Sustainability Draft Supplementary Planning Document

(5) 3 Technical and General Guidance

Figure 12 - Passive solar heating

• Using energy-efficient materials and appliances which can help reduce the amount of energy needed to heat, cool, and light a building.
• Designing for passive solar heating and cooling through spatial planning and orientation which can help reduce the need for active heating and cooling systems.
• Using renewable energy sources which can help reduce reliance on fossil fuels.
• Water conservation which can be achieved through features such as rainwater harvesting and greywater recycling.
• Indoor air quality which can be improved through features such as ventilation and filtration systems.

(1) Passive Design and Energy Efficiency

• Sustainable materials that are recycled, recyclable /adaptable for future reuse, or sustainably sourced.

Site Layout and Design

Passive design uses layout, fabric, and form to reduce or eliminate mechanical cooling, heating, ventilation and lighting demand. All new developments should consider optimising efficiency using passive design systems during the design phase. Whilst 'active' systems such as solar panels and other renewable energy technologies play a part in reducing carbon emissions, 'passive' measures are usually less expensive

Where possible, taller buildings should be placed towards the northern section of a site to reduce the effect of shadowing across the site – but this should not be done in a regimented or artificial manner and should be applied where it will provide overall benefits. Similarly, parking facilities such as garages can usefully be placed towards the north of buildings for similar reasons, provided they don't harm the amenities of neighbouring sites and land uses.

The spacing of buildings on sites should also be considered to strike a balance between gaining an optimum level of natural heat and light, including also considering efficiencies of reduced loss of heat through compact development, whilst avoiding contributing to the Urban Heat Island Effect in locations where this might be an issue.

Where the topography of a site allows, the best use should be made of opportunities for building into slopes or into the ground, where this can offer thermal buffering and the exploitation of ground heat. This can also offer protection to buildings from harsher weather conditions, allowing for adaptation to climate change. However, as sites are configured to allow for optimum benefit from the sun's power and for adapting to climate change, the siting of solar photovoltaic panels and arrays on buildings in the vicinity of the site also need to be taken into account (in the same way as neighbouring amenities) and this may therefore inhibit the preferred choice of design/layout for the new development. Nonetheless, passive gains for a new development at the expense of the ability of established sites to run sustainably will not be acceptable, and this will need to be factored into the calculations for designs.

Building Orientation

On all development sites, but particularly larger sites, developers will be expected to demonstrate that consideration has been made as to how buildings are arranged for maximum natural energy and cooling, as well as associated health benefits.

In residential developments where there is an east-west axis, the orientation of dwellings will maximise solar gain on the south elevation. With such a site orientation, habitable rooms are best located on the south elevation with kitchens and bathrooms located on the north side. Such orientation will maximise heating from the sun in the winter, but this would need to be balanced with the risks of overheating in the summer when shading may be required either from trees or other forms of planting, or from louvres.

Figure 14 - Maximising passive heating on a north-south oriented site

On sites with a north-south axis, the orientation of the buildings will maximise heating in the morning and evening when it is most needed. This layout also helps to reduce overshadowing between buildings due to the angle of the sun's path. Habitable rooms, including living rooms and bedrooms, would best be located on the west elevation to maximise the heating and lighting effects from solar gain later in the day.

Thermal Mass

The choice of building materials will have an important bearing on how temperatures are moderated in a building. High thermal mass materials absorb heat during the day and release it during the night, helping to regulate the temperature within the building. Materials that have a high thermal mass include brick and block with plaster finishes, whereas timber framed buildings have a lower thermal mass (though this can be weighed against the benefits of lighter insulated materials and modern constructions methods in reduced embodiment of carbon, and it is for the developers to determine the merits of each for energy efficiency and reduced carbon emissions). Choice of materials will depend upon the scheme, but the embodied carbon will need to be considered.

Thermal mass is a design feature, not a method of insulation. It can reduce the cooling load of a building in summer and the heating load in winter, therefore reducing carbon emissions.

In the summer, thermal mass helps prevent buildings from overheating by absorbing heat from the sun and from the building's occupiers, rather than heating the building's interior. In an office building, for example, the peak internal temperature is usually in the afternoon, particularly in the summer when the building is occupied, and heat is being generated from the occupants, computers, and lighting. At night when the building is vacated, the heat diminishes, external temperatures fall, and heat is released from the thermal mass of the building. This absorption of heat by the building's fabric and its release at night will help reduce the need for air conditioning, reducing energy consumption and carbon emissions.

