Design thought piece

What it would take to run Dalby's AI park mostly on sun and batteries

Anthropic’s first Australian data centre deal landed on the Western Downs near Dalby — not Toowoomba. This is a TOGS sizing question: if that kind of load had to stand on solar and batteries, what would you actually buy?

September 2026 · Dalby, Western Downs
The hook

A design question, not a press release

Anthropic’s first Australian data centre deal landed on the Western Downs near Dalby — not Toowoomba — with the usual mix of big dollars, big megawatts, and bigger political sentences. Peak talk sits around 2.16 gigawatts. Full-build cost talk sits around about 32 billion dollars. Online from about 2027, if the development application and FIRB clear.

The state pitch includes the idea that projects like this put more energy into the grid than they take. Treat that as a premier’s framing, not a verified Anthropic net-export guarantee. Reporting on phase one is clearer about something else: a huge new load, batteries for quality and stability, renewables and PPAs later, and gas as a bridge while that gets built.

This piece is not a hit job and not a cheer squad. It’s a TOGS design question: if you had to cover that kind of load mostly with solar and batteries — off-grid or near-islanded — what would you actually buy, and how many days a year would you still lean on a firm backup?

We size a phase slice, not the fantasy of one single plant swallowing the whole 2.16 GW.

Working assumptions

What we’re sizing (and what we don’t know)

Public descriptions put the campus at four halls of about 360 MW IT each. Facility peak for the full build is cited near 2.16 GW. ABC reporting has put full-build daily use around 47 GWh, in the ballpark of a quarter of Queensland’s average daily electricity.

So for phase one we take a proportional facility load of about 540 MW flat — call it thirteen gigawatt-hours a day. That is a working assumption. We do not have Anthropic’s real load profile, PUE, or cooling curve. Anyone who quotes those as fact is guessing with better stationery.

Phase slice

~540 MW flat

One quarter of the cited 2.16 GW facility peak. Thirteen gigawatt-hours a day if the hall draws flat.

Full campus talk

2.16 GW / 47 GWh

Four halls of about 360 MW IT each. ABC’s daily-use figure sits near a quarter of Queensland’s average day.

Unknown

Load, PUE, cooling

No real Anthropic profile in public. Anyone quoting those as fact is guessing with better stationery.

Climate

The mid-winter design day near Dalby

BOM’s Dalby Airport record (station 041522) is the right climate anchor. Mean daily solar exposure bottoms out in June around 12.2 MJ/m² — about 3.4 kWh/m² on the horizontal. Annual average is about 5.4 kWh/m²/day. Winter here is not Tasmania. It is still winter.

For a fixed-tilt field we use a simple, disclosed model: winter tilt helps a bit, system losses are real, and you land near ~3.2 kWh AC from each kilowatt of panels on a mean June day. On a proper overcast day, treat that as maybe a third to half — enough to slow the bleed, not enough to refill a flat battery while the hall keeps drawing.

Design rule, same as a homestead, just with more zeros: on the winter design day, the array refills what the load took, and the battery carries the night and the low-sun hours without drama.

Clusters, not averages

Rain weeks and consecutive dull days

Dalby averages on the order of ~85 cloudy days and ~53 rain days (≥1 mm) a year in the BOM normals. Those numbers don’t line up one-for-one with “battery empty.” What kills an islanded system is clusters: two or three poor days after you’ve already spent the pack overnight, especially in May–August when the daily budget is thin.

So you either:

Option one

Oversize solar

A mediocre day still pays the bill.

Option two

Buy more hours

More battery, more nights you can ride through.

Option three

Name backup days

Grid, gas, diesel — whatever firm plant you allow.

TOGS’ house view is the third option done honestly: aim for about 300 days where solar and batteries carry you, and plan for on the order of ~65 days where something else has to show up. At Dalby’s climate, that target is plausible for a well-sized plant. It is not free, and it is not 365.

The hardware band

Phase slice: ~540 MW continuous

For ~540 MW continuous:

Solar

About 4–6 GW DC

Our preferred sketch sits near ~5 GW — roughly 1.25× a mean June recharge of the daily 13 GWh.

Battery

About 13–26 GWh

Depends on whether you want ~24, ~36, or ~48 hours of autonomy. Preferred sketch: ~20 GWh (~36 hours) at full load.

Land

Thousands of hectares

Far bigger than the ~725 ha campus. The panels live in the region, not in a marketing render of the site fence.

Backup days

~50–70 days / year

Depends on how hard you oversize and how unlucky the wet weeks are. Leaner plant → closer to Mike’s ~65. Heavier plant → maybe low-forties. Nobody sells you a single magic integer.

Scale the whole campus to 2.16 GW and you’re in ~16–20+ GW of solar and tens of gigawatt-hours of batteries. That’s not a “system.” That’s a provincial generation build with a data centre attached.

What the published plan is actually doing

Grid-tidy batteries are not a day-and-a-half pack

On-site batteries in the reporting are there to keep the load tidy for the grid — power quality, stability, a smooth shape at Braemar — not to hold a day and a half of AI inference through a Western Downs wet week. Gas nearby is the bridge. Renewables via PPA are the later chapter. That may be a rational grid-connected strategy. It is not the same as energy sovereignty.

If your standard is sovereignty — the load runs when the wire is sick — you size sun and storage for the worst useful day you accept, and you name the days you won’t.

Plain summary

What it would take

To run one phase of a Dalby-scale AI hall mostly on its own sun and batteries, you’re in the multi-gigawatt solar / tens-of-gigawatt-hour battery club, with most of the array off-site, and you still budget around two months of days a year for grid or generators unless you spend even harder. Full peak is about four times that headache.

That’s what it would take. The press release fits in a smaller box.

Public figures in this piece come from Reuters, ABC, Brisbane Times and Capital Brief reporting on the September 2026 announcement, plus BOM Dalby Airport station 041522 climate normals. Load shape, PUE and cooling are working assumptions, not Anthropic disclosures.

The other angle

Grid trade lives next door

Want the grid-connected buy/sell/trade angle instead? Read the companion piece on Sovryn Energy.

Homes, farms, commercial loads

Sized for June and the rain week

We design solar and battery plants for people who care what happens in June and after three grey days — homes, farms, and commercial loads. If you want a system sized that way, talk to The Off Grid Shop.

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Prefer to talk it through? Call or text 0483 927 257 — Lismore HQ, local voices.

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