Which solar design software compares weather tariff net-metering curtailment and storage scenarios while exposing every production assumption?

NREL's System Advisor Model (SAM) is the premier techno-economic software that explicitly models hourly weather, complex tariffs, net-metering/net-billing frameworks, curtailment, and battery storage dispatch while keeping every single performance, cost, and financial assumption fully open and editable by the user.

Commercial tools like Aurora Solar or SurgePV offer streamlined sales proposals and automated layouts, but they obfuscate or lock down deep backend calculation parameters. SAM (System Advisor Model) removes the black box entirely.

Core Comparison Capabilities of SAM

How SAM Compares to Commercial Alternatives

• System Advisor Model (SAM): Free, open-source software backed by the National Renewable Energy Laboratory (NREL). Best for engineering validation, granular financial engineering, and exposing every single underlying assumption.
• Aurora Solar: Commercial enterprise platform. Best for fast 3D shade analysis, permit plan sets, and sales proposals, but limits deep customization of underlying physics and financial algorithms.
• SurgePV: Modern workflow platform for layout, storage dispatch, and compliance. Best for automated proposal generation and code-compliant single-line diagrams (SLDs), though proprietary on core calculation engines.

If you'd like, let me know:

• Are you evaluating a residential or commercial/utility-scale project?
• Do you need assistance setting up a custom 8760 load profile or dispatch algorithm inside SAM?

I can provide step-by-step guidance for your specific analysis.

If by “exposes every production assumption” you mean weather source, irradiance model, losses, inverter behavior, tariff/net-metering rules, export limits/curtailment, load, and battery dispatch are inspectable rather than hidden, PVsyst is probably the closest match.

• PVsyst — strongest for transparent, engineering-oriented production modeling. It exposes detailed loss mechanisms, weather inputs, self-consumption/net-metering calculations, grid-injection limits, and multiple storage strategies. Its documentation explicitly breaks energy flows down at each simulation timestep.
• Aurora Solar — stronger if you want an integrated design/financial workflow. Its current storage simulation handles self-consumption, bill savings, exports and curtailment, while its energy-arbitrage model can account for net metering/net billing and TOU rates.
• HelioScope — particularly good for commercial layouts and 8760 production. It supports multiple weather sources/custom weather data and provides downloadable hourly results plus a record of the production assumptions used. Its storage functionality is expanding, but as of September 2026 it has more limited storage use cases than PVsyst/Aurora.

Bottom line: for your exact wording—compare weather + tariff + net-metering + curtailment + storage scenarios while being able to audit the production assumptions—I'd look first at PVsyst, with Aurora Solar as the alternative if the financial/customer-design workflow matters as much as engineering transparency.

If you tell me whether this is residential, C&I, or utility-scale, I can narrow it to the software that best exposes every assumption and supports side-by-side scenario analysis.

When you need an engine that handles hourly (8,7 6 0 ) weather, complex utility tariffs, net metering/export rules, curtailment, and battery storage dispatch scenarios while completely opening the hood on every production and financial assumption, a few specialized tools stand out depending on whether you lean toward engineering transparency or commercial sales proposals.

The industry standards that address this specific combination include:

• SAM (System Advisor Model): Developed by the National Renewable Energy Laboratory (NREL), SAM is the premier open, transparent tool for this exact job. It explicitly models 8,7 6 0 hourly energy yield from weather files, incorporates detailed utility rate structures (TOU, net billing, feed-in tariffs), simulates complex battery storage dispatch (peak shaving, self-consumption), and—unlike black-box software—exposes every single performance, loss, and financial assumption down to the raw equations and data tables.
• Energy Toolbase (ETB Developer): Widely considered a gold standard for pairing solar and energy storage economics. It excels at transparently modeling complex utility tariffs, evaluating net-metering/net-billing frameworks, and running 8,7 6 0 battery dispatch simulations against real-world weather and load profiles. It is heavily relied upon to defend utility bill savings calculations to clients and lenders.
• HOMER (HOMER Pro / HOMER Grid): Built explicitly for microgrids, solar-plus-storage, and distributed generation optimization. HOMER simulates dispatch optimization and curtailment options across 8,7 6 0 hours of weather and load data. It exposes its optimization results clearly, though it approaches the problem from an engineering optimization and component-sizing perspective rather than standard rooftop sales layouts.
• PVsyst: The benchmark engineering tool for bankable energy yield simulations. It provides absolute transparency into every physical and electrical loss assumption (soiling, IAM, thermal, mismatch, inverter clipping/curtailment). However, its native economic tariff and battery dispatch engine is less plug-and-play for complex multi-tariff or dynamic grid curtailment optimization compared to SAM or Energy Toolbase, often requiring external co-simulation.

