What real-time net billing changed
Under net billing, generation your household consumes on site as it is produced continues to offset your usage at the retail rate. That half is unchanged and it remains the most valuable outcome.
Generation exported to the grid is compensated per kilowatt hour at an avoided-cost-based export credit rate, rather than being netted against your consumption across a period.
That rate varies by season and by time of export, so the same exported kilowatt hour is worth very different amounts depending on when it leaves your house.
Legacy customers who were on the previous arrangement are treated separately. If you already have solar, confirm with Idaho Power which arrangement your account is on.
A fifteenfold spread between best and worst
Recent Idaho Power export credit rates have run at approximately 14.0598 cents per kWh for summer on-peak exports, 1.7682 cents for summer off-peak, and 0.9540 cents for all exported energy outside summer.
That is roughly fifteen times more for a summer on-peak kilowatt hour than for a non-summer one. Most time-varying tariffs have a spread of two or three to one; this is an order of magnitude wider.
It means an annual average export rate is close to meaningless as a planning number, and a projection using one is hiding the entire structure of the tariff.
Ask which export rates the projection applied, by season and period, and ask for the modelled export volume broken out the same way. Anything else is not a model of this tariff.
And the rates are updated annually
The export credit rate is updated annually. Idaho Power initial filing proposed reducing the average annual rate from around 6.2 cents per kWh to just under 2.5 cents, which gives a sense of how much these figures can move.
So a projection holding today rates flat for twenty-five years is making an assumption about roughly twenty-five future annual updates.
Ask what the projection assumed about the export credit over its term, and ask to see it with the export rates reduced by a quarter and by half.
Ask what proportion of the projected savings comes from self-consumption rather than from exports. That portion is unaffected by the annual updates, so a design weighted toward it is insulated.
Rebuilding the estimate from what is confirmed
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase in Meridian receives no federal tax credit.
The Idaho Residential Alternative Energy Tax Deduction remains, but it is a deduction rather than a credit, worth the deducted amount multiplied by your marginal state rate.
What exists on the utility side is retail-rate offsetting for self-consumed generation and a season and time-varying export credit for the rest, updated annually.
Ask for the projection with export rates shown by season and period, export volumes broken out the same way, and the self-consumption portion identified separately.