Site selected and acquired
Great South reported that 20 sites were assessed before a suitable Makarewa property was selected and purchased.
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Datagrid Makarewa
A living intelligence file covering site works, power, connectivity, delivery milestones, community impacts and the surrounding investment landscape.
EARLY WORKS + STRATEGIC COMMITMENTSMakarewa · SouthlandCONTINUOUSLY MONITOREDUpdated 25 September 2026
PROPOSED CAMPUSUp to 280 MW
POWER OPTION140 MW · 15 years
MERCURY STAKE12.7%
SUBSTATION360 MVA proposed
DELIVERY STAGEEnabling works
WHY IT MATTERS
Strategic significance
Datagrid is a test of whether Southland can convert renewable electricity, land and geographic resilience into an export-oriented compute industry. The project connects four systems that must be judged together: the data-centre campus, electricity supply, international fibre and anchor demand. Progress in only one layer does not establish a commercially operating campus.
CURRENT ASSESSMENT
The project has moved beyond consent and secured strategic commitments, but not beyond its decisive commercial gates.
Mercury’s minority investment and 140 MW power-purchase option, the Tasman Ring Network supply-and-installation contract, and the start of horizontal works are meaningful execution signals. They do not yet demonstrate a final investment decision for the complete campus, energised supply, an operating cable, data-hall construction, contracted customer load or revenue.
EVIDENCE GATES
What is confirmed—and what remains open
The project passed its principal planning gate
The project moved beyond its earlier concept and consenting phase. Consent should not be read as evidence of finance, customer demand or completed construction.
Mercury becomes a strategic minority investor
Mercury invested US$30m (reported as NZ$53m) for a 12.7% stake. This is material strategic capital, not evidence that the full campus is financed.
140 MW power pathway
A 15-year Power Purchase Option Agreement with Mercury covers up to 140 MW and 1.2 TWh a year. An option agreement is not the same as delivered or energised supply.
Tasman Ring Network delivery contract
Datagrid announced a supply-and-installation contract with Alcatel Submarine Networks and OMS for the 2,300 km Invercargill–Melbourne cable. Survey, manufacture, lay, commissioning and service remain delivery gates.
Horizontal works have begun
HEB Construction has begun access-road and earthworks on the campus. The initial works are intended to create platforms for the data centre, cable landing station and substation.
Large electricity connection
Public project material refers to a 360 MVA substation and a campus concept of up to 280 MW. Delivered capacity and ramp-up remain to be verified.
International connectivity
A hyperscale export proposition requires diverse, high-capacity subsea connectivity. Route, landing, procurement, financing and ready-for-service dates remain material gates.
Anchor demand and contracted capacity
No reviewed public evidence establishes the identity, term or scale of anchor customer commitments needed to support full campus construction.
Finance and construction scale
Enabling works do not establish financing for the complete campus, data-hall construction or the timing of phased capacity.
Regional value capture
Jobs, supplier spend, rates, skills, community effects and wider investment must be measured as delivered outcomes, not inferred from headline project value.
KEY FIGURE RECONCILIATION
Do not treat unlike numbers as equivalent
A proposed ultimate scale, not operating IT load, contracted capacity or current electricity demand.
Substation design capacity is not equivalent to customer load, energised capacity or annual consumption.
Provides an electricity contracting pathway and price-risk mechanism; it does not establish energised capacity or consumption.
A US$30m minority investment is a strong partner signal, but not full-project finance or a final investment decision.
Historic regional documents used different scopes for onshore, offshore and full-project investment; the figures should not be treated as a current committed construction budget.
DELIVERY & OPERATING STACK
The layers behind the headline
Site and civil worksEnabling worksAccess, earthworks, drainage, site platform and geotechnical delivery.
ElectricityOption contractedA 140 MW power-purchase option exists; grid connection, 360 MVA substation, firm energisation and transmission timing remain.
International fibreSupply contract signedASN and OMS are contracted for the Tasman Ring Network; marine survey, manufacture, permits, landing and ready-for-service remain.
