The short answer
- A true-up is the once-a-year settlement on a solar account: the year's energy charges and credits are added up, and you pay the balance (or leftover credits are paid out or zeroed).
- On NEM 2.0 you may pay energy charges once a year; on net billing you pay all charges monthly and only export credits roll to the true-up.
- Leftover NEM credits are paid at a low "net surplus compensation" rate: about 2ยข per kWh.
NEM 2.0 at SCE
On the Annual Billing Option you pay fixed delivery and non-bypassable charges monthly and settle net energy charges once a year; the Monthly Billing Option pays everything monthly. At year end, if you used more than you made you owe the balance; leftover credits are paid at the net surplus compensation rate and the balance resets (SCE).
NEM 2.0 at SDG&E
SDG&E bills monthly, but residential customers may pay only part and settle at true-up. Credits carry forward within the 12 months and are applied back to earlier months; unused credits don't carry into the next year (SDG&E). SDG&E's surplus rate for October 2026 is $0.02003 per kWh (SDG&E).
Net billing (NEM 3.0)
You pay all charges every month. Imports and exports are never netted: exports earn dollar credits by the hour, which roll forward to an annual true-up (D.22-12-056; SCE). You can ask once to change your true-up month.
Avoiding a big true-up bill
- Watch the running balance on your monthly bill; a growing charge in summer can mean a large true-up.
- Credits from spring and summer offset winter use, so don't judge a system by one month.
- If your use grew (an EV, a heat pump), a small expansion within NEM 2.0's 10%-or-1-kW limit may keep you on it (details).
Checked against official sources on Oct 1, 2026. Sources are linked in the text. Not legal, tax or financial advice.