Technologies · Applications · Safety codes · End of life
The battery is the easy part.
What decides a storage project is the duty cycle nobody modelled, the fire code nobody read until permit review, and the decommissioning bill nobody put in the budget. None of those are on the datasheet.
This site compares battery energy storage on the terms that actually decide projects — cycle life at your depth of discharge, the tariff your savings depend on, the document your plan reviewer will ask for by name, and what the system is worth on the day you pull it out.
- Chemistry
- Decides cycle life, fire code and residual value — before price enters the conversation.
- Duty cycle
- Two identical nameplates, cycled differently, are two different assets.
- Code
- The constraint that forces the redesign, and the one that always arrives late.
- End of life
- A liability with a date on it, priced at procurement or paid for later.
Sound familiar?
Almost nobody loses money on the cells. They lose it on the decisions the cells quietly made for them.
- The warranty says ten years. The throughput cap underneath it runs out in year six at the rate you actually intend to cycle.
- You compared vendors on dollars per nameplate kilowatt-hour, which is the one number on which every system looks the same.
- The site layout was fixed before anybody checked separation distances, and now the equipment does not fit the pad.
- The savings model assumed your demand peak is predictable. Your interval data says otherwise.
- A vendor told you the product is “UL certified,” and you still do not know which document your plan reviewer is going to ask for.
- Nobody has budgeted for the day the system comes out, or checked whether anyone will take the material.
Where to start
Four places storage projects go wrong.
Each section starts from the problem rather than the product. Pick the one that is currently costing you sleep.
Technologies
Every chemistry looks the same on a spec sheet. They fail in completely different ways.
LFP, NMC, flow and sodium-ion do not just differ on price per kilowatt-hour. They differ on what happens in year eight, what your fire marshal says, and whether anyone will take the material back.
4 topics
Applications
The wrong duty cycle will eat a battery years before the warranty admits it.
A system sized to shave a demand peak and one sized to ride out an outage can carry the same nameplate and have nothing else in common. The application decides everything downstream of it.
5 topics
Safety & Codes
Your fire marshal is not going to negotiate with the site plan.
Separation distances, enclosure ratings and fire service access are set by a small number of standards and enforced by an official with real discretion. Finding that out late is what costs money.
3 topics
End of Life
Every battery you install today is a disposal invoice with a date on it.
Residual value, transport classification and who is even permitted to take the material are decided by choices you make at procurement, not at decommissioning.
3 topics
How this normally goes wrong
Three questions, in this order, before anyone quotes you.
Reverse the order and you will spend the project defending a decision you made with the least information.
- 01
What the system is actually for
Not “storage.” The specific job: shaving a billed demand peak, riding through outages, absorbing clipped solar, or participating in a market. The answer sets the duty cycle, and the duty cycle sets everything else.
- 02
What the AHJ will let you build
Confirm the adopted code edition, the local amendments, and what the fire department expects for access — before the layout is fixed. This is the cheapest hour you will spend on the project.
- 03
What happens at the end
Establish the decommissioning route and whether the chemistry has recoverable value while you still have competing vendors and leverage. Afterwards you have neither.
Reasonable scepticism
The fair questions about a site like this.
“Can I not just get this from the vendor?”
You can, and you should — vendors know their own equipment better than anyone. What they will not do is tell you which of their numbers stops being true under your conditions, or hand you the question that makes their product look worse than the alternative. That gap is the entire reason this site exists.
“Is this not all in the standards documents already?”
It is, at a length and in a register that assumes you already know the answer. NFPA 855 will not tell you that the difference between a UL 9540 listing and a UL 9540A test report is the thing deciding your spacing. We write the version you would want a colleague to explain to you before the meeting.
“Who is behind this, and who pays for it?”
Xenco Labs, which also publishes comparison and directory sites in adjacent industries. Nobody pays for coverage or placement here today. If that ever changes, it will be labelled on the page where it happens rather than buried in a policy document.
“How current is any of this?”
Code adoption and product certification both move, and a page that was right eighteen months ago can be wrong now. Anything time-sensitive carries the date it was checked, and where a jurisdiction or a certification is the deciding factor we tell you to confirm it locally rather than pretending a web page is authoritative.
A storage system is a fifteen-year commitment specified in about six weeks. Nearly every expensive surprise in those fifteen years traces back to a question nobody asked during those six weeks.
Get the analysis as it publishes.
New pieces on chemistry, duty cycle, fire code and residual value, as they publish. Nothing else.
Questions
Before you go any further.
What does this site actually compare?
Four things that decide storage projects: the technologies and what separates them in practice, the applications and whether each business case pays, the safety codes and what your AHJ will enforce, and the end-of-life pathways along with what the material is worth. It is written for the people who have to specify, permit and pay for these systems.
Do you sell batteries or take a commission?
No. We are not an equipment vendor, an installer or an integrator, and there is nothing to buy here. That is also why we can tell you when a technology is a poor fit for your application.
Where do I start if I am new to this?
Start with the technology pages if you have not settled on a chemistry, and with the applications pages if you have a business case to justify. If you already have a design and a deadline, read the safety and codes pages first — that is where late-stage surprises come from.
How big does a project need to be for this to be relevant?
The physics and the code apply at every scale, but the economics do not. Most of what is here is aimed at commercial, industrial and utility-scale systems, where the sums are large enough that getting the duty cycle or the code pathway wrong has real consequences.