A recent surge in proposals for the development of large data centres across urban and rural Scotland has seen a spike in interest on this topic across communities, planning authorities, and businesses. This issue has also featured in recent Scottish Parliament debates and questions. This briefing provides background information on data centres, their scale, energy and water consumption, and the policy approach to their development.
This is an extended post, so we have added a pop-out table of contents to help with navigation.
What is a data centre?
A data centre is a structure, or part of a structure, used to house computing and data storage resources that support many aspects of modern life, including e-commerce, banking, public service delivery, and applications such as cloud computing and artificial intelligence (AI). The key components of a data centre typically include servers, storage systems, networking equipment, power supply, and cable management.
Data centres come in various forms, including:
- Enterprise: a data centre hosted within the premises of its owner/user.
- Public cloud and hyperscale data centres: stand-alone facilities used by multiple people and organisations.
- Managed data centres and co-location facilities: where organisations lease or own data centre resources operated by a data centre management provider – these facilities are themselves often located in public and hyperscale data centres.
This post is largely concerned with public and hyperscale data centres. While there is no formal definition of “hyperscale”, it is typically understood as a data centre that utilises at least 5,000 servers (a server is essentially a high performance computer that is similar in size to a laptop or desktop PC) and covers a minimum of 930 square metres of floor space, although most hyperscale centres are many times larger.
What is a green data centre?
There is no agreed definition of what constitutes a “green data centre”. The term is generally applied to data centres that maximise the use of renewable energy sources, employ energy efficient technologies and processes, seek to minimise water consumption, and support the re-use of excess heat. It is worth noting that larger and hyperscale data centres labelled as “green” still make significant resource demands, particularly in relation to land take, water consumption, and energy demand – an environmental concern where electricity cannot be continuously provided from renewable sources. These issues are explored in more detail below.
How big is a data centre?
Data centres can vary greatly in size, from a server room within an office building to the largest hyperscale centres. Given the current focus on public and hyperscale data centres, it is worth considering the physical size of a couple of hyperscale data centres currently proposed in Scotland.
- Proposed Cato data centre, Auchtertool, Fife: the buildings that make up this proposed site would cover an area of 280,000 square metres – equivalent to almost 40 football pitches. The main data centre buildings would be up to 35 metres high, roughly equivalent to the height of a 12-storey block of flats
- Proposed Larbert data centre campus: includes two data centre buildings with a floor area of 128,863 square metres with a building height of 25 metres (with flues extending to 28 metres). It also includes an 11,500 square metre electricity substation and associated facilities.
Measuring the electricity consumption and computing power of a data centre
The measures of energy consumption and data centre processing power use very similar terminology, meaning they are easy to confuse.
Energy Consumption: The base measure of energy consumption is the ‘Watt hour’ (Wh). A single Wh is the amount of energy used in one hour by a device with a power of one Watt. The measure of energy consumption for large scale data centres is typically the gigawatt hour (GWh), one GWh equates to a billion Wh, i.e. the energy consumed in one hour by a device with a power of a billion Watts. The Energy Statement of Intention that accompanies the planning application for the Cato Data Centre proposed for Auchtertool in Fife states that:
Development of Cato is expected to be phased, with an early phase annual energy usage of perhaps around 400 GWh, with an ultimate potential usage of 4000 GWh.
Processing power: A data centre’s processing power is typically described in Watts. A Watt is a measure of the rate of power used at a specific moment. As the maximum power available in a data centre dictates how many servers it can house – this ultimately places a cap on the processing power available. The processing power of a hyperscale data centre is normally measured in megawatts (MW, one MW being one million Watts), e.g. the Rufus data centre project proposed for Hurlford near Kilmarnock is badged as 540MW, meaning the maximum power that it could draw at any point in time would be 540MW, and hence the cap on its processing power.
Data centre processing speed is measured in FLOPS (Floating Point Operations Per Second), although data centres typically operate at Tera, Peta, or ExaFLOPS – performing trillions, quadrillions or quintillions of operations per second.
How much electricity does a data centre consume?
Hyperscale data centres are major consumers of electricity. As quoted above, the developer of the Cato data centre states that annual electricity consumption will start at 400GWh per year and potentially rise to 4000GWh per year, 4000GWh can also be described a 4TWh (terawatt hours).