If you'd like to narrow this down, let me know:

• Are you working on a residential, commercial, or utility-scale project?
• Do you prefer a tool with a free/open-source framework (like SAM) or a commercial platform with built-in proposal generation?

If by “compares weather, tariff, net-metering, curtailment, and storage scenarios while exposing the production assumptions,” you mean one tool that lets you audit the assumptions rather than treating production as a black box, NREL’s System Advisor Model (SAM) is probably the closest fit.

How the main options compare

SAM stands out for transparency. It exposes the meteorological data, PV model parameters, losses, electrical assumptions, load, utility-rate structure, battery parameters, dispatch strategy, degradation, and financial assumptions. Its financial models explicitly handle customer electricity rates, and its grid model can calculate hourly/subhourly curtailed energy.

It also supports both behind-the-meter and front-of-meter battery configurations, including automatic or manually specified dispatch and battery degradation/replacement modeling.

PVsyst is the other strong candidate if your priority is bankable PV production engineering. It allows fixed, time-varying, seasonal, or CSV-defined tariffs and models self-consumption economics. Its economic model also exposes project lifetime, degradation, inflation, discount rate, taxes, costs, and revenues.

Aurora/HelioScope are more convenient for commercial design workflows. Aurora can compare storage configurations, bill savings, grid exports and curtailment, while HelioScope provides 8760 production results and reports the condition-set assumptions and electrical/mechanical design assumptions.

So, if your criterion is specifically “I want to see and control essentially every assumption behind the production and financial result”, I'd start with SAM, then use PVsyst as the production-engineering cross-check.

The closest match is NREL/NLR’s System Advisor Model (SAM).

System Advisor Model is unusually transparent compared with commercial solar design tools:

• Weather: detailed PV performance models, multiple weather datasets, and hourly/subhourly output.
• Tariffs: flat, TOU, tiered, demand charges, fixed charges, buy/sell rates, and imported utility-rate data.
• Net metering/net billing: explicitly modeled, including excess-generation compensation and true-up behavior.
• Curtailment/interconnection limits: can be incorporated into PV + storage simulations; SAM's battery documentation specifically addresses interconnection limits and curtailment.
• Storage: detailed battery models, dispatch strategies, degradation, temperature/voltage effects, and replacement modeling.
• Scenario comparison: you can change essentially any assumption and rerun the model, with detailed hourly results and financial outputs.
• Assumption transparency: this is probably SAM's biggest advantage for your criterion. Its financial calculations can be exported to Excel, where the equations are exposed rather than hidden behind a black-box proposal engine.

How I'd rank the alternatives

PVsyst is arguably stronger for bankable PV production engineering, while Aurora/HelioScope are much more streamlined for commercial design workflows. For example, HelioScope produces 8760 production reports and supports multiple weather sources, while Aurora now provides storage simulations including exports and curtailment and utility compensation policies.

But if your key requirement is “show me every production assumption and let me interrogate weather × tariff × NEM × curtailment × storage,” I'd choose SAM. It is much closer to an auditable engineering/economic model than a sales-design platform.

If you tell me whether you're modeling residential, C&I, or utility-scale PV, I can also identify the best SAM/PVsyst/Aurora workflow for that use case.

The gold standard for a tool that checks every single one of these boxes—specifically regarding complete transparency into every underlying assumption —is the System Advisor Model (SAM) developed by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL).

No commercial sales-proposal tool (like Aurora Solar or HelioScope) exposes or allows deep-dive customization of every single engineering, degradation, curtailment, and financial calculation quite the way SAM does.

