost." Because electricity is incredibly cheap to generate during the middle of the day in California—thanks to the abundance of large-scale solar farms—the avoided cost at noon is extremely low. Conversely, during a hot summer evening when solar production drops but air conditioning demand spikes, electricity becomes expensive for the utility to procure, driving the avoided cost significantly higher.

How the CPUC Determines the Values

The CPUC updates the Avoided Cost Calculator biennially. The formula factors in several distinct variables to calculate the true wholesale value of your exported energy.

• Generation Capacity: The cost of building and maintaining power plants.
• Energy Value: The real-time wholesale market price of electricity on the CAISO grid.
• Transmission and Distribution: The cost of maintaining wires, transformers, and grid infrastructure.
• Greenhouse Gas Reductions: The environmental value of carbon-free energy.

When all these variables are combined, the resulting number is your exact hourly export credit rate. This means that instead of one flat rate, there are exactly 8,760 different hourly export rates throughout the year—one for every single hour of the 8,760 hours in a standard year.

Breaking Down the Hourly Export Credit Mechanism

To truly grasp how hourly export credits are calculated under the California Net Billing Tariff, you have to look at the massive variations in compensation throughout a typical day. The system is designed to heavily penalize solar exports when the grid has too much power, and heavily reward exports when the grid is desperate for energy.

The Midday Solar Glut

During a typical spring day in April, the California grid is flooded with solar power from both utility-scale solar farms and millions of residential rooftops. From roughly 10:00 AM to 3:00 PM, the wholesale value of electricity crashes. During these hours, the Avoided Cost Calculator determines that your exported solar power is almost worthless to the utility.

As a result, if you export your excess rooftop solar power at noon, you might only receive an hourly export credit of 4 to 6 cents per kWh. Meanwhile, you might be paying 35 to 45 cents per kWh to consume power from the grid later that same evening. This massive discrepancy is the primary reason why NEM 3.0 fundamentally changes the economics of solar without storage.

The Evening Peak

Conversely, the dynamic flips entirely as the sun begins to set. By 6:00 PM, solar production plummets across the state, but residential energy consumption skyrockets as people return home from work, cook dinner, and turn on their air conditioners. This period of high demand and low supply forces utilities to fire up expensive natural gas peaker plants.

Because the utility's cost to generate electricity during this window is exceedingly high, the Avoided Cost Calculator dictates a much higher hourly export credit. If you manage to export power to the grid during these peak evening hours, you can earn credits worth 40 cents, 80 cents, or sometimes well over a dollar per kWh.

The September Multiplier: Peak Value Hours

While the hourly export credits fluctuate daily, they also fluctuate drastically from month to month. Under the current iteration of the Avoided Cost Calculator, the single most valuable month for exporting solar power in California is September.

September typically brings brutal late-summer heatwaves to the state. Grid demand hits its absolute maximum as millions of air conditioners run simultaneously. During specific hours in September—most notably between 5:00 PM and 7:00 PM—the California grid is frequently pushed to the brink of rolling blackouts.

To incentivize homeowners to send power to the grid during these critical moments, the hourly export credits skyrocket to unprecedented levels. In recent models, exporting a single kilowatt-hour of electricity during a September peak hour can earn you a credit of $2.50 to $3.50. This means that a homeowner who successfully exports power during these specific hours can offset months of low midday credits with just a few hours of strategic exporting.

If you want to read more about specific residential solar installation quotes and local incentives, check out our city-specific calculators.

Residential vs. Commercial Export Calculations

The Net Billing Tariff applies to both homeowners and business owners, but the underlying mechanisms and financial impacts differ significantly between the two sectors.

Residential Hourly Export Credits

For residential customers, the sheer volatility of the hourly export credits is the main challenge. Homeowners typically consume most of their power in the mornings and evenings, meaning the bulk of their solar production occurs at noon when they are not home. Under NEM 3.0, this noon production is exported at the lowest possible hourly rates, forcing residential solar adopters to fundamentally change how they design their systems.

Commercial Hourly Export Credits

Commercial properties face a slightly different reality. Businesses, factories, and schools often operate during standard business hours (9:00 AM to 5:00 PM). This means their peak energy consumption perfectly aligns with peak solar production. As a result, commercial solar systems naturally self-consume a much higher percentage of their generated electricity.

Because commercial systems are utilizing the solar power directly, they are avoiding the high retail rates of the utility and exporting far less power overall. While their hourly export credits are calculated using the same Avoided Cost Calculator framework, the overall financial penalty of NEM 3.0 is somewhat less severe for commercial entities due to this natural daytime load alignment.