In the winter, as in the summer, during the day the building absorbs heat but at night the thermal mass prevents the building from getting cold. This reduces the amount of energy needed to heat the building the following day to bring the building up to an appropriate temperature, thereby minimising carbon emissions and saving energy.

Wind Driven Ventilation

Figure 15 - Wind driven ventilation


Figure 16 - Passive stack ventilation

Wind driven ventilation utilises pressure differences that occur when air flows over a building. The appropriate placement of ventilation openings will draw air through the building openings thereby providing natural ventilation.

Passive Stack Ventilation

Passive stack ventilation is driven by differences in internal and external temperatures and is achieved by placing ventilation openings at different heights. It is based on the 'stack' effect whereby warm air naturally rises and is replaced with cooler air entering at a lower level. In order to make a passive stack approach work, vents should be placed in rooms which require fresh air to replace moisture-laden or odorous air. Ducts draw the warm air up and out of the building, and ventilation openings (such as trickle vents in winter or open windows in summer) draw in fresh air from 'dry' rooms.

Insulation

Around half of the heat lost in a typical home is through the walls and roof spaces. Increasing insulation levels significantly beyond current building regulations requirements is the cheapest and most effective method of reducing CO₂ emissions, and energy needs. It requires minimal maintenance and should last the life of the building. It reduces heat losses and gains through the fabric of the building and minimises the costs of heating and cooling systems. Buildings are kept warmer in the winter and cooler in the summer. Insulation measures include:

• Loft insulation;
• Tanks and pipe insulation;
• Cavity wall insulation;
• Solid wall insulation;
• Floor insulation;
• Draught proofing; and
• Double and triple glazing.

However, as with all measures, this should be weighed against other design considerations. In particular, the use of solid wall insulation should be avoided where this can affect the appearance of traditional brickwork and tile-hangings.

Thermal insulation is measured using 'U values'. The U value is a measure of how readily heat will flow through the structure. The lower the U value, the less heat is transferred through the fabric of the building. An increased thickness of insulating materials will increase energy efficiency and reduce the U value. More information on home insulation can be found at the Energy Saving Trust.

Airtightness

Significant reductions in heat loss can also be achieved by reducing air infiltration through the building fabric and making the building air tight. Air leakage occurs in several places, particularly draughty windows and doors and joints between ceilings and walls. This can be reduced through careful construction practices, to ensure gaps in the fabric are minimised (Figure 17).

Figure 17 - Energy loss through a building

Measures include:

• Ensuring gaps around window and door frames are properly sealed;
• Draught-stripping external windows and doors (other than bathrooms unless other ventilation measures are included);
• Using controlled ventilation in kitchens (with draught-stripping);
• Sealing holes around services passing through the external walls including water pipes, gas pipes, boiler flues and electrical cables;
• Choosing airtight light fittings, or sealing gaps around light fittings and ceiling pull cords;
• Sealing the joint between the ceiling and the external wall; and
• Sealing the joint between the dry-lining and the skirting board.

Solar Gain and Overheating

Whilst reducing energy needs – and associated carbon emissions - through retaining as much heat as possible is important, this does nonetheless need to be balanced against the issue of overheating, which in the built environment is also a growing issue; twenty per cent of homes in England already experience overheating in the summer months, and with temperatures rising, this should be addressed in advance through appropriate measures. The UK's Climate Change Risk Assessment identifies high temperatures and the threat this poses to health, wellbeing and productivity as one of the six priority risk areas for action.

Properties at a higher risk of overheating include:

• Flats with south and west facing facades due to excess solar gain;
• Top floor flats with heat gain through the walls and roof;
• Single aspect flats (no cross-ventilation allowance);
• Properties with district heating or similar, where excess internal gains arise from poorly placed or poorly insulated pipe work;
• Buildings with heat recovery systems that have no summer bypass mode; and
• Buildings with poorly designed thermal mass coupled with insufficient secure ventilation to enable night purge of heat to take place.

Air conditioning is commonly used to address overheating, but this is energy intensive with high associated levels of carbon emissions. It also places a cost on future occupiers in terms of both energy bills and maintenance costs. Therefore, the Council's preferred approach to overheating is that the design of developments should follow a 'cooling hierarchy', subject to taking a balanced approach to this and other design considerations.

