Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Site visit made on 11 November 2025 by R C Kirby BA(Hons) DipTP MRTPI an Inspector appointed by the Secretary of State Decision date: 16 January 2026 Appeal Ref: APP/N1920/W/25/3368845 Land West of Hilfield Lane, Aldenham, Hertfordshire WD25 8DD • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a failure to give notice within the prescribed period of a decision on an application for planning permission. • The appeal is made by Ms A Murray of BW ESS Development UK Limited against Hertsmere Borough Council. • The application Ref is 25/0153/FUL. • The development is proposed development of a Battery Energy Storage System (BESS) including ancillary works and access arrangements. Decision 1. The appeal is allowed and planning permission is granted for a Battery Energy Storage System (BESS) including ancillary works and access arrangements at Land West of Hilfield Lane, Aldenham, Hertfordshire WD25 8DD in accordance with the terms of application Ref 25/0153/FUL and subject to the 33 conditions in the attached Schedule. Preliminary Matters 2.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision During the course of the appeal the Council undertook publicity in respect of the proposal affecting the setting of nearby listed buildings, in accordance with Regulation 5 of The Planning (Listed Buildings and Conservation Areas) Regulations 1990. 3. The appeal has been made on the basis that the Council failed to determine the planning application within the prescribed period. Had the Council determined the application it has indicated as part of this appeal that it would have granted planning permission subject to a number of conditions as set out in its Committee Report. Main Issues 4. Notwithstanding the above, I consider that the main issues in this case are: • whether the proposal would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework (Framework) and relevant development plan policies; • the effect upon the openness and purposes of the Green Belt, • the effect upon designated heritage assets; • the effect upon the character and appearance of the area, and https://www.gov.uk/planning-inspectorate

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 • Whether other considerations clearly outweigh the harm to the Green Belt and any other harm so as to amount to the very special circumstances required to justify the proposal. Reasons 5. The appeal site comprises approximately 2.4 hectares of agricultural land adjacent to the M1 motorway. The proposal is for a battery energy storage system (BESS), comprising approximately 80 battery containers, inverters, a spare parts storage container, substation, control room and access road. The containers would be enclosed by 3 metre high wire mesh fencing, as would the substation. CCTV cameras around the perimeter of the enclosures are also proposed, along with 2 water tanks. Planning permission is sought for a period of 30 years, after which time the land could be reverted to agricultural use. Whether inappropriate development 6. The appeal site is located within the Metropolitan Green Belt. National planning policy contained within the Framework makes it clear that development in the Green Belt is inappropriate unless a number of exceptions apply, as set out within paragraph 154. None of these exceptions apply to the proposal.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Paragraph 160 identifies that when located within the Green Belt, elements of many renewable energy projects will comprise inappropriate development and in such cases developers will need to demonstrate very special circumstances if projects are to proceed. 7. Both main parties consider that the appeal site comprises grey belt land. In this regard, paragraph 155 of the Framework establishes that development in the Green Belt of homes, commercial and other development should not be regarded as inappropriate where all of the criteria identified in a. to d. apply. 8. Criterion a. of paragraph 155 requires development to utilise grey belt land and that it would not fundamentally undermine the purposes (taken together) of the remaining Green Belt across the area of the plan. Criterion b. requires that there is a demonstrable unmet need for the type of development proposed and criterion c. requires the development to be in a sustainable location, with particular reference to paragraph 110 and 115 of the Framework. Criterion d) relates to the ‘Golden Rules’, but as the proposal does not relate to housing, criterion d) is not relevant in this case. 9.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision In order to qualify as ‘grey belt’ the glossary to the Framework in Annex 2 sets out that it is ‘land in the Green Belt comprising previously developed land and/or any other land that, in either case, does not strongly contribute to any of purposes (a), (b), or (d) in paragraph 143. ‘Grey Belt’ excludes land where the application of the policies relating to the areas or assets in footnote 7 (other than Green Belt) would provide a strong reason for refusing or restricting development. 10. The five purposes of Green Belt are set out in Framework paragraph 143. Purpose a) is to check the unrestricted sprawl of large built-up areas; b) is to prevent neighbouring towns merging into one another and d) is to preserve the setting and special character of historic towns. Purpose c) is to assist in safeguarding the countryside from encroachment and e) is to assist in urban regeneration, by encouraging the recycling of derelict and other urban land. https://www.gov.uk/planning-inspectorate 2

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 11. The Council refer to a Stage 1 Green Belt Assessment, which included the appeal site, as part of its draft Local Plan evidence base, and the appellant refers to its Green Belt Statement. Neither of these documents have been submitted as part of this appeal. The Council has provided me with Map B ‘Bushey and Elstree’, which amongst other things shows a green line which is denoted as the boundary of the Green Belt. What is not clear from this information is the extent of the Green Belt within the Council’s plan area. There is also uncertainty as to whether Bushey is within the Green Belt, or excluded from it, given the presence of a green line around the built form of the settlement. Moreover, it is not clear whether the settlements of Bushey, North Bushey, Bushey Heath, Elstree and Borehamwood on the plan are villages, towns or large built-up areas. 12. Even if I were to accept that the appeal site comprises grey belt land, it is clear that the proposed development of this open agricultural field as proposed would inevitably result in encroachment into the countryside such that there would be conflict with Green Belt purpose c).

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Moreover, the proposal would not recycle derelict and other urban land to assist in urban regeneration, in conflict with Green Belt purpose e). 13. Although the site is of a modest size I am unable to determine on the evidence before me whether or not conflict with these Green Belt purposes would or would not fundamentally undermine the purposes (taken together) of the remaining Green Belt across the area of the plan. Given this, it is not necessary to determine whether the proposal complies with paragraph 155 b. or c. because to qualify as not inappropriate development in the Green Belt all of the criteria of paragraph 155 needs to be complied with. 14. Therefore, on the evidence before me, I have insufficient evidence to demonstrate that the proposal would not be inappropriate development in the Green Belt. Inappropriate development in the Green Belt is, by definition harmful to the Green Belt. Openness and purposes 15. The Government attaches great importance to Green Belts. The fundamental aim of Green Belt policy is to prevent urban sprawl by keeping land permanently open. Openness is an essential characteristic of Green Belts with spatial and visual aspects, and is a matter of planning judgement.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The development of the appeal site with structures, fencing and access roads, where there is no development at present would inevitably reduce the openness of the Green Belt, both spatially and visually. 16. The Planning Practice Guidance (PPG) sets out factors which can be taken into account when considering the potential impact of development on the openness of the Green Belt. These include the duration of a development and its remediability, including taking into account any provisions to return land to its original state or to an equivalent (or improved) state of openness1. Whilst 30 years is a considerable period of time for the proposal to be on the site, the openness of the Green Belt would not be permanently lost. Planning conditions limiting the time period of the planning permission and requiring decommissioning and restoration would temper the impact on the Green Belt to a limited extent. Overall, given the scale of the 1 PPG Paragraph: 013 Reference ID: 64-013-20250225 https://www.gov.uk/planning-inspectorate 3

