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Whole-life Carbon

Aim: Reduce carbon emissions at every stage of the project’s life cycle

Energy Efficiency

Aim: Reduce the energy demand by occupants in the home / building

Passive Design

Aim: Reduce energy needed to heat or cool the home/building/place

Renewables

Aim: Maximise the amount of renewable energy generated

Energy Management

Aim: Reduce carbon emissions at every stage of the project’s life cycle

Whole-life Carbon

Whole life carbon is a measure of the total amount of carbon emitted throughout the life cycle of a building or infrastructural asset, and include both upfront emissions generated through construction, and operational emissions generated during the building’s use.

The UK Green Building Council’s ‘Net zero carbon framework’ provides a useful approach to guide projects in reducing carbon across all stages to mitigate climate change.

1. Use a whole-life carbon assessment method to inform the design process, and reduce carbon at every stage.

   Embedding a whole-life cycle assessment into the design process will ensure every design decision considers its impacts on the embodied and operational carbon emitted. It should also encourage design for flexibility, adaptability and deconstruction to minimise end-of-life impacts and enable a ‘circular economy’ within the built environment.

2. Use a circular economy approach to reduce upfront carbon.

   Upfront carbon can be significantly reduced through the re-use and retrofit of existing buildings / infrastructure, the pursuit of a circular economy approach in the design and specification of products and materials , and the reduction of waste. The ‘upfront carbon’ metric provides a summary of how much carbon is emitted during construction.

3. Reduce operational energy needed:

   Reducing the energy demanded by a building when in use will make it much easier to be operationally net-zero carbon, regardless of whether the energy is generated by on site renewable sources or the national grid. This can be achieved by using a combination of passive design to reduce the energy needed for servicing the building, using efficient electrical devices and systems within the building, and providing smart energy management systems to allow users to monitor and manage energy use into the future. The ‘Energy Use Intensity’ is a measure of how much energy per m2 is required by the building per annum.

4. Use passive design to reduce the energy needed for heating / cooling

   Passive design aims to use the conditions and climate of a site, and the design of the building’s external walls, roof and floors to minimise energy needed to keep occupants comfortable throughout the year. The ‘operational heating demand’ metric provides a measure of how well passive design has been applied.

5. Generate renewable energy

   Generating energy on site helps to reduce demand on the national grid, decarbonise the national grid, and off-set the energy demanded by the site. The ‘operational renewables’ metric provides an understanding of whether a site is reliant on the decarbonisation of the national grid to achieve operational net-zero by 2050, or can claim to be net-zero upon completion.

6. Provide metering, monitoring and reporting to help users reduce their energy use.

   Incorporating smart energy/building management systems can allow users to better manage and reduce their energy usage. The reporting of the buildings / project’s in-use energy on an annual basis will improve our ability to further reduce carbon across the industry.

Energy Efficiency

We can maximise the energy efficiency of our homes and buildings by using passive design to reduce the amount of heating and cooling needed, using low-carbon heating, efficient water system design and ultra-efficient electrical devices. The total energy used per unit gross floor are to heat and cool homes and buildings, and for lighting, cooking and powering our devices is called the energy use intensity.

1. Use Passive design to create a comfortable climate and reduce the energy required to heat and cool the home, building or place.

2. Use a district heating system or microgrid if available in the local area.

   While there are no heating networks in Ebbsfleet currently, this may change during the remaining build out period, and design teams should explore the availability of a local heat network, ambient loop and micro-grids to power heating systems. EDC will provide further information if and when such systems are planned. Bear in mind that connecting to an existing district energy scheme means that it would not be possible to reach zero carbon if the main energy source uses fossil fuels unless it is refurbished at a later date to be fed from heat pumps or other renewable source.

3. Use a zero-carbon heating system

   The national grid is continuing to decarbonise, and therefore the most likely low-carbon heating system within Ebbsfleet will be electricity powered heat pumps or boilers. Heat pumps are preferred over electric boilers, as they are more efficient and cheaper to run. Heat pumps can either be sized for individual homes/buildings, or communal to serve a network of homes or buildings. Heat pumps run more efficiently at lower temperatures (35-45°C degrees), which means radiators may need to be slightly larger to emit the same amount of heat as they would in a conventional gas-fired boiler heated home. However, this may be countered by the fact that ultra-low energy buildings will require less heat. Heat pumps are particularly suited to underfloor heating

   Heat pumps will require a hot water cylinder, which will need to be accommodated in an easily accessible cupboard, but which should not result in a net loss of storage space within the home. These cylinders will need to be heated to around 60oC intermittently to prevent the growth of the legionella bacterium.

