Objections to proposals for development at Pinewood Nurseries

Details of the Parish Council's objections

16th September 2026

Here are the Parish Council's objections to plans for development which have been submitted for Pinewood Nurseries on Wexham Street in Stoke Poges.

You can view the application and make a comment on it on Buckinghamshire Council's website.

Planning Application: PL/26/06414/OA

Stoke Poges Parish Council objects to the proposed development based on the scale and nature of the on-site fossil fuel electricity generation required to operate the proposed data centre and the resulting potential impacts on air quality, human health, residential amenity, noise, climate change, biodiversity and the wider environment.

This is not simply a conventional data centre obtaining its electricity from the national grid. The proposal incorporates a 49.5 MW gas-fired Energy Centre comprising eleven natural gas engines. The applicant’s documents indicate that a firm unrestricted grid connection may not be available for approximately ten years and that the Energy Centre would initially operate as the primary electricity supply. In addition, 43 diesel standby generators are proposed. The environmental effects of this substantial generating infrastructure must therefore form an integral part of the planning assessment.

Scale and Duration of the Gas-Fired Energy Centre

The proposed Energy Centre comprises eleven gas engines with approximately 49.5 MW of installed generating capacity. This is not merely emergency standby generation.

During the initial phase, the Energy Centre is proposed to provide the primary electricity supply because adequate firm grid capacity is not expected to be available for approximately ten years.

The Council should establish clearly:

how many gas engines could operate simultaneously;
their expected annual operating hours;
whether they would operate continuously overnight;
the expected duration of each phase of gas generation;
the circumstances in which the development would move from gas generation to grid electricity;
whether that transition would be secured by enforceable planning conditions.

Air Pollution and Human Health

The combustion of natural gas produces nitrogen oxides (NOx), carbon dioxide and other combustion emissions.

Unlike electricity generated remotely and supplied through the national grid, these combustion emissions would be released directly from the proposed development.

This is particularly important because of the proximity of residential properties, including proposed development of 680 new dwellings, Park Hall Clinic and Wexham Park Hospital.

The Council should therefore be satisfied that the air quality assessment represents credible worst-case operating conditions and adequately considers both long-term and short-term exposure at sensitive receptors.

Particular scrutiny should be given to the assumptions concerning the number of gas engines operating simultaneously and their annual hours of operation.

Wexham Park Hospital and Other Sensitive Receptors

The proximity of Wexham Park Hospital materially increases the sensitivity of the location. The potential effects of additional local air pollution and operational noise should therefore be carefully assessed at the hospital as well as at nearby residential properties and other sensitive receptors.

The Council should satisfy itself that the assessment adequately considers relevant hospital buildings and other locations potentially affected by emissions or operational noise.

Noise from Continuous Gas Generation

We would like the Council to consider other speculative applications within Stoke Poges for approximately 1700 new dwellings and another pending application for another data center at Sefton Business Park.

Noise from the proposed Energy Centre is an important planning and amenity consideration. The gas engines are fundamentally different from conventional emergency standby generators because they are proposed to provide the site’s primary electricity supply during the initial phase. They may therefore operate for prolonged periods, including throughout the night.

The Council should require the applicant to demonstrate the predicted noise effects under credible worst-case operating conditions, including:

simultaneous operation of multiple gas engines;
continuous nighttime operation;
engine exhaust and ventilation noise;
any tonal, intermittent or otherwise distinctive characteristics;
starting and stopping of generating equipment;
appropriate octave band source data;
the effectiveness of proposed acoustic enclosures and silencers; and
cumulative noise from the Energy Centre together with other data-centre plant.

This concern is supported by published Environment Agency guidance on industrial noise assessment.

The Environment Agency requires industrial noise impact assessments submitted for environmental permitting purposes to use BS 4142 methodology. Its guidance specifically requires consideration of the acoustic characteristics of industrial sound and identifies matters including tonality, impulsivity and intermittency. The Environment Agency also states that worst-case impact scenarios should be considered and recognises that noise-sensitive receptors may be particularly affected where background sound is low or propagation conditions are favourable.