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 development proposed, it is my judgement that moderate harm would be caused to the spatial and visual openness of the Green Belt. 17. I have found that the proposal would conflict with Green Belt purposes c) and e) for the reasons set out above. The development of the site as proposed would, given its size and relationship to settlements with open land between, be unlikely to result in the unrestricted sprawl of large built-up areas (purpose a)) or result in neighbouring towns merging into one another (purpose b)). I have little evidence before me in respect of purpose d), so am unable to conclude on this purpose. 18. Whilst the loss of openness would be moderate and the harm to its purposes would be slight, harm would be caused to the Green Belt. Green Belt conclusion 19. Overall, the proposal would comprise inappropriate development in the Green Belt in conflict with Hertsmere Local Plan Development Plan Document Core Strategy (adopted January 2013) (Core Strategy) Policy SP1 which, amongst other matters seeks to avoid inappropriate development in the Green Belt.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The proposal would also result in a moderate loss of openness, and harm some of the purposes of the Green Belt, on a long term, but temporary basis. The harm to the Green Belt carries substantial weight. 20. The Framework makes it clear that inappropriate development should not be approved except in very special circumstances. ‘Very special circumstances’ will not exist unless the potential harm to the Green Belt by reason of inappropriateness, and any other harm resulting from the proposal, is clearly outweighed by other considerations. 21. Before I can assess whether or not other considerations amount to very special circumstances, it is necessary to assess other matters raised by the proposal and by interested parties, so that these can be taken into consideration in my assessment. Designated Heritage Assets 22. There are number of listed buildings within the vicinity of the appeal site.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision In this regard and acknowledging that the proposal would not affect the fabric of the listed buildings, I have had regard to my duty under section 66(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 which, amongst other matters, requires me to have special regard to the desirability of preserving the setting of a listed building. 23. Hilfield Castle is a Grade II* listed building located in an easterly direction of the appeal site accessed via a long drive. Dating from 1798-1799, constructed as a house replacing Slys Castle, its significance and special interest lies in part to its age, fine Gothic architecture and its historical interest as well as its cultural and historic associations to other designated heritage assets upon the estate. Set in landscaped grounds, it is an imposing feature in the wider landscape. The upper parts of the building are visible from parts of the appeal site, which forms part of the largely open, agricultural setting to this property, contributing to its significance. 24.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The Lodge to Hilfield Castle is Grade II listed and dating from the same time as the Castle its significance derives in part from its age, architecture and surviving historic fabric as well as its historic and cultural relationship to the Castle. Its https://www.gov.uk/planning-inspectorate 4

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The Lodge to Hilfield Castle is Grade II listed and dating from the same time as the Castle its significance derives in part from its age, architecture and surviving historic fabric as well as its historic and cultural relationship to the Castle. Its https://www.gov.uk/planning-inspectorate 4

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 immediate setting is the grounds within which it is located, but the wider landscape setting, of which the appeal site forms part also contributes to its significance to a lesser degree. 25. The development of the appeal site as proposed would erode the open setting of these designated heritage assets, and to a small extent their significance through the industrialisation of this open, agricultural field. The setting of the listed buildings would not be preserved. The proposal conflicts with Policy CS14 of the Core Strategy which requires development proposals to conserve or enhance the historic environment in the Borough. 26. Between Hilfield Lodge and Hilfield Castle is the Grade II listed Gatehouse to Hilfield Castle. Its significance is derived from its age, architectural and historical interest and historical association to Hilfield Castle and its Lodge. Set within the grounds of Hilfield Castle its setting comprises the Castle’s grounds. The appeal site does not form part of its setting, a matter agreed by the Council, such that its development as proposed would have a neutral effect upon the significance of this designated heritage asset. 27.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision In terms of the Framework, I find that the harm that would be caused to the significance of the designated heritage assets Hilfield Castle and The Lodge to Hilfield Castle would be less than substantial, at the lower end of the scale. These harms do not however equate to less than substantial importance and weight. Indeed, I attach considerable importance and weight to these harms. In accordance with the Framework, the identified harms need to be weighed against the public benefits of the proposal. This is considered later in my decision. Character and Appearance 28. Policy SADM11 of the Site Allocations and Development Management Policies Plan (November 2016) (SADMPP) expects development to be managed to help conserve, enhance and/or restore the character of the wider landscape across the borough. 29. The appeal site is not within a designated landscape. It comprises agricultural land largely enclosed by hedgerows and mature landscaping. There is a public right of way which leads from Hilfield Lane close to the proposed access, across the fields which form part of the appeal site in a westerly direction, which would be in close proximity to the proposed substation and security fencing.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The site is relatively flat and to the west of the site is the M1 motorway, which is at a lower level than the site. Close to the southern boundary of the appeal site is the A41 which bridges above the M1. Immediately to the north of the appeal site is a haulage depot, beyond which is woodland. The Elstree Substation is located on the opposite side of Hilfield Lane to the appeal site in a northerly direction at a distance of 150 metres as calculated by the Council. The Elstree Aerodrome is located in an easterly direction with reference being made to this being 600 metres from the appeal site. Overhead power lines cross part of the appeal site and there are a number of electricity pylons in proximity to it. 30. Although the proposal seeks to retain existing landscaping and supplement it, the proposal would effectively sever the existing farmland pattern in this location and place infrastructure development on it. Although infrastructure is present nearby and the effect on the landscape would be for a temporary period and limited given the proposed landscaping, size of the site and scale of the proposal, taken https://www.gov.uk/planning-inspectorate 5

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 together it is my judgement that the proposal would have a harmful effect on the landscape character of the area. 31. Other than the point of access on Hilfield Lane, the proposal would unlikely be visible from this road due to intervening vegetation. From the M1, any views of the proposal would be limited and filtered by existing and proposed landscaping, such that the proposal would have a negligible visual effect from this highway. From the A41 within the vicinity of the site there would likely be some filtered views through the intervening landscaping in the winter months, but again any views would be limited such that at most it is my view that the effect would be slight adverse. 32. The proposal would however be prominent and intrusive from the public right of way (restricted byway 036) that crosses the site particularly where it runs close to the southern boundary of the equipment proposed. From here the notable change to the character and appearance of the area would be particularly noticeable. The open, farmed landscape views would be replaced with regimented rows of storage containers and a substation surrounded by high mesh fencing. 33.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The appellant proposes that the southern boundary of the site would be planted with a native hedgerow and that a native tree and hedge plantation would be planted to the south and southeast to provide screening from the public right of way. This would clearly take time to mature, and until it does the proposal would be viewed as an unsightly imposition, even factoring in the presence of infrastructure in the landscape, including tall pylons and the Elstree Substation. 34. I acknowledge that the imposition would be for a short stretch of the public right of way, and in the context of the highway network the enjoyment of this right of way would be tempered in the vicinity of the appeal site. That said the industrial nature of the proposal in this rural location would be at odds with the otherwise agricultural landscape for a considerable period of time. 35. Given the above, the proposal would be harmful to the character and appearance of the area, which, whilst mitigated to some extent over time, would not be sufficient to meet the expectations of SADMPP Policy SADM11, or the conserving and enhancing of the natural environment objectives of Core Strategy Policies CS12 and CS16. Other Matters Public Safety 36.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Concern has been raised by many interested parties and groups about the safety of the BESS installation, particular the fire risk associated with the equipment. My attention has been drawn to the closure of the fire station at Radlett with the closest stations being at Borehamwood or Watford which are further from the site than Radlett. 37. I do not take these concerns lightly and I am mindful that development plan policies, notably SADMPP Policy SADM20 and Core Strategy Policy SP1 set out that development should not result in any adverse impact to public health or wellbeing, that it ensures a safe and healthy living environment for residents and does not create an unacceptable level of risk to the local community and wider environment. https://www.gov.uk/planning-inspectorate 6

