Why solar buyback rates matter so much

Texas doesn't have net metering as a matter of law. In states that mandate it, your meter effectively runs backward when you produce more than you use, so a kWh you export and a kWh you buy back later are guaranteed to be worth the same, by regulation. Texas has no such requirement. Each retail electric provider (REP) sets its own export credit, and most price it well below the retail rate.

That said, "no net metering" doesn't mean no REP ever offers something close to it. A few competitive plans voluntarily price solar exports at (or near) the same rate as usage, as a product feature rather than a legal requirement. TXU Energy's "Solar Buyback System Flex" plan is a real, current example and this app's own source for that distinction: its Electricity Facts Label prices solar buyback at the plan's own indexed usage rate, so the two move together kWh-for-kWh. This app's plan data reflects that directly: see it for yourself on the Plans step for CenterPoint, Oncor, or AEP Texas Central. A plan like this is the exception, not the rule, and its rate is indexed (it moves month to month), not a fixed guarantee, but it's real, and worth specifically shopping for if a low buyback rate is your main solar concern.

That matters because most homes don't self-consume most of what their panels produce. Panels make the most power around midday; most household usage happens in the morning and evening. Earlier versions of this app netted a whole month's production against that month's usage, which hid this mismatch entirely and made "energy cost after solar" look better than a real EFL-priced plan would actually produce.

This app now estimates self-consumption from published research (the European Commission's Joint Research Centre has studied this relationship extensively, and it matches separate U.S. findings, since the underlying cause, solar timing vs. usage timing, isn't specific to any one country): a system that offsets roughly a third of a home's annual usage typically self-consumes 60-90% of what it makes, while a system sized to offset 100% of usage typically self-consumes only 20-40% of what it makes, because it's making far more than the house needs at midday regardless of size. Rather than pick one flat number, this app interpolates between real points on that curve based on your own system's offset percentage.

For utility territories without real plan data yet, the "energy cost after solar" fallback estimate uses this same self-consumption split, paired with a buyback-to-retail-rate ratio computed directly from this app's own real plan data (roughly 40%, the actual mean/median across every real, EFL-sourced plan shown on the Plans step that credits solar export) rather than an outside guess.

Everything above is also the reason this app doesn't currently price a battery into your numbers: doing that accurately means pricing a shift from exported to self-consumed energy against each provider's own real, specific terms, not one flat assumption applied everywhere.

Read the full reasoning, alongside the other plan types this app doesn't model yet.

Exported solar credit is capped so it can never make your annual bill negative. This app used to subtract it without limit, which could show a provider paying you more than your entire bill. Real Texas solar credit has no cash value: TXU Energy's own Solar Buyback FAQ states that banked credits carry no cash, credit, or other redemption value, and a cross-check across several major providers confirms the pattern: credit typically only offsets the energy charge, not the fixed base or delivery fees, and it rolls over or is capped (TXU banks up to $1,000) rather than ever being paid out in cash. This app now floors export credit at your year's energy charge, so your annual cost with solar can drop to zero for that charge but never below the fixed fees you'd owe regardless.