Developer proposals and predictions are labelled as such. Source links let you inspect the material and reach your own conclusions.
Web sources checked 25 September 2026 · Page publication dates not stated unless noted in the originals.NBC News · Short video report recorded near a data centre in the United States. Illustrates the kind of sound neighbours describe; not a recording of the proposed M40 Campus.
Wikipedia · Gas turbine: air is compressed, fuel is burned in it and the hot gas drives a turbine. A jet engine uses the remaining energy for thrust; a power-station turbine uses an extra turbine to drive a generator. Aeroderivative turbines are adapted directly from aircraft jet engines.
Planning Inspectorate · Appeal APP/P0430/W/18/3204545, 16 September 2019: the site lies in the Green Belt within a 145 ha former mineral site; parts already restored for agriculture or woodland; permissions required full restoration by 31 December 2017, extended to 31 December 2021. Buckinghamshire refused a permanent waste facility in December 2017 for harm to Green Belt openness and to the site’s restoration; the appeal was dismissed.
Computer Weekly · 2 April 2026: about 1.59GW of installed UK data centre capacity across just under 190 sites (government electricity performance certificate data).
SDC M40 Campus · CCER printed pp. 5 and 23: the site lies in the Metropolitan Green Belt (a draft council assessment calls the area “provisional grey belt”); nearby conservation areas at Hedgerley Green (c. 220m), Hedgerley Village (c. 950m), Beaconsfield Old Town (c. 1.2km) and Gerrards Cross Common (c. 1.4km); Chilterns National Landscape c. 1.75km.
SDC M40 Campus · CCER printed pp. 10 and 32–33: 216 units; diesel assumed for worst-case air-quality modelling; monthly and annual testing; all generators operating for 72 hours in a total-supply-failure scenario.
SDC M40 Campus · CCER printed p. 33: possible small human-health threshold exceedances in the 72-hour emergency case, considered acceptable by the developer. Printed pp. 40–41: SCR and ammonia-slip considerations; final controls under development.
Environment Agency · Scope-specific guidance on engine emissions and testing: minimise tests, less than 50 hours annually, one engine at a time, avoiding poor air quality. Not SDC-specific permit conditions.
Environment Agency · Emissions to air from fossil-fuel combustion, including nitrogen oxides, particulate matter, carbon dioxide and carbon monoxide; other pollutants depend on fuel and technology.
SDC M40 Campus · Page 10: buildings approximately 40m; backup stacks estimated up to 66m above ground. Page 12: energy-centre stacks modelled at 140–180m (reference level not specified in this passage). Page 33: final stack heights still to be determined.
SDC M40 Campus · September 2026 pack. Pages 3–12: context and project plans; 13–15: campus and power options; 16: site section; 17–19: methodology and viewpoint map; 20–82: proposed views. Pages 28/29 and 44/45: completion and year-15 comparisons. Page 25: opening image.
SDC M40 Campus · user-supplied photograph · View looking southwest from Footpath CSP/35/1. Power strategy scenario 1, technology solution 1B. Title transcribed from the supplied photograph; booklet edition and date not established.
InterGen · 300 MW open-cycle gas plant, operational since 2019; excludes the adjacent combined-cycle plant.
RWE · 382 MW combined-cycle gas plant, from the operator’s decarbonisation overview.
RWE · Grimsby 40 MW; Cowes 140 MW (diesel); Great Yarmouth 411 MW; Didcot B 1,440 MW. Operator-published capacities. Dedicated Little Barford page gives up to 750 MW gross, used in the comparison.