The cooling hierarchy is as follows:

• Passive design - Minimise internal heat generation through energy efficient design and reduction of the amount of heat entering the building in the summer and shoulder months through consideration of orientation, overhangs and shading, albedo, fenestration, insulation, and green roofs. Where heat is to be managed within the building through external mass and high ceilings, provision must be made for secure night-time ventilation to enable night purge to take place.
• Passive/natural cooling - Use of outside air, where possible pre-cooled by soft landscaping, a green roof or by passing it underground to ventilate and cool a building without the use of a powered system. This includes maximising cross ventilation, passive stack and wind driven ventilation and enabling night purge ventilation. Single aspect dwellings should be avoided for all schemes as effective ventilation can be difficult or impossible to achieve. Windows and/or ventilation panels should be designed to allow effective and secure ventilation.
• Mixed mode cooling - Use of local mechanical ventilation/cooling to supplement the above measures (in order of preference):
  1. Low energy mechanical cooling (e.g. fan powered ventilation with/without evaporative cooling or ground coupled cooling).
  2. Air conditioning – last resort as these systems are energy intensive.

Full building mechanical ventilation/cooling system - Use only the lowest carbon/energy options once all other elements of the cooling hierarchy have been utilised.

Glare

In addition to solar gain, it is also important to consider the potential effects of glare at the design stage. As with overheating this can be addressed through effective layout and design and the inclusion of effective solutions such as low eaves-height blinds; brise soleil screening; external shuttering; lighter colour palettes; and the use of photochromic/ thermochromic glass, to be selected with consideration of other design matters, such as local distinctiveness and character.

(3) On-Site Low Carbon and Renewable Energy

With the transition away from traditional gas boilers major schemes should consider implementation of on-site low carbon and renewable energy generation systems.

Applicant should therefore submit a sustainability statement outlining details of on-site low carbon and renewable energy generation systems.

Solar Photovoltaic Panels

Solar photovoltaic technology converts the energy from the sun into electricity. The greater the intensity of light, the greater the generation of electricity, meaning that solar panels are often located on south facing roofs^[20] or amounted on flat roofs as an array. While solar panels can be visually intrusive, careful placement can avoid or limit impact. It is also possible to buy solar panels which mimic the design of roofing tiles.

By connecting a PV system to the National Grid, the surplus daytime electricity that has been generated can be sold to the local utility provider, who would supply electricity outside of daylight hours. At least 10m2 of PV is needed.

PV products can be used on all types of roofs - even flat ones, though the optimal roof angle is 30^o to 40^o in the UK.

A north facing PV roof will generate 60% of the amount of electricity that a south facing roof would.

Solar panel installations (both PV and thermal) can be sited anywhere – including free-standing in the garden or on the roof of a property, garage or outbuilding – as long as it does not regularly get overshadowed.

Recent technological advancements in this field have led to the development of solar tiles and transparent solar PV. These are more discreet options than traditional solar PV, which provide more opportunities to improve a building's energy efficiency. These technologies are particularly relevant for listed/historic buildings, which may experience more difficulty when looking to install traditional solar PV.

PV tiles can be used as a roof covering and are maintenance free. The PV tiled roof of a house could prevent 34 tonnes of greenhouse gas emissions during its lifetime.

PV tiles cost at least £500 per m2, but they do act as a roof covering, save money on electricity and surplus energy can be sold.

Solar panels do not generate any noise, have no moving parts and in general have a long life with low maintenance making them an ideal approach in most urban and rural locations. The economic viability is however only realised over a long period.

Solar Thermal Heating

Solar thermal systems use sunlight to heat a fluid (depending on the application, it can be water or a water/glycerol mixture).

Two main types of solar hot water collector are available: Flat plate and evacuated tube. In both systems water or an antifreeze mixture travels through the collector picking up heat from the sun and then passing through a copper coil in the hot water tank. Solar panels work best when located in direct sunlight on a sloping roof. Care needs to be taken to make sure that the panels are not overshadowed. A well designed system can provide between 50 and 70% of a household's annual hot water with the peak period being between May and September. In the winter the water can be fully heated to the required temperature using a conventional boiler.

The necessary equipment does not generate noise and requires little maintenance but does require an area of south facing roof where it is possible to access the existing water heating system. Solar water heating systems can often be designed discretely into new buildings.

Solar Photovoltaic – Thermal

Solar thermal units heat water which is integrated to a building's hot water system using a heat exchanger or colocation. These systems operate by harnessing sun light to heat a fluid in a solar roof panel which circulates through the system and heats the water tank. This preheats the water, reducing the amount of other energy needed from elsewhere to heat the water.

Solar Water Heating systems are most effective in large family homes and large building complexes where large quantities of hot water are needed. Systems can supply up to 50% of hot water use.