The Environment Agency’s guidance on noise modelling also requires information including plant sound power levels, preferably in octave bands, operating times, receptor locations, modelling assumptions and evidence supporting proposed noise mitigation.

Although environmental permitting and planning are separate regulatory regimes, this published guidance provides useful evidence of the level of technical scrutiny considered appropriate when assessing environmental noise from substantial industrial plant. This distinction is also relevant to National Planning Policy Framework Policy DM7 – Relationship with Other Regulatory Regimes, which addresses the relationship between planning decisions and matters controlled under other regulatory regimes. The existence of a separate environmental permitting regime does not prevent relevant land-use and environmental implications from being material planning considerations.

It therefore reinforces the need for the Council to establish whether the proposed gas engine noise assessment uses representative manufacturer source data, realistic operating conditions and credible nighttime and worst-case assumptions.

Noise from the 43 Diesel Generators

The development also proposes 43 diesel standby generators. Although these are principally intended for resilience, testing and maintenance rather than continuous electricity generation, their noise impacts should not be disregarded.

The Council should establish:

how frequently each generator would be tested;
the duration of each test;
permitted testing hours;
whether testing could occur during evenings, nights or weekends;
how many generators could be tested simultaneously;
the maximum number capable of operating simultaneously during an emergency;
whether diesel operation could coincide with operation of the gas Energy Centre;
what noise would result from the credible worst-case operating scenario.

There is published evidence demonstrating that consideration of such scenarios is established practice in data centre noise assessment. For example, an Environment Agency acoustic audit concerning the Iron Mountain LON-3 Data Centre considered separate scenarios for normal operation, generator testing and emergency operation involving all diesel generators operating simultaneously.

The Environment Agency’s Acoustics and Air Quality Modelling and Assessment Unit undertook sensitivity modelling of generator testing and simultaneous emergency operation before reaching its conclusions regarding the acceptability of noise from that development.

Another published UK data centre noise assessment for a Harlow facility considered several generator scenarios, including maintenance testing, full load testing, a simulated mains failure test and an emergency scenario involving all generators operating.

These examples are relevant because they demonstrate that simultaneous generator operation, maintenance testing, grid failure scenarios and emergency operation are recognised matters capable of being explicitly assessed in data centre noise studies.

The Council should therefore establish whether equivalent credible scenarios have been assessed for the 43 diesel generators proposed at Pinewood.

Any restrictions on generator testing which are necessary to make the development acceptable should be secured through enforceable planning conditions rather than existing only as assumptions within the applicant’s noise assessment.

Cumulative Operational Noise

Individual noise sources should not be considered in isolation. The development contains numerous potentially significant mechanical noise sources, including:

eleven gas engines;
43 diesel generators;
cooling plant;
fans and ventilation equipment;
pumps;
transformers and electrical equipment;
exhaust and air-intake systems; and
other associated mechanical plant.

The applicant’s information identifies 31 free cooling chillers with approximately 62 MW of installed cooling capacity. Consequently, the relevant question is not simply whether one gas engine or one diesel generator can satisfy a particular noise limit.

The Council needs to understand the combined operational sound environment when the data centre and the infrastructure necessary to power and cool it are operating simultaneously.

Published Environment Agency data-centre assessments demonstrate the importance of this approach. For example, the Iron Mountain LON-3 assessment considered normal operation involving chillers and condensers, normal operation combined with generator testing and emergency generator operation. The Environment Agency also requires modelling assumptions to be transparent and requires source data to be representative of the conditions under which equipment is expected to operate. This is particularly important at Pinewood because the gas Energy Centre is proposed to operate as primary generation rather than simply being retained for rare emergencies.

The Council should therefore establish whether the applicant’s cumulative noise assessment includes realistic simultaneous operation of the gas engines, cooling plant and other continuously operating mechanical equipment, together with appropriate scenarios for diesel generator testing and emergency operation.

Nighttime Noise

Nighttime operation deserves specific consideration. A data centre operates continuously and the proposed gas Energy Centre may similarly operate throughout the night.