4. Reduce water usage, particularly hot water demand see water use

   In very low energy buildings, the energy required to heat hot water can meet or exceed the amount of energy required for space heating. Consider;

   • Reduced flow rates: Refer to Water sections in most recent BREEAM and HQM protocol to optimise realistic flow rates.

   • Minimise distribution loss: This issue is often overlooked by architects but can easily be improved by the following simple measures.

   • Try to cluster taps close to the hot water source,

• Ensure all pipework is insulated.

• Aim to use the smallest diameter pipework possible but taking account of peak demands.

• Consider if there is a need for hot water tanks and super-insulate all tanks.

• Consider wastewater heat recovery (WWHR).

5. Ensure all electrical appliances supplied at fit-out are the best energy rating possible.

Passive Design

Passive design works with the local climate to maintain a comfortable temperature in a building or a place throughout the year, reducing or eliminating the need for additional heating or cooling, thus reducing the energy demand and the associated operational carbon emissions.

The following guidance will help to create a more comfortable internal environment in buildings and reduce the amount of energy needed to heat or cool buildings throughout the year.

1. Orientation

The first pre-application meeting should consider the optimal orientation to optimise solar gains, avoiding overheating or excessive cooling load, whilst preventing significant overshadowing in the winter.

Maximise the number of dual aspect, homes/ spaces.

Locate the highest-occupied rooms along the southern facade where feasible.

Avoid overshadowing of PVs from adjacent buildings, trees and taller parts of the building.

Aim to minimise overshadowing of communal and private outdoors spaces where feasible.

2. Building form

Compact forms have less external surface area and thus lose less heat, but can compromise architectural expression, and lead to generic architecture, and a less varied silhouette and streetscape.

Carefully consider the building form to balance the compactness of the form alongside the need to formally express the chosen design narrative and respond to the townscape context of the site.

Design teams should focus on the compactness of the ‘thermal envelope’ rather than the general architectural form. The thermal envelope is defined by the wrapping of continuous insulation to enclose all heated spaces within the building. Careful detailing can avoid cold bridging through the thermal envelope, while allowing additional articulation of the buildings form through balconies, stepped roofs, projections and overhangs.

Group ‘unheated’ spaces such as bin stores and cycle stores outside the thermal envelope together, preferably to the northern façade, to aid compactness.

Consider the use of external access cores and deck access to apartment blocks, to reduce the thermal envelope, and the amount of space that needs heating and cooling.

3. Thermal fabric and air tightness

The forthcoming changes to the Building Regulations in 2025 will continue the pathway towards more insulated and more air-tight thermal envelopes, and deeper façade build-ups. EDC’s performance indicators do not assess fabric efficiency, using the Energy Use Intensity metric to frame overall performance, and preserving the flexibility for design teams.

4. Window locations and sizes

Getting the right glazing-to-wall ratio on each façade is a key feature of energy efficient design. Minimise heat loss to the north (smaller windows) while providing sufficient solar heat gain from the south (larger windows) whilst mitigating against the risk of overheating.

5. Ventilation

The most important aspect of ventilation is controlled air flow to ensure the building sustains a comfortable temperature, while avoiding issues such as condensation and overheating. Mechanical Ventilation with Heat Recovery (MVHR) systems work by extracting and recovering heat from warmer rooms and distributing clean air around the building. They are critical in maintaining good air quality and reducing heat losses within a home.

Renewables

Net zero carbon can be achieved through generating energy using renewable technologies such as photovoltaics (PV). Generating sufficient energy onsite to be self-reliant is much easier at lower densities, but the density of development in much of Ebbsfleet will require a mix of onsite photovoltaics and potentially offsite renewables to supplement / aid the decarbonisation of the national grid.

1. Locate and orientate the roof to maximise solar access / energy generation

Photovoltaic panels can be located on both flat roofs and pitched roofs, as well as mounted on carports, garages and garden structures.

Houses: Most houses have sufficient space onsite to generate most of the energy needed on an annual basis but will require a battery to be fully self-sustainable.