To put this into perspective, Scotland generated a total of 51.8TWh of electricity in 2024, of which 91.5% was from renewable sources. Running at the full 4TWh, the proposed Cato data centre would consume 7.7% of all electricity generated in Scotland during 2024.
How does this compare to typical domestic electricity usage? Power sector regulator Ofgem considers the typical household to consume 2,500kWh (kilowatt hours) of electricity each year. This means the proposed Cato data centre running at full capacity would consume the same amount of electricity as 1.6 million typical households in a year.
What does this mean for electricity generation in Scotland?
This is a difficult question to answer, given the variables involved. However, future electricity generation requirements are currently being assessed and planned by the National Energy System Operator (NESO – a Britain-wide organisation responsible for planning and delivery of energy infrastructure). Economic Advisory Firm Oxford Economics has forecast that data centre electricity usage:
…could grow more than fivefold by 2030—reaching 26.2 TWh (Fig. 2). We estimate that data centres’ demand will represent 8.8% of total UK electricity demand, or 30.4% of UK commercial electricity consumption in 2030.
NESO is working on a Strategic Spatial Energy Plan (SSEP), with a draft due for consultation in early 2027 and the final version by the end of that year. It is also working on Regional Energy Strategic Plans (RESP; for which Scotland will be a single region) due for publication by the end of 2028. Transitional versions of the RESP were published in early 2026.
These plans will be informed by NESO research into Options for Optimising Data Centres, completed in July 2025.
Data centres and water use
According to the UK Parliamentary Office for Science and Technology (POST), data centres use water in three ways:
- Cooling systems for servers to maintain stable operating temperatures and prevent overheating. Not all data centre cooling methods use water. Air cooling, liquid coolants or hybrid systems are also used. However, data centres often use drinking-quality water (tap water) because it can be reliably sourced from existing water infrastructure and prevents clogging and contamination of components.
- Electricity supply, which may come from gas and nuclear power stations which evaporate water during operation.
- Semiconductor chip manufacturing, which requires large amounts of processed water to rinse residue from silicon wafers during various stages of the manufacturing process.
The POST briefing notes that regional climate affects the viability and efficiency of air-based cooling, which are better suited to seasonal variation and cooling of high‑density chips typically used in UK data centres.
Information and figures on water use in Scottish data centres vary. A BBC article reports that most use “open loop” systems requiring a constant mains water supply. In contrast, Scottish Water states that most rely on closed loop systems, which reuse water with only minimal top‑ups.
The BBC also reports that data centres powering artificial intelligence in Scotland use enough tap water each year to fill 27 million half‑litre bottles, equivalent to an extra 2.48 litres per person, and that data centre water use has quadrupled since 2021.
However, Scottish Water says data centres account for a small share of total demand. The 13 sites currently operating use around 97 cubic metres per day, or 0.006% of the 1.6 to 1.8 billion litres supplied daily to homes and businesses.
Scottish Water acknowledges concerns about water use and that future growth raises sustainability questions. It forecasts that total water demand across Scotland, not just from data centres, could exceed supply by 240 million litres per day by 2050 unless demand falls or new supplies are developed. It emphasises the importance of planning, given more variable rainfall, longer dry periods, and climate change, and supports using land use planning to promote data centres that use closed loop cooling systems.
The Scottish Government’s AI Strategy adds that Scottish Water is advising the sector by guiding site selection, encouraging reuse of treated wastewater, and promoting closed loop systems to reduce demand.
Scottish Government data centre policy
The Scottish Government sets out is policies on data centre development in its 2021 Green data centres and digital connectivity: vision and action plan for Scotland, which is supportive of their development and sees green data centres as delivering significant economic benefits. This positive policy approach to facilitating green data centre development is carried through in the Scottish Government’s 2026 Scotland’s AI Strategy. Scottish Government data centre planning policy is considered separately below.
Planning policy and data centres in Scotland
The emergence of hyperscale data centres as a major planning issue has outpaced national and local planning policy development in Scotland, meaning most planning policy documents are silent on the issue.
The Scottish Government has designated “green data centres” as part of a national development (National Development 12: Digital Fibre Network) in National Planning Framework 4. National development status is not an award of planning permission but means that the principle of the development cannot be challenged during the planning application process. In practice, this means any objections to a development considered a green data centre must focus on the detail of a proposal rather than the need for the development itself.