The Environment Agency’s published guidance recognises that background sound levels vary with time and location and that assessments may need to account for periods of low background sound and worst-case propagation conditions.

The Council should therefore be satisfied that nighttime background measurements are representative and that the assessment has not obscured potential impacts by relying upon daytime or otherwise unrepresentative background conditions.

The assessment should also consider whether the sound from engines, exhausts, cooling plant and associated equipment would possess characteristics that make it more noticeable than an equivalent broadband environmental sound level.

Biodiversity and Ecological Effects

The environmental assessment should also consider the effects of the gas-fired Energy Centre on biodiversity and nearby habitats. Combustion emissions containing nitrogen compounds can contribute to atmospheric nitrogen deposition. Sensitive habitats can be affected by increased nutrient deposition and changes in environmental conditions. The ecological assessment should therefore consider not merely the physical footprint of the development but also potential effects arising from:

NOx emissions;
nitrogen deposition;
acid deposition where relevant;
noise and vibration;
artificial lighting;
heat and mechanical infrastructure;
cumulative effects with other developments.

The Council should establish whether all relevant designated sites, priority habitats and other sensitive ecological receptors have been appropriately considered.

Climate Change and Fossil Fuel Generation

The proposal would involve substantial on-site combustion of natural gas potentially continuing for a period of approximately ten years before adequate firm grid capacity becomes available. This creates an important distinction between this proposal and a data centre capable of operating from grid electricity from the outset.

The environmental consequences of constructing a data centre in a location where the electricity network cannot presently provide its required firm supply should form part of the planning balance. The Council should require a clear assessment of the expected annual and lifetime greenhouse gas emissions associated with the Energy Centre and establish what reasonable lower-carbon alternatives have been considered.

Cumulative Effects with Other Development

This application should not be considered in isolation. This existing concentration is particularly relevant when considering the cumulative environmental and infrastructure effects of further major data-centre development at Pinewood Nurseries as well as together with several near by major housing proposals.

There is a substantial and growing concentration of existing, consented and proposed data centre development across Slough, Iver, Denham and the M40/A40 corridor.

Slough already contains one of the largest concentrations of data centres in Europe, while a number of major data centre developments have been permitted or proposed in the Iver and Iver Heath area.

This concentration is continuing to expand. A further major data centre is currently proposed on land north of the M40 and both sides of Denham Court Drive, Denham (Planning Application PL/26/04446/OA), comprising up to approximately 60,000 sq m of data centre development across two buildings with an anticipated IT load of up to 100 MW.

In addition, the proposed SDC M40 Campus at Wapseys Wood, between the M40 and A40 near Gerrards Cross and Beaconsfield, represents a further very substantial data centre proposal. The project has been directed by the Secretary of State into the nationally significant infrastructure planning regime and is reported to comprise approximately 300 MW of data centre capacity together with substantial associated on-site energy generation. The applicant’s Environmental Statement uses a general cumulative search radius of approximately 3 km, whereas significant data centre development extends considerably further across the surrounding area. The Council should therefore consider whether the geographical scope of the cumulative assessment is adequate for each relevant environmental and infrastructure effect.

Particular consideration should be given to cumulative:

air pollution;
greenhouse-gas emissions;
noise;
electricity demand;
gas demand;
water demand;
ecological effects;
traffic and infrastructure impacts;
effects upon surrounding communities.

National and Local Planning Policy

The application should be considered against the National Planning Policy Framework (August 2026) and the relevant policies of the development plan, including the made Stoke Poges Neighbourhood Plan. The Draft Local Plan for Buckinghamshire 2045 – Regulation 19 is also a material consideration, with the weight to be afforded to its emerging policies being a matter for the decision maker.

Particular weight should be given to policies concerning pollution, air quality, protection of human health and amenity, noise, climate change, biodiversity, ecological protection, landscape and cumulative environmental effects.

The Council should demonstrate clearly how the proposed long duration of approximately 10 years of on-site fossil-fuel generation accords with these policy objectives.

