Evidence Series — Scottish Energy Compact — June 2026
Hyperscale data centres are among the most water-intensive industrial facilities ever built. Scotland’s planning system has no standardised requirement to assess abstraction volumes, cooling methodology, or catchment impact. Not one application in the current pipeline has been subject to a published cumulative water impact assessment.
Section 1 — How Much Water Do These Facilities Use?
Data centres generate enormous quantities of heat. Every server, every switch, every power unit converts electricity into computation — and waste heat. At hyperscale, that heat must be removed continuously, 24 hours a day, 365 days a year. Water is the primary medium for doing so.
The two principal cooling methods have very different water profiles:
Water is circulated through cooling towers where it absorbs heat and evaporates. This is the most common method in older and mid-generation facilities. A 1MW facility using evaporative cooling can consume approximately 26 million litres of water per year. At 600MW, that is 15.6 billion litres annually — equivalent to the annual water consumption of a city of 130,000 people.
Modern hyperscale facilities increasingly use outside air directly for cooling, drawing on ambient temperature rather than water evaporation. Scotland’s cool climate is genuinely advantageous here. However, air-side economisation still requires water backup for hot days, and many facilities use hybrid systems that revert to evaporative cooling above certain ambient temperatures. Scotland does experience heat events, and climate projections suggest these will intensify.
A middle-ground technology that uses water misting to pre-cool incoming air without direct contact with servers. Lower water consumption than wet towers but still significant at hyperscale. A 100MW facility using adiabatic cooling may consume 3–5 million litres per day in summer peak conditions.
| Facility Size | Cooling Method | Peak Daily Use | Annual Use |
|---|---|---|---|
| 100MW | Evaporative | ~5.2M litres | ~1.9bn litres |
| 100MW | Air-side hybrid | ~0.8M litres | ~280M litres |
| 500MW | Evaporative | ~19M litres | ~6.9bn litres |
| 500MW | Air-side hybrid | ~3.5M litres | ~1.2bn litres |
| Full pipeline (8,700MW) | Mixed | Up to 330M litres | Up to 120bn litres |
Estimates based on US DoE and Lawrence Berkeley National Laboratory benchmarks applied to Scottish pipeline. Peak daily figures assume summer conditions at maximum evaporative load. Air-side hybrid assumes 85% air-side, 15% evaporative at peak. Full pipeline estimate is indicative upper bound.
The industry metric for water consumption is Water Use Effectiveness — litres of water consumed per kilowatt-hour of IT load. The global average WUE for data centres is approximately 1.8 L/kWh. Best-in-class facilities achieve 0.2–0.5 L/kWh. No Scottish planning application has been required to declare a WUE target or commit to one as a condition of consent.
Source: Uptime Institute Global Data Centre Survey 2024; Green Grid WUE whitepaper
Section 2 — Scottish Catchments at Risk
Scotland’s water resources are generally abundant but unevenly distributed and seasonally variable. Summer low-flow periods in Scottish rivers can be severe — particularly in the east, where several of the largest proposed sites are located. The cumulative abstraction of multiple large facilities drawing from the same or connected catchments in a hot, dry summer has never been modelled.
The Auchtertool site sits within the River Ore catchment in Fife. The River Ore is a relatively small watercourse with low summer flows. A 600MW facility using evaporative cooling could draw up to 19 million litres per day at peak — a volume that would represent a significant fraction of the river’s summer baseflow. No SEPA abstraction impact assessment has been published. No low-flow analysis has been required.
Ravenscraig (550MW, Apatura), Drumshangie (500MW, Apatura) and Newhouse (400MW, ILI Group) form a cluster of over 1,450MW in North Lanarkshire. All three draw on the same regional water infrastructure and potentially the same catchment systems. No cumulative water assessment has been published for this cluster. Each application has been treated in isolation by the planning authority.
The Killean site carries an option to expand to 2,000MW — the largest single facility in the pipeline. Argyll’s west coast location provides relatively high rainfall, but the site’s scale means water demand at peak could exceed local catchment capacity during drought conditions. No hydrological impact assessment has been published for the full 2,000MW scenario.
Hurlford (540MW) and Ochiltree (200MW) sit in East Ayrshire, both drawing on the River Irvine catchment system. Combined peak water demand from these two sites alone could reach 24 million litres per day under evaporative cooling. The River Irvine is already subject to abstraction pressures from agricultural and industrial users.
Duns (225MW) and Coldstream (300MW) sit in the Scottish Borders, close to the River Tweed system — one of Scotland’s most ecologically important rivers and a designated Special Area of Conservation. Any significant abstraction from connected catchments would require SEPA scrutiny. No such assessment has been published or required.
