Data center carbon accounting: PUE, tenant Scope 2 and BRSR Core

Every rack has a carbon number. Your tenants want theirs.

Your tenants report Scope 2. Send them a statement they can file.

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TENANT CARBON STATEMENTCage C-14, 20 racks, 160 kW · Sep 2026
Ref.
TECS/C14/2609
IT energy, cage meter
80,640 kWh
Site PUE, measured
1.50
Total attributable
1,20,960 kWh
Supply
60% green open access
Market-based
32.7 t
Location-based
81.6 t
Per IT kWh, market
0.405 kg
Reconciles

Example. Illustrative sites and figures.

The short answer

How do colocation tenants calculate data center emissions?

Take the IT energy from your cage meter and multiply it by the site’s measured PUE for the same period. That adds cooling and power losses. Then apply the grid factor: CEA v22 gives 0.675 t CO2 per MWh for 2025-26. For market-based Scope 2, count only renewable power with open access or REC evidence.

Last verified 3 October 2026. Sources at the end.

Your servers draw 100 kWh.
The building draws about 150.

Average PUE has barely moved for years (Uptime Institute, 2025 global survey). On a 6 MW site at 80% load in India, every extra 0.1 of PUE is 4,205 MWh and 2,838 t CO₂ a year at the grid average.

Count the renewables by the hour.

Your renewable contract says 60%. Count it by the hour, the way the GHG Protocol proposes.

What lands in the NOC inbox.

Colocation operators

Forty tenants, forty templates, and every one wants the PUE explained.

Enterprises and GCCs in colocation

Our BRSR Core assurer wants the kWh behind the colo line. The provider sent an invoice.

Built-to-suit and hyperscale suppliers

They want 100% carbon-free power by 2030. Our open access contract settles monthly.

Typical requests from tenants, customers and assurers. Illustrative.

Free data center carbon calculator

Your site, per rack.

Set IT load, PUE, renewables, diesel and refrigerant. See tonnes a year, per rack and per kW.

0

How this is worked out
  • Grid: 0.675 t CO2 per MWh, India’s weighted average for 2025-26 (CEA CO2 Baseline Database v22). It covers CO2 only. We add it to the CO2e total as is.
  • Diesel: 2.66 kg CO2e per litre (UK government 2026 conversion factors). DG fuel use 0.27 litres per kWh is illustrative.
  • R-134a: GWP 1,300 (IPCC AR5) or 1,530 (AR6), per the GHG Protocol GWP table.
  • Market-based Scope 2 treats evidenced renewable power as zero and the rest at the CEA average. India has no published residual mix.
  • Leak rate and DG hours are illustrative. Use your service records and DG logs.
  • Embodied carbon of buildings and IT hardware is left out.

Answer the tenant’s request with a number.

A tenant asks its colo provider for data. Same question, two answers.

Colo_Data_Request_FY26.xlsxSheet: Scope 2 · cage C-14
Request 3 For 1 Apr 2025 to 31 Mar 2026, please provide electricity used by our cage, the PUE and how you allocate facility overhead, the renewable share with evidence, location-based and market-based Scope 2 with emission factors, and our share of site Scope 1. Our BRSR Core assurer will review this.

Wording modelled on tenant data requests.

  • Keep the tenant. Send the statement before their assurer asks.
  • Answer supplier questionnaires. Large buyers ask for Scope 1, 2 and 3 with evidence.
Straight answer: we measure and document. Assurance comes from your auditor or an assurance provider. Hourly matching is a proposal, so we show it beside the annual figure, not instead of it.
Why now

Who’s asking, and by when.

FY 2026-27

BRSR Core checked

The top 1,000 listed companies need BRSR Core assessed or assured. Scope 1, Scope 2, energy and water are in it.

1.8 GW

Capacity growing

India’s operational capacity hit 1.8 GW of IT. It added 258 MW in H1 2026, 59% more than a year earlier.

PUE 1.35

Subsidy tier

Uttar Pradesh’s 2026 policy gives its largest subsidy increments, for sites with a top green building rating, for PUE 1.35 or lower and renewables above 70%.

Hourly

Matching proposed

The GHG Protocol consulted on hourly renewable matching for Scope 2. Revised guidance is expected in 2027.

How it works

From the BMS to every tenant.

Carbon-OS reads your meters, invoices and logs. One method for every cage and every report.

  1. Connect

    BMS, cage meters, open access invoices, DG logs, service records.

  2. Map

    Owned halls, tenant cages and shared plant.

  3. Calculate

    Both Scope 2 methods, the hourly view and Scope 1.

  4. Publish

    Tenant statements, BRSR Core tables, supplier packs.

