Net Zero Carbon Development Plan Document - Regulation 19
(13) 5 Overarching strategy – Achieving Net Zero Carbon Development
5.1 New development that falls within the scope of this Development Plan (as set out in 5.11 below) is expected to comply with the whole Plan.
(4) Policy NZC1: Achieving Net Zero Carbon Development
New development of one or more new dwellings (C3 or C4 use class) and/or 1,000sqm or more of new non-residential floorspace, hotels (C1 use class) or residential institutions (C2 use class) should achieve net zero operational regulated carbon emissions by implementing the energy hierarchy.
Proposals should demonstrate application of the energy hierarchy through submission of an energy statement which identifies:
- For new dwellings, a minimum 63% reduction in carbon emissions is achieved by on-site measures, as compared to the baseline emission rate set by Building Regulations Part L 2021 (SAP 10.2).
- In non-residential buildings, hotels and residential institutions at least a 35% reduction in carbon emissions through on-site measures compared to the rate set by Building Regulations 2013 (or equivalent percentage reduction on Building Regulations 2021).
- Compliance with the energy efficiency and renewable energy provisions set by policies policy NZC2(A) & (B) and by presenting the carbon savings achieved across each step of the energy hierarchy (demand reduction, efficient supply, renewable and other low-carbon technology).
- Any residual operational regulated carbon emissions (over the course of 30 years) will be calculated and offset to zero in accordance with policy NZC2(C). Offsetting will only be considered an acceptable solution to net zero carbon requirements if it can be demonstrated that carbon reductions achieved via on-site measures (and near-site renewables) are demonstrably unfeasible or unviable.
Where full compliance is not feasible or viable proposals must demonstrate through the energy statement that carbon reductions to the greatest extent feasible have been considered and incorporated through applying the energy hierarchy. In applying the energy hierarchy, proposals are expected to implement fabric energy efficiency and low carbon heating before incorporating renewable electricity generation and then offsetting.
A condition will be applied to planning permissions requiring as built SAP or SBEM calculations to be submitted prior to occupation and demonstrating that the finished building meets the standard set in Policy NZC1.
Alternatively, applications may demonstrate the requirements of Policy NZC1 are met through the Passivhaus standard with accompanying PHPP calculations submitted within the energy statement (without the use of fossil fuels on site including gas). A condition will be applied requiring Passivhaus certification prior to occupation.
5.2 This strategy has been designed to deliver the objectives set out in section 4 above. The focus is on providing a practical and viable approach to deliver new development which is net zero carbon in operation – in other words the net zero carbon emissions will occur following completion of the development.
5.3 Improving energy efficiency and minimising our energy demand is the most cost-effective way to minimise new infrastructure that will be required to achieve a zero-carbon energy system and thus represents the starting point for the whole net zero journey. Improving energy efficiency in new homes will reduce the need for costs and future carbon emissions in retrofitting buildings at a later date and contribute to the total reduction in energy demand.
5.4 As a District that can demonstrate levels of development viability that can accommodate energy efficiency measures that go beyond the 2021 Part L building regulations, Policy NZC1 requires developments to achieve building performance that is broadly consistent with national ambitions as set out in the proposed Future Homes Standard to be introduced in 2025.
5.5 The percentages derived in NZC1 reflect the emissions reductions required for buildings to align with the Future Homes Standard, based on 2021 Building Regulations.[6]
5.6 The strategy seeks to achieve this by requiring applicants to address carbon emissions by applying the energy hierarchy (as shown in Figure 1) sequentially in three ways:
- Reduce energy demands. Developments should be designed to minimise demand for energy in operation, thereby minimising carbon emissions. This involves:
- Considering the potential for technology that enables occupants to live in ways that minimise energy demands.
- Maximising energy efficiency.
- Zero or low carbon energy sources. To meet energy demands in operation, developments should incorporate or utilise zero or low carbon energy sources. This involves:
- Considering the potential to utilise large scale renewable or low carbon energy sources such as heat networks or local large-scale renewable energy generation sources, through a direct connection.
- Incorporating passive and renewable energy sources within the development.
- Carbon Offsetting. Developments that result in residual operational carbon emissions having incorporated stage 1 and stage 2, will be subject to carbon offsetting requirements to bring the total operational carbon emissions to net zero.
Figure 1: Energy Hierarchy
5.7 A condition will be applied to relevant planning permissions requiring as built SAP or SBEM calculations to be submitted prior to occupation and demonstrating that the finished building meets the standard set in Policy NZC1. For sites of over 10 dwellings where standard house types are used, a sample of at least 20% of all dwellings (and including all house types) shall be tested.
5.8 To ensure the SAP or SBEM calculations identifying the carbon emissions are as accurate as possible, applicants will be required to perform SAP or SBEM[7] calculations at the following points of the design:
- Pre-planning, using design values and submitted within the planning application energy statement
- Post-construction and preoccupation, using figures from the building as constructed, incorporating the following:
- Any specification changes to design values made to any SAP/SBEM regulated building element during construction
- The measured air-permeability, tested in accordance with the procedures set out in TM23, and reported as statutory compliance in Section 7 Part L.
- Accredited construction detail performance as confirmed by infra-red thermographic survey and selective borescope surveys
- Commissioning logbooks provided to demonstrate that ventilation and heating systems are operating as intended.
If the completed building fails to meet the conditioned standard, the developer must take reasonable remediation measures. Any residual operational regulated carbon emissions will be required to be offset in accordance with Policy NZC2(C) whether identified at application stage or pre-occupation, unless this is demonstrated to be unviable.
5.9 Furthermore, to ensure the energy performance gap is minimised we recommend the use of a recognised quality assurance process that ensures the 'as built' performance (energy use, carbon emissions, indoor air quality, and overheating risk) matches the calculated design performance of buildings. Examples of these include BEPIT (Building Energy Performance Improvement Toolkit), the Passivhaus accreditation process and the Assured Performance Process (NEF/GHA).
5.10 A condition will be applied to planning permissions requiring developers to produce a home user guide in accordance with the updated approved document L template.
5.11 Policy NZC1 sets out what is required of development proposals to demonstrate the delivery of this strategy. The policies in this plan will apply to the following new developments (except where otherwise specified):
- All new residential developments of 1 dwelling or more (C3 or C4 use)
- All new non-residential buildings, hotels (C1 use class) or residential institutions (C2 use class) of 1,000sqm or more floorspace.
[6] Using a compound percentage based on government statements about the carbon reductions that will be achieved in 2021 and 2025 compared to 2013, the targets have been calculated with the following assumptions: Part L 2021 is a 31% reduction on Part L 2013, The Future Homes Standard is a 75% reduction on Part L 2013, which equates to the FHS being a 63.8% reduction on Part L 2021.
[7] Calculations should be performed using the latest version of the SAP 10.2 methodology (current version 20.08.2021). Government has confirmed that this calculation will become the statutory methodology by June 2022 along with the interim uplift to Part L.
