If your Southern California Edison bill includes a baseline credit, a solar-plus-battery PPA comparison should explain how the future utility rate treats it. Getting this detail right helps you evaluate the potential benefits of solar and storage using a realistic household budget.
Does the baseline credit continue on TOU-D-PRIME?
SCE lists a baseline credit on its TOU-D 4–9 p.m. and 5–8 p.m. options, but no baseline credit on TOU-D-PRIME. Its current time-of-use comparison shows these as different rate structures. Do not carry a credit from one option into a forecast for another.
For a residential project entering the SCE Solar Billing Plan, SCE identifies TOU-D-PRIME as the applicable rate. Solar imports and exports then have separate billing values, with export credits depending on when electricity reaches the grid.
If you already have legacy NEM solar, ask SCE which rules apply to your account and proposed changes. This article’s Solar Billing Plan requirement should not be read as saying that every existing solar account must immediately change plans.
How can an old credit distort a new estimate?
Consider an illustration with invented amounts, not an SCE rate quote. Suppose your current bill includes an $18 baseline credit. A proposal correctly estimates the future utility bill at $95, but then mistakenly subtracts that old $18 again. It would display $77 instead of $95.
If the proposed PPA payment were $145 for that month, the combined amount would be $240, not $222, before any separately charged items. This example isolates one modeling error; it does not estimate your savings or imply that the new plan always costs more.
The useful comparison recalculates the whole bill under each applicable rate. A missing credit can coexist with different energy prices, fewer grid purchases and battery operation that changes when electricity is purchased.
What should the proposal show?
Ask for a monthly forecast that identifies:
- Your current rate and the actual credits already included in historical bills.
- The proposed utility rate, expected grid imports and exports, and applicable recurring charges.
- The separate PPA payment and any additional battery charge.
- Planned changes in electricity use, such as an EV or heat pump.
SCE notes that its displayed rate examples assume both delivery and generation from SCE. If another provider supplies generation, have the forecast use that provider’s applicable prices. Our guide to SCE solar credits and the Base Services Charge explains another part of the remaining utility bill.
How do batteries and PPA terms fit?
SCE explains that storing extra solar energy for use during expensive hours can help reduce electricity costs. Ask the designer to show the battery schedule and the energy reserved for outages in the same forecast.
Backup needs their own review: supported circuits, output limits, available charge and expected loads. PG&E’s general battery guidance explains why higher usage and a lower reserve shorten backup, and why nighttime or cloudy conditions can limit solar recharging. Compatible equipment is necessary; a billing forecast is not a runtime guarantee.
A qualifying no-upfront PPA can offer access to provider-owned solar without an upfront equipment purchase. The CPUC solar guide explains that you still pay for generated electricity under the agreement. Confirm eligibility, starting price, any escalator, term, battery ownership and scope, maintenance, and home-sale transfer provisions. Savings depend on the actual offer and usage.
Bring a recent SCE bill and proposal to a West Coast Alternatives consultation to organize a comparison that reflects your utility rate, payment plan and backup priorities.