Policy Option 01 - Sustainable Design and Construction

  • Central to Oxfordshire's efforts to achieve net zero carbon, in accordance with challenging targets will be to address the main sources of greenhouse gas emissions in Oxfordshire.
  • An assessment undertaken as part of the Oxfordshire Energy Strategy identifies the main sources of greenhouse gas emissions in Oxfordshire as road transport and housing.
  • The diagram below illustrates the contribution that a number of key sectors have historically made to overall carbon dioxide emissions in Oxfordshire. Although there has been a decrease in overall emissions since 2008, they remain high with road transport, residential development, public services and commercial services contributing the majority of these.
  • To successfully achieve net zero carbon emissions, the focus needs to be on the highest emitters in a way that ensures targets are met, without impacting on the delivery of necessary infrastructure and services to meet the needs of Oxfordshire's communities.
  • It is essential that the Oxfordshire Plan takes steps to mitigate the impact of new development by reducing its carbon footprint.
  • There are a significant number of planned houses in the pipeline that will be constructed to existing building standards and will therefore contribute less to achieving the ambitious national and local carbon reductions targets that have been set.
  • The Government have confirmed that from 2025, the Future Homes Standard will ensure that new homes produce at least 75% lower CO2 emissions compared to those built to current standards. In the short-term this represents a considerable improvement in the energy efficiency standards for new homes. Homes built under the Future Homes Standard will be ‘zero carbon ready’, which means that in the longer-term, no further retrofit work for energy efficiency will be necessary to enable them to become zero carbon homes as the electricity grid continues to decarbonise.
  • From 2021, new homes will be expected to produce 31% less CO2 emissions compared to current standards. This will deliver high-quality homes that are in line with our broader housing commitments and encourage homes that are future-proofed for the longer-term.
  • Notwithstanding the Government commitment to improve building regulations, it is important to note that local authorities have the ability to set local targets for the design and construction of new buildings. The NPPF does not prevent local authorities from setting higher ambitions particularly in relation to energy efficiency standards that exceed Building Regulations.
  • Such achievements are a clear signal that net zero carbon can be achieved in developments at a range of scales, when there are strong policies in place and when developers have an opportunity to test construction techniques and use of materials supported by sufficient investment.
  • For Oxfordshire to go further than existing and proposed Government standards, a consistent county-wide definition of net zero carbon needs to be established. This requires consideration of existing and emerging definitions for net zero carbon.

The Eco Town Definition

The definition of zero carbon for eco-towns set out in the Planning Policy Statement (2009) is that, over a year, the net carbon dioxide emissions from all energy use within the buildings on the eco-town development, as a whole, are zero or below. The initial planning application and all subsequent planning applications for the development of the eco-town should demonstrate how this will be achieved.

The definition excludes embodied carbon and emissions from transport but includes all buildings – not just houses but also commercial and public sector buildings which are built as part of the eco-town development.

UKGBC Net Zero Carbon Buildings – A Framework Definition (UK Green Building Council)

From November 2018 to March 2019, UKGBC brought together an extensive range of industry stakeholders, including a task group, to build consensus on a framework definition for net zero carbon buildings in the UK.

The primary focus of the framework is to set in place a path to achieve net zero carbon buildings in both construction and operation (in-use energy consumption), whilst beginning to provide direction for addressing whole-life carbon in the industry.

The Framework definition of Net Zero Carbon Buildings consists of two definitions:

1. Net zero carbon – construction (for new buildings and major renovations). When the amount of carbon emissions associated with a building's product and construction stages up to practical completion is zero or negative, through the use of offsets or the net export of on-site renewable energy.

2. Net zero carbon – operational energy (for all buildings in operation). When the amount of carbon emissions associated with the building's operational energy on an annual basis is zero or negative. A net zero carbon building is highly energy efficient and powered from on-site and/or off-site renewable energy sources, with any remaining carbon balance offset.

A third definition, 'new zero carbon – whole-life' is also proposed at a high level, but further work is needed to develop the detail of this approach. 

