The project that landed on my desk in August 2024
In August 2024, I got pulled into something I had zero experience with. Our facilities team submitted a proposal for a 2.2 MWh battery energy storage system—peak shaving on two high-load production lines, plus backup power for the main plant. Three sites, roughly 450 employees total.
I manage procurement. Since 2019, my world has been software renewals, office supplies, and one agonizing warehouse lease negotiation that took six months and probably cost me a few years of my life. Battery energy storage was not on the list of things I knew anything about.
Two things became obvious fast: the BESS market has a lot of suppliers. And their numbers do not line up. At all.
We shortlisted six vendors through a mix of industry referrals and some very late nights on Google. LG Energy Solution was on the list. So were two regional distributors for global OEMs, a couple of mid-size integrators out of the Midwest and West Coast, and one outfit that pitched itself as a "full-stack" supplier with a quote that was 18% below the next lowest bid.
The quote that almost got me in trouble
I'll be honest: my first reaction to that 18% number was excitement. I've been doing procurement long enough that I know I shouldn't feel that way. But a 500K delta on a 2.8M budget gets your attention. It gets your CFO's attention too.
I almost pushed that vendor straight to the next round. What stopped me was something small—they couldn't produce a UL 9540A test report.
For anyone who doesn't know (I didn't, at first): UL 9540A is the standard test method for evaluating thermal runaway fire propagation in battery energy storage systems. It's not always a hard requirement depending on your local AHJ and the specific installation. But an OEM that can't produce one is either selling a product that hasn't been tested to that standard, or they have a documentation problem. Neither of those is what you want in your procurement file.
I flagged it to our facilities director. He said, "Good catch." Then he asked me to request IEC 62619 certificates, cell-level traceability documentation, and clarification on warranty terms—specifically what the warranty covers and what it does not cover if degradation outpaces projections.
That's when things got interesting.
The cheap vendor responded quickly to the first email. Less quickly to the second. The third email is still unanswered, if you're curious.
What an independent engineer taught us
We brought in an outside firm around week four—an engineering consultancy that does storage project reviews for industrial clients. Not cheap. I think it was somewhere in the $15-20K range for the scope we gave them. Worth every dollar.
They walked us through the questions that actually matter. I'm not a battery chemist, so I'll summarize what I understood:
- Cell origin and traceability—can the OEM tell you which cells are in which modules, and from which manufacturing batch?
- BMS architecture details, including how the system handles cell imbalance and thermal events.
- Cycle life validated at the system level, not just cell-level datasheet numbers.
- Manufacturing footprint and service infrastructure in your region.
- Spare parts availability and lead times, ideally written into the contract.
After those questions went out to all six on the shortlist, the field narrowed fast. Three dropped to "maybe." One dropped out entirely. That left us with two—LG Energy Solution and one other global OEM with a North American assembly operation.
I want to be clear about something: I'm not an expert on pouch cells or energy density or any of the technical specifics that differentiate these products. What I could evaluate was whether a supplier could answer our questions clearly and back up their claims with documentation. LG Energy Solution brought pouch cell technology credentials and a global manufacturing footprint into the conversation—but so did the other finalist, in different ways.
The differentiator for us came down to how thoroughly they engaged with our engineer's questions, including the uncomfortable ones. Both passed. LG Energy Solution edged ahead on the specificity of their service commitments in our region.
The call I almost got wrong
Here's where I have to admit something. In mid-October, the cheap vendor came back. They'd found a workaround on the documentation issue, they said. And they were now willing to go another 8% below their original quote.
I sat with that number for a day. My counterpart in finance was very interested. On paper, it made our project look significantly better.
Then I thought about it differently. If a supplier can drop 18%, then drop another 8%, what exactly are they cutting? I don't know the answer to that. But I know it's one of two things: either they're compromising on cell grade or system integration quality, or they're planning to recover margin on service and support after the sale.
In my opinion, a BESS contract isn't a battery purchase. It's a 10-15 year relationship. The system will degrade. Something will need servicing. Regulations will change, and someone will have to update your compliance documentation. All of that depends on the supplier still being there and still being competent.
We didn't go with the cheapest quote. We went with the supplier who could explain what they were delivering, including the parts that weren't flattering—warranty exclusions, degradation thresholds, what happens if the system underperforms.
Looking back, I should have built the outside engineering review into the budget from day one. I spent three weeks reading about thermal runaway testing standards that a firm with experience could have walked me through in an afternoon.
What the installation looks like now
The systems went live in January 2025 across all three sites. So far, so good—though I'd caveat that heavily. We're four months in on a system with a 15-year expected lifespan. Ask me again in 2030.
There's something satisfying about seeing a project you shepherded through procurement actually running. The peak shaving numbers are tracking close to the projections, which is more than I expected in the first quarter.
But the real payoff was the process itself. I now have a template for evaluating any complex technical supplier that I didn't have before. Ask for the documentation first. If they hesitate, that tells you something. If they can't answer basic questions about their own product architecture, that tells you more.
What I'd tell the next procurement person
I can only speak to our situation: mid-size manufacturing, first-time BESS buyer, three sites in the same state. If you're a utility-scale developer or working internationally, the calculus is different. There are probably factors I'm not even aware of.
My experience is limited to a handful of supplier evaluations. But within that limited sample, one pattern held: the vendors who could provide detailed, verifiable documentation on their products were also the vendors who engaged seriously with our other questions.
That correlation might not hold everywhere. But it held for us.
If I could redo one thing: I'd hire the independent engineer before sending out the first RFQ, not after getting the first round of quotes back.
The lesson, if there is one, isn't "always pick the most expensive option." We might have gone with the other finalist depending on how the details landed. The lesson is that in a market where the technical differences are real and the stakes are long-term, the price sheet is the worst place to start your evaluation.