Data-centre constructionNext major gateData halls, cooling, equipment procurement, commissioning and phased IT capacity.
Customers and capitalNot publicly establishedAnchor tenants, contracted MW, financing structure and construction commitment.
Community and environmentContinuousWater, noise, traffic, ecology, resilience, local engagement and consent compliance.
Regional economyOutcome trackingConstruction spend, permanent employment, specialist skills, suppliers, rates and follow-on investment.
VERIFIED TIMELINE
Milestones and status changes
- 2020–21Great South assists Datagrid with fibre and power route planning, mapping, radiometric and soils information while the project is positioned as a zero-emissions hyperscale proposal.
- 2021–22Great South reports that 20 potential sites were investigated and the Makarewa site was selected and purchased.
- 2022–24Regional energy planning treats Datagrid as a potentially significant new electricity load alongside other large Southland industrial proposals.
- Consent phasePlanning approvals move the project from proposition to an executable site opportunity, subject to conditions and other delivery gates.
- 18 Mar 2026Datagrid and Mercury announce a 15-year Power Purchase Option Agreement for up to 140 MW and approximately 1.2 TWh a year.
- 23 Jul 2026Mercury invests US$30m (NZ$53m) for a 12.7% minority stake; a Mercury director joins the Datagrid board and FID remains expected later in 2026.
- 30 Jul 2026Datagrid signs ASN and OMS to supply and install the 2,300 km Tasman Ring Network between Invercargill and Melbourne, with at least eight fibre pairs and stated capacity of at least 160 Tbps.
- 18 Aug 2026Horizontal works are announced, with HEB Construction beginning access-road and earthworks.
- 4 Sep 2026An independent commissioner declines to initiate a review of the existing consent conditions. Council retains its compliance, monitoring and enforcement responsibilities.
- CurrentThe case is in enabling works; full construction scale, electricity delivery, cable service and anchor demand remain the decisive commercial tests.
STAKEHOLDER MAP
Who shapes the outcome
- Datagrid and its investors
- HEB Construction and specialist contractors
- Transpower, electricity generators and network participants
- Subsea-cable developers, suppliers and landing partners
- Southland District Council, Environment Southland and Great South
- Makarewa and wider Southland communities
- Potential hyperscale, AI and cloud customers
- Iwi, land, water and environmental stakeholders
DEPENDENCIES
What must align
- Completion of consent conditions and site platforms
- Conversion of the power option into energised supply, grid connection and substation delivery
- Marine survey, manufacture, permits, landing and commissioning of the contracted subsea-cable route
- Anchor customers and bankable capacity commitments
- Final investment decision and capital for phased campus construction
- Cooling and water design with credible environmental performance
- Construction supply chain and specialist workforce
- Alignment between cable, power, data-hall and customer schedules
RISKS & OPEN QUESTIONS
What is unresolved
- Enabling works may be mistaken for full campus construction
- Proposed MW and MVA figures may be reported as operating capacity
- Cable and grid programmes can create schedule dependency and concentration risk
- New large electricity demand may affect regional supply, transmission and pricing debates
- Anchor demand and financing remain commercially sensitive and largely undisclosed
- Historic headline investment figures may combine unlike project scopes
- Community benefits and permanent employment can be overstated before delivery
- Technology, customer density and cooling design may change during a long build-out
NEXT SIGNALS
What Digital.nz will watch
- Final investment decision
- Completion and scope of the first site platform
- Substation procurement, construction and energisation dates
- Conversion of the 140 MW option into delivered supply
- Tasman Ring marine survey, manufacture, permits, landing and commissioning
- Named anchor customers or disclosed contracted capacity
- Financing and notice to proceed for the first data hall
- Cooling, water, noise and environmental compliance evidence
- Local procurement, construction employment and permanent operating roles
- Any revision to ultimate campus scale or phased delivery dates
CORE EVIDENCE REGISTER