Hunterston (~450MW) and the proposed Irvine site (1,000MW pre-planning) represent over 1,450MW on the North Ayrshire coast. Both sites are coastal, which opens the possibility of seawater cooling — as used at Google’s Hamina facility in Finland. However, no cooling methodology has been specified for either site, and seawater cooling carries its own environmental impact requirements under the Marine (Scotland) Act 2010.
Scotland’s planning system currently assesses each data centre application in isolation. There is no requirement for a developer to consider the combined water abstraction impact of neighbouring facilities. There is no requirement for SEPA to publish a catchment-level assessment of cumulative demand before consent is granted. The Scottish Government has issued no guidance to planning authorities on how to assess water impact for facilities of this scale. This is a structural gap in the consent process — not a fringe concern.
Section 3 — The Regulatory Position
The Scottish Environment Protection Agency (SEPA) is the statutory body responsible for regulating water abstraction in Scotland. SEPA has the powers to require abstraction licences for significant water extraction. However, the current planning process for data centres does not systematically trigger SEPA involvement at the pre-application stage.
The result is that planning authorities grant consent without a binding SEPA abstraction assessment in place. By the time a facility is built and operational, the abstraction is a fait accompli — enforcement against an operational facility consuming millions of litres per day is politically and practically difficult.
The planning system currently asks communities to accept major new water-intensive infrastructure without a transparent evaluation of the impact on local rivers, lochs, and groundwater. That is a failure of due diligence, not a fringe concern.
Michael Knox — Scotland’s Data Centre Reckoning, June 2026The CAR regulations require authorisation for abstracting water from inland freshwaters above certain thresholds (typically 10 cubic metres per day for registerable activities, higher for licensing). A 500MW data centre drawing 19 million litres per day would require a CAR licence. However, this licence is sought after planning consent is granted — not as a precondition of it.
National Planning Framework 4 (NPF4) requires Environmental Impact Assessments for major developments, which should in principle cover water. In practice, EIAs for data centre applications have not included standardised water abstraction and cooling assessments. There is no NPF4 guidance specifically requiring WUE targets, cooling methodology disclosure, or maximum abstraction declarations for data centre applications.
Ireland’s experience is directly relevant. Ireland’s 2020 Data Centre Strategic Review found that data centres accounted for 14% of national electricity consumption and raised significant water concerns. By 2021, several Irish local authorities were refusing data centre applications citing water infrastructure constraints. The cumulative impact had not been assessed before the pipeline was approved — exactly the position Scotland is now in.
Section 4 — What Must Change
The Scottish Energy Compact’s Condition 3 covers water impact and cooling standards. It requires no new primary legislation — it requires a ministerial direction to SEPA and planning authorities, and an amendment to NPF4 guidance. Both are within the Scottish Government’s existing devolved powers.
Standardised EIA requirement. Every application above 50MW must include a water impact assessment covering: maximum daily abstraction volume, cooling methodology, source water identification, catchment baseflow analysis, and cumulative impact assessment with neighbouring facilities within the same catchment.
Cooling standards. Closed-loop or air-side cooling required as the default standard. Evaporative or open-loop cooling permitted only where the EIA demonstrates no material impact on local water resources, baseflows, or downstream ecology.
SEPA pre-assessment mandatory. A SEPA abstraction licence pre-assessment must be completed and published before planning consent is determined — not after. The licence assessment must address both individual and cumulative catchment impact.
WUE target binding. Each facility must declare a Water Use Effectiveness target as a condition of consent, with annual reporting to SEPA. Facilities failing to meet declared WUE targets within three years of operation face consent review.
All assessments public. Every water impact assessment, SEPA pre-assessment, and annual WUE report must be published in full on the relevant planning authority’s portal.
Pending the full Compact, one action can be taken immediately within existing powers:
MINISTERIAL DIRECTION — NOW
The Cabinet Secretary for Net Zero and Energy should issue a ministerial direction to SEPA and all Scottish planning authorities requiring standardised water abstraction and cooling methodology assessments for any data centre application above 50MW, with all results published before consent is determined.
This requires no new legislation. It requires no amendment to primary statute. It requires a minister to sign a direction.
US Department of Energy — Data Centre Water Usage report
Lawrence Berkeley National Laboratory — Data Centre Water Benchmarking Study
Uptime Institute — Global Data Centre Survey 2024
Green Grid — Water Use Effectiveness (WUE) whitepaper
SEPA — Water Environment (CAR) Regulations guidance
NPF4 (2023) — Scottish Government
Ireland Data Centre Strategic Review 2020
ASHRAE TC 9.9 — Thermal guidelines for data processing environments
Schneider Electric WP-176 — Adiabatic cooling in data centres
Marine (Scotland) Act 2010 — seawater abstraction requirements
River Tweed SAC designation — NatureScot