Best C&I battery sizing software (2026): criteria and tools

Who wrote this, and how

Zorowatt wrote this article, and Zorowatt is one of the tools in it. The facts about the other tools come from their own public pages (and, where named, a press release or a trade magazine), read on 2026-10-28; we have not run the other tools ourselves. Where a page did not say something, this article says "not stated in the pages read", not "no". Nobody paid to be included and there are no affiliate links. If a vendor finds an error, write to [email protected] and we correct it with the date.

Because we make one of the tools, this article does not rank them. It states the criteria, shows what each tool's own pages say against them, and says which job each one fits. You can apply the same criteria to any tool that is not listed here.

The six criteria

1. Tariffs for the country where the site is. What a battery saves on a business site depends on the tariff: a kW charge, a kW contract, time-of-use or dynamic energy prices. A tool either carries that country's tariffs, with their source and year, or you type them in for every study.
2. Meter data import and checks. A year of 15-minute data is 35,040 values (365 × 96). Gaps, the doubled hour of the autumn daylight-saving day, kW read as kWh or a cumulative register will size the battery for you if nobody catches them.
3. The bill rebuilt and checked against the invoices. If the model cannot reproduce last year's bill from last year's data, its savings figure has nothing to stand on.
4. Dispatch. How the battery is assumed to run: a rule a real energy management system can follow, or an optimum with perfect foresight, and whether the tool handles peak charges, a connection limit, solar and arbitrage.
5. Financials and the client report. NPV, IRR and payback with degradation and replacement, and a report a client's finance team can follow.
6. A price you can see, and a way to try it. Many consultants decide before a demo call.

Not criteria here: user reviews and ratings (not collected for this article), market share (no source found) and speed (we did not time the tools).

Which tool for which job

• North American sites, or wind and EV charging in one least-cost design: HOMER Grid. Its built-in tariff database covers much of North America, Mexico and Canada (HOMER Grid). See HOMER Grid vs Zorowatt.
• US solar and storage development with proposals and controller hardware from one company: Energy Toolbase (pricing page). See Energy Toolbase vs Zorowatt.
• A free, open-source optimiser with an API, inputs prepared by you: REopt (US DOE, REopt.jl). See REopt vs Zorowatt.
• Designing the PV array in 3D, with the battery as part of the PV system: PV*SOL premium (Valentin Software). See PV*SOL vs Zorowatt.
• A detailed PV yield simulation: PVsyst (pvsyst.com). It answers a different question from battery sizing. See PVsyst vs Zorowatt.
• German, Austrian, Swiss or Spanish C&I sites, with operation and trading from the same company for 150 kW and more: Furo (furoenergy.com, press release). See Furo vs Zorowatt.
• Many sites, assets and energy markets at once: Gridcog (gridcog.com). See Gridcog vs Zorowatt.
• An occasional study with a simple tariff: a spreadsheet you build yourself. See Excel vs Zorowatt.
• Dutch, German or Romanian sites where the bill has to be rebuilt from 15-minute data and checked against the invoices before the battery is sized: Zorowatt, the tool that wrote this article.

Published prices

Read on 2026-10-28 on the pages linked in each row; Zorowatt's own prices are today's. Prices exclude VAT where the vendor says so.

The criteria, tool by tool

"Not stated in the pages read" means the public pages read on 2026-10-28 did not say; it does not mean the tool cannot do it.

Sources for each cell: HOMER Grid, Energy Toolbase, REopt.jl, PV*SOL premium, PVsyst, Furo and pv magazine on Lumera, 17 Feb 2026, Gridcog. Each of Zorowatt's comparison pages links the source next to every cell.

Notes on each tool

HOMER Grid (UL Solutions) is the broader engineering model: grid-connected PV, wind, batteries and EV charging, the least-cost configuration, ROI and battery life, and client-facing proposals (HOMER Grid). For a US or Canadian portfolio its tariff database is the reason to choose it. UL's price list also shows a shared licence at $10,100 a year (UL Solutions).

Energy Toolbase sells ETB Developer for modelling and proposals next to its own ETB Controller and ETB Monitor hardware; Monitor starts at $4,700 and Controller bundles at $12,400 or $34,000 (pricing page). Its help pages on rates and data import were seen only as search snippets, so this article makes no claim about its European coverage.

REopt is the strongest optimiser here and costs nothing; it has a web tool, an API and a Julia package, and is aimed at federal agencies, researchers and engineers (US DOE, web tool). Zorowatt has no customer API yet, so for programmatic work REopt is ahead.

PV*SOL premium is the fuller PV design tool, with a battery database, load-profile import, a 20-year financial analysis and reports in 24 languages (Valentin Software). Many installers will design the array there and size the battery elsewhere.

PVsyst is PV yield simulation with a profitability calculation (pvsyst.com). It is in this list because it is often named next to battery tools, not because it competes on battery sizing.

Furo (formerly Lumera Energy, Munich) is the closest to Zorowatt: upload a load profile, get the optimal size, the use cases and customer-ready documents, and since May 2026 real-time optimisation and automated trading for systems of 150 kW and more (Furo, press release). Its press release reports more than 3,500 sites planned or optimised and about 100 paying customers.

Gridcog models many sites, assets and markets, for utility-scale developers, e-mobility businesses, consultants and energy majors (Gridcog). It does more than a single-site behind-the-meter study needs; for portfolio work that is the point.

A spreadsheet is cheap, flexible and fully under your control. Its cost shows in the second and third study, when the import, the daylight-saving days and the tariff are rebuilt or re-checked. See Excel vs a feasibility tool.

Where Zorowatt is the weaker choice

• No API for customers yet (REopt has one).
• The Workspace and the PDF report are in English only; the public site and the free tools are also in Dutch, German and Romanian (PV*SOL's reports come in 24 languages).
• Built-in tariffs for three countries; anywhere else you enter the rates in a generic template (HOMER Grid has North America built in).
• Planning only: no live battery control and no trading (Furo operates and trades larger systems).
• No wind, CHP or front-of-meter projects (HOMER Grid, REopt and Gridcog go further).
• The PDF is printed from the browser; there is no Word export.
• Zorowatt is new. Its engine is tested against analytical cases; a comparison against REopt and HOMER Grid and an independent expert review of the bill reconstruction are planned, not done.

How to choose in an afternoon

1. List the countries of your next ten sites. If a tool has no tariffs for them, count the time to type them in, every year they change.
2. Take one real site with 12 months of 15-minute data and its invoices. Run the file through the free meter data checker first, so every tool gets clean data.
3. Run that site in each tool's free trial. Compare the rebuilt bill with the invoices before you compare battery sizes.
4. Look at the report as your client would: can a finance team see the tariff, the assumptions and where each saving comes from?
5. Then compare prices for the number of studies you actually do a month.

Sources

• HOMER Grid product page and pricing; UL Solutions price list
• Energy Toolbase pricing
• US DOE on REopt, REopt.jl on GitHub, REopt web tool
• PV*SOL premium
• PVsyst and PVsyst shop
• Furo, Furo press release, pv magazine, 17 Feb 2026
• Gridcog and Gridcog pricing

Last checked: 2026-10-30. Facts about other tools were read on 2026-10-28 from the pages linked next to them; prices and features change, so check the vendor's page before you rely on one. Examples marked illustrative are not real customers. This list is refreshed once a year.