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 38. These policies accord with the Framework’s objectives of ensuring that planning policies and decisions should promote public safety2. In this respect the Framework sets out that the layout and design of developments should be informed by the most up-to-date information available from the police and other agencies about the nature of potential threats and their implications. This includes appropriate and proportionate steps that can be taken to reduce vulnerability, increase resilience and ensure public safety and security. It also establishes that the safety of children and other vulnerable users in proximity to potential hazards should be considered in planning and assessing proposals for development. 39. The National Fire Chiefs Council (NFCC) sets out guidelines for facilities such as that proposed here. The proposal would be served by one vehicular access from Hilfield Lane and the internal access road would provide access to the south of the compound and along the eastern edge of the equipment which is denoted as ‘Emergency Access Only’ on the submitted drawings.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision I note the suggestion that the NFCC guidance requires that 2 access are provided, but it is not clear from this whether or not this means accesses onto the public highway or the site of the facility itself. What is clear though is that this requirement is sought to account for opposite wind conditions/direction. As both accesses would be coming from a southerly direction the proposed accesses would not comply with the guidance in this regard. It is noteworthy that the Hertfordshire Fire Protection Regulatory Services (HFPRS) found similarly in this regard. 40. In terms of the spacing of the units the NFCC guidance sets out that a minimum of 6 metres is provided between BESS units, unless suitable design features can be introduced to reduce that spacing. This distance is based on 2017 information set out within FM Global (2017) Property Loss Prevention Data Sheets: Electrical Energy Storage Systems, para. 2.3.2.2. Since this time the datasheet has been updated in July 2023 and January 2024.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The 2024 datasheet3 establishes that for containerized LIB-ESS comprised of lithium iron phosphate (LFP) cells, that an aisle separation of at least 1.5 metres on sides that contain access panels, doors, or deflagration vents is provided and where wall construction of the containers is unknown or has an ASTM E119 rating less than 1 hour, that aisle separation of at least 4 metres on sides that contain access panels, doors, or deflagration vents is provided. Where the containers have at least a 1-hour rating in accordance with ASTM E119, the datasheet indicates that an aisle separation of at least 2.4 metres is acceptable. 41. The distance between the proposed BESS units is shown to be 3 metres and the appellant has confirmed they would comply with ASTM E119 1-hour fire rating which would be a requirement of the selection of the BESS units. In this regard the containers would be designed such that their separation would not conflict with the most recent guidance. 42. The proposal includes water tanks at each end of the scheme which could be used in the event of a fire. Each has a capacity of 240,000 litres which exceeds the minimum water supply set out within the NFCC guidance.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Notwithstanding this the HFPRS have indicated that fire hydrants should be located across the development. Details of water supply could form part of the Fire Mitigation Report which could be secured by planning condition. 2 Framework paragraph 102 3 FM Global Property Loss Prevention Data Sheets 5-33 Interim Revision January 2024 https://www.gov.uk/planning-inspectorate 7

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Notwithstanding this the HFPRS have indicated that fire hydrants should be located across the development. Details of water supply could form part of the Fire Mitigation Report which could be secured by planning condition. 2 Framework paragraph 102 3 FM Global Property Loss Prevention Data Sheets 5-33 Interim Revision January 2024 https://www.gov.uk/planning-inspectorate 7

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 43. In the eventuality of a fire, it is clearly essential that it can be stopped as quickly as possible with no health or other impacts caused, including to Elstree Aerodrome and nearby land uses including residential and the National Animal Welfare Trust. However, it is also important to be mindful of the probability of a fire event occurring in the first place, with the measures that could be in place including fire detection and suppression system fitted to the containers, remote monitoring and control, automated shut down and gas detention measures to allow for preventative interaction, which could form the basis of a Detailed Battery Safety Management Plan. 44. The evidence before me indicates that fires at BESS facilities are rare. Whilst ‘numerous fires’ are referred to by interested parties; these have not been substantiated. In this respect I find the appellant’s evidence more convincing with reference made to approximately 117 operational BESS sites in the UK with a further 91 under construction4, and there being one reported BESS fire at Carnegie Road in Liverpool in September 2020 that required Fire and Rescue Service attendance.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision In this case the evidence indicates that the fire was monitored, and the resultant composition of the plume was determined as being negligible in toxic gas concentration. 45. The appellant has provided an Outline Battery Safety Management Plan5 (OBSMP) which defines a proposed safety strategy, requirements and processes necessary to meet safety objectives and to set a level of safety performance that the installation would be measured against. The OBSMP sets out the processes that should be followed to ensure safety controls and good practice including the BESS procurement, design safety, testing, maintenance, emergency plans and decommissioning. Whilst at this stage the details of the BESS technology is not known, the OBSMP indicates that if planning permission is granted a Detailed Battery Safety Management Pan will need to be produced which would build upon the OBSMP and reflect on the technology utilised, assessing the level of residual risk posed, include the emergency and contingency plans and recommendations for improvement . These matters, as well as the submission and implementation of an Emergency Response Plan can be controlled by planning condition, 46.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision I note the concerns that the safety measures are not determined at this point but given the changes to battery technology it would not be reasonable to require that a certain type of technology is utilised in the scheme. 47. Whilst the proposal at this stage does not accord with some of the NFCC guidelines, these guidelines are just that. They are not mandatory requirements. Other legislation outside of the planning system would however need to be adhered to including that relating to the design of the batteries and containers themselves, the construction of the development, during the operational stage and decommissioning. The Framework makes it clear that the focus of planning policies and decisions should be on whether proposed development is an acceptable use of land, rather than the control of processes or emissions…Planning decisions should assume that these regimes will operate effectively6. HFPRS has confirmed that it would work with the developer as the project develops to ensure that it complies with the statutory responsibilities that 4 As of October 2024 5 Abbott Risk Consulting Limited ARC-1275-005-R1 Issue 3 April 2025 6 Framework paragraph 201 https://www.gov.uk/planning-inspectorate 8

