Imagine a tender for a 50 MW/100 MWh battery. Two suppliers put those figures on the first page of their proposals. One quotes installed DC energy at commissioning, while the other commits to usable energy delivered at an agreed AC measurement point. A spreadsheet that places their prices side by side has already assumed that both suppliers are selling the same thing. The example is illustrative, but the question belongs in every utility-scale battery tender. What exactly do the quoted numbers describe, and for how long does the supplier stand behind them?
In my conversations in the Netherlands and Belgium, I see demand for larger battery projects becoming more concrete. Many developers and EPC contractors bring valuable experience from solar, but battery procurement now requires them to specify how an asset should perform as it ages, and how that performance relates to its intended use.
Define what the project must deliver
The buyer should first describe the required output at a clearly identified measurement point. If the business case assumes energy delivered at the grid connection, the tender needs to account for the equipment and losses between the battery cells and that connection, including how auxiliary consumption, such as cooling, is treated. Buyer and suppliers also need to agree on the conditions under which capacity and efficiency will be tested, since a round-trip efficiency figure has limited value in a comparison if the offers use different boundaries or operating conditions.
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The same applies to performance over time, since an energy capacity stated at commissioning does not establish what will be available in year ten. The tender should therefore identify which performance is required at handover and how it will be assessed after that. Suppliers can then explain how their proposed systems meet those requirements. A strong manufacturer may be entirely capable of honouring its commitments, but the buyer still needs to establish what those commitments cover, because financial strength cannot resolve an ambiguity in the specification.
Put an operating profile behind the guarantee
Performance requirements need an operating basis. Expected energy throughput, charging and discharging power and the permitted state-of-charge range should be available to bidders, and the assumptions must also respect the project’s import and export limits. Where the future trading strategy is still uncertain, buyers should make that uncertainty visible. They can ask suppliers to identify the operating limits covered by the offer and explain what would change under a more intensive scenario, which is more useful than allowing each bidder to choose its own favourable assumptions.
DNV’s degradation assessment looks at temperature, throughput, power relative to battery capacity and how widely the state of charge varies. A headline cycle count on its own therefore gives buyers only part of the picture. If one proposal covers the intended operating profile and another needs a restriction to keep its guarantee valid, that difference has to be part of the evaluation. If it isn’t, the financial model may assume the battery can trade more freely than the purchased system allows on the quoted terms.
Make future capacity part of the offer
Consider two possible ways of meeting a project’s longer-term energy requirement. One supplier might propose enough initial capacity to accommodate expected degradation, while another might plan to add capacity later, a process commonly called augmentation. Either approach can be appropriate, but their costs and obligations need to be visible on the same basis. Does the price include the future equipment and its installation? Who pays for integration and testing? Has the physical and electrical design allowed for the addition? The tender should distinguish firm commitments from options and from owner-funded assumptions.
Expected reductions in battery prices can be explored in the financial model, but they do not establish a contractual price or a guarantee that a future addition will be straightforward. Where the owner retains that uncertainty, it should remain visible in the investment assessment. I would want a bidder to explain how the proposed capacity plan supports the required output over time. A generic degradation curve is useful background, but a project-specific commitment needs defined operating conditions and a clear allocation of the work and cost required to meet it.
Specify how performance will be demonstrated
Acceptance testing should be designed alongside the performance requirements. The buyer needs an agreed method for demonstrating usable capacity, power and efficiency, with clear responsibilities for measurement and access to the supporting data. The future operations and maintenance provider can play a useful role here during procurement, by checking that the promised performance can be verified with the proposed meters and data, and that the same definitions will still apply after handover. A test result at commissioning should then serve as the reference for later assessments.
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Availability needs particular care, as a system may remain connected while part of its capacity is unavailable. The tender should explain how such a condition affects the performance calculation, so that all bidders apply the same definition. Excluded periods also need to be visible when offers are compared. The agreements should then state what happens when measured performance falls short. A commitment to investigate, an obligation to restore capacity and a financial remedy are different promises, and their conditions and limits matter to the investment case. Buyers need to understand the exposure they retain after those provisions have been applied.
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InfoLink’s assessments of 30 September and 28 October show Chinese battery-grade lithium carbonate falling from RMB 120,000 to RMB 97,000 per tonne, a decline of 19.2 percent. The average price of 280 Ah and 314 Ah LFP storage cells fell by 2.2 percent, from RMB 0.363 to RMB 0.355/Wh, while the four-hour AC storage system benchmark stayed at RMB 0.53/Wh. For PV, the average TOPCon module benchmark outside China stood at $0.114/W on both dates. These are two dated assessments, not monthly averages or European turnkey quotations.
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For a tender that includes future capacity additions, these uneven price movements are a reason to examine the price assumptions separately. Bidders should identify which additions are included at an agreed price and which will be quoted later, a distinction that can remain material even when current equipment prices are stable.
Give bidders a common basis
I would like to see more utility-scale tenders built around a shared performance specification, with supplier deviations clearly identified. Manufacturers should still have room to propose different designs, but the comparison should show what each design delivers and which costs or obligations remain with the owner. A shared specification would also make the discussion with financiers more precise. The project team could show how the contracted performance supports the investment assumptions, which carries more weight than a headline capacity and a familiar supplier name.
Before requesting a final commercial offer, I would ask each bidder to demonstrate how its proposal meets the same output requirements over the same period and under the same operating conditions. Once those answers are clear, the buyer can assess which differences justify a premium and which risks call for a different design. (Gerard Scheper/hcn)
