RTW solar buyback: wholesale vs. fixed export rates

What is an RTW solar export plan?

RTW means real-time wholesale. An RTW solar buyback plan credits electricity you send to the grid at a changing wholesale market price. A fixed buyback plan pays a stated rate, such as 2¢ or 3¢ per kilowatt-hour (kWh). The rate you pay for electricity from the grid is a separate part of either plan.

Your panels power your home first. Exports are the surplus that leaves through your meter; imports are electricity you buy when your home needs more than your system supplies. ERCOT, the operator of most of the Texas grid, publishes the wholesale prices used in these agreements.

This guide focuses on homes in Texas areas where you can choose an electricity provider. Municipal utilities and electric cooperatives set their own buyback rules; start with the Texas solar buyback guide for those areas.

Is RTW better than a fixed buyback rate?

It can be, but neither structure always wins. In 2025, the average North-zone wholesale price from 10 a.m. to 4 p.m. was about 2.24¢/kWh. That falls between an illustrative fixed credit of 2¢ and 3¢. Your own RTW result depends on when you export and how your agreement calculates credits.

A fixed export rate is sometimes called unmatched buyback because it is set separately from the import energy rate. “Matched” or “1:1” buyback ties the credit to the plan’s retail energy charge. Here, the main comparison is between a separate fixed export rate and RTW.

For this example, a 3¢ fixed credit earns about $36 more a year than the RTW benchmark. But paying just 1¢ more on 6,000 imported kWh costs $60 a year. An extra $5 monthly fee also costs $60. Either difference can reverse the result.

Use the annual solar buyback comparison method to include imports, delivery charges, fees, and usable credits.

What to check before you enroll

Read the buyback agreement and Electricity Facts Label (EFL), which summarizes your grid electricity charges.

What happens when wholesale prices go negative?

Your agreement decides whether a negative market price produces no credit or a deduction. Do not assume RTW includes a zero floor. In 2025, 7.4% of North-zone midday intervals were at or below zero; that includes both zero-price and negative-price intervals.

Negative prices can occur when supply is abundant relative to demand. Generator operating constraints, incentives, and transmission limits can all contribute. A zero floor, a price cap, or a deduction changes the result from the raw market averages below.

What has RTW paid during solar hours?

Across the four load zones shown here, 2025 midday wholesale averages ranged from 2.01¢ to 2.63¢/kWh. These are historical market benchmarks. They are not measured household credits or forecasts.

A load zone is a region for wholesale pricing. The settlement point price is the price ERCOT publishes for the location named in your agreement. This analysis uses its historical 15-minute prices, with the midday window defined as 10 a.m. up to 4 p.m., Central time.

Each interval has equal weight in these averages. Your home exports more in some intervals than others, so its effective buyback rate is different: total export credits divided by total exported kWh. Roof direction, shading, weather, household use, and battery operation all affect that number. Contract adjustments matter too.

The January–August 2026 figures cover only eight months. Comparing them with all of 2025 mixes different seasons, so the difference does not establish a year-over-year trend.

Why are midday prices often lower?

Many solar systems produce at the same time. That extra supply can lower midday wholesale prices. Later, solar production falls while homes and businesses still need electricity, which can push prices higher.

ERCOT’s independent market monitor reported a 2025 solar captured price of $21/MWh, or 2.1¢/kWh: the generation-weighted price received by utility-scale solar. It supports the broader pattern, but uses different locations and production weights from a rooftop export credit. It cannot establish what your roof would earn. See the 2025 State of the Market report, pages 19–20.

Can a few price spikes make up the difference?

Sometimes a high-price interval can add meaningful credit, if you export during it and your agreement passes the price through. In the North zone’s 2025 midday window, those intervals contributed a limited share of the total.

These figures already include the spikes. Adding a separate “spike bonus” to the average would count them twice. Another year, location, or export pattern can produce a different result.

How do you estimate your own effective rate?

Match your exported kWh to the price for the same interval, apply the agreement’s rules, and add up the credits. This historical calculation is most useful when exports make up a meaningful part of your bill.

1. Get a full year of export data. Smart Meter Texas reports surplus generation separately from grid consumption. Use exports, not total panel production. For a new system, ask the installer to combine expected production with your home’s usage to estimate exports by time of day.
2. Get the matching prices. Download ERCOT’s Historical RTM Load Zone and Hub Prices and select the settlement point in your agreement. Use the same dates as the export data.
3. Align the intervals. Check time zones, daylight-saving repeated hours, and whether timestamps mark the start or end of a period. ERCOT delivery hour 11 covers 10–11 a.m.; intervals 1–4 divide that hour into quarters. Do not silently omit missing records.
4. Calculate the credit. ERCOT reports dollars per megawatt-hour (MWh). Divide by 1,000 for dollars per kWh, then apply the contract’s adjustments, floor, and cap in the specified order. Multiply each interval’s eligible exported kWh by that rate and sum the results.
5. Compare complete annual bills. Divide the export credit by exported kWh for the effective buyback rate. Account for credit-use limits, import costs, delivery charges, and fees separately when comparing plans.

For example, 2 exported kWh × $25/MWh ÷ 1,000 = $0.05 of credit before adjustments. A different interval gets its own price. Test more than one complete year if possible, without treating historical results as a promise.

RTW solar buyback FAQ

What does RTW stand for in solar buyback?

Real-time wholesale. The export credit follows a wholesale market price under the formula in your agreement, instead of a fixed cents-per-kWh rate.

What is a typical RTW buyback rate in Texas?

There is no guaranteed RTW rate. In 2025, simple 10 a.m.–4 p.m. wholesale averages ranged from 2.01¢ to 2.63¢/kWh across the North, Houston, South, and West load zones. A home’s actual credit depends on its export timing and contract terms.

Is RTW better than a 2¢ or 3¢ fixed buyback rate?

Either can win. The 2025 North-zone midday benchmark was 2.24¢/kWh before contract adjustments, between those two illustrative fixed rates. Compare usable export credits alongside import costs and fees over a full year.

Can I be charged for exporting solar on an RTW plan?

A negative market price can reduce your credit if the agreement passes it through. A zero floor prevents that part of the calculation from going negative. Check the agreement’s floor and any separate deductions.

How does a battery affect this comparison?

Battery operation changes when and how much electricity a home imports and exports. The midday market averages in this guide do not model that behavior or establish which plan is best for a battery-equipped home. See the battery and virtual-power-plant guide for more context.

Isn’t wholesale-indexed pricing banned in Texas?

Texas prohibits retail providers from offering residential and small commercial customers products whose price for electricity they buy is indexed to the real-time wholesale market. An export credit pays for electricity sent to the grid and is a separate part of the agreement. Read the import EFL and export terms separately; see Texas Utilities Code §39.110.

Sources and methodology

Price figures come from ERCOT’s Historical RTM Load Zone and Hub Prices for 2025 and January–August 2026. We average 15-minute prices equally within each stated time window, before contract adjustments; actual credits depend on your export timing and plan terms.

Potomac Economics’ 2025 State of the Market Report for ERCOT, pages 19–20, provides context on solar captured prices and the timing of grid demand. ERCOT’s real-time market page explains the price reports.

Reviewed September 14, 2026. This guide provides general educational information, not legal advice. Rules and plan terms can change; confirm current PUCT materials and your plan documents for your situation.