In short
- Check in this order: power, land, fibre, water, hazards, climate, community, cost.
- Get the grid offer in writing: MW, voltage and energisation date.
- Grid waits reach 7–10 years in Europe's main hubs, against 1–3 years on average in the US.
- Published campuses use roughly 3.5–5 MW per hectare (1.4–2 MW per acre).
The eight checks, in order
| # | Check | What to confirm |
|---|---|---|
| 01 | Power | MW offered, voltage, distance to transmission, energisation date in writing |
| 02 | Land | Size, shape, zoning for data centers, room for every phase and buffers |
| 03 | Fibre | Two or more carriers on diverse routes, long-haul links to the operator's regions |
| 04 | Water | Supply and discharge for the chosen cooling, or a closed loop |
| 05 | Hazards | Flood zones, seismic and ground conditions, air quality status for generators |
| 06 | Climate | Free-cooling hours; cooler, drier climates cut energy and water |
| 07 | Community | Permits, local support, noise and traffic; engage before filing |
| 08 | Cost | Tax, labour, incentives; build cost varies from under $8M to over $15M per MW |
The order matters: a cheap site without power is not a site. The same list is in the site selection section.
Why power comes first
Land can be bought in months. A transmission connection for hundreds of megawatts needs grid studies, a new substation and often new lines, and it waits in a queue with every other large load. The energisation date drives the whole programme: buildings finished before the power arrives earn nothing.
- Ask for capacity and date in a signed connection offer, not a letter of interest.
- Check whether the offer is firm or curtailable in the first years.
- Understand the queue rules: readiness-based queues, as in the UK, favour sites with land, permits and design in hand.
Grid connection waits by market
| Market | Wait | Source |
|---|---|---|
| Frankfurt, London, Amsterdam, Paris, Dublin | Up to 10 years | IEA via The Register |
| Europe, general | Up to 7 years | AWS EMEA via The Register |
| Northern Virginia | About 7 years | IEA 2025 |
| United States, average | 1–3 years | IEA 2025 |
| US transmission, worst cases | Up to 12 years | Google via IES |
Bridging power until the grid arrives
| Path | Role | Watch out |
|---|---|---|
| On-site gas generation | Bridge for early phases, later backup or export | Air permits, gas supply, emissions targets |
| Battery storage | Peak shaving, grid support, ride-through | Hours, not days, of energy |
| Fuel cells | Modular on-site power in blocks | Fuel supply and cost per MWh |
| Renewable PPAs | Annual energy matching | Do not give firm capacity on their own |
Many AI campuses now start on site generation and switch to the grid when the substation is energised. The grid side is covered in depth on allinMW.
How much land per megawatt
Published campuses work out at roughly 1.4–2 MW per acre, or 3.5–5 MW per hectare: one hyperscaler asked for 200 acres for 400 MW; Meta's Hyperion has 3,650 acres for up to 5 GW. Storeys, rack density, setbacks and on-site power move it a lot. Buildings typically cover only about a quarter of the site.
Build cost by market
The 2026 average is about $11.3M per MW (JLL), above $15M in Silicon Valley and Tokyo and below $8M in India and Southeast Asia. Liquid cooling adds $1–2M per MW. IT equipment comes on top and usually costs more than the building.
Questions about site selection
What is the most important factor in data center site selection?
Power: the capacity on offer and, above all, the date it can be energised. Without it, every other advantage of a site is theoretical.
How far from a substation can a data center be?
Closer is better: every kilometre of high-voltage line adds cost, permits and time. Many campuses build their own substation on site next to an existing transmission line.
Does climate still matter with liquid cooling?
Less than before, because warm-water cooling works in most climates, but cooler sites still save energy and water and need fewer chiller hours.
How do I avoid local opposition?
Engage early, before filing: explain noise, traffic, water and jobs, and offer benefits such as heat reuse. Late opposition is one of the main causes of delay.
Sources
- IEA 2025 and IEA via The Register; AWS EMEA via The Register; Google via IES (grid waits).
- JLL 2026 (build cost); DCD (Hyperion land area).
- Land and cost ranges are planning values; local conditions decide.