As mentioned above, the Scottish Government has not offered a firm definition of what constitutes a “green data centre”. Ross Greer MSP asked the First Minister to clarify this definition at First Minister’s Question Time on Thursday 18 June 2026. The First Minister stated:
The Government’s definition of a green data centre is one that has been approved with due account taken of the environmental implications of all required developments. That will, of course, cover a range of the issues that Mr Greer highlighted in his question.
In defining green data centres, it is for planning authorities to interpret and apply national planning policy to the circumstances of each case. They should consider factors such as renewable energy use, energy-efficient technologies, reduced water consumption and the opportunities to reuse excess heat. The Government’s planning hub has been working with planning authorities to ensure that there is a wide and consistent understanding of those factors when coming to those conclusions.
In effect, requiring planning authorities to decide what constitutes a green data centre on a case-by-case basis, rather than by reference to a nationally defined standard. However, when asked again about data centres and planning policy at First Minister’s Questions on 25 June 2026, the First Minister stated:
I am giving active consideration to whether the Scottish Government should provide planning guidance to balance the rapid expansion of hyperscale data centres with national energy and climate goals, which are vital to our future prosperity.
The First Minister went on to state that consideration would also be given to whether decisions on hyperscale data centres should be taken at a local or national level, given the potential cumulative impact that the development such facilities across Scotland could have on energy consumption – such a national view being outside the usual scope of planning authority decision making processes.
Do data centre planning applications need an Environmental Impact Assessment?
Environmental Impact Assessment (EIA) is a standardised process used to assess the likely effect of proposed large-scale developments on features such as soil, air, water, biodiversity, human health, and the climate.
The types of development that require an EIA fall into two categories. ‘Schedule 1’ developments always require an EIA, these include developments such as nuclear power stations, steelworks, chemical works, major road or runway projects or large-scale incinerators. Data centres are not considered a ‘Schedule 1’ development.
An EIA may be required for a ‘Schedule 2’ development, which includes certain mining, chemical, manufacturing, and other potentially environmentally damaging development types that meet certain criteria defined in regulations.
It is possible that a proposed data centre could fall within the definition of a Schedule 2 development, but that is dependent on the characteristics of the scheme in question and the view taken by the planning authority. There are instances of large data centre proposals, such as the 200MW data centre proposed for the Gogar area of Edinburgh, being deemed not to need an EIA by a planning authority.
Number of current and planned data centres in Scotland
There is no single, official source of data on the number, location, or size of current and proposed data centres in Scotland. The Scottish Futures Trust/Host in Scotland, Crown Estate Scotland and Scottish Enterprise published a ‘Shortlist for Data Centre Site Development’, last updated in June 2023. Further to this, in November 2023 the same organisations published a long list of 33 potential data centre locations in Scotland, which were entirely distinct from the 20 included in the June 2023 list.
Action to Protect Rual Scotland (APRS) has produced a map of proposed data centres in Scotland, which currently lists 26 proposals, although they highlight that this may not be a comprehensive list.
Could the Scottish Government introduce a moratorium on new data centre development?
In principle, yes. The Scottish Government already has policies of “no support” for new coal mines and oil and gas developments which employ hydraulic fracturing (fracking) in Scotland.
These are not technically “bans” on such developments. A developer can submit a planning application for a new coal mine or fracking development. Such applications must be considered by the relevant planning authority. That consideration will be influenced by the Scottish Government’s policy of “no support”.
Despite this policy, a planning authority could potentially decide to grant permission for such a development. However, the Scottish Government has put administrative processes in place that require any authority minded to grant permission for a new coal mine or fracking development to first notify Scottish Ministers of their intention. This allows Scottish Ministers the opportunity to “call-in” the application for their own decision which, given their policy of “no support”, would likely be exercised to refuse permission. Scottish Ministers normally only use their power to call-in an application for their own decision where it raises an issue of national importance, as set out in the Ministerial Statement on circumstances for call-in,
Further reading
More information on data centres is available in the House of Commons Library research service briefing on Data centres: planning policy, sustainability, and resilience, and the UK Parliamentary Office of Science and Technology (POST) note What are data centres and how sustainable are they?
Alan Rehfisch, Damon Davies, Niall Kerr, and Rebecca Bartlett, SPICe
Main image courtesy of Google: Google data centre, Douglas County, Georgia, USA