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 the Service enforce. The appellant has indicated that it is their intention to work with them. 48. The Council has indicated that the details submitted with the planning application would satisfy concerns with regard to fire safety and that the safety risks identified could be suitably managed by planning conditions. Elstree Aerodrome have also raised no objection subject to mitigation measures being put in place in the event of a fire incident. On the evidence before me, I reach the same conclusion. As such I am satisfied that appropriate and proportionate steps have, and can be taken to reduce vulnerability, increase resilience and ensure public safety and security, including to children and other vulnerable users. Accordingly, there would be no conflict with the safety objectives of SADMPP Policies SADM20 or SADM41 or Core Strategy Policy SP1. There would also be no conflict with the Framework in this regard. Highway Safety 49. The appeal site would be accessed from Hilfield Lane. From the Hartspring Lane direction, Hilfield Lane is covered by a 30mph speed restriction.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The road passes through Patchetts Green where parked vehicles and the width of the road make 2- way traffic difficult. Whilst my observations were a snapshot in time, I have no reason on the evidence before me to indicate that the conditions are not the norm. From the southerly direction of the appeal site, Hilfield Lane is covered by the national speed limit, the road is wider and traffic flows freely in both directions. 50. Along with a number of commercial and residential properties, Bhaktivedanta Manor and Hare Krishna Temple are also accessed off Hilfield Lane close to Patchetts Green. I am told that at times many visitors attend festivals and celebrations at this venue with reference being made to approximately 50,000 visitors (across 2 days) attending the Janmashtami event in the summer of each year. During such periods I am in no doubt that the area becomes very congested with vehicles. 51. The appellant initially indicated that delivery vehicles would access the site through Patchetts Green. Such a route would not be suitable given the local highway conditions and the size of the vehicles that would be delivering equipment to the site during the construction phase.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Consultation with the Highway Authority has however resulted in a revised route for construction vehicles being agreed. This would mean that construction and delivery vehicles would access Hilfield Lane from Sandy Lane, thereby avoiding Patchetts Green and the entrance to Bhaktivedanta Manor. No substantive evidence has been produced to indicate that the revised route could not accommodate construction traffic associated with the proposal for the duration of the works. The Construction Traffic Management Plan (CTMP) will need to be amended to reflect this revised routing, and a suitably worded planning condition could be imposed to secure this. 52. The CTMP also sets out traffic management principles for construction traffic, including signage being erected during the construction phase, advising drivers of the delivery route, providing contact details of the site manager for local residents in the event of issues with vehicles delivering to the site and employment of a Banksman. The site manager would also monitor the public highway and assess whether measures would need to be taken to maintain road cleanliness. When https://www.gov.uk/planning-inspectorate 9

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 festivals were being held at Bhaktivedanta Manor the CTMP sets out deliveries at the site would be adjusted accordingly. 53. The Highway Authority and National Highways have raised no concerns about the suitability of the access to the site and whilst inconvenience to other road users is likely to be caused at times during the construction phase, this would be for short periods each day during this period, and thereafter the level of traffic visiting the site would be likely to be imperceptible. On the evidence before I have no reason to find differently to these statutory consultees, mindful that national planning policy sets out that development should only be prevented or refused on highway grounds if there would be an unacceptable impact on highway safety, or the residual cumulative impacts on the road network, following mitigation, would be severe, taking into account all reasonable future scenarios.7 The proposal accords with the highway safety objectives of Policy SP1 of the Core Strategy and SADMPP Policy SADM40. 54. Any damage to the highway caused by vehicles frequenting the development would be difficult to quantify or demonstrate.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision In any event the repair of the highway is the responsibility of the Highway Authority. The appeal does not fall on this matter. Living Conditions 55. The proximity to the road and motorway network mean that traffic sound is audible in the locality as observed on my visit. Whilst this is likely to reduce during the nighttime, the roads and particularly the M1 would still be used by vehicles, such that noise from this highway would contribute to background noise levels. It is my judgement that the area is not tranquil. 56. There are a number of residential properties within proximity to the appeal site, with Hilfield Farm House being the closest residential sensitive receptor. On the opposite side of the motorway is the National Animal Welfare Trust with residential accommodation associated with this. 57. Noise associated with the construction phase would be likely to impact nearby occupiers and users of the public right of way across the site. However, such disturbance would be temporary and would likely occur when background noise levels were higher during the day, as opposed to during the nighttime.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Given the context of the site, it is my judgement that the effect of the construction period on living conditions of nearby occupiers would not be to the degree that would give rise to significant effects on health or the quality of life. 58. Once operational, the appellant has indicated that fans would be used to cool the batteries and inverter units. The fans would operate intermittently, on a demand- led basis. Given the background noise levels, the evidence suggests that occupiers of sensitive receptors would be unlikely to be impacted by the proposal, even during the nighttime. To secure this the Council’s Environmental Health Officer has recommended that operation noise levels be controlled. A separate condition could require the CTMP to include details of delivery hours during the construction period and hours of working during this phase to protect the living conditions of nearby occupiers. 7 Framework paragraph 116 https://www.gov.uk/planning-inspectorate 10

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 59. Users of the public right of way would similarly be unlikely to be adversely affected by noise from the proposal once operational, given the background noise levels in the locality. 60. The proposal would clearly alter the appearance of the site from an undeveloped open field to a quasi-industrial development. Between the nearest residential property and the appeal site is mature vegetation and taken with the intervening distance I am satisfied that the proposal would not be overbearing or harmful to outlook. 61. Given the above, I am satisfied that noise from the proposal would not give rise to significant adverse impacts to the living conditions of nearby occupiers. Moreover, given these findings and that Bhaktivedanta Manor is located further away from the appeal site, I am satisfied that there would be no adverse effects upon the enjoyment of this facility. Accordingly, there would be no conflict with Framework paragraph 198, the noise or amenity objectives of SADMPP Policies SADM20 or SADM30, or the prevention of unacceptable risks objectives to the local community as set out in Core Strategy Policy CS16, or the amenity objectives of Core Strategy Policy SP1. Pollution 62.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The appeal site is located close to Hilfield Brook which runs along the eastern boundary of the proposed BESS facility. It is located within Source Protection Zone 1 which is the most vulnerable groundwater area. To prevent contamination of this watercourse and other groundwater, measures could be incorporated into the surface water management strategy to prevent the uncontrolled release of water run-off in the event of a fire. This could include water containment areas which would allow stored water to be tested before release. Any contaminated waters could be removed from the site. 63. The Environment Agency considered that the proposal was acceptable subject to conditions including a remediation strategy and verification report, restriction on drainage systems for the infiltration of surface water to the ground as well as control of any contaminants. 64. I have had regard to the concerns raised about the effect of the proposal on air quality. As set out earlier in my decision, the evidence suggests that in the event of fire that toxic gas composition of any plume would be negligible, having regard to the information collected in the Carnegie Road event.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Accordingly, and in the absence of substantive evidence to demonstrate otherwise, whilst smoke from any fire on the site could affect air quality, this would likely to be for a short time period until any fire was extinguished. The Council’s Environmental Health Officer raised no objections in this regard, and having regard to the evidence before me I have no reason to find that the proposal would have an adverse effect on air quality in the locality. 65. In light of the foregoing, I find that the proposal could mitigate and reduce to a minimum any harmful effects of likely pollution on health, living conditions and the natural environment, including nearby water courses and bodies, in accordance with the Framework8. Furthermore, subject to suitably worded conditions the proposal would satisfy the requirements of Core Strategy Policy CS16 in respect of 8 Framework paragraph 198, and the objectives if https://www.gov.uk/planning-inspectorate 11

