What PV bidder evidence should show whether REopt battery…

Summary

Request direct SAM evidence that REopt ran successfully, replaced Desired bank capacity and Desired bank power, and changed dispatch to input battery power targets or PVWatts Custom dispatch with populated hourly battery targets.

Key Takeaways

• A bidder’s REopt claim needs SAM-file evidence, not a narrative statement.
• SAM says successful REopt optimization replaces Desired bank capacity and Desired bank power.
• For PVWatts, successful REopt optimization sets dispatch to Custom dispatch and populates Battery dispatch targets.
• REopt sizing and dispatch requires PV - Battery or PVWatts - Battery and an hourly simulation time step.
• For Detailed PV, REopt sizing and optimization does not work when more than one subarray is enabled.
• Missing SAM inputs or dispatch tables mean the REopt replacement evidence is unknown, not proven.

Procurement Question

For a PV-plus-battery bid using SAM, the useful evidence is not a general statement that REopt was used. The bidder should show whether the REopt optimization was actually successful and whether SAM then replaced battery sizing and dispatch inputs. SAM states that, after a successful REopt optimization, it replaces the battery size inputs and changes dispatch to input battery power targets; for PVWatts, this appears as Custom dispatch populated with optimized values. SAM PVWatts System Design

Evidence to Request

Ask the bidder for a SAM evidence pack that includes the model type, battery setup, time step, and the battery size and dispatch fields after the REopt run. This is a recommendation, not a SAM requirement. SAM says REopt optimal sizing and dispatch is available for PV behind-the-meter systems with battery storage, and that the performance model must be PV - Battery or PVWatts - Battery. It is not available for Custom Generation Profile - Battery, hybrid systems, or other storage models. SAM PVWatts System Design

The pack should show the project used an hourly simulation time step, because SAM says REopt sizing and dispatch does not work with subhourly simulations. It should also show that battery bank sizing was in Set Desired Bank Size mode before optimization, because SAM lists that mode as a requirement. SAM PVWatts System Design

For a Detailed PV model, the bidder should disclose whether more than one subarray was enabled. SAM says the REopt sizing and optimization does not work for the Detailed PV model if more than one subarray is enabled. SAM PVWatts System Design

Proof That REopt Replaced Battery Size

The clearest evidence is a before-and-after record of the battery size fields. SAM says users should not set Desired bank power and Desired bank capacity before calling REopt, because these values will be set automatically. If the optimization is successful, SAM replaces Desired bank capacity and Desired bank power with data from REopt. SAM PVWatts System Design

For procurement review, request screenshots, exported input tables, or a SAM file comparison showing the values in Desired bank capacity and Desired bank power after the REopt result was accepted. The source document supports the fact that SAM replaces these fields after successful optimization; it does not define a required procurement format, so the exact evidence format is a buyer recommendation. SAM PVWatts System Design

Proof That Dispatch Changed to Custom Hourly Targets

The bidder should show the dispatch setting and the populated time-series dispatch data. SAM says that, if REopt optimization is successful, SAM sets the dispatch option to Input battery power targets; for PVWatts, this is Custom dispatch. SAM also says it populates Time series battery power targets; for PVWatts, this is Battery dispatch. SAM PVWatts System Design

For PVWatts Custom Dispatch, SAM defines positive kW values as discharge and negative kW values as charge for each simulation time step. Because REopt requires an hourly simulation time step for this workflow, a reviewer should expect hourly target values when the cited REopt workflow is used. SAM PVWatts System Design

What Is Unknown Without the Evidence

Without the SAM file, screenshots, exported inputs, or time-series dispatch table, it is unknown whether the bidder actually accepted the REopt replacement. The source explains what SAM does after a successful REopt optimization, but it does not prove that any specific bidder ran REopt, accepted the replacement, or used the resulting hourly targets. SAM PVWatts System Design

Do not treat AC degradation inputs as proof of REopt dispatch. SAM’s AC Degradation page describes how annual AC output decline is modeled over time, and notes that battery degradation depends on Battery Life page inputs for systems with battery storage. That page does not state that AC degradation proves REopt sizing or custom dispatch was applied. SAM AC Degradation

Practical Bid Review Recommendation

A strong bidder submission should therefore include: the SAM performance model name, battery sizing mode, hourly time-step evidence, post-REopt Desired bank capacity and Desired bank power, dispatch mode after optimization, and the populated hourly battery power target table. If any of these are missing, mark the REopt sizing or dispatch claim as unsupported rather than rejected outright, because the supplied documents describe SAM behavior but do not establish the contents of a bidder’s file.

FAQ

What is the main evidence that REopt replaced SAM battery sizing inputs?

Post-optimization SAM inputs showing Desired bank capacity and Desired bank power populated by REopt, ideally with before-and-after records.

What dispatch evidence should a PVWatts bidder provide?

The dispatch option should show Custom dispatch, and the Battery dispatch time series should be populated with target values.

Does SAM require hourly data for REopt sizing and dispatch?

Yes. SAM says REopt sizing and dispatch requires an hourly simulation time step and does not work with subhourly simulations.

Which SAM models support this REopt workflow?

The cited SAM help says the performance model must be PV - Battery or PVWatts - Battery.

Can this evidence be assumed for hybrid systems?

No. SAM says optimal sizing and dispatch is not available for hybrid systems in the cited workflow.

What should reviewers check for Detailed PV models?

They should check whether more than one subarray is enabled, because SAM says REopt sizing and optimization does not work in that case.

Do AC degradation inputs prove REopt dispatch was used?

No. AC degradation models annual AC output decline and does not prove REopt sizing or custom dispatch replacement.

What if the bidder does not provide the SAM file or dispatch table?

Then the evidence is unknown. The supplied sources describe SAM behavior, but they do not prove what happened in a specific bid file.