Green Mountain FRA-Mainz / Green Rocks Campus

Ingelheimer Aue, Mainz, Rhineland-Palatinate, GermanyUnder construction

Headline capacity: Not established in published records
Updated: Oct 28, 2026

Green Mountain's current FRA-Mainz operator page, checked October 28, 2026, states that the entire 54 MW facility is contracted to one hyperscale client. This is a leasing statement, not confirmation of operating capacity; the earlier 36 MW agreement remains part of the project's history. Green Mountain and KMW are building a three-building data center campus on Ingelheimer Aue in Mainz. Current sponsor pages disagree between 54 MW and 80 MW, and the first section is targeted for Q4 2026.

Capacity

Operating IT capacity: Not established in published records

A missing figure does not mean zero. Planned, utility and generation figures are not operating IT capacity.

Development

Building 1 / first sectionUnder construction

1 building

18 MW original phase; current RFS target Q4 2026.

Building 2 / second sectionUnder construction

1 building

Second section started; 18 MW and about 6,000 sqm IT space.

Building 3Announced or preconstruction

1 building

No verified construction start.

Anchor-customer staged handoverAnnounced or preconstruction

3 buildings

Capacity handover over roughly 3.5 years; phase allocation undisclosed.

Milestones (5)

Official construction start marked

Oct 30, 2023 · Recorded actual event

Completed · Construction started

Source not linked

Campus topping-out milestone

Feb 7, 2025 · Recorded actual event

Completed · Status changed

Source not linked

36 MW long-term tenant agreement announced

Sep 1, 2025 · Recorded actual event

Completed · Customer commitment

Source not linked

Building 2 construction begins

Jan 21, 2026 · Recorded actual event

Completed · Construction started

Source not linked

54 MW emergency-power plant approved

Jul 20, 2026 · Recorded actual event

Completed · Permit approved

Source not linked

Participants

Azrieli Group

Investor

Sources by role

Green Mountain

Operator

Sources by role

Green Mountain KMW Data Center GmbH

Owner

Sources by role

Undisclosed international hyperscale tenant

Customer

Sources by role

Other participants (1)

Groß & Partner

Contractor

Sources by role

Site & development

Milestone construction start

Actual

Official construction start marked

Source

Milestone construction progress

Actual

Campus topping out milestone

Source

Milestone construction start

Actual

Building 2 construction begins

Source

Additional project facts

Ready for service target

Forecast

Q4 2026

Source

Milestone transaction close

Actual

Green Mountain and KMW form 50:50 project company

Source

Milestone customer commitment

Actual

36 MW long term tenant agreement announced

Source

Milestone ready for service target

Actual

Current sponsor/utility target

Source

Milestone permit approved

Actual

54 MW emergency power plant approved

Source

Infrastructure & permits

Technical details (7)

Electric grid

Under construction

54 MW

Green Mountain current figure and original approved plan.

Electric grid

Under construction

18 MW

Per-building IT figure for three-building plan.

Site facility

Under construction

18,000 sqm

Three buildings of about 6,000 sqm each.

Heat reuse

Planned or represented

60 MW thermal

Heat output, not IT load or electrical generation.

Onsite generation

Permitted or installed

54 MW electrical

Twelve-engine H2-ready plant; also expected to serve grid hours.

Electric grid

Planned or represented

110 kV

Redundant supplies; renewable-energy portfolio claim.

Cooling system

Planned or represented

Rhine water cooling with heat-reuse priority.

Public-source research. Plans may change. See Evidence for sources and qualifications.