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 minimising pollutants, and Policy SADM20 of the SADMPP in respect of controlling contamination and pollution. Ecology 66. The planning application was accompanied by a Preliminary Ecological Appraisal to which the Council’s Ecologist raised no concern. A precautionary approach to construction is however recommended and this could be secured by planning condition. The proposal whilst developing much of the site with the proposal includes new tree planting, mixed scrub, grassland, removal of encroachment from the adjoining watercourse and hedgerows such that the mandatory Biodiversity Net Gain of more than 10% is achieved for habitat units, hedgerow units and watercourse units. 67. I note the suggestion that overwintering birds on Hilfield Park Reservoir would be affected by the proposal, but this has not been substantiated. Accordingly, I am unable to attach weight to this matter. Site Security 68. The BESS and substation would be secured by fencing. Whilst there would not be an on-site presence once operational, the site would be monitored remotely and CCTV cameras would be installed. No concerns have been raised by the Police in respect of this matter, or the Council.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision I have no reason to find differently in this regard. Insurability 69. It is cited that local homes would not be able to get house insurance if the development is granted planting permission and that the development itself would be uninsurable. This matter has not been substantiated and in any event is not a land use planning matter. It is not a determining factor in this appeal. Planning History 70. My attention has been drawn to a development of solar arrays and BESS facility9 which included part of the appeal site. This appeal was recovered by the Secretary of State who refused planning permission for the development. The Council has indicated in its Committee Report that this development covered a much larger area to that before me. It is clear that in determining that planning permission should be granted for the proposal before me that the planning history of the site was considered by the Council. Although I do not have a copy of the Secretary of State’s decision, I have determined this appeal on the evidence before me. Each planning application and appeal is determined on its own merits. Effect on Local Community 71.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision I am aware that applications such as this raise a lot of concerns to the local community, as is evidenced in this case from the number of representations submitted at both the application and appeal stage. I have addressed specific concerns relating to the main issues, to fire risk, pollution and living conditions. Reference is made to members of the local community having disabilities and long 9 Ref 21/0050/FULEI https://www.gov.uk/planning-inspectorate 12

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision I am aware that applications such as this raise a lot of concerns to the local community, as is evidenced in this case from the number of representations submitted at both the application and appeal stage. I have addressed specific concerns relating to the main issues, to fire risk, pollution and living conditions. Reference is made to members of the local community having disabilities and long 9 Ref 21/0050/FULEI https://www.gov.uk/planning-inspectorate 12

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 term health conditions, being elderly, and children being adversely affected by the proposal. 72. As such I have had due regard to the Public Sector Equality Duty set out under s149 of The Equality Act 2010, but am satisfied that minimal risk of fire and evacuation, noise, pollution and harm to living conditions, based on the evidence before me, would not cause discrimination in particular against persons with the protected characteristics of age and /or disability. 73. I also have significant sympathy as to the cited stress caused to local residents resulting from the application and appeal, however, I have to assess the proposal on the evidence before me. The Council raised no concerns on the basis of any impact to these residents, and I find that the safety measures and separation distances from the proposal to nearby properties is such that they are acceptable. It would be proportionate to allow the appeal on this basis, subject to the Planning Balance below. Other Considerations 74. The Council declared a climate emergency in 2019 and is committed to achieving net-zero carbon emissions no later than 2050.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The PPG10 identifies that Battery Energy Storage Systems enable the use of energy more flexibly and de-carbonise the energy system cost-effectively, deferring or avoiding the need for costly network upgrades and new generation capacity. 75. I note the suggestion from interested partes that the need for the proposal has not been demonstrated. The Framework at paragraph 168 sets out that applicants should not be required to demonstrate the overall need for renewable or low carbon energy. Moreover, the development plan does not require that need is demonstrated. Furthermore, well publicised national ambitions to achieve net zero identify and support the essential national need for BESS facilities, such as Clean Power 2030 and the Overarching National Policy Statement for Energy (EN-1) as a material consideration. The Framework paragraph 161 requires that the planning system should support the transition to net zero by 2050, minimise vulnerability and improve resilience and support renewable and low carbon energy and associated infrastructure.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision At paragraph 168 it requires that significant weight is given to the benefits associated with renewable and low carbon energy generation and the proposal’s contribution to a net zero future. 76. The proposal would deploy up to 170MW / 425mwH of electricity, the equivalent of enough to power 1 million homes for 1 hour/s. Storing renewable energy at times of optimal generation and feeding it back into the regional network when most needed, the proposal would contribute to fulfilling a crucial role as part of the clean energy mix, the pathway to a fully decarbonised system and the UK’s transition to Net Zero. 77. BESS schemes have specific locational requirements. These requirements strongly influence where such facilities will be viable and feasible in both commercial and operational terms. The proximity to the Elstree Substation was a determining factor for the appellant in the site selection and a grid connection has been secured meaning that the development could be storing and exporting 10 Paragraph: 032 Reference ID: 5-032-20230814 https://www.gov.uk/planning-inspectorate 13

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 energy by July 2030, based on planning permission being secured by the end of June 2026. 78. The appellant indicates that there are no other suitable feasible locations for the proposal. The Council does not dispute this, and I am required to assess the proposal before me on its merits. The consideration of alternatives for renewable energy scheme site selection, in any event, is not mandated by the PPG or Framework. Nonetheless, the lack of available alternative sites may provide support for very special circumstances. 79. I note the suggestion that Elstree Substation has bought nearby land to expand the facility, but there is little information before me to demonstrate that this land would accommodate a proposal similar to that proposed, or that the facility could not accommodate the proposed BESS, even if the alleged land was used for a similar facility. Accordingly on the evidence before me I am satisfied that the appeal site has been demonstrated to be the most suitable available site. 80.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The proposal would also be able to achieve a substantial on-site biodiversity net- gain through additional planting and enhancement, above the 10% statutory biodiversity net gain, particularly with regard to hedgerow units that would be provided. It would also secure economic benefits including employment opportunities. Planning and Heritage Balance 81. Paragraph 153 of the Framework makes clear that substantial weight should be given to any harm to the Green Belt, and that very special circumstances will not exist unless the potential harm to the Green Belt by reason of inappropriateness, and any other harm resulting from the proposal, is clearly outweighed by other considerations. 82. The proposal would reduce the openness of the Green Belt spatially and visually, and would be inappropriate development in the Green Belt, which is harmful by definition. It would also conflict with two of the purposes of including land within the Green Belt, notably c) and e). I therefore attach substantial weight to that harm as required by the Framework paragraph 153, albeit in this instance I find the harm in totality would be moderate, and not permanent. 83.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision I have found that harm would be caused to the setting of two designated heritage assets, which whilst at the lower end of the less than substantial scale is of considerable importance and which holds great weight in each case. 84. Harm to the character and appearance of the area would be caused by the proposal, albeit this would be localised given the scale of the development and the harm would reduce over time as landscaping matures. There would however remain some harm which would endure for the operational lifetime of the development of 30 years. This harm should be given moderate weight. 85. An absence of harm to the matters set out elsewhere in this decision is neutral in the overall planning balance, neither weighing against or in favour of the proposal. 86. Against these harms are the contribution that the proposal would make to achieving net-zero in accordance with local and national planning policies and the presumption in favour of sustainable development. These are public benefits which carry significant weight in favour of the proposal. Paragraph 160 of the Framework https://www.gov.uk/planning-inspectorate 14

