Before you decide
What is net metering, and why does it keep changing?
The short answer
Net metering is the arrangement under which your utility credits the electricity your system exports to the grid. It is set by state regulators and by the utility, it varies enormously, and it has been revised in many jurisdictions towards crediting exports at less than the retail rate — which changes solar economics more than any equipment choice does.
Why it dominates the arithmetic
A system generates most of its output in the middle of the day, and most households use most of their electricity in the morning and the evening. What happens to the surplus is therefore most of the value. Full retail net metering makes that surplus worth the same as the power you buy; an export rate well below retail makes self-consumption worth far more than export, which changes the right system size and the case for a battery.
What to establish for your own address
- What arrangement your utility currently offers, and whether it is closed to new customers.
- Whether existing customers are grandfathered under the previous terms, for how long, and what triggers the grandfathering.
- Whether there are time-of-use rates, and how export is credited at different times.
- Any fixed charges or minimum bills that apply to solar customers specifically.
Get the export arrangement in writing in the proposal, with the source. A savings estimate built on an arrangement that is closing is a savings estimate for a different customer.
Also asked
Will my net metering arrangement change after I install?
Many jurisdictions grandfather existing customers for a defined period when rules change, and the terms and the length differ and are set by the regulator rather than by your installer. Ask what applies where you are, and ask for the regulator's document rather than a summary of it.
General information about solar and about hiring, not advice about your roof or your tax affairs. Incentives, net metering and contractor licensing are set federally, by state, and by your utility, and all of them change. The authority that publishes the rule is the current answer.