Draft Local Plan for Buckinghamshire 2045 – Regulation 19

The proposal should also be considered in the context of Buckinghamshire Council’s Draft Local Plan for Buckinghamshire 2045 (Regulation 19). While the emerging Plan is not yet adopted and the weight to be afforded to it is a matter for the decision maker, it is relevant that the Council has introduced a specific Policy EC5 – Data Centres, reflecting the particular infrastructure and environmental issues associated with this form of development.

The emerging policy requires consideration of whether the electricity, digital connectivity and water requirements of data centres can be met without adverse impacts upon supplies available to local residents and businesses, while also seeking to maximise sustainable heating and cooling technologies and renewable and low-carbon energy.

This is particularly relevant at Pinewood Nurseries because the applicant’s own documents indicate that a firm unrestricted grid connection may not be available for approximately ten years, with the proposed solution being a 49.5 MW on-site gas-fired Energy Centre comprising eleven gas engines, initially operating as the development’s primary electricity supply. This raises an important question as to whether a location which cannot presently provide the electricity infrastructure required by the development without potentially prolonged reliance upon substantial on-site fossil fuel generation represents an appropriate and sustainable location for such a development.

The issue is reinforced by emerging Policy NE21 – Pollution, Air Quality and Contaminated Land, which addresses the effects of potentially polluting and significant noise-generating development, and by the emerging Plan’s wider objectives concerning health, climate change and environmental protection.

The Council should therefore consider the combined implications of the proposed gas generation and associated 43 diesel standby generators, including NOx and other atmospheric emissions, greenhouse gas emissions, operational and nighttime noise, effects upon nearby residents and Wexham Park Hospital, and potential effects upon sensitive ecological receptors.

The relevance of the emerging Local Plan is not that it automatically determines this application, but that Buckinghamshire Council’s own current policy direction recognises electricity capacity, low-carbon energy, pollution, noise and infrastructure availability as important considerations in determining the suitability of data centre development. In this context, the Council should require the applicant to demonstrate clearly why Pinewood Nurseries is an appropriate location when the development apparently cannot obtain the firm grid electricity it requires without relying upon a substantial fossil fuel generating installation for potentially a decade.

National Planning Policy Framework – August 2026

The following national decision-making policies of the National Planning Policy Framework (August 2026) are considered particularly relevant to this application:

DM6 – Use of Planning Conditions and Obligations – relevant where restrictions on gas-engine operation, generator testing, noise mitigation, operating hours or transition to grid electricity are necessary to make the development acceptable. The policy requires planning conditions to satisfy the applicable statutory requirements and to be sufficiently precise and reasonable.
DM7 – Relationship with Other Regulatory Regimes – relevant because environmental permitting and planning are separate regulatory regimes. The policy confirms the relationship between planning decisions and matters subject to other regulatory controls. The existence of an environmental permitting regime does not prevent relevant land-use implications from being material planning considerations.
CC2 – Mitigation of Climate Change – requires relevant development proposals to contribute to climate-change mitigation and the transition to net zero, including through energy- and resource-conserving design and consideration of opportunities to minimise greenhouse gas emissions.
E2 – Meeting the Need for Business Land and Premises – relevant to the specific locational requirements of data-centre development and expressly recognises the importance of infrastructure availability, including adequate electricity-grid connections, together with opportunities to co-locate large-scale generators and users of power such as data centres.
P3 – Living Conditions and Pollution – of particular relevance to the proposed Energy Centre and diesel generators. Development must be appropriate for its location having regard to the likely effects, including cumulative effects, of pollution upon health, living conditions and the natural environment, including effects occurring off-site.
P3 – Air Quality provisions – relevant to NOx and other combustion emissions and their cumulative effects, including consideration of relevant air-quality objectives, sensitive receptors and the effects of development upon local air quality.
P3 – Noise provisions – relevant to operational, nighttime and cumulative industrial noise and to ensuring that adverse noise effects on health and living conditions are appropriately avoided or mitigated.
N2 – Improving the Natural Environment – requires development to consider habitats and landscape character, conserve and enhance important natural features, strengthen ecological networks and minimise adverse biodiversity impacts. It also recognises the role of green infrastructure and nature-based solutions in environmental protection, pollution management and climate-change mitigation.

