Three or four to one
Electricity you consume at the moment it is generated displaces a purchase at the retail rate, around 11 to 12 cents per kWh in North Dakota.
Electricity you export is usually credited at avoided cost, roughly 2 to 4 cents. So the same kilowatt hour is worth three or four times more used than exported.
That ratio, rather than the total generation, determines what a system is worth. Two identical arrays on identical roofs can produce very different results depending only on household patterns.
So the self-consumption share is the assumption a quote most needs to state, and the one most often left implicit.
What share is realistic
A household with someone home during the day, or with a heat pump, shop or electric vehicle charged at home, consumes a high share of its generation directly.
A household that leaves at eight and returns at six exports most of its midday production at the low rate.
Ask what share the model assumed and what it was based on. An assumption from your actual usage pattern is far stronger than a generic figure.
Ask to see the projection at a lower share. If the case only works at an optimistic assumption about when you use power, that is worth knowing before you sign.
Improving the share
Shifting flexible loads into daylight is free and, at a three or four to one ratio, unusually valuable. Dishwasher, laundry, any pool pump and daytime electric vehicle charging all count.
A battery does the same automatically and at larger scale. Under this ratio the arbitrage is real, though it has to be weighed against the cost of storage in a state where the underlying rate is low.
Ask for the system modelled with and without storage so the incremental cost and value both appear as numbers, and ask what round-trip losses the model assumed.
And weigh sizing first. Reducing the array to match your daytime load achieves much of the same effect for less money than adding a battery to a larger one.
Costing it out where the incentives are thin
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 receives no federal tax credit, and North Dakota has no state solar tax credit.
Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask what a provider claims and what reaches you in the rate.
What exists is retail value for self-consumed generation, avoided cost for exports, and a five-year property tax exemption.
Ask for the self-consumption share stated, the projection at a lower share, and a smaller system modelled alongside the proposal.