Procurement guide

A disciplined way to buy commercial energy storage.

Eight stages, written for the person who has to justify the decision internally. No vendor names, no estimated savings, no assumed incentives — just the sequence that keeps quotations comparable and the assumptions visible.

Method

The eight stages.

Establish why you want storage

Demand-charge reduction, resilience, self-consumption and grid services are different projects with different shapes. A system sized for a four-hour peak shave is not a system sized to ride through an eight-hour outage. Write the primary reason in one sentence before anything else.

Define discharge power, then duration

Power (kW or MW) is how hard the system must push. Duration (hours) is how long it must keep pushing. These two numbers drive almost every downstream decision, and they are the two most commonly left vague in enquiries.

Convert to requested delivered energy

Delivered energy = power in kW × duration in hours, giving kWh; divide by 1,000 for MWh. This is what you are asking to receive at the point of use. It is deliberately not a nameplate capacity — the supplier must tell you what nameplate and usable capacity is needed to deliver it under their own efficiency and degradation assumptions.

Document the site honestly

Space, indoor or outdoor, ambient extremes, access for delivery, fire separation, noise limits, tenancy and insurance. A supplier who learns about a constraint after quoting will revise the price; a supplier who learns before quoting will price it once.

Clarify the grid connection position

Whether you are connected, constrained, exporting, or waiting on an application changes scope, schedule and risk allocation more than the battery choice does. 'Unknown' is a legitimate answer — record it as unknown so it gets resolved rather than assumed.

Fix the timeline and the decision path

State the target window and who signs. Suppliers allocate engineering attention to enquiries with an owner, a date and a described approval route. Vague timing reads as a tyre-kick and gets a template reply.

Issue one identical brief to every supplier

Same document, same blank comparison table, same deadline. The moment two suppliers answer different questions, comparison becomes impossible and the decision defaults to whoever presented most confidently.

Compare only written figures, attributed by name

Every number you use in a business case should be traceable to a named supplier's written statement, with its assumptions attached. A verbal figure, a slide, or a third-party estimate is not a commitment and should not enter your model.

Worked example

How the delivered-energy calculation works.

Requirement stated by the owner

Discharge power = 500 kW

Discharge duration = 4 hours

500 kW × 4 h = 2,000 kWh

2,000 kWh ÷ 1,000 = 2.0 MWh

If the owner had entered 2 MW × 4 h: 2,000 kW × 4 h = 8,000 kWh = 8.0 MWh

What this figure is not.

It is not the battery you will buy. Real systems lose energy to conversion and thermal management, reserve capacity for depth-of-discharge limits, and fade over their life. Those factors are product-specific, so the supplier — not us — states the nameplate and usable capacity required to deliver your requested energy in year one and in the final warranty year.

Question bank

Eight questions suppliers should answer in writing.

Sizing

What nameplate power and usable energy do you propose to deliver our stated kW and hours, and what efficiency, depth of discharge and end-of-life assumptions are inside that?

Performance

How is round-trip efficiency measured, at what state of charge and temperature, and does the stated figure include auxiliary loads and thermal management?

Warranty

What is the warranty term, what throughput or cycle limit applies, what performance floor is guaranteed, and what voids it?

Scope

What exactly is inside your price — enclosure, transformer, switchgear, protection, civil works, interconnection, commissioning, spares, training? Name what is excluded.

Schedule

What is the lead time from order, what sequencing do you assume on site, and what are the liquidated consequences of delay?

Service

Who attends a fault, in what response time, for how many years, and at what escalating cost after the initial term?

Grid

Which interconnection tasks are yours and which are ours, and what happens commercially if the utility imposes a condition neither of us assumed?

End of life

Who owns decommissioning, recycling and residual value, and what is assumed in your figures?

Put your own numbers through it

The configurator applies this sequence and produces the brief for you.

Open the configurator