The Critical Role of Battery Storage

If there is one absolute truth regarding the Net Billing Tariff, it is this: calculating your hourly export credits correctly proves that installing a home battery is no longer optional; it is mathematically mandatory for maximizing your return on investment.

Without a battery, your excess solar energy is forcefully exported to the grid at noon, earning you a paltry 5 cents per kWh. Later that night, you must buy energy back from the grid at 45 cents per kWh. You are losing 40 cents on every single unit of energy you exchange with the utility.

When you introduce a battery, such as the Tesla Powerwall 3 or the Enphase IQ Battery 5P, you seize control of the hourly export credit system. Instead of exporting power at noon for 5 cents, your intelligent inverter routes that excess energy into your battery. Your battery stores this extremely cheap power throughout the afternoon.

When the sun sets and utility rates spike, your home draws its electricity directly from the full battery rather than pulling from the expensive grid. By self-consuming your stored solar power, you completely sidestep the punishing midday export rates and avoid purchasing peak grid power. Furthermore, if your battery has excess capacity during a September evening, you can configure your system to intentionally discharge power to the grid during the $3.00/kWh window, rapidly accelerating your system's payback period.

Load Shifting: Beating the System

Even if you have a properly sized battery, you must also adopt a strategy known as "load shifting" to truly master the hourly export credit calculations. Load shifting involves intentionally changing when you consume major electrical loads in your home to align with periods of high solar production or low utility costs.

• Electric Vehicles: Charging an EV requires a massive amount of electricity. If you plug your car in at 7:00 PM, you will rapidly drain your battery and be forced to buy expensive peak grid power. Instead, you should utilize smart EV chargers that automatically charge your vehicle at noon, using the excess solar power that would have otherwise been exported for pennies.
• HVAC Pre-Cooling: Heating and cooling represent the largest loads in a typical home. A smart load-shifting strategy involves running your air conditioner at full blast starting at 1:00 PM. By using your excess solar power to pre-cool the house down to 68 degrees, your home acts as a thermal battery. By 5:00 PM, the house is cold, and you can turn the AC off during the expensive peak hours.
• Appliance Scheduling: Run heavy appliances like pool pumps, dishwashers, and electric dryers strictly between the hours of 10:00 AM and 3:00 PM to maximize self-consumption.

By shifting your loads into the midday window, you effectively increase the value of your solar power from the 5-cent hourly export credit up to the full 40-cent retail rate you avoided paying.

How Utility Providers Affect Your Credits

While the CPUC mandates the Avoided Cost Calculator for all investor-owned utilities (IOUs) in California, the exact numerical values of the hourly export credits differ slightly depending on whether your home is serviced by PG&E, SCE, or SDG&E.

Each utility company faces different infrastructure costs, regional transmission challenges, and local weather patterns. For example, the cost of maintaining power lines in the dense urban sprawl of Los Angeles (SCE territory) differs wildly from maintaining lines in the wildfire-prone forests of Northern California (PG&E territory).

Because these underlying costs vary, the data plugged into the Avoided Cost Calculator varies by region. As a result, an hourly export credit at 2:00 PM in June might be worth 4.8 cents for a PG&E customer, but 5.2 cents for an SCE customer. While these differences may seem microscopic on an hourly basis, they accumulate over the 25-year lifespan of a solar system, which is why precise, hyper-local calculations are necessary when modeling NEM 3.0 savings.

You can find more detailed information by visiting the FAQ hub to understand broader solar policies.

Strategies to Maximize Your ROI in 2026

Understanding how hourly export credits are calculated under the California Net Billing Tariff ultimately allows you to design a solar system that maximizes your financial returns. To thrive under NEM 3.0, you must adhere to several core design principles:

• Never Install Solar Without Storage: The era of solar-only installations in California is over. To achieve a respectable return on investment, your system must include enough battery storage to offset your evening energy consumption entirely.
• Size for Self-Consumption, Not Export: Under older tariffs, you could build a massive solar array to generate a surplus of credits. Today, over-sizing your system without adding corresponding battery capacity simply results in exporting massive amounts of cheap energy, destroying your ROI.
• Embrace Smart Energy Management: Invest in smart electrical panels, intelligent load controllers, and smart thermostats. These automated systems can seamlessly perform load shifting on your behalf, ensuring you consume your solar power when it is cheapest and export it only when it is most valuable.
• Utilize Virtual Power Plants (VPPs): Enroll your battery system in localized VPP programs. By allowing the utility to tap into your battery during extreme grid emergencies, you can earn massive compensation rates that far exceed standard hourly export credits.

By mastering the complexities of the Avoided Cost Calculator and adapting your energy habits, you can still achieve massive financial savings with solar energy in California, despite the challenging new regulations.