Relevant legislation

Whilst the installation of solar panels on residential buildings may be 'permitted development' in certain circumstances, wildlife legislation still applies as follows:

• All species of bat and their roosts are protected under both the Wildlife and Countryside Act 1981 (as amended) and the Conservation of Habitats and Species Regulations 2010 (as amended).
   
• All wild birds are protected by the Wildlife and Countryside Act 1981 (as amended), which protects the birds themselves, their eggs and nests whilst being built.

Raised slates/tiles provide suitable opportunities for roosting bats as well as nesting birds, fitting solar panels may cause harm or disturbance to them. Other retrofitting options such as cavity wall insulation, solar thermal, externally applied solid wall insulation, roof insulation at rafter level and timber casement window draught proofing may also affect ecology, as such the potential presence of protected species requires careful consideration. If retrofitting is planned within or adjacent to known nesting swift sites, then extra caution will be required.

To avoid breaching wildlife legislation, a bat scoping and nesting bird inspection should be undertaken. These surveys should inform the timing of works in order to avoid disturbing roosting bats if present and necessary licensing requirements. Further advice can be sought from the Bat Conservation Trust which is free of charge or if planning consent is required, from the Council's planning advice/pre-application service. In addition, the broad location of known swift nesting sites can be found on the I Share Maps website (detail provided at Postcode level).

Heat Pumps

Heat pumps work by extracting heat from a source outside the building and concentrating it to heat the home. This heat can come from the ground, the outside air or even a nearby body of water. Heat pumps are electrically driven and are normally most efficient when the increase in temperature is minimised. They work well with underfloor heating systems which operate at lower temperatures. Heat pumps are best used with a well-insulated new build property or an existing dwelling undergoing major refurbishment. They are particularly well suited to homes in areas that do not have access to mains gas.

(1) Ground Source Heat Pumps

Ground source heat pumps uses the stable high volume / low level warmth of the earth^[21] and converts it into low volume / high level heat. The recovered heat can then be used to heat water or spaces.

There are two basic forms of ground source heat pump:

• The first comprises a bore hole where a long pipe is driven vertically down deep into the ground.^[22]
• The second is a trench system, in which a loop or coil is laid out horizontally at a shallow depth.^[23] In both systems, heat is transferred by water running through the pipe into a compressor which raises it to a usable higher temperature. Being almost entirely underground ground source heat pumps cause little or no visual impact.

Air Source Heat Pumps

Air source heat pumps work by converting the temperature of the outside air into heat for the building and supplying energy for the hot water system. The only outside space required is an external wall, making this system ideal for compact forms of development such as flats or smaller houses. They are cheaper to install than ground source heat pumps but these lower costs may be offset by the variability in air temperature.

Air source heat pumps are designed to work in combination with other heating systems rather than acting as the sole energy source and buildings must be sufficiently well insulated to maximise results.

Biomass

Biomass or wood burning systems use pelleted or chipped wood. They differ from other renewable energy sources because although they release carbon dioxide (CO2) when they are burnt, but this is equal to the carbon absorbed when the tree was growing so the process is essentially carbon neutral. In order for biomass to be a truly renewable energy source, the fuel must come from a sustainable source i.e., the wood is replanted, and it should be used close to where it was grown. Wood burning stoves and boilers are available in any size depending on whether they are required to heat one room or the whole building. They can achieve efficiencies of 80-90% and can be used in homes and commercial buildings. Some types of appliances can be fed automatically from an external store.

Biomass refers to the use of organic material such as wood and waste to generate heat and electricity. Itcan be categorised into two types: dry biomass and wet biomass. The use of dry biomass involves combustion,whereas the use of wet biomass involves fermentation or digestion.

(1) Dry Biomass

The most common source of dry biomass material is wood form forests, urban tree pruning farmed coppices or wood waste from farms. The raw material is normally processed into pellets or wood chips. Dry biomass is considered carbon neutral as the CO2 emitted during burning is balanced with the CO2 absorbed in growing the organic material.^[24] To ensure that the benefits of biomass are not outweighed by the impact of transporting the material, it is essential that there is a local and adequate supply.

Biomass can be burnt directly to heat water and/or spaces or be used in more efficient combined heat and power systems to generate both heat and electricity (see related section for further information). It can be used across all types of development, including single dwellings, however, the need to provide space for the combustion plant and storage facilities make small sites impractical. Arrangements also need to be in place for the disposal of ash.^[25]

Under the right economic and supply conditions, the payback for biomass can be shorter than other renewable technologies. However, the technology requires higher maintenance and monitoring to ensure compliance with legislation such as the Clean Air Act.