Method and boundary

Boundary
GHG Protocol, operational control for operators. Tenants report colo under their own boundary.
PUE
ISO/IEC 30134-2, measured monthly, not design PUE.
Tenant allocation
Cage IT kWh × site PUE for the same period. Vacant and office load stays with the operator.
Scope 2
Location-based at CEA v22. Market-based from open access and REC evidence.
Hourly view
Load vs contracted generation by hour, beside the annual figure.
Scope 1
DG diesel and refrigerant top-ups × GWP (AR5 default, AR6 option).
Factors
More than a million emission factors, including CEA, DEFRA and IPCC.
What you get

Three outputs, one set of numbers.

Every month

Tenant statements

kWh, PUE, renewable share and both Scope 2 figures, per cage. They add back to the site total.

Every year

BRSR Core tables

Scope 1, Scope 2, energy, renewable share and water intensity, with the evidence your assurer samples.

On request

Supplier disclosure pack

Scope 1, 2 and 3 for a hyperscale or enterprise customer, with the hourly view beside the annual one.

Glossary

Data center words, made plain.

PUE
Total facility energy ÷ IT energy. 1.50 means 0.5 kWh of overhead for each IT kWh.
WUE
Litres of water per kWh of IT energy.
IT load
Power drawn by servers, storage and network gear, metered at the rack or cage.
Colocation
You rent space and power in someone else’s data center for your own hardware.
Location-based
Scope 2 at the average grid factor, whatever power you bought.
Market-based
Scope 2 that reflects the power you contracted, with evidence.
Hourly matching
Counting renewable power only in the hour it was used.
Green energy open access
Indian rules that let a consumer from 100 kW buy renewable power directly.
Where are you today?

Where does your site stand? Three questions.

See where we'd start with you.

Who asks you for carbon data most?

How do you allocate energy to tenants today?

How do you buy renewable power?

Questions operators ask.

How do I calculate a colo cage’s emissions?

Multiply metered IT kWh by the site’s PUE for the same period, then by the grid factor. CEA v22 gives 0.675 t CO2 per MWh for 2025-26.

Location-based or market-based?

Report both. Market-based reflects open access or REC purchases with evidence. Location-based uses the grid average.

Are data centres covered by India’s CCTS?

No. The notified intensity targets cover industrial sectors such as aluminium, cement, paper and refining. Data centres aren’t among them.

Is there a mandatory PUE limit in India?

Not nationally, as far as we found. BIS has adopted the ISO/IEC 30134 KPI standards, but they’re voluntary. Uttar Pradesh links subsidy increments to PUE.

What PUE earns Uttar Pradesh’s top booster?

1.35 or lower, under the Uttar Pradesh Data Center Policy 2026. A renewable share above 70% earns the top renewable band. The site also needs one of the top two green building rating levels.

Does BRSR Core apply to data centre companies?

Yes, if they’re in the top 1,000 listed companies. Assessment or assurance is required from FY 2026-27.

Can a data centre buy renewable power directly?

Yes. The Green Energy Open Access Rules allow it from 100 kW of contracted demand, with monthly banking.

What is hourly matching?

Counting renewable power only in the hour it’s used. The GHG Protocol consulted on it until 31 January 2026. Revised Scope 2 guidance is expected in 2027.

Do EU data centre rules apply to Indian sites?

No. Regulation (EU) 2024/1364 covers sites in the EU with 500 kW of IT power or more. They report PUE, WUE and renewable KPIs every year.

Which factor applies to DG diesel?

The UK government’s 2026 factors give 2.66155 kg CO2e per litre of mineral diesel.

How much do refrigerant leaks add?

At IPCC AR5, each kg of R-134a lost is 1.3 t CO2e. A 200 kg top-up is 260 t.

Does Climes assure the numbers?

No. We measure and document. Assurance comes from your auditor or an assurance provider.

Bring one month of meter data. We’ll build the tenant statement.

Twenty minutes. Your site, your PUE, your contract. You leave with Scope 2 both ways.

Book the 20-minute callor write to carbon-os@climes.io

Sources

  1. CEA CO2 Baseline Database, version 22: grid 0.675
  2. UK government GHG conversion factors 2026: diesel
  3. GHG Protocol, GWP values (August 2024): R-134a AR5 and AR6
  4. GHG Protocol, Scope 2 public consultation: hourly matching proposal
  5. SEBI circular, 28 March 2025: BRSR Core top 1,000
  6. Uttar Pradesh Data Center Policy 2026: PUE and renewable bands
  7. Green Energy Open Access Rules, 2022: open access and banking
  8. Delegated Regulation (EU) 2024/1364: EU data centre reporting
  9. Indian Infrastructure, on Savills H1 2026: 1.8 GW, 258 MW, 59%
  10. Uptime Institute, Global Data Center Survey 2025: average PUE 1.54

Facts on this page last verified 3 October 2026. Interactive figures are illustrative unless a source is named.

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