AirTrunk has announced a third Sydney data centre, SYD3, which it says will be the largest single campus in Asia-Pacific outside China, at more than 320 megawatts of capacity. The site will sit less than a kilometre from the company's flagship SYD1, which is nearing full capacity, and the two connected campuses take what AirTrunk calls the Western Sydney region to more than 450 megawatts.

SYD1 is rated at more than 130 megawatts and SYD2, in the city's north, at 110 megawatts. SYD3 will be built in nine phases across 8.3 hectares, powered by an on-site 132 kilovolt substation, and designed to a power usage effectiveness of 1.15, the company says.

Capacity on paper, tenants on the ground

AirTrunk describes the project as bringing a multi-billion-dollar investment into New South Wales and creating hundreds of jobs across construction and operation. It does not give a figure for that investment, and multi-billion covers a wide range. The company also says each of its data centres has been anchored by cloud service providers, which is the part of a data centre that pays: a campus is a shell until someone signs a long lease for the racks inside it.

The careful number is the water claim, roughly 80 per cent less than a traditional data centre, because it is measured against a stated baseline. The capacity figure, by contrast, is what the site could hold if it is fully built and fully let, which is two conditions and not one. What the release does not contain is a tenant, a lease term or a start date. A campus of this size is announced on the strength of the power it has secured, and that is the part AirTrunk has bought.