The framework includes five steps, shown in diagram below. Some of the steps are relevant to the definition for construction and some to the definition for operational energy. However, a building targeting net zero carbon for construction should be designed to achieve net zero carbon for operational energy.

Each step has a set of principles that have been ordered in terms of priority and should be reviewed in that order. Each principle sets out the approach that should be followed, including a rationale for the principle, associated technical requirements and, where relevant, any areas for future development.

Broadly speaking the definitions seek to: 

1) ensure that a whole-life carbon assessment is undertaken,
2) prioritise reductions in energy demand and consumption over all other measures,
3) report annually on in-use energy consumption, 
4) prioritise on-site renewable energy sources and require any off-site renewable energy to demonstrate additionality,
5) offset any remaining carbon using a recognised offsetting framework and publicly disclose this.

UKGBC Net Zero Carbon Buildings – A Framework Definition (UK Green Building Council)

The London Energy Transformation Initiative (LETI) was established in 2017 to support the transition of London's built environment to net zero carbon, providing guidance that could be applied to the rest of the UK.

A network of over 1,000 built environment professionals have worked collaboratively to compile evidence-based recommendations for London Plan and London Environment Strategy policies. The LETI Climate Emergency Design Guide defines what good looks like in context of the climate emergency for new buildings.

The guidance focusses on delivering net zero carbon new buildings which means having regard to whole-life carbon, which in the context of the document means;

i) Operational carbon – net zero operational carbon means that buildings burn no fossil fuels, are 100% powered by renewable energy and achieve a high level of energy performance in line with national climate change targets.

ii) Embodied carbon – The carbon emissions emitted producing a building's materials, their transport and installation as well as disposal at the end of life.

A key recommendation of the guidance is that the Energy Use Intensity (EUI) of a building should replace carbon emission reductions as the primary metric used in policy, regulations and design decisions. EUI is an annual measure of the total energy consumed in a building. EUI is regarded as a good metric as it depends on how the building performs in use.

EUI includes all the energy consumed in the building including regulated energy (heating, hot water, cooling, ventilation and lighting) and unregulated energy (plug loads and equipment e.g. kitchen white goods, ICT and AV equipment). It does not however include charging of electric vehicles.
The guidance makes recommendations for operational energy which includes the fabric efficiency of building materials, window areas and energy consumption. It also makes recommendations for embodied carbon emissions.

To achieve Net Zero Operational Carbon, LETI propose ten key requirements for new buildings:

1) Total energy use of different building typologies not to exceed Energy Use Intensity (EUI) targets for energy uses in buildings including regulated and unregulated energy.

2) A fabric first approach ensuring that space heating demand for all building types is below 15kWh/m2/yr.

3) Annual energy use and renewable energy generation to reported for the first year post completion as part of a measurement and verification process.

4) Embodied carbon of construction materials should be assessed to reduce impacts of construction process.

5) Heating and hot water should not be generated from fossil fuels.Average annual carbon content of heat supplied (gCO2/kWh) should be reported.

6) On-site renewable electricity should be maximised.

7) Energy demand response and storage measures should be incorporated, and the building annual peak energy demand should be reported.

8) An annual carbon balance calculation should be undertaken to demonstrate that a building achieves a net zero carbon balance.

9) Any energy use not met on-site should be met by investment into additional renewable energy capacity off-site.

The Circular Economy

In addition to different definitions for net zero carbon development, it is also useful to consider circular economy principles and how these relate to resource consumption, waste and carbon emissions.

A circular economy keeps products, components and materials at their highest use and value. In a circular economy, every item or material is useful and valuable to another part of the economy. It provides an alternative to the current 'linear' economy – in which we make, use and dispose of products, components and materials and recover little value from them.

Significant greenhouse gas emissions arise from consumption habits in society. A circular economy seeks to shift away from a linear pattern of resource extraction, use and wastage to one in which products and materials are retained and used at their highest use value for longer through maintenance, repairs and upgrades. 