Wet Biomass

Wet biomass involves the fermentation or digestion of waste to provide a gas which is then burned to produce heat and/or electricity. The process has the benefit of using materials which are otherwise difficult to dispose of including agricultural, household and industrial residues and sewage sludge.

Due to the nature of wet biomass, site selection for plants needs to carefully consider transport movements to and from the site and the effects of odour.^[26]

Wind Energy

Wind turbines convert the power of the wind into electricity using rotating blades to drive a generator. To be effective the turbine must be sited where it would benefit from adequate wind and where the blades would be free to rotate without interference or turbulence. There are two types of wind turbine: horizontal blade turbines and vertical blade turbines.

There are three categories of turbine:

• Large: A collection of large-scale wind turbines located in countryside locations (hub height can be as much as 100m). These are often referred to as wind farms. Electricity is provided for use in the national grid.
   
• Small: Individual Free Standing: often smaller turbines than within a wind farm but can still be significant structures (hub height typically 6m to 25m). Usually located in non-residential areas. Generally provides electricity to nearby properties.
   
• Micro: small turbines mounted on buildings so that the blades extend above the roof of a building. Generally provides on-site electricity generation.

Turbines can be effectively integrated into the design of buildings, however, local wind speed should be monitored for at least 6 months to ensure the viability of the location. Due to their size and prominent appearance consideration must be given to their visual impact. Issues of noise also need to be considered if in proximity to houses and other sensitive activities or designations.

The electricity generated can be linked to the National Grid or can be used to charge batteries. Modern wind turbine designs tend to be very near silent in operation such that the wind in the leaves on trees can be louder. Wind turbines typically cost from £2,500-£5,000 per kilowatt of generating capacity installed.

A design and access statement will need to be submitted to cover the majority of developments and parking is a key aspect that must be covered. In some cases parking arising from development will require measures to be put in place to manage the impact of parking on the public highway. This includes physical protection against parking (i.e. on verges) or protection via Traffic Regulation Orders against short/long stay parking at inappropriate locations (i.e. at junctions, in locations that may conflict with pedestrian movements). All parking management required as a result of new development must be provided by the developer and should have regard to the Council's Parking Strategy and other parking management in the area.

Energy Storage

Home energy storage systems store generated electricity or heat (e.g. solar, PV, wind, or hydroelectric systems) and can in the form of electrical batteries or heat storage systems. Such systems are useful for households generating their own renewable energy as it allows them to store surplus energy and use it as when required. This is particularly helpful in planning electricity usage for charging Electric vehicles or domestic heat pumps.

Government Financial Incentives

Capital allowances: Investment on energy-efficient items including low or zero-carbon technology can be claimed back as capital allowances, enabling the deduction of the full costs of qualifying assets from profits before tax.

Reduced rate of VAT: A reduced rate of 5% VAT is available for installing specific energy saving material in residential homes. This also includes the curtilage of residential accommodation and applies to the price of the goods to be installed (it won't apply to the purchase of goods without the installation process). There are conditions attached such as the supply of the installation being to a qualifying person (over 60 or in receipt of certain of benefits) or to a relevant housing association. The incentive includes insultation, solar panels, heat pumps, micro–Combined Heat and Power (CHP) units, central heating/ hot water system controls and wood fuelled boilers. The reduced rate of VAT is also available for grant-funded installations of heating appliances, central heating and renewable source systems.

Climate Change Agreement (CCA) scheme: The Climate Change Levy (CCL) is an energy tax which aims to increase energy efficiency. The main rates of the Levy apply to energy intensive commercial and industrial businesses on the electricity, gas or solid fuels they yes. However, exemptions from the levy apply if energy is supplied from certain combined heat and power (CHP) schemes reregistered under the CHP quality assurance programme. Exemption also applies where electricity was generated from renewable sources.

The Home Upgrade Grant: The Home Upgrade Grant (HUG) will provide energy efficiency upgrades and low carbon heating via local authority funding, to households in England that are low income, off the gas grid and have energy performance certificates between bands D&G. Phase 2 of the Grant applies to certain LPAs between 2023 and 2025.

The Social Housing Decarbonisation Fund: Provides government funding to improve the energy performance of social homes in England. The scheme runs with a fabric first principle to maximise the dwelling's suitability for low carbon heating either now or in the future. Registered providers must improve their stock using a fabric first approach to at least a minimum of EPC C.

Hertfordshire County Council's environmental improvement grant scheme^[27] is available to support small projects that will help deliver the Council's biodiversity objectives/; to enhance nature by 20% by 2050 and to establish at least 1.8m trees across the county by 2030.

