Comparison

Energy Optima vs NREL SAM

SAM (System Advisor Model) is the reference tool of the research world — free, open source, and used across NREL's own publications. Energy Optima is a commercial platform. If cost is the deciding factor, SAM is hard to beat. Here is what you trade.

What NREL SAM does genuinely well

SAM is a serious, well-documented model produced by the National Renewable Energy Laboratory. It is used in academic research, utility resource planning and early-stage feasibility, and it covers a genuinely wide technology set.

Free and open source. No licence cost, no seat limits, no vendor relationship.
Transparent and citable. Its algorithms are documented in peer-reviewed publications, which is why it appears in research so often.
Broad technology coverage. PV, CSP, wind, geothermal, biomass and battery storage in one tool.
Configurable battery dispatch. Peak shaving, self-consumption and arbitrage rules can be scripted.
Scriptable (PySAM). The Python bindings make batch and parametric studies genuinely practical.

Where SAM is a heavy lift commercially

Battery degradation is a single annual fade rate. There is no calendar/cycle separation and no C-rate-dependent interpolation, which is the core of BESS lifetime economics.
No manufacturer component database. You enter battery specifications by hand, so a model built this way can drift from the datasheet it is supposed to represent.
Dense desktop interface. The learning curve is real, and it is not a shared, multi-user workspace.
Reporting is a modelling output, not a deliverable. Producing a formatted client report with loss waterfalls and investor cashflows means post-processing outside SAM.

What Energy Optima does

BESS degradation from manufacturer tables via 3D interpolation across year, C-rate and cycles per day.
Component selection from datasheets rather than manual parameter entry.
LP-optimized sizing with rule-based, economic and predictive MPC dispatch.
Report generation in .docx, .pdf and .xlsx with engineer, investor and owner audience variants.
Multi-user collaboration and API access on higher tiers.

Where SAM beats us

Put plainly: SAM is free, its method is fully documented in the open literature, and it covers CSP, geothermal and biomass that Energy Optima does not model at all. For a research paper, a parametric academic study, or a technology screen where budget is zero, SAM is the correct tool. PySAM's scripting story is also more mature than our API for very large batch campaigns.

Feature comparison

Capability	Energy Optima	NREL SAM
Cost	Free tier; paid plans from $99/mo	Free, open source
Battery degradation	3D interpolation: year × C-rate × cycles/day	Single annual fade rate
Component database	Manufacturer datasheets with degradation tables	Manual parameter entry
PV modelling	Multi-array, MPPT string sizing, 10-category waterfall	Detailed but no 3D shading
Optimization	LP auto-design + economic/predictive dispatch	Rule-based dispatch; parametric sweeps via PySAM
Technologies covered	PV, battery, grid, diesel, wind	PV, CSP, wind, geothermal, biomass, battery
Reporting	Formatted .docx/.pdf/.xlsx, 3 audience types	Model outputs; post-process externally
Automation	REST API on Team and above	PySAM Python scripting

Assessment based on published documentation and each tool's documented modelling approach. SAM is produced by NREL and is free to use; always confirm current capability against its official documentation for your release version.

Which should you choose?

Choose NREL SAM if…

Budget is zero and the work is research or academic.
You need CSP, geothermal or biomass in the same model.
You want a fully documented, peer-citable method.

Choose Energy Optima if…

You need BESS degradation that tracks a real cell datasheet.
The output must be a client- or lender-ready report, not a model dump.
A team needs to work in one shared project workspace.

Frequently asked

Is NREL SAM really free?

Yes. SAM is developed and distributed by the National Renewable Energy Laboratory at no cost, and its source code is publicly available. There is no licence fee, unlike PVsyst or HOMER Pro.

Is SAM accurate for battery storage?

SAM's battery model is adequate for screening but treats degradation as a single annual fade rate. For projects where replacement timing and 20-year capacity retention drive the financial result, that simplification is the main gap.

Why would I pay for Energy Optima when SAM is free?

You would not, if SAM covers your need — for research and early screening it often does. Teams pay for the manufacturer degradation data, LP sizing, formatted reports and shared workspace that a commercial deliverable requires.

What does the free Energy Optima plan include?

Unlimited projects — each up to 1 MW PV / 1 MWh storage — with Battery + PV + Grid topology, 1-year simulation, rule-based auto-design, payback analysis, and PDF export. No credit card required.

Try it on a real project

Unlimited projects — each up to 1 MW PV / 1 MWh storage — with Battery + PV + Grid topology, 1-year simulation, rule-based auto-design, payback analysis, and PDF export. No credit card required.

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