Apartment blocks: Within Ebbsfleet it should be possible for apartment blocks that are six stories or less in height to achieve a net zero energy balance on site using rooftop solar PV arrays, assuming the blocks achieve the Energy Use Intensity performance level for ‘towards net zero’.

2. Aim to maximise panel density

A large south facing mono-pitch roof will generate the most energy for a scheme. For apartment blocks with a flat roof, east/ west facing concertina type solar arrays will generate up to twice the amount of energy as the conventional approach of orientating rows of south facing panels, with a large offset between each row to avoid overshading. While the concertina layout generates less energy per panel, they do not require the offset to avoid interrow shading, and thus achieve a greater overall area of PV.

3. Aim to specify high performing PV panels

Design teams and planners should look to ensure the following criteria are met for PV panels to ensure a high-quality PV panel is specified;

• Aim to specify high efficiency panels with an output of 300W or greater per panel.

• Check the panel supplied provides a ‘linear warranty’ to ensure the panel will continue to generate energy levels comparable to when new, for longer.

• Confirm that the PV system includes Module Level Power Electronics, (MLPE) such as a micro converter or DC Optimiser.

4. Review energy balance

The total designed renewable energy generation on-site should equal the total predicted energy use, which will provide a zero-carbon on-site balance.

Energy Management

Measuring how a building / project performs once it is completed and in use allows us to pro-actively manage the performance, as well as verify whether the completed building performs in the way it was planned and modelled to do at the design stage. This verification stage is critical to improving our understanding of where and how our design approaches and modelling needs to be improved in future projects.

1. ‘The performance gap’ is a term that has been coined to capture the difference between a building’s modelled performance at the design stage (usually in terms of water use, and energy generated, saved and used) and the actual performance of the building once completed and in use. The use of so called ‘smart’ technology can help us to better understand how a building is operating, and to help us manage energy use, as well as inform our behaviour, to drive energy and water efficiency even further.

2. Smart control systems

   The use of ‘smart’ technology to meter, monitor and control renewable energy generating devices and our heating, cooling, ventilation and other devices will enable us to achieve even greater energy efficiencies.

   Enable home energy management systems to be demand responsive. If a home or building is built to be ‘Demand response’ ready, it means the energy supply can be managed to either reduce or increase consumption for a period of time. This could be managed by the homeowner, to take advantage of cheaper off -peak supply, or by the energy provider to manage peak-demand and create a more stable grid.

   •All homes should include a Smart Thermostat / Home Energy Management System that is WIFI enabled, and supports ‘Active demand response’ (see below)

   • EV Charging points should include ‘Vehicle to Grid’ / ‘Vehicle to Home’ technology to support demand responsive grid network management.

   • Providing battery storage within a home will allow PVs to supply a larger proportion of a dwelling total energy demand, and potentially enable a net zero energy balance.

   • All homes should use LED lighting as standard.

3. Metering

   Locate the electricity smart meter display in the hallway or kitchen, to allow easy monitoring. Locate water meter/ use display in highly visible locations where their visibility can influence user behaviour, such as locating water usage display adjacent to the kitchen sink.

   Consider where sub-meters should be provided in addition to general meters to enhance homeowners and building managers/users understanding of energy and water usage and allow them to actively manage and control their usage more

   effectively.

4. Handover

   Handover is a critical stage in ensuring the homeowners and building managers operate the building as was envisaged at design stage, to ensure it performs as designed.

   Provide building and operational information to residents in the form of site inductions and building user guides. Ensure they understand how the building and systems are designed to operate. Guides should include photos and instructions of actual systems and controls installed.

   EDC projects should adopt a ‘Soft Landings’ approach to planning for the handover and operation of the project after completion, which will include planning for the monitoring of performance.

5. Monitor and report performance

   Design teams should consider how the metering and reporting systems specified at design stage will allow reporting in alignment with the targeted performance metrics. I.e., how easy will it be for homeowners and building occupiers to compare their annual energy usage and water usage against the performance metrics stated in this guide?

   For non-residential projects, the design team should set out a plan for monitoring the building post-completion, specifically stating what data should be collected, how it will be collected and by whom, as well as processes for monitoring and verifying the data.

   Design teams should consider how they plan for the reporting of building performance back to them for the first 5 years, to help to reduce the performance gap. The RIBA 2030 Sustainable outcomes programme advocates that Architects share the operational performance of completed buildings for the first 3 years of operation, to address the performance gap, and share the data with the RIBA to allow them to create a national database.