How the data centre model works

Total IT load

Σ phase MW (the single capacity input)

Data halls

⌈ IT load ÷ MW per hall ⌉

Total racks

⌊ IT load × 1000 ÷ rack kW ⌋

Facility power

IT load × PUE

Equipment count (Tier III = N+1)

⌈ served load ÷ unit rating ⌉ + 1 spare

Per-phase sizing and shared spares

each phase’s base units are sized from its own MW; the spare unit is added once (with phase 1) and shared across the facility, not repeated per phase

Equipment subtotal

Σ (unit count × unit cost), all four systems

Site-wide costs (paid once)

Σ site-wide lines

Costs for each data hall

Σ per-hall lines × number of halls

By what it is for

every line sorted into land, building, power, cooling, IT, security or soft costs

Subtotal

equipment + site-wide + per-hall

Buffer for surprises (contingency)

subtotal × 8%

Interest during construction (IDC)

total × loan% × interest% × (months ÷ 12) × ½

Total project cost

subtotal + buffer + IDC

When costs are paid (upfront or phased)

upfront = paid once with phase 1 (land, grid, design…); phased = paid in proportion as each phase is built. The buffer and IDC are split so upfront + phased = total.

Build price rise

each phase’s phased cost × (1 + 5%)^(build year). Phase 1 (year 0) has no rise, so a build in one go is unaffected; staging later raises the as-built total.

Land: own or lease

owned land sits in the set-up cost; leased land is left out of it and paid as a yearly running cost instead

Stamp duty on land

land value × 6%: owned land only, added to the land cost (never depreciated, insured or maintained). 5–7% depending on the state; Uttar Pradesh and Tamil Nadu data centre policies waive it.

GST (planning note, not a model line)

18% GST applies on equipment and construction services; the GST on the building shell can’t be claimed back (section 17(5) of the CGST Act), so budget it as cost

Set-up cost per MW (worked out)

total project cost ÷ IT load

Facility power drawn

IT × occ + (PUE−1) × IT × (fixedOH + (1−fixedOH) × occ)

Energy cost

facility power × 8760 h × tariff × 1000 × (1+esc)^(yr−1)

Power pass-through (revenue)

when pass-through is on, energy is billed back on the revenue side (margin-neutral)

Generator fuel

facility power × test hours × 1000 × 0.27 L/kWh × diesel price × (1+esc)^(yr−1)

Maintenance (split by asset type)

building base × 1% + equipment base × 3% (land excluded)

Insurance (land left out)

installed assets, not land, × 0.35% a year

Upkeep only on what is built

in a staged build, maintenance, insurance and generator-test fuel scale with the share already built; phases not yet built carry no upkeep

Land lease (leased land only)

land value × 8% a year: only when land is leased

Fixed lines escalate

base × (1 + 5%)^(yr−1)

Rent revenue

occupied IT kW × rent per kW a month (₹7,200) × 12 × (1+esc)^(yr−1) + (pass-through ? energy : 0)

Power pass-through

pass-through on → tenant energy billed on top of the rate; off → you absorb the power cost

Lease-up (per phase, straight line)

start + (steady − start) × (age − 1) ÷ (years to fill − 1)

When a phase opens (set year, or when the previous one fills)

phase 1 opens in its set year; a later phase either has a set year or opens once the previous phase reaches its fill level, plus the years to build

One schedule for everything

the phases are the only schedule, capacity = Σ phase MW; each phase is paid for the year before it opens and fills on its own curve; site-wide costs are carried by the first phase

Loan and your money

loan = total cost × loan% ; your money = the rest

Repayment holiday (moratorium)

interest only for the first N years after opening, then repay principal

Equal principal repayment

loan ÷ (loan term − holiday) in each repayment year

Fixed EMI option

loan × r ÷ (1 − (1+r)^−(loan term − holiday))

Interest

outstanding balance × interest rate

Depreciation (straight-line, by asset type)

building cost ÷ building life + equipment cost ÷ equipment life (from the build-cost categories; land left out, soft costs, buffer and IDC shared in proportion)

Tax (with loss carryforward)

max(0, PBT − losses) × 25% ; losses carry forward

Operating profit (EBITDA)

revenue − running costs

Project cash flow

EBITDA − project tax − set-up cost (project tax ignores interest)

Cash to you

PAT + depreciation − principal − set-up cost paid from your money

Value above your hurdle (NPV)

Σ project cash flow ÷ (1 + minimum return)^t

Payback

year the running total of project cash flow first turns positive

Loan cover (DSCR)

cash for loan (CFADS) ÷ loan repayment ; CFADS = EBITDA − tax (repayment years only)

Loan-life cover (LLCR)

today’s value of CFADS over the loan’s life ÷ loan

Money back per ₹1 (equity multiple)

Σ cash returned to you ÷ your money put in

Sale value at the end (exit)

exit multiple × final-year EBITDA (− capital-gains tax)

Break-even occupancy

steady-state occupancy at which NPV = 0

Actual power overhead (PUE)

facility power ÷ IT power (at or above the design figure when some overhead is fixed)

Design availability (by tier)

Uptime Institute target; downtime = (1 − uptime) × 525,600 min

Carbon

grid energy (net of renewables) × grid factor + diesel test energy × diesel factor

Water

WUE × IT energy

What limits the build

min( racks by power, by server floor, by cooling )