Solar True-Up Guide — Vacaville, CA
Why Is My Solar True-Up Bill High in Vacaville, CA?
2026 Guide — NEM 2.0 Solar Homeowners · PG&E TOU Rate Plans
2026 Guide — NEM 2.0 Solar Homeowners · PG&E TOU Rate Plans
Vacaville NEM 2.0 solar homeowners typically see true-up bills of $600–$2,000 per year. The city's inland heat creates substantial summer cooling loads that run well into PG&E's 4–9 PM peak window — prime time for expensive grid imports. Solar credits earned during warm days partially offset this, but Vacaville's hot evening temperatures mean peak-rate grid purchases are a consistent part of the annual energy picture.
Upload your True-Up statement to get your free TrueUp Score — a 0–100 rating that shows exactly what's driving your bill and what would reduce it most.
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A True-Up bill is PG&E's end-of-year accounting for NEM 2.0 solar customers. Rather than settling every month, PG&E tracks two running totals throughout your solar year: (1) credits earned when your panels generate more than you use, and (2) charges for grid power imported when solar isn't enough. On your anniversary date, those totals are reconciled. If your charges exceed your credits, the difference is your True-Up bill.
For Vacaville homeowners, this annual statement often arrives as a surprise — especially when it's significantly larger than expected. The reason is usually not that the solar system is broken. It's that the timing of solar production doesn't match the timing of peak electricity consumption.
During January through April, most Vacaville solar systems generate credits — days are mild, usage is low, and panels run surplus energy back to the grid. These credits are real but they're banked, not paid out. Then summer arrives. From June through September, evening cooling loads, appliance use, and any EV charging draw grid power during PG&E's 4–9 PM peak window — the most expensive hours of the day. Those charges accumulate through four months of heat. At year-end, the summer charges often wipe out the spring credits.
PG&E's standard Time-of-Use plan charges significantly different rates depending on when you use electricity:
Peak (4–9 PM weekdays): ~$0.45–$0.55/kWh Off-Peak (all other hours): ~$0.30–$0.38/kWh
Every kWh of grid power imported during the 4–9 PM window costs 40–80% more than off-peak imports. For a household that runs AC, cooks dinner, and charges an EV during those hours, the daily peak-rate exposure can add up to $3–$8 per day in summer — or $270–$720 over a four-month summer season.
Solar panels generate the most power between roughly 9 AM and 2 PM, when the sun is high. Peak electricity prices apply 4–9 PM. That 2–7 hour gap between peak generation and peak pricing is the fundamental driver of True-Up bills. Surplus solar produced at noon doesn't earn the same value as peak-rate imports cost at 6 PM — especially under NEM 2.0's crediting structure, which ties export value to your time-of-use rates.
The result: homeowners who look only at their system's annual kWh production often underestimate their True-Up bill. What matters is not just how much the system produces, but when it produces relative to when you use the most power.
Climapp's TrueUp Score is a 0–100 rating that measures how efficiently a solar home is managing its relationship with PG&E's Time-of-Use rate structure. The score is derived from your actual True-Up statement — the peak/off-peak usage data printed on the bill — and reflects two things: how much grid power you import during expensive peak hours, and how much of your solar production displaces that expensive power versus exporting at lower credit rates.
Along with the score, the tool generates a specific recommendation — either battery storage, solar expansion, or a combined upgrade — sized to your actual usage pattern. The recommendation is based on your bill's peak/off-peak net usage data and local PVWatts solar production estimates for Vacaville.
A home battery — typically a Tesla Powerwall (13.5 kWh) or similar — stores midday solar surplus and dispatches it during the 4–9 PM peak window. This directly reduces peak-rate grid imports, which is the primary driver of most True-Up bills. For many Vacaville homeowners, a single battery can reduce the annual True-Up bill by $800–$1,500 per year by eliminating 60–80% of peak-hour grid imports.
If your current solar system is undersized relative to your consumption — common when usage has grown due to an EV or home addition — adding panels increases the total credits available to offset your peak-hour imports. The TrueUp Score tool uses PVWatts production data for Vacaville to estimate exactly how many additional kW would be needed to meaningfully reduce your annual bill.
Without any hardware investment, shifting EV charging, laundry, and dishwasher use to before 4 PM or after 9 PM can reduce peak-rate exposure. This is free and can meaningfully improve your TrueUp Score — though the impact is smaller than battery storage for households with very high evening AC loads.
Vacaville sits between Sacramento and the Bay Area, inheriting inland heat that pushes summer highs to 98–106°F. The city's position means it misses the Bay Area's marine cooling influence while experiencing Central Valley-style summer heat spikes. For NEM 2.0 solar homeowners, Vacaville's summers create a predictable true-up driver: strong solar production followed by extended evening AC loads during PG&E's peak pricing window.
To get your personalized TrueUp Score for your Vacaville home, upload your most recent PG&E True-Up statement using the tool above. It will show you:
Upload your PG&E True-Up statement and find out exactly what's driving your Vacaville solar bill — and what would fix it most.
Analyze My True-Up Bill →