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Data centres, explained

Drafted with AI help (22 Oct 2026); not yet reviewed. Issuer definitions are added only from a stored source.

What's inside

Data centre: A building or campus that houses computers, storage and network equipment, with the power, cooling and backup to keep them running all the time.

How they're built

Embodied carbon: Greenhouse gases from making and building the materials (steel, concrete), as opposed to running the building. A reduction is against the company's own baseline.
Construction waste diversion: The share of construction waste kept out of landfill by weight, as reported by the builder or operator.
Plan: Site selection, design and permits, before construction starts.
Build: Construction, often in stages over several years, while earlier stages operate.
Operate: Running: computers, cooling and backup working, customers moving in.
Refit and re-equip: Replacing equipment and upgrading cooling or power inside the building.
Decommission or reuse: Closing, demolishing or converting the site, and who pays for it.

Built and used capacity

IT capacity: How much electrical power the computer equipment is designed to draw, in megawatts. It's a design figure: not the power actually used.
Planned capacity: The total IT capacity the operator says the whole site is planned for, once every stage is built and fitted out.
Built capacity: IT capacity in halls that are finished and fitted out. Operators define it in their own words; where one does, its definition is shown too.
Capacity in progress: Planned IT capacity in stages being designed or built, not yet ready for customers.
IT demand: The power the computer equipment actually draws, measured over time. Usually well below capacity, and rarely published per site.

MW and MWh

MW (megawatt): A rate of power: how much electricity can flow at one moment. 1 MW running for an hour is 1 MWh.
MWh (megawatt-hour): An amount of energy: power over time. Yearly electricity use is counted in MWh.
Electricity used: All the electricity the site draws in a year, measured at its boundary: computers, cooling, lighting and losses together.

PUE

IT-equipment electricity: The part of the site's electricity used by the computer equipment itself. It's the denominator of PUE and WUE.
PUE (power usage effectiveness): All the site's electricity divided by the IT equipment's electricity. 1.0 would mean nothing is spent on cooling or losses. A target is not a measured result.

Cooling

Cooling: How heat from the computers is taken away: air, chilled water, evaporative cooling towers or liquid cooling. Each uses water and electricity differently.
Heat reuse: Waste heat piped to a neighbour (a pool, homes, a greenhouse) and metered where it's received. Zero until something is connected.

Water

Water withdrawn: All the water a site takes in during a year, from mains, recycled water, rain or bores. A pressure on water supplies, not a measure of nature's condition.
Water consumed: Water taken in and not returned: mostly what evaporates in cooling. Always less than or equal to water withdrawn.
Water stored on site: How much water the tanks hold at once. Storage is not use: a full tank says nothing about how much is drawn in a year.
Water reserve: How long the stored water would last if supply stopped, as the operator states it. It depends on load and weather, so it's a design figure.
Water source: Where the site's water comes from: drinking-water mains, recycled water, rainwater or groundwater.
Waterway condition: The health of the creek or river, measured with the waterway manager's or regulator's own indicators, not a PLOT score.
Reference pool: A PLOT convention for picturing water: a 50 × 25 m pool, 2 m deep, holds 2.5 ML. Converting units never changes what a figure counts.
ML (megalitre): One million litres.

WUE and reference points

WUE (water usage effectiveness): Litres of site water per kilowatt-hour of IT electricity. Companies count the water differently (withdrawn or consumed, which uses); compare only like with like.
Published reference point: A figure another operator published for its own boundary (a region, a portfolio). Shown with that boundary, never pooled into a ranking.

Backup power

Fuel reserve: How long stored diesel would run the backup generators in an outage, as the operator states it.
Diesel and generators: Backup generators run in outages and in regular tests. Their fuel, hours, noise and exhaust are pressures to report separately for tests and outages.
Boundary noise: Sound level measured at the nearest homes, in A-weighted decibels, against the applicable limit.

Footprint, floor area and habitat

Native habitat on site: Area of native vegetation or habitat within the site, mapped by an ecologist. Landscaping and lawn are not native habitat.
Gross loss: Habitat removed, counted on its own before any gain. PLOT never shows a net figure without the gross loss and gross gain beside it.
Gross gain: Habitat created or restored, counted on its own. Planting is activity, not proof of recovery.
Mapped building footprint: The outline of the building's roof as volunteers traced it in OpenStreetMap from imagery. Approximate, dated, not surveyed.
Mapped construction area: The area OpenStreetMap shows as under construction, traced from imagery on the date given. Not a building outline.
Floor area: The area of all floors added together. Floor area laid flat is not the building's footprint on the ground: a three-storey hall's floor area is three times its footprint.
Gross floor area (GFA): All floor area inside the outer walls, every storey added together.
Campus land: The land parcels the site occupies. A parcel is not a building: much of it may be roads, yards or open ground.
MCG playing arena: The Melbourne Cricket Ground's arena, about 174 × 149 m fence to fence. PLOT treats it as an ellipse to give a familiar area; the method is shown.

Who's who

Operator: The organisation that runs the facility day to day.
Developer or applicant: Who applied for the planning permit and is building the project. It may be the operator, or not.
Registered landowner: Who holds title to the land, from the land register. Often different from the operator.
Contractor: A company engaged to build all or part of the project. Responsible for its own site practices.
Planning authority: The body that decides the planning permit: a council or the state, depending on the project.
Regulator: An agency that sets and enforces rules on pollution, water or energy at the site.
Community group: A group of residents or volunteers. Shown as an organisation with its public contact route; individual residents are never profiled.
Traditional Owner organisation: The organisation recognised as speaking for Country here. Shown as organisational context only; no individual is named without their authority and consent.
Public-role profile: A person shown only in a public role (a councillor, a company executive named in its own report), with the source for the role. Not a personal profile.
Nominated representative: Someone an organisation has named as its contact for PLOT. Different from a publicly sourced role: being named in a report doesn't make someone the contact.
Public professional reference: A link to where the person or organisation describes the role publicly. Confirmed (a named source links it), or a likely match. Not identity verification.

Reading a PLOT facility page

Archetype: The kind of facility a page is built for. It decides which measures and questions the page asks; it says nothing about how well the facility does.
Pressure: Something the facility does or draws on that can affect nature, such as water or electricity use. A pressure is not a measure of nature's condition.
Condition: The state of nature itself (habitat extent, waterway health), measured with a stated method.
On the record: At least one claim with its source answers this.
Partly on the record: Something is on the record, but not the measure asked for: a target instead of a result, or one part of the answer.
No record yet: PLOT holds nothing that answers this yet. Missing is never zero.
Reviewed and published: A person checked the claim against its source and published it.
Not reviewed: Proposed for the record but not yet checked by a person. Shown only to staff.
Design or target: What the operator plans or aims for. Not a measured result.
Reported by a source: A figure or statement as a source published it, not checked independently.
Observed: Measured or seen with a stated method.
Modelled or forecast: An estimate from a model or a projection, not a measurement.
What the operator says: From the company that runs the facility. Never independent evidence.
Government reported: From a council, agency or regulator's own publication.
NextStep: The record's current proposal for the most useful next move, with the barrier it clears and who could move it.
Evidence gap: Something PLOT looked for and didn't find, recorded so someone can fill it.
Light spill: Light from the site reaching beyond its boundary, measured in lux against the adopted standard.
Complaints: Complaints received by the operator or regulator, and how long they took to close.
Jobs: Full-time-equivalent construction and operating jobs, and the local share only where it's disclosed.
Scenario arithmetic: Conditional arithmetic from numbers you choose. Not a forecast for this facility.

How a facility could give back to its place: design patterns.