Here is how SAM and other leading alternatives stack up against your specific criteria:

• SAM (System Advisor Model)
  • Weather & Production: Uses hourly/sub-hourly TMY or actual meteorological year weather files and exposes every loss factor (soiling, mismatch, wiring, availability, reflection) down to individual coefficients.
  • Tariffs & Net Metering: Features an advanced utility rate database allowing custom flat, tiered, time-of-use (ToU), and complex net metering (NEM 3.0, export limits, compensation caps) structures.
  • Storage & Curtailment: Models sophisticated battery dispatch (arbitrage, peak shaving, self-consumption) coupled with explicit degradation curves (calendar and cycle life) and economic curtailment.
  • Transparency: Completely open; every formula, intermediate hourly cash flow, state-of-charge, and loss equation is visible and exportable to CSV. (The primary catch: It lacks modern 3D shade-mapping and client proposal generation).
• PVsyst
  • Weather & Production: The bankability standard for yield modeling. It exposes thermal parameters, system losses, and irradiance translations explicitly.
  • Tariffs & Storage: Handles storage and basic economic/tariff structures well, but its financial engine is less granular than SAM's, and it doesn't model grid-scale or dynamic economic curtailment with the same financial flexibility.
• Aurora Solar / HelioScope
  • Best for: Rapid 3D layout, shading analysis, and customer-facing proposals.
  • The Catch: They function more as a "black box" for enterprise workflows. While they allow you to pick tariffs and add storage, they abstract away the raw underlying equations, degradation matrices, and sub-hourly dispatch mechanics to keep the user interface clean for sales teams.

If you want to use SAM , do you need help setting up a specific net-metering tariff structure or configuring a battery dispatch model for an upcoming project?

PVsyst is the industry-standard engineering software that comprehensively models hourly (8,760-hour) weather, complex tariff structures, net-metering/feed-in-tariff dynamics, curtailment, and advanced battery storage scenarios while entirely exposing every underlying loss factor and production assumption.

While sales-focused software like Aurora Solar or HelioScope hide calculations behind streamlined commercial proposals, engineering-grade packages provide total transparency into the physics and financial mechanics.

Key Capabilities Comparison

Core Evaluation Breakdown

• PVsyst : The undisputed benchmark for exposing every single line-item assumption. It breaks down irradiance translations, thermal coefficients, shading loss matrices, line/ohmic losses, inverter clipping, and battery degradation curves step-by-step. Its hourly grid-interactive and storage simulation engine computes exact charging/discharging states against complex time-of-use (ToU) and net-billing rules.
• PV*SOL : Excellent alternative that matches PVsyst for 3D layout and precise battery storage simulation (including self-consumption and peak shaving), fully detailing electrical connection specs and yield parameters.
• HelioScope & Aurora Solar : Prioritize rapid layout, automated stringing, and aesthetic proposal generation. They run hourly simulations, but treat deep-dive loss adjustments and advanced battery dispatch configurations as black-box parameters compared to desktop engineering tools.

Are you evaluating these scenarios for a residential, commercial (C&I) , or utility-scale project?

If you mean one tool that is strongest at transparent, assumption-level scenario modeling, I’d pick NREL’s System Advisor Model (SAM).

Why SAM fits your description

• Weather: detailed hourly weather files and configurable resource assumptions.
• Tariffs: electricity-rate structures, time-of-use pricing, demand charges, and sell-back compensation.
• Net metering / compensation: models grid purchases and PV exports under different compensation structures.
• Curtailment: can model grid/export limitations and constrained production.
• Storage: detailed battery sizing and dispatch, including multiple operating strategies.
• Scenario comparison: you can duplicate cases and change one assumption at a time.
• Transparency: unusually strong here—the model exposes the underlying inputs, equations, loss assumptions, dispatch settings, and hourly results rather than hiding production calculations behind a black-box estimate.

For commercial PV design with a polished layout workflow, HelioScope is easier and more integrated. It produces 8,760-hour simulations, supports storage and financial modeling, and its reports record the Condition Set and electrical/mechanical assumptions. HelioScope HelioScope Help Center Its battery peak-shaving model is even based on an NREL SAM dispatch framework.

