A headline saying batteries now beat gas turbines for data centers tells you very little about whether storage pays off at your hotel, apartment community, dealership or retail site. A sound commercial battery storage evaluation starts with your own interval data and utility tariff, not with industry-wide cost comparisons. The seven questions below help you test any proposal, whichever vendor wrote it.
One caution first. The research supplied for this article did not include evidence on battery or turbine economics, so this piece makes no claims about current prices, savings percentages or incentive levels. Treat any such figure in a proposal as something the vendor must document, and verify time-sensitive items such as incentives and tariff rules with the utility and the relevant agency before you sign.
Why a data-center comparison stops applying at a small site
A data-center comparison pits batteries against generation built to supply large, steady, round-the-clock loads. A commercial property buys power from a utility and has a very different problem: it wants to lower what it pays, ride through occasional outages, or add EV charging without an expensive service upgrade.
Three differences matter:
- The alternative is not a turbine. Your real alternatives are doing nothing, load controls, a tariff change, a service upgrade, or on-site generation you may already own.
- Your savings depend on a rate schedule. The value comes from specific tariff lines, not from a generic cost per kilowatt-hour.
- Scale changes the economics. Fixed costs such as engineering, interconnection, permitting and switchgear weigh more on a small project.
Key takeaway: A cost comparison from another industry is context, not evidence. A proposal earns trust when it ties every dollar of projected value to a line on your bill and a pattern in your meter data.
Seven questions to ask every battery storage proposal
1. What does the interval data actually show?
Ask which meter data the vendor used, for what period, and at what interval. Fifteen-minute interval data covering a full year is the usual basis for sizing, because monthly bills hide the short spikes that drive demand charges. If the vendor worked from bills alone, the sizing is a guess.
Look for three things in the load profile:
- How tall the peaks are above your typical load.
- How long they last. A 20-minute spike is a good battery target. A six-hour plateau is far harder to shave.
- How often and when they occur, including seasonal patterns.
2. Which tariff lines does the battery reduce?
Batteries typically create value through demand charges, time-of-use energy arbitrage, backup power or some mix. Ask the vendor to name the exact rate schedule used and to show which charges the savings come from. Check whether your demand charge is based on a short measurement window, whether there is a ratchet that keeps a high peak on your bill for months, and whether the utility has signaled rate changes. A model built on a tariff that is about to change can overstate savings.
If you pay no meaningful demand charge, the case rests on other value streams, and the proposal should say so plainly.
3. Is the system sized for power, energy, or both?
Power (kW) determines how much peak the battery can clip. Energy (kWh) determines how long it can do so. A proposal should explain why the chosen ratio fits your peak shape. Oversizing raises cost without added savings. Undersizing leaves peaks that the battery cannot cover, and a single missed peak in a billing period can erase much of the month’s benefit.
4. How does it interact with EV charging?
Charging can create sharp, unpredictable load spikes, especially with fast chargers at dealerships, hotels or retail sites. Storage can buffer those spikes, which may help when the electrical service is constrained. But it is not the only tool.
Ask the vendor to compare against alternatives:
- Managed charging that caps or staggers sessions.
- A modest service upgrade, where the utility allows it.
- Fewer or lower-power chargers at first, with room to expand.
Also ask whether the battery controller and the charging software will communicate, and who is responsible when they conflict. For multifamily properties, confirm who is billed for the charging load and which meter it sits behind.
5. What do the warranty and degradation terms really promise?
Batteries lose capacity over time, so the warranty details matter as much as the price. Request the actual warranty document and look for:
- Capacity retention guarantee: what percentage is guaranteed at what year, and whether it is measured under stated conditions.
- Throughput or cycle limits: the warranty may assume a maximum number of cycles or energy throughput. Daily peak shaving plus arbitrage can use these up faster than the vendor’s base case.
- Operating conditions: temperature and installation requirements that, if unmet, void coverage.
- Who honors it: the manufacturer, the integrator or a third party, and what happens if that company exits the market.
- Remedies: repair, replacement or a prorated credit, and who pays for labor and removal.
Check that the savings model uses degraded capacity in later years, not nameplate capacity throughout.
6. What is and is not included in the price?
Hardware is only part of the project. Ask for a line-item scope covering interconnection and utility studies, electrical upgrades, permitting, fire-code and insurer requirements, installation location, software and monitoring fees, and ongoing maintenance. Then ask about ownership: purchase, lease, or a storage-as-a-service arrangement. Each shifts risk differently, and each has different contract lengths and exit terms.
If the proposal assumes incentives or tax benefits, ask for the specific program, eligibility conditions and documentation. Eligibility rules change, so confirm with a tax or legal advisor rather than relying on the vendor.
7. What happens if the assumptions are wrong?
A credible proposal shows how results change if the tariff shifts, peaks move, or the site adds load. Ask for a sensitivity range, not a single number. Also ask how savings will be measured after installation, against what baseline, and whether the vendor shares any performance risk. A guaranteed savings clause is worth little if its exclusions swallow it.
What to check by property type
These are typical considerations, not predictions. Your data decides.
| Site type | Often worth checking | Common trap |
|---|---|---|
| Hotel | Morning and evening peaks from HVAC, kitchens, laundry; backup value for guest operations | Assuming occupancy-driven load is predictable year-round |
| Multifamily | Which meter the owner pays on; common-area load vs. tenant load; shared EV charging | Demand charges sitting on meters the battery cannot affect |
| Dealership | EV charging for inventory and service, shop equipment, lighting; service capacity limits | Sizing for today’s chargers and ignoring planned expansion |
| Retail | Long operating hours, daytime HVAC peaks, tariff structure | Peaks that are broad rather than short, which batteries shave poorly |
A simple scorecard for comparing proposals
To compare vendors on equal terms, score each proposal from 0 to 3 on every one of the seven questions: 0 means unanswered, 1 means asserted without evidence, 2 means supported by documents, and 3 means supported and stress-tested. Add a column for what you would still need to verify. A proposal with a lower headline price but several zeros usually carries more hidden risk than one with a higher price and documented answers.
Hypothetical illustration: Two proposals for the same dealership. Proposal A shows a large savings figure but used monthly bills and one assumed tariff. Proposal B shows a smaller figure, uses a year of 15-minute data, names the rate schedule, and includes a degradation schedule. On the scorecard, B will rank higher even if A looks better on the cover page.
Practical checklist before you sign
- Pull 12 months of interval data and a current copy of your rate schedule, and share them with every bidder.
- Ask each vendor to state the value streams they are counting and the tariff lines behind them.
- Request the full warranty, the degradation assumptions and the cycling limits.
- Get a line-item scope that lists interconnection, electrical work, permitting and software fees.
- Compare against at least one non-battery option, such as load management or a tariff change.
- If EV charging is planned, require a joint design for storage and charging controls.
- Confirm incentive eligibility independently.
- Define post-installation measurement, the baseline, and what remedies apply if results fall short.
Where to go from here
Storage can make sense for some commercial sites, and the data-center story may be a fair signal that the technology is maturing. It is not a reason to skip your own analysis. If you are weighing storage alongside EV charging at a hotel, multifamily community, dealership or retail location, a vendor-neutral review of the proposals can help you compare them on equal footing. You can start by exploring MoJo Tech Group’s technology service offerings and requesting a consultation on your energy and EV charging plans.