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 identifies that very special circumstances for renewable energy projects may include the wider environmental benefits associated with increased production of energy from renewable sources. In this regard the proposal would support energy security and reduce vulnerability, storing energy at periods of low demand and exporting it during periods of higher demand. The ability to provide flexible input into the grid when needed is a major benefit of the proposal. 87. In totality, and as directed by the Framework paragraph 168 I give significant weight to the proposal’s contribution as a renewable energy project to local and national net zero ambitions and to mitigating climate change. I give great weight to the absence of other local more preferential sites, moderate weight to improved biodiversity, and limited weight to the economic benefits given that these would largely be during the construction phase of the development. 88. Overall, I am persuaded that the wider public benefits of the scheme are of sufficient magnitude to outweigh the harm that would be caused to the significance of each of the nearby designated heritage assets and the considerable importance that this carries.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Accordingly, the proposal complies with the historic environment objectives of the Framework and Policy SADM29 of the SADMPP which requires planning applications to be considered in accordance with the Framework. It also accords with the expectations of section 66(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990. 89. I find that the other considerations advanced are cumulatively sufficient such that they amount to very special circumstances which clearly outweigh the Green Belt harm and any other harm and thus justify the proposal in this case. Conditions 90. I have considered the suggested conditions in light of the advice in paragraph 57 of the Framework and have amended some of them for conciseness and precision. Some of the conditions are pre-commencement conditions and the appellant’s agreement has been received in respect of these. The parties views were also sought in respect of a condition not suggested by the Council (condition 33), which I have subsequently amended for the reasons set out in paragraph 95. 91. In addition to the standard time limit condition (condition 1), it is necessary to define the permission and reference the plans upon which the decision is made (condition 2).

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision To limit the period of the planning permission condition 3 is reasonable and necessary, as is condition 4 which requires decommissioning and a scheme of restoration to be undertaken. 92. In the interests of the character and appearance of the area, levels on the site should be controlled (condition 5), as should details of materials to be used in the development (condition 6), storage of topsoil (condition 21) and measures to protect trees (conditions 7 and 8). Landscaping also needs to be controlled (conditions 9 and 10) for the same reasons. Conditions 5, 7 and 8 need to be pre- commencement conditions because they include works that need to be controlled prior to construction taking place. 93. To protect the environment, including the water environment from any pollution, conditions 11 to 17 are reasonable and necessary. To ensure that the site is suitably drained conditions controlling details is necessary (conditions 29-32). In the interests of highway safety conditions 18 to 20 are necessary, as is condition https://www.gov.uk/planning-inspectorate 15

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision Appeal Decision APP/N1920/W/25/3368845 28. Conditions 11, 14 and 29 and 32 need to be pre-commencement conditions because they include works that need to be controlled prior to the construction phase. 94. To protect the historic environment, notably archaeology, condition 23 is necessary. In the interests of ecology and biodiversity, conditions 24, 25 and 26 are reasonable and necessary. Conditions 23, 25 and 26 need to be pre- commencement conditions because they include works that need to be controlled prior to construction taking place. 95. To protect the living conditions of nearby occupiers a condition controlling noise from plant is necessary (condition 22) as well as controlling construction delivery vehicles (condition 19). The suggested condition in this regard has been amended cross referring the CTMP submitted at application stage to ensure that other matters set out in this document are complied with. Although not suggested by the Council, a condition controlling working hours during construction and controlling delivery times is reasonable and necessary to protect the living conditions of nearby occupiers (Condition 33).

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The details relating to these matters in the April 2025 CTMP are not sufficiently precise or enforceable in this regard. 96. In the interests of public safety and pollution control a condition requiring details of a Fire Mitigation, Verification and Compliance Report and updated Battery Safety Management Plan and Emergency Response Plan (condition 27) is necessary. This needs to be a pre-commencement condition because it relates to works including the design of the batteries and containers. I note the Council’s suggestion that an informative/directive is attached requiring consultation with the Hertfordshire Fire and Rescue Services when preparing these documents. As set out earlier, the appellant has indicated that they will work with HFRS, and in any event the Service is likely to be involved in discharging the condition in respect of these matters. I am therefore satisfied that the Fire and Rescue Service will have appropriate input in ensuring that the development is safe. 97.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — Appeal Decision The effect of paragraph 13 of Schedule 7A of the Town and Country Planning Act 1990 is that planning permission granted for development of land in England is deemed to have been granted subject to the Biodiversity Gain Condition which states that development may not begin unless: (a) a biodiversity gain plan (BGP) has been submitted to the planning authority, and (b) the planning authority has approved the plan. Based on the information available, this permission is considered to be one which will require the approval of a BGP before development is begun because none of the statutory exemptions or transitional arrangements are considered to apply. Because the Biodiversity Gain Condition has a separate statutory basis as a planning condition, it is not necessary for me to include it within the schedule of conditions on this decision. Conclusion 98. For the reasons given above, and subject to the imposition of conditions dealing with the above matters, I conclude that the appeal should be allowed.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby INSPECTOR https://www.gov.uk/planning-inspectorate 16

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby INSPECTOR https://www.gov.uk/planning-inspectorate 16

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 Schedule Conditions 1. The development hereby permitted shall be begun before the expiration of 3 years from the date of this permission. 2. The development hereby permitted shall be carried out in complete accordance with the following approved plans: - • PSP002-SP-01_rev09 • PSP002-PL-01_rev16 • PSP002-PL-02_rev15 • PSP002-PL-03_rev12 • PSP002-SD-04_rev03 • PSP002-SD-05_rev03 • PSP002-SD-06_rev03 • PSP002-SD-07_rev05 • PSP002-SD-08_rev03 • PSP002-SD-09_rev03 • PSP002-SD-10_rev02 • PSP002-SD-11_rev02 3. The development hereby approved is for a period of no more than 30 years from the date when electricity is first exported from the Battery Energy Storage Scheme to the electricity network (the First Export Date) Written confirmation of the First Export Date shall be given to the local planning authority within 14 days of the First Export Date. 4. Decommissioning of the Battery Energy Storage System, comprising discontinuance and removal of all buildings, works, uses of land and other development hereby permitted and the restoration of the land to its former condition shall take place within 12 months of the expiry of this permission.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby At least 6 months before the planning permission is due to expire, a Decommissioning Method Statement (to include a timetable for implementation and a scheme to restore the land to its former condition) shall be submitted to and approved in writing by the Local Planning Authority. The site shall be decommissioned and restored in accordance with the approved Statement. 5. No development shall commence until full details of the finished levels, above ordnance datum, of the proposed buildings and infrastructure in relation to existing ground levels have been submitted to and approved in writing by the Local Planning Authority. The development shall only be carried out in accordance with the approved details. 6. Prior to above ground works, details of the materials, colour and finish of any structures and containers, poles, fencing and gates have been submitted to and approved in writing by the Local Planning Authority. The https://www.gov.uk/planning-inspectorate 17