Environment Agency · Sound character and noise assessment
US Environmental Protection Agency · Particle sizes and human hair reference
SDC M40 Campus · Dimensions, generators and cooling
SDC M40 Campus · Scenarios 1 and 2
SDC M40 Campus · Construction programme and access
SDC M40 Campus · Employment and economic forecasts
SDC M40 Campus · Air quality, noise and ground conditions
SDC M40 Campus · Bunding, planting and nature trails
SDC M40 Campus · Deadline, response routes and events
SDC M40 Campus · DCO route and indicative timetable
SDC M40 Campus · Illustrative layout; subject to change
SDC M40 Campus · Published location map and interactive map
SDC M40 Campus · Community Consultation Environmental Report and supporting material
Defra · Nitrogen dioxide and particulate matter
Planning Inspectorate · Relevant representations and interested parties
SDC M40 Campus · Existing-site aerial photograph
Project dimensions come from the developer’s published consultation pages. These establish what is proposed, not whether a prediction will come true. The environmental report and underlying assessment should be read alongside summaries.
The height study uses a linear 0–200m scale in its default all-stacks view and 0–70m in the building and backup-flue detail views: an illustrative 8m house, an approximately 40m building and backup-generator flues estimated up to 66m above ground (CCER, p. 10). The 26m difference is 66 minus 40. Widths, forms and flue count are schematic. The energy-centre range of 140–180m (pp. 12 and 33) is included as a distinct column of reported numerical values. Its common zero is a comparison reference, not surveyed ground: the quoted passage does not specify the energy-centre height datum. These are preliminary modelling figures, not final approved heights. The football-pitch comparison uses a stated rectangular area. Neither graphic is a verified architectural view or site layout.
The chart uses a linear scale starting at zero: 0–500 MW in the closer-size view, and 0–1,600 MW in the wider view. Selected UK generating plants use RWE and InterGen published capacities, checked on 25 September 2026. Cowes uses diesel fuel; Spalding Expansion is the 300 MW open-cycle plant, excluding the adjacent CCGT. Little Barford uses its dedicated operator page’s up-to-750 MW gross rating, while Didcot B is 1,440 MW net. The published figures therefore do not all use identical net/gross conventions. SDC’s approximate 200 MW proposal is shown separately. Its summary does not specify the net/gross basis. The comparison does not establish similar annual output, equipment, land area, emissions or noise.
The 15-second airflow, hum and pulsing examples are original synthesised audio with gentle fades. They demonstrate sound character only. They are not site recordings, modelled receptor noise, calibrated decibel levels or equal-loudness comparisons. Actual effects require site-specific assessment.
The developer’s published location map retains its boundaries and original legend. The masterplan is indicative. The opening image comes from page 25 of SDC’s published Stage Two visualisations pack: Photomontages B, looking southwest from Footpath CSP/35/1, power strategy scenario 1, technology solution 1B. This is the digital version of the view in the user-supplied workshop photograph. It depicts the proposal, not an existing built development. The PDF page was rendered at 3,000 pixels wide; the hero crops the page to exclude margins and the key, while a full-resolution page is linked. No AI-generated enhancement is used. The supplied booklet photograph remains linked in the sources. The printed 50 cm viewing instruction relates to the physical page; this screen display is not a calibrated visual assessment. The conceptual night graphic is not a photomontage or impact prediction.
The viewpoint explorer uses original views A–M (including D1 and D2), pages 20–82. Scenario labels follow the visible page headings. The planting comparison uses matched completion and year-15 illustrations from pages 28–29 and 44–45, holding Scenario 1, technology 1A constant. These are proposed outcomes, not before-and-after photographs. The campus diagram and alternative power layouts come from page 13. The three aligned land sections come from page 16. Map topics reproduce separate original plans with their keys; they are not registered overlay layers. Website crops remove page furniture without generating new landscape or buildings. The full source pages remain linked. Pack pages 17–18 explain viewing methodology and the limitations of extended panoramas.
The website reports SDC’s qualification about potential threshold exceedances in its modelled emergency-generator scenario; it does not independently predict an exceedance or establish regulatory acceptance. No prediction is made that screening will fail. The construction programme dates need clarification. Independent validation of the developer’s assessments has not been carried out for this website.
Evidence priority: statutory and official documents; the developer’s original project material; authoritative technical explainers; then clearly labelled interpretation. Source availability does not establish independent verification.