These national decision-making policies should be read together and alongside the statutory development plan when determining the application.

Stoke Poges Neighbourhood Plan – Made Plan

The Stoke Poges Neighbourhood Plan is part of the statutory Development Plan. Its policies are:

SP1 – Design Code – Stoke Poges Sites
SP2 – Design Code – Wexham Street Site
SP3 – Sefton Park
SP4 – Housing Mix and Tenure
SP5 – Addressing the Energy Performance Gap
SP6 – Design Code – Parish Wide
SP7 – Local Heritage Assets
SP8 – Shared Woodland Area
SP9 – Green Infrastructure
SP10 – Local Green Spaces
SP11 – Local Access Network
SP12 – Dark Skies

For the matters raised in this representation, particular consideration should be given to SP5, SP6, SP8, SP9, SP10, SP11 and SP12, insofar as they are applicable to the application site and the environmental effects of the proposed development.

Information and Safeguards Required Before Determination

Before determining the application, we ask Buckinghamshire Council to satisfy itself that the applicant has adequately demonstrated:

The realistic number of gas engines that would operate simultaneously and their annual operating hours.
The air quality consequences of a credible worst-case gas generation scenario.
The effects upon Wexham Park Hospital, nearby homes and other sensitive receptors.
The cumulative noise from the gas engines, diesel generators, cooling equipment and other mechanical plant.
The nighttime noise impact of prolonged gas engine operation.
The frequency, duration and permitted hours of testing of the 43 diesel generators.
The noise consequences of credible simultaneous diesel generator operation.
Whether appropriate manufacturer sound power and octave band data have been used.
Whether appropriate corrections have been considered for tonal, intermittent or otherwise distinctive industrial sound.
Whether assumptions concerning acoustic enclosures, silencers and other mitigation are supported by appropriate technical specifications.
Whether all assumptions necessary to achieve acceptable noise levels would be secured through enforceable planning conditions.
The effects of NOx and atmospheric nitrogen deposition upon sensitive habitats.
The cumulative environmental effects alongside other major developments.
The expected annual and lifetime greenhouse gas emissions from on-site generation.
Why substantial on-site fossil fuel generation is necessary and what reasonable alternatives have been considered.
How and when reliance upon the gas Energy Centre will cease once adequate grid capacity becomes available.

Where the acceptability of the development depends upon particular operating assumptions, those assumptions should not simply remain statements within technical reports. They should, where appropriate, be secured through enforceable planning conditions or obligations.

Conclusion

The proposed gas-fired Energy Centre should not be treated merely as an engineering solution to a temporary shortage of grid capacity. It is a substantial component of the proposed development with potential consequences for air quality, human health, residential amenity, noise, climate change and biodiversity.

The presence of eleven gas engines together with 43 diesel standby generators means that the environmental effects of 54 combustion engines need to be understood alongside the substantial cooling and other mechanical infrastructure required by the data centre.

Published Environment Agency guidance and assessments from other UK data centre developments demonstrate that generator testing, simultaneous generator operation, nighttime conditions, acoustic characteristics and credible worst-case operating scenarios are legitimate and established matters for detailed noise assessment.

Those examples do not establish what the noise level at Pinewood will be. They do, however, demonstrate why the scale and operating regime of the proposed Pinewood generating installation requires rigorous site-specific assessment.

The proximity of Wexham Park Hospital and residential properties, as well as pending applications for an additional 680 new dwellings, makes careful assessment of both air pollution and noise particularly important.

The Council should therefore be satisfied, on the basis of robust evidence and credible worst-case operating assumptions, that the proposed Energy Centre, diesel generation, cooling plant and associated equipment would not result in unacceptable effects upon human health, residential amenity or the natural environment.

If those matters have not been adequately demonstrated before determination, that deficiency should weigh significantly against the grant of planning permission.

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