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 development shall be implemented in accordance with the approved details. 7. No development shall take place until the tree protection measures as set out in the Arboricultural Report (Treework Environmental Practice, 250117-2.1-HLAW-AIA-JBW Revision 2.1 dated 30/01/2025) have been erected in accordance with BS 5837: 2012. The measures shall be retained throughout the construction phase until completion of the development. 8. No development shall take place until an Arboricultural Method Statement detailing ground protection for retained trees and any root pruning methodology works to be undertaken, has been submitted to and approved in writing by the Local Planning Authority. The development shall thereafter be carried out in accordance with the approved details. 9. Prior to above ground works, a landscape planting plan, together with a timetable for implementation shall be submitted to and approved in writing by the Local Planning Authority. The approved landscaping plan shall be implemented in accordance with the approved details.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Any trees or shrubs planted or retained in accordance with this condition which are removed, uprooted, destroyed, die or become severely damaged or become seriously diseased within 5 years of planting shall be replaced within the next planting season by trees or shrubs of similar size and species to those originally required to be planted. 10. The development hereby approved shall not be brought into first use until a schedule of landscape maintenance for a minimum period of 10 years has been submitted to and approved in writing by the Local Planning Authority. The schedule shall include details of the arrangements for its implementation. The schedule shall be implemented in accordance with the approved schedule. 11. No development shall commence until a remediation strategy that includes the following components to deal with the risks associated with contamination of the site has been submitted to and approved, in writing by the local planning authority: 1. A site investigation scheme, based on the previously submitted Phase 1 Assessment of Land Quality – Ground Investigation Ltd Report No.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby P1977.1.1 (Rev 1) dated 16th January 2025 to provide information for a detailed assessment of the risk to all receptors that may be affected, including those off site. 2. The results of the site investigation and the detailed risk assessment referred to in (1) and, based on these, an options appraisal and remediation strategy giving full details of the remediation measures required and how they are to be undertaken. 3. A verification plan providing details of the data that will be collected in order to demonstrate that the works set out in the remediation strategy in https://www.gov.uk/planning-inspectorate 18

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby P1977.1.1 (Rev 1) dated 16th January 2025 to provide information for a detailed assessment of the risk to all receptors that may be affected, including those off site. 2. The results of the site investigation and the detailed risk assessment referred to in (1) and, based on these, an options appraisal and remediation strategy giving full details of the remediation measures required and how they are to be undertaken. 3. A verification plan providing details of the data that will be collected in order to demonstrate that the works set out in the remediation strategy in https://www.gov.uk/planning-inspectorate 18

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 (2) are complete and identifying any requirements for longer-term monitoring of pollutant linkages, maintenance and arrangements for contingency action. 12. The development shall not be brought into use until a verification report, demonstrating completion of works set out in the approved remediation strategy and the effectiveness of the remediation, has been submitted to and approved, in writing, by the Local Planning Authority. The report shall include results of sampling and monitoring carried out in accordance with the approved verification plan to demonstrate that the site remediation criteria have been met. 13. No drainage systems for the infiltration of surface water to the ground are permitted other than with the written consent of the Local Planning Authority. Any proposals for such systems must be supported by an assessment of the risks to controlled waters. The development shall be carried out in accordance with the approved details. 14.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby No development should take place until a long-term monitoring and maintenance plan in respect of contamination including a timetable of monitoring and submission of reports to the Local Planning Authority, shall be submitted to and approved in writing by the Local Planning Authority. Reports as specified in the approved plan, including details of any necessary contingency action arising from the monitoring, shall be submitted to and approved in writing by the Local Planning Authority. Any necessary contingency measures shall be carried out in accordance with the details in the approved reports. On completion of the monitoring specified in the plan a final report demonstrating that all long-term remediation works have been carried out and confirming that remedial targets have been achieved shall be submitted to and approved in writing by the Local Planning Authority. 15.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby If, during development, contamination not previously identified is found to be present at the site then no further development shall be carried out until the developer has submitted a remediation strategy to the Local Planning Authority detailing how this unsuspected contamination shall be dealt with and obtained written approval from the local planning authority. The remediation strategy shall be implemented as approved. 16. A scheme for managing any borehole installed for the investigation of soils, groundwater or geotechnical purposes shall be submitted to and approved in writing by the Local Planning Authority. The scheme shall provide details of how redundant boreholes are to be decommissioned and how any boreholes that need to be retained, post-development, for monitoring purposes will be secured, protected and inspected. The scheme as approved shall be implemented prior to the first use of any part of the development. https://www.gov.uk/planning-inspectorate 19

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 17. Piling, deep foundations and other intrusive groundworks using penetrative measures shall not be carried out other than with the written consent of the Local Planning Authority. The development shall be carried out in accordance with the approved details. 18. The vehicular access shall be constructed in accordance with the approved plans prior to other development associated with the Battery Energy Storage System installation and shall be thereafter retained in accordance with details/specifications to be submitted to and approved in writing by the Local Planning Authority prior to these works being commenced. Such works shall include surfacing of the access route for a minimum of 20 metres measured from the carriageway edge. 19. No development shall commence until a revised Construction Traffic Management Plan based on the April 2025 Construction Management Plan, setting out revised routing options to limit impacts upon Patchetts Green, has been submitted to and approved in writing by the Local Planning Authority. The development shall thereafter be carried out in accordance with the approved details. 20.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby The development hereby permitted shall not be brought into use unless and until the access, parking and turning areas shown on the approved plans have been provided and made available for those purposes. The approved facilities shall thereafter be retained for the duration of the planning permission. 21. No development shall take place until details of the method of storage of topsoil within the site, or alternative measures to remove it from the site, has been submitted to and approved in writing by the Local Planning Authority. The development shall thereafter be carried out in accordance with the approved details. 22. Noise from plant and equipment associated with the development shall be 10dB (LAeq) below the background noise level (LA90) at the nearest residential properties (5dB below the background noise level if evidence is provided which shows that no tonality or other character is present). 23. A. No development shall take place until an Archaeological Written Scheme of Investigation has been submitted to and approved by the Local Planning Authority in writing. The scheme shall include an assessment of archaeological significance and research questions; and: 1.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby The programme and methodology of site investigation and recording 2. The programme and methodology of site investigation and recording as required by the evaluation 3. The programme for post investigation assessment 4. Provision to be made for analysis of the site investigation and recording 5. Provision to be made for publication and dissemination of the analysis and records of the site investigation 6. Provision to be made for archive deposition of the analysis and records of the site investigation https://www.gov.uk/planning-inspectorate 20

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby The programme and methodology of site investigation and recording 2. The programme and methodology of site investigation and recording as required by the evaluation 3. The programme for post investigation assessment 4. Provision to be made for analysis of the site investigation and recording 5. Provision to be made for publication and dissemination of the analysis and records of the site investigation 6. Provision to be made for archive deposition of the analysis and records of the site investigation https://www.gov.uk/planning-inspectorate 20