(3) Transport

In some circumstances the traffic generated by a new development will require a Transport Assessment to be submitted as part of the planning application.

Full guidance on the transport assessment process is available at: http://www.dft.gov.uk/pgr/regional/transportassessments/guidanceonta

Additional information can be found in Roads in Hertfordshire.

Transport assessments will be required for:

• Residential development in excess of 25 units (50 for retirement dwellings) or,
• Where traffic levels to and from the proposed development are likely to exceed 5% of the two-way traffic flow on the adjoining highway from which it takes access
• Where traffic congestion exists or will exist within the assessment period; and
• In sensitive locations such as adjacent or close to traffic lights or roundabout junctions.

Design and Access statements will need to be submitted to cover the majority of developments and parking is a key aspect that must be covered.

In some cases parking arising from development will require measures to be put in place to manage the impact of parking on the public highway. This includes physical protection against parking (i.e. on verges) or protection via Traffic Regulation Orders against short/long stay parking at inappropriate locations (i.e. at junctions, in locations that may conflict with pedestrian movements). All parking management required as a result of new development must be provided by the developer and should have regard to the Council's Parking Strategy and other parking management in the area.

Electric Vehicle Charging Points

In January 2022 the Government adopted amendments to Building Regulations, to require new developments to provideEV charging points. The amendments in Part S of Schedule 1 to the Building Regulations 2010 took effect on 15 June 2022 for use in England. Whilst most of the requirements of these Building Regulations are reflected in the advice in this document, additional guidance is provided on the requirements by development type.

Car & Cycle Parking

NHDC's Vehicle Parking at New Development SPD was adopted in November 2011 and provides guidance on parking provision at new developments in line with national policy that promotes local decision making on appropriate parking standards.

The standards apply a 'minimum' parking standard to residential development that takes into account levels of car ownership and expected growth, whilst retaining 'maximum' provision for non-residential development along with the zonal approach to parking restraint.

Applications for new residential development must seek to promote walking, cycling and public transport and in doing so developers may make a case for negotiating the provision of parking below the minimum standard. Clear evidence must be provided that residents and visitor parking demand will not exceed the parking provided OR that alternative short and long stay daytime and evening parking will be readily available to future residents and visitors. The developer should identify examples of this evidence from other developments or locations in similar circumstances to those found in the district. The Council does not consider, however, that residents will chose not to own cars if they live within the most accessible areas or corridors.

Parking provision with development proposals should link in with a Sustainable Travel Strategy and include EV charging points.

Sustainable Transport

The NPPF expects development proposals to ensure that "appropriate opportunities to promote sustainable transport modes can be – or have been – taken up, given the type of development and its location".

Sustainable transport should be considered at the outset when designing new developments taking into account the potential impacts on congestion and air quality (see Air quality section). The emphasis should be on reducing reliance on private vehicles and promoting modal shift through public transport and active travel provision. Ideally, new development should incorporate segregated pedestrian and cycle paths located away from motorised traffic.

For larger strategic developments the provision of local services and facilities can also help the need to travel further afield to access such services (e.g. retail, health and education). Further information is provided by the North Herts Transport Strategy.

Development proposals are therefore required to include travel plans and transport assessments and statements demonstrating how they deliver sustainable transport objectives and support modal shift.

The layout of streets should be designed to facilitate efficient bus operation. Consideration should be given to including bus gates and priority at traffic signals. All bus stops should be connected to the surrounding area by direct and safe walking routes. Railway stations and bus stops on major corridors, served by 'express' services, should include secure cycle parking and safe cycling routes from the surrounding area.

Well-designed secure cycle parking within dwellings and other areas should be conveniently located to encourage greater use.

Electric vehicle/cycle spaces and charging points need to be suitably located to avoid street clutter.

Development should consider access for servicing such as refuse collection, deliveries, and removals. Further guidance is provided in the National Design Guide.

Sport England's Active Design guidelines sets out active design guidelines on how to incorporate public transport, and active travel networks through development and into existing communities.

NHS England's Putting Health into Place provides further guidance including case studies showing how active travel provides the most sustainable from of transport and how it can facilitate improved health and wellbeing.

Car-sharing schemes and car clubs are actively sought in the district, including in new developments, to give residents a practical alternative to owning a car, especially a second or third car, which may be used only occasionally..

Enhanced digital connectivity such as high-speed broadband services can help facilitate home working thus reducing the need to travel helping maintain the post Covid trend towards hybrid working.

