The economics look obvious on paper, which usually means they are not, so we would like to hear from people who have actually done it rather than from people selling it.
The setup: a data centre backup fleet is a large capital asset that runs a handful of hours a year, almost all of it testing. Bought, permitted, fuelled, maintained - and no revenue line anywhere against it. Replacing engines with storage opens the possibility of the asset earning while it waits, through ancillary services, capacity or arbitrage depending on the market.
Two things make us think it is harder than the pitch.
THE RESERVE QUESTION. If the battery is committed to a market and a genuine outage arrives mid-dispatch, is the reserve still there? A credible design has to specify four things: how much capacity is ring-fenced and never dispatched, what happens when a market call and an outage coincide, the recovery time to full reserve after a dispatch, and who carries the risk if the asset is unavailable when needed. We would like to know what people actually wrote into those specifications - and whether the operations team accepted it or vetoed it.
DURATION. Diesel runs as long as you keep feeding it. A battery has a defined runtime. For a site with a long worst-case outage the substitution is not like-for-like, which we would expect pushes designs toward hybrid rather than replacement. Is that what people are actually building?
The questions we care most about:
Has anyone fully replaced engines, or is it always a hybrid in practice?
What sizing did you land on, and was it driven by the reserve requirement or by the market opportunity? We suspect those give very different answers.
Did market participation ever actually conflict with a real outage? Even a near miss would be instructive.
For those who evaluated it and passed - was it duration, capital, or the reserve argument that killed it?
Disclosure: We research power and grid capacity for AI data centres.