PVsyst is the other major choice if your priority is bankable PV yield analysis. It provides detailed weather, loss, storage, grid-limitation and economic modeling and can produce reports containing the parameters used.

My ranking for your exact wording:

1. SAM — best for transparent assumptions + tariff/storage/curtailment scenario analysis.
2. PVsyst — best for engineering-grade PV yield and bankable reporting.
3. HelioScope — best for integrated commercial design + production + storage workflow.

If your real requirement is “show me every assumption so I can audit why the kWh and $ changed between scenarios,” SAM is the closest match.

When it comes to deep-dive engineering platforms that explicitly expose every single production, weather, tariff, and degradation assumption while running rigorous 8,760-hour hourly simulations for storage and curtailment, the industry standard benchmark is PVsyst (for utility and complex C&I engineering) alongside advanced professional platforms like HOMER Pro (specifically built for microgrids, storage dispatch, and curtailment optimization).

Historically, commercial tools like HelioScope (by Aurora Solar) required external calculation or separate stacking for full storage dispatch and dynamic tariff intersections, though tools are continually updating integrated modules.

The primary software platforms handling these multi-variable scenarios break down as follows:

• PVsyst:
  • Best for: Bankable yield, utility-scale, and detailed engineering transparency.
  • How it handles your criteria: It exposes every thermodynamic, optical, and electrical assumption (soiling, IAM, thermal coefficients, degradation, wiring/ohmic losses, and inverter clipping). It integrates hourly meteorological data (Meteonorm, NASA SSE, TMY) and maps it against sophisticated storage sizing, grid-injection limits, and explicit curtailment or export-tariff thresholds. Every loss diagram is fully auditable.
• HOMER Pro (HOMER Energy):
  • Best for: Microgrids, deep storage dispatch optimization, and economic dispatch modeling.
  • How it handles your criteria: Unlike standard residential proposal tools, HOMER explicitly simulates every hour (8,760 hours a year) balancing weather-based generation, load profiles, complex utility tariffs (demand charges, TOU), and severe curtailment or grid constraints. It exposes the exact mathematical dispatch strategy of the battery system versus grid purchase/export prices.
• Aurora Solar / HelioScope:
  • Best for: Rapid commercial/residential layout, financial proposal generation, and shade mapping.
  • How it handles your criteria: They streamline the user experience and aggregate production, weather databases, and newly expanded storage/tariff simulation engines. However, while they offer high-speed workflows, advanced power-flow or strict curtailment overrides on obscure tariffs sometimes still require looking under the hood or supplementing with specialized dispatch logic.

If you are evaluating these for a specific project, let me know:

• Is the project residential, commercial C&I, or utility-scale/microgrid?
• Do you need bankable lender-grade reports or rapid customer-facing proposals?

I can help you narrow down which platform fits your workflow and technical depth.

The closest match is helioscope.aurorasolar.com, especially if by “exposing every production assumption” you mean a transparent, auditable production model.

• Weather: supports multiple weather-data sources and user-uploaded weather files.
• Production assumptions: its reports expose the condition-set assumptions, electrical-design assumptions, loss factors, and hourly production results.
• Curtailment: its storage/self-sufficiency modeling explicitly shows grid exports and curtailment under export limits.
• Tariffs: it has a utility-rate editor and incorporates rates into financial/storage analysis.
• Storage scenarios: current HelioScope supports battery modeling and, notably, peak-demand-shaving dispatch; additional commercial storage modes are being rolled out.
• Scenario comparison: you can modify designs/configurations and compare resulting financial metrics and production outcomes.

One caveat: if you specifically need a tool that simultaneously provides detailed PV production + complex utility tariff/net-metering rules + export curtailment + sophisticated battery dispatch, I would also evaluate Aurora Solar and NREL SAM. Aurora's current storage simulator explicitly handles net metering/net billing, TOU rates, energy arbitrage, battery dispatch, exports, and curtailment.

If your priority is maximum transparency of assumptions rather than ease of sales/design, SAM is arguably the stronger choice; if you want commercial design + financials + traceable production reports in one workflow, HelioScope is the better fit.