Digital technologies can also be used to enable digital transport service platforms such Mobility as a Service (MaaS) systems^[28]that enable users to access, pay for, and get real-time information on, a range of public and private transport options. Examples of MaaS include the app Whim in the West Midlands, and MaaS Scotland. The former offers a range of monthly plans, bringing in National Express, Transport for West Midlands, Gett, Nextbike and Enterprise rent-a-car as transport providers.

Electric Vehicle Charging Points

New residential dwellings are required to include vehicle charging points in accordance with the requirements set out in the Building Regulations and HCC's and NHDC's standards.

Checklist:

(1) Air Quality

The NPPF states that air pollution is a material planning consideration therefore an assessment of air quality must be included with applications identifying any potential adverse effects on local air quality. The impacts of exiting pollution (including cumulative effects) on proposed development should also be taken into consideration as part of the assessment.

The main pollutants of concern are nitrogen dioxide (NO₂), and particulate matter (PM10 & PM2.5) from vehicular traffic. Levels of NO₂ are close to exceeding a national air quality objective around the A505 in the Hitchin Street / Whitehorse Street area of Baldock. Of particular concern is the area in the south of Hitchin. Notably Stevenage Road (A602) near the Hitchin Hill roundabout, which has been designated an Air Quality Management Area (AQMA) and the Payne's Park roundabout at the A602 junction with the A505 which was designated an AQMA in 2016.

The NPPF states that "planning policies and decisions should sustain and contribute towards compliance with relevant limit values or national objectives for pollutants, taking into account the presence of Air Quality Management Areas and Clean Air Zones, and the cumulative impacts from individual sites in local areas." It adds that "Opportunities to improve air quality or mitigate impacts should be identified, such as through traffic and travel management, and green infrastructure provision and enhancement"

The national pollutant objective limits relevant to vehicular traffic and are outlined below:

Adaptation to higher temperatures

Extreme heat events can pose significant risk to human health, infrastructure and economic productivity. Therefore, it is important for development to include adaptation measures to improve resilience to extreme heat events.

Built up areas tend to be hotter than rural or countryside areas due to the concentration of buildings, paving and tarmac which absorb heat. This 'urban heat island effect' is most noticeable during hot summer days and can have serious adverse effects on health and infrastructure. The following measures can mitigate the urban heat island effect:

• Trees: provide shade and cool air through transpiration in addition to other benefits such as removing carbon dioxide and enhancing biodiversity.
• Green roofs and walls: help insulate buildings from heat and cool air temperatures through transpiration/ evaporation with additional carbon sequestration and biodiversity benefits.
• Shade providing structures: such as pergolas, arcades, canopies and awnings.
• Colours: unlike darker colours which absorb sunlight, lighter colour reflect light helping to reduce heat.
• SuDS: provide cooling effects through evaporation and help counteract some of the effects of hard impervious surfaces in urban areas which rapidly convey water away, preventing cooling associated with evaporation. Again, this can provide multiple benefits including to biodiversity, flood risk reduction, water filtration and conservation.
• Water features: such as fountains create spray which provides cooling effects through evaporation.

(3) Water efficiency standards

• Design: passive cooling techniques can be incorporated into buildings and design measures such as layout and using a variety of heights can facilitate better air flow to convey heat away more efficiently. The use of less heat absorbing materials can also help.

North Herts district is within an area of 'serious water stress'^[31]. This implies that demand is high compared to available water resources. Population growth coupled with droughts and extreme weather events associated with climate change are expected to exacerbate this issue. Therefore, it is important to ensure the long-term sustainable management of water supplies as well as the protection of our local rivers and wildlife.

The NPPF (paragraph 153) expects plans to proactively mitigate and adapt to the long-term implications of climate change including on water supply.
The Building Regulations include a requirement for all new dwellings to achieve a water efficiency standard of 125 litres of water per person per day (lpd). They also include an optional, higher efficiency requirement (part G) of 110 lpd for new residential development. The NHLP seeks the lower 110 lpd water consumption figure as the District lies in an area of serious water stress. The Council supports adopting higher efficiency standard where practicable.

NHDC is responsible for determining planning applications for renewable development of 50 megawatts or less installed capacity. Domestic installations are discussed elsewhere in this document and schemes above 50 megawatts are determined by the Secretary of State for Energy. NHL's policies NE12 and SP11 support renewable and low carbon energy development in appropriate locations subject to assessment of the impacts on the landscape, environment, heritage assets, transport, air quality, aviation and amenity. The policy also supports decentralized energy schemes associated with strategic development allocated in the plan. Application are likely to be refused where proposed schemes are considered to give rise to significant adverse impacts which outweigh the wider benefits of renewable energy development identified above. However, the Council will consider to what extent any adverse impacts can be mitigated through the design and siting of proposals or by applying appropriate planning conditions and will take the views of local communities into consideration when determining applications.

