NEM 3.0: Why You Might Still Get a True-Up Bill (And How to Avoid It)

Are you a California homeowner wondering why you might still be getting a true-up bill, even with solar? This guide breaks down the math behind NEM 3.0 and what it means for your electricity costs, especially with utilities like SCE, PG&E, and SDG&E.

Key Takeaways

• Under NEM 2.0, a true-up bill usually means your system wasn't sized correctly for your energy needs or your energy usage patterns changed significantly.
• NEM 3.0 introduces monthly net billing, meaning you'll likely have a true-up bill every month unless you have a battery system.
• Proper system sizing and understanding your energy consumption are crucial for minimizing costs under NEM 3.0.
• Utility-specific rules (SCE, PG&E, SDG&E) can impact your net metering and billing.

Understanding True-Ups Under NEM 2.0

If you got solar under the old Net Energy Metering 2.0 (NEM 2.0) rules and are still seeing a true-up bill, it usually comes down to a couple of main reasons. First, your solar system might not have been sized large enough to cover your total annual electricity usage. If your system was designed to offset, say, 80% of your energy needs, you'll still be paying for the remaining 20% at retail rates. This often happens on your anniversary billing date, which is your annual true-up.

Another common reason is a change in your energy consumption. Maybe you added an electric vehicle (EV) that you charge at home, or you started using more air conditioning. If your usage increases significantly after your system was installed, your solar production might not be enough to cover it, leading to a true-up bill. It's also possible that you were holding back on energy use because it was expensive, and once you got solar, you relaxed your habits, using more power than anticipated. Remember, solar isn't unlimited power; your system has a set production capacity.

The Shift to NEM 3.0: Monthly True-Ups

NEM 3.0, also known as the Net Billing Tariff, changes the game. Under this new structure, you're likely to face a monthly true-up bill. This is because the way utilities credit you for excess energy sent back to the grid is different and generally less favorable than under NEM 2.0. Instead of a one-to-one credit for exported energy, NEM 3.0 uses a net billing approach where the value of exported energy is lower, especially during peak production hours.

If you don't have a battery system, you'll be buying electricity from the grid at retail rates during times when your solar panels aren't producing enough (like at night or on cloudy days). Any excess energy your system does produce during the day will be credited, but at a much lower rate, and you'll receive this credit annually. This means you'll likely have a bill to pay the utility company every month for the energy you consume that your solar system didn't cover in real-time.

The Role of Batteries in NEM 3.0

Adding a battery system is becoming increasingly important under NEM 3.0 to avoid significant monthly bills. A battery allows you to store the excess solar energy generated during the day and use it at night or during peak demand hours when grid electricity is most expensive. This self-consumption significantly reduces your reliance on the utility grid and helps you avoid those monthly true-up charges.

However, even with a battery, proper sizing is key. If your battery isn't large enough to store all your excess solar energy, or if your overall energy consumption (including future additions like EVs or increased AC use) exceeds what your solar and battery system can provide, you might still face a true-up bill. Some battery options are now focused solely on self-consumption, which can be more affordable than systems that also offer grid backup, but they still need to be sized correctly for your needs.

Utility-Specific Considerations (SCE, PG&E, SDG&E)

It's important to remember that each major California utility has its own nuances:

• PG&E (Pacific Gas and Electric): Serves Northern and Central California. Their Time-of-Use (TOU) rates are a key factor in NEM 3.0 calculations.
• SCE (Southern California Edison): Serves much of Southern California. Similar to PG&E, TOU rates are critical for understanding your billing under NEM 3.0.
• SDG&E (San Diego Gas & Electric): Serves San Diego County and parts of Orange County. They also operate under TOU rates that influence NEM 3.0 outcomes.

While the core principles of NEM 3.0 apply across the board, the specific TOU periods, peak pricing, and credit rates can differ slightly, impacting the exact financial outcome for homeowners in each service area.

What This Means If You're in Southern California (e.g., San Diego)

If you're in a city served by SDG&E, like San Diego, understanding NEM 3.0 is particularly important. With SDG&E's rates, especially during peak summer hours, the cost of electricity can be quite high. Under NEM 3.0, if you don't have a battery, you'll likely be buying power back from SDG&E at these higher retail rates during evenings and nights, while only getting a fraction of that back for the energy you export during the day.

This makes a solar system paired with a battery a much more compelling option to maximize savings and avoid substantial monthly bills. Without a battery, you can expect a monthly true-up charge from SDG&E, the amount of which will depend heavily on your daily energy consumption patterns and how much solar energy you can self-consume versus export.