As construction waste accounts for the largest proportion of waste within the Oxfordshire waste cycle, circular economy principles are relevant to the Oxfordshire Plan, particularly efforts to achieving net zero carbon emissions through the design and construction of new development.

The use of natural or recycled materials in construction, designing buildings for adaptability and changing uses over time as well as the ability to dismantle and recover materials at the end of a building's life would all help to minimise resource extraction and waste arising from construction in Oxfordshire.

This would help to minimise carbon emissions associated with construction and development over the lifetime of the Plan.

Consideration of circular economy principles through the Oxfordshire Plan has potential to deliver a wide range of benefits beyond tackling waste and reducing carbon emissions with positive social implications, new jobs, improved skills and new business opportunities.

  • The Government's proposals to strengthen Building Regulations and to define future standards for new buildings have the potential to deliver a consistent approach for the delivery of zero carbon buildings and take a big step on the pathway to net zero carbon. However, they may not be ambitious enough to meet targets for achieving net zero carbon in Oxfordshire.
  • Consideration should be given to elements of other emerging design standards which could assist in accelerating our efforts, particularly where better regard is had to the whole-life carbon of buildings, including embodied carbon, operational energy use and renewable energy generation.
  • The various industry consensus definitions developed by LETI and the UKGBC are more ambitious in scope compared to recently adopted local plan policies which focus on achieving carbon reductions rather than addressing whole-life carbon.
  • Well-designed places are those that respond to the impacts of climate change through energy efficiency, minimising greenhouse gas emissions and embodied carbon, as well as adapting to anticipated events such as rising temperatures and increased flood risk.

Policy Options

  • The preferred policy approach is to define an Oxfordshire-wide definition for net zero carbon design and construction for development in Oxfordshire. This will assist in achieving the County's objectives in achieving net zero carbon emissions over the lifetime of the Oxfordshire Plan with multiple benefits including supporting the health and wellbeing of communities and encouraging clean growth and innovation, consistent with Strategic Vision and Oxfordshire Plan objectives.

Preferred Policy Option

Policy Option 01: Sustainable Design and Construction

To include in the Oxfordshire Plan a policy setting out sustainable design and construction requirements to be applied to major residential and non-residential developments within Oxfordshire.

This policy would be subject to viability and deliverability testing but with the objective to achieve net zero whole-life carbon for both residential and non-residential buildings, taking account of embodied carbon, low energy use and renewable energy supply.

Developments should be fossil fuel free and fossil fuels should not be used to provide space heating, hot water or fuel for cooking. Demand for energy should be balanced by the provision of on-site renewable energy generation.

Carbon offsetting would only be permitted where it is demonstrable that net zero carbon cannot be achieved on site.

A financial contribution based on defined calculation would be made to carbon offsetting projects including off-site renewable energy generation or carbon sequestration consistent with defined natural capital and nature recovery approaches defined in the Plan.

Buildings should be designed to be resilient to the effects of a changing climate, including overheating.
New buildings should be designed to be durable but flexible and adaptable to changing needs over time.
Residential and non-residential buildings should be designed and built to maximise the use of natural or recycled material in construction and to enable disassembly at the end of a building's life in accordance with circular economy principles.

Alternative Policy Option 01-1

  • One alternative policy option is to defer standards for the design and construction of new buildings to district local plans. National policy does not prevent local authorities from setting higher ambitions, particularly in relation to energy efficiency standards that exceed Building Regulations.
  • This is not a preferred option as different targets and timescales for achieving net zero carbon development in local plans could hinder efforts to achieve net zero carbon emissions in Oxfordshire during the lifetime of the Plan.

Alternative Policy Option 01-2

  • Another alternative is to defer guidance on sustainable design and construction to building regulations and the Future Homes and Future Buildings Standards.
  • This is not a preferred option as failure to introduce more stringent national standards for the design and construction of new development could hinder Oxfordshire's efforts to achieve net zero carbon emissions during the lifetime of the Plan.

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