(1) Siting principles for standalone renewable energy schemes

Solar/ PV developments should be sited where they would have the least adverse impacts. Proposals which would contribute towards reducing greenhouse gas emissions will be permitted subject to an impact assessment demonstrating that proposed schemes:

• Do not harm the role and purposes of the Green Belt^[32] unless they can demonstrate very special circumstances.
• Minimise impacts on the landscape character and locally sensitive features, particularly in relation to the Chilterns Area of Outstanding Natural Beauty.
• Do not produce adverse impacts on:
  • Biodiversity sites
  • Air quality
  • The historic environment
  • The transport networks
  • Aviation interests
  • Landscape quality, landscape character and visual amenity, including consideration of cumulative impacts of development;
  • The amenity of residents

The Hertfordshire renewable and Low Carbon Energy Technical Study was commissioned to assess the potential for renewable energy generation schemes in the District. This may assist developers to choose the appropriate renewable technology, depending on the location of the development.

Proposals for solar farms involving the best and most versatile agricultural land and proposals for wind turbines will be determined in accordance with policy NE12 of the NHLPand national policy. Opportunity areas in District were identified in the Hertfordshire Renewable and Low Carbon Energy Technical Study.

In assessing renewable and low carbon energy proposals against the above criteria the Council will give significant weight to their local and wider benefits, particularly the potential to reduce greenhouse gas and other harmful emissions, and the social benefits of community owned schemes where this is relevant.

Proposals for decentralised energy schemes associated with development of the strategic sites allocated in the Plan will be encouraged subject to an assessment of the impacts above.

In all cases, end of life/redundant plant, buildings, apparatus, and infrastructure must be removed and the site restored to its former state or a condition agreed with the Council.

(1) Application process

Typically the application process involves the following steps:

• Contact NHDC Planning team for initial advice/ guidance
• Pre application stage: consult HCC, Natural England, Historic England, the Environment Agency, the Highways Agency, MoD and Internal Drainage Boards.
• Obtain Environmental Impact Assessment (EIA) Screening Opinion from NHDC. An Environmental Statement (ES) will be required is the development is screened-in for EIA.
• Provide a Statement of Community Consultation.
• Design and Access Statement.
• Landscape & Visual Impact Assessment including impacts on the Chilterns AONB and on the Green Belt.
• Heritage Statement.
• Ecological Survey identifying any adverse impacts and including management plans and mitigation measures.
• Noise Impact Assessment.
• Air Quality Impact Assessment.
• Transport Statement.
• Decommissioning and Restoration Statement.

(1) Community Energy Schemes

Community energy schemes can make a significant contribution to the decarbonisation of the District while supplying community benefits such as affordable energy. These could include neighbourhood or village heat networks, solar PV schemes, or community run hydro's^[33]. Further information and technical support is available through the Greater South East Energy Hub and the council will support in principle community led schemes. Macro-renewable schemes are expected to include an element of community investment such as through local shareholder investment, the provision of lower cost energy to community services such as schools and community centres, and/or setting up a community fund or trust.

^[20] While overshadowing will reduce energy production only daylight is required to generate electricity and not direct sunlight, meaning that it will continue to operate throughout the year and on cloudy days.

^[21] At several metres below the earths surface the ground maintains a constant temperature of 11-13oC

^[22] 15m to 150m depending on ground conditions and the size of the system.

^[23] Approximately 2m.

^[24] Plants absorb CO2 during photosynthesis.

^[25] Ash is produced at a rate of around 1% of the total weight of biomass burned. The ash from most biomass fuels can be safely returned to the soil as fertiliser

^[26] It should be noted that anaerobic digestion can bring benefits in terms of odour reduction over the raw fuel.

^[27] Further details available here: www.hertfordshire.gov.uk

^[28] Mobility as a Service (MaaS) in the UK: change and its implications (publishing.service.gov.uk)

^[29] Natural England - Process Journey for Developers and Design Teams

^[30] Natural England Green Infrastructure Principles

^[31] Environment Agency report: 'Water stressed areas - final classification 2021'

^[32] The NPPF defines the 5 purposes of the Green Belt as : to check urban sprawl, prevent coalescence, safeguard countryside from encroachment, preserve character of historic tons and facilitates recycling ro derelict and other urban land.

^[33] See Halton Lune Hydro example