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 7. Nomination of a competent person or persons/organisation to undertake the works set out within the Archaeological Written Scheme of Investigation. B. The development shall be undertaken in accordance with the programme of archaeological works set out in the Written Scheme of Investigation approved under condition A. C. The development shall not be used until the site investigation and post investigation assessment has been completed in accordance with the programme set out in the Written Scheme of Investigation approved under condition 23A and the provision made for analysis and publication where appropriate. 24. The development shall be undertaken in accordance with the mitigation measures and recommendations as set out within the Preliminary Ecological Appraisal (Western Ecology, January 2025, Report reference WOR-5039). 25. No development shall take place (including demolition, ground works and vegetation clearance) until a Construction Environmental Management Plan (CEMP) for biodiversity, has been submitted to and approved in writing by the local planning authority. The CEMP shall include, but not necessarily be limited to, the following: i.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Risk assessment of potentially damaging construction activities; ii. Identification of ‘biodiversity protection zones’; iii. Practical measures (both physical measures and sensitive working practices) to avoid or reduce impacts during construction (may be provided as a set of method statements); iv. The location and timing of sensitive works to avoid harm to biodiversity features (e.g. daylight working hours only starting one hour after sunrise and ceasing one hour before sunset); v. Use of protective fences, exclusion barriers and warning signs, including advanced installation and maintenance during the construction period; vi. A non-native invasive species protocol (e.g. for Japanese knotweed); vii. The times during construction when specialists ecologists need to be present on site to oversee works; viii. Responsible persons and lines of communication; ix. The role and responsibilities on site of an Ecological Clerk of Works (ECoW) or similarly competent person(s); x. Ongoing monitoring, including compliance checks by a competent person(s) during construction and immediately post-completion of construction works; and xi.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby The submission of a verification report by the EcOW or similarly competent person(s) to the local planning authority at the end of the construction period. The development shall be undertaken in accordance with the approved details. https://www.gov.uk/planning-inspectorate 21

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby The submission of a verification report by the EcOW or similarly competent person(s) to the local planning authority at the end of the construction period. The development shall be undertaken in accordance with the approved details. https://www.gov.uk/planning-inspectorate 21

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 26. Prior to the commencement of the development hereby approved, a Habitat Management and Monitoring Plan, in line with an approved Biodiversity Gain Plan, must be submitted to the Local Planning Authority and approved in writing. The content of the Habitat Management and Monitoring Plan should include the following: A management and monitoring plan for onsite significant enhancements, including 30-year objectives, management responsibilities, maintenance schedules and a methodology to ensure the submission of monitoring reports in years 2, 5, 10, 15, 20, 25 and 30 from commencement of development, demonstrating how the Biodiversity Net Gain is progressing towards achieving its objectives, evidence of arrangements and any rectifying measures needed. The development shall be undertaken in accordance with the approved details. 27. No development shall commence until a detailed Fire Mitigation, Verification and Compliance Report and updated Battery Safety Management Plan has been submitted to and approved in writing by the local planning authority.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby The submitted strategy shall: • Confirm the battery technology intended to be utilised and identify how any specific risk associated with this technology will be intended to be mitigated against. • Confirm the protection measures which will be implemented within the design of battery cabinets to mitigate against the risk of contaminant release to sensitive environmental receptors, notably underlying ground. • Provide details of water supply/hydrants to be utilised in the event of a fire. • Detail the specification fire detection system intended and its operation, including the specific operating parameters of the detectors and how they will be monitored. • Detail the specification and duration of fire protection provided by the partitions between battery cabinets and by the enclosure of the battery unit, offering justification as to why this is appropriate relative to risk posed. • Detail the intended fire suppression system specification and its operation, including detail of the suppression technology intended and product to be utilised for the purpose of suppression. • Detail the design methodology for the deflagration vents and/or explosion prevention measures.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby • Provision of an Emergency Response Plan (to include details of the emergency, environmental and recovery plan which would be enacted in the case of emergency event occurring, and details demonstrating how it will be ensured that potential release of adverse contamination to the surrounding environment will be prevented and mitigated against effectively, considerate to emergency water supply and discharge requirements). https://www.gov.uk/planning-inspectorate 22

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby • Provision of an Emergency Response Plan (to include details of the emergency, environmental and recovery plan which would be enacted in the case of emergency event occurring, and details demonstrating how it will be ensured that potential release of adverse contamination to the surrounding environment will be prevented and mitigated against effectively, considerate to emergency water supply and discharge requirements). https://www.gov.uk/planning-inspectorate 22

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 The development shall be undertaken in accordance with the approved details. 28. A 3 metre-wide buffer shall be maintained upon the site between the boundary of the M1 motorway land. No planting of trees or shrubs shall be undertaken within 3 metres of this boundary. 29. Prior to the commencement of development, construction drawings of the surface water drainage network, associated sustainable drainage components and flow control mechanisms and a construction method statement shall be submitted and agreed in writing by the Local Planning Authority. The scheme shall then be constructed as per the approved drawings, method statement and Flood Risk Assessment (Amber Planning, July 2025), remaining in perpetuity for the lifetime of the development. 30. No use of the development shall occur until details of the maintenance and management of the sustainable drainage scheme have been submitted to and approved in writing by the Local Planning Authority. The drainage scheme shall be managed and maintained in accordance with the approved details for its lifetime.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby The Local Planning Authority shall be granted access to inspect the sustainable drainage scheme for the lifetime of the development. The details of the scheme to be submitted for approval shall include: i. a timetable for its implementation. ii. details of SuDS feature and connecting drainage structures and maintenance requirement for each aspect including a drawing showing where they are located. iii. a management and maintenance plan for the lifetime of the development which shall include the arrangements for adoption by any public body or statutory undertaker, or any other arrangements to secure the operation of the sustainable drainage scheme throughout its lifetime. This will include the name and contact details of any appointed management company. 31. Upon completion of the surface water drainage system, including any SuDS features, and prior to the first use of the development; a survey and verification report from an independent surveyor shall be submitted to and approved in writing by the Local Planning Authority. The survey and report shall demonstrate that the surface water drainage system has been constructed in accordance with the approved details.

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Where necessary, details of corrective works to be carried out along with a timetable for their completion, shall be included for approval in writing by the Local Planning Authority. Any corrective works required shall be carried out in accordance with the approved timetable and subsequently re-surveyed with the findings submitted to and approved in writing by the Local Planning Authority. 32. Development shall not commence until details and a method statement for interim and temporary drainage measures during the construction phase has been submitted to and approved in writing by the Local https://www.gov.uk/planning-inspectorate 23

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Where necessary, details of corrective works to be carried out along with a timetable for their completion, shall be included for approval in writing by the Local Planning Authority. Any corrective works required shall be carried out in accordance with the approved timetable and subsequently re-surveyed with the findings submitted to and approved in writing by the Local Planning Authority. 32. Development shall not commence until details and a method statement for interim and temporary drainage measures during the construction phase has been submitted to and approved in writing by the Local https://www.gov.uk/planning-inspectorate 23

Land West Of,Hilfield Lane, Aldenham, Hertfordshire, WD25 8DD — Hertsmere Borough Council — R C Kirby Appeal Decision APP/N1920/W/25/3368845 Planning Authority. This information shall provide full details of who will be responsible for maintaining such temporary systems and demonstrate how the site will be drained to ensure there is no increase in the off-site flows, nor any pollution, debris and sediment to any receiving watercourse or sewer system. The site works and construction phase shall thereafter be carried out in accordance with approved method statement. 33. Prior to the commencement of development details of working hours and deliveries during construction shall be submitted to and approved in writing by the local planning authority. The approved hours shall be adhered to throughout the construction period. End of Schedule https://www.gov.uk/planning-inspectorate 24