Ene04 - Low carbon design – Above Green

(3 credits available)

Aim

To encourage the adoption of design measures, which reduce building energy consumption and associated carbon emissions and minimise reliance on active building services systems.

Assessment criteria

This issue is split into two parts:

Passive design (2 credits)
Low or zero carbon technologies (1 credit)

The following is required to demonstrate compliance:

Passive design

One credit - Passive design analysis

The first credit within issue Hea 04 Thermal comfort has been achieved to demonstrate the building design can deliver appropriate thermal comfort levels in occupied spaces.

The project team carries out an analysis of the proposed building site during the Concept Design stage and identifies opportunities for the implementation of passive design solutions that reduce building energy demand (see CN3).

The building uses passive design measures to reduce the overall building energy demand, primary energy consumption or CO₂ emissions by at least 5%, in line with the findings of the passive design analysis.

One credit - Free cooling

The passive design analysis credit is achieved.

The passive design analysis, carried out under criterion 2 , includes an analysis of free cooling and identifies opportunities for the implementation of free cooling solutions.

The building is naturally ventilated or uses any combination of the free cooling strategies listed in CN3.1

Low and zero carbon technologies

One credit - Low zero carbon feasibility study

A feasibility study has been carried out by the completion of the Concept Design stage by an energy specialist (see Relevant definitions) to establish the most appropriate recognised local (on site or near site) low or zero carbon energy sources for the building or development (see CN3.3).

A local LZC technology has been specified for the building or development in line with the recommendations of this feasibility study.

Checklists and tables

None.

Compliance notes

Ref	Terms	Description
Shell and core (non-residential and residential institutions only)
CN1	Applicable assessment criteria	Passive design analysis, criteria 1 to 3 Shell only: Criterion 1 - Hea 04 is not applicable to Shell only assessments; however to achieve the Ene 04 Passive design credit, compliance with Hea 04 criteria 1, 2 and 3 must be demonstrated. Shell and core: All criteria relevant to the building type and function apply. Free cooling, criteria 4 to 6 Shell only: All criteria relevant to the building type and function apply subject to the following: Only free cooling options 1 to 3 listed in CN3.1 are applicable. Shell and core: All criteria relevant to the building type and function apply. LZC feasibility study, criteria 7 to 8 Shell only: All criteria relevant to the building type and function apply, subject to the following: Criterion 7 : The LZC feasibility study must be completed as part of the shell only design, based on the expected building use and loads specified in the design brief or, where these are not specified, for likely scenarios. Criterion 8 : The built form should allow for the future installation of the most cost effective LZC options. Shell and core: All criteria relevant to the building type and function apply. Refer to Appendix D – Shell and core project assessments for a more detailed description of the shell and core assessment options.
Residential - Partially fitted and fully fitted
CN2	Applicable assessment criteria - Single and multiple dwellings	Both options: All criteria relevant to the building type and function apply. Refer to Appendix E – Applicability of BREEAM New Construction to single and multiple dwellings, partially and fully fitted for a more detailed description of residential assessment options.
General
CN3	Passive design analysis. See criterion 3 .	As a minimum, the passive design analysis should cover: Site location Site weather Microclimate Building layout Building orientation Building form Building fabric Thermal mass or other fabric thermal storage Building occupancy type Daylighting strategy Ventilation strategy Adaptation to climate change.
CN3.1	Free cooling analysis. See criterion 7 .	The free cooling analysis should demonstrate consideration of appropriate technologies from the following: Night time cooling (which could include the use of a high exposed thermal mass) Ground coupled air cooling Displacement ventilation (not linked to any active cooling system) Ground water cooling Surface water cooling Evaporative cooling, direct or indirect Desiccant dehumidification and evaporative cooling, using waste heat Absorption cooling, using waste heat.
CN3.2	Free cooling scope	The free cooling should apply to all occupied spaces in the building. Small IT rooms and lift motor rooms are excluded. Mechanical ventilation may only be used for small areas, e.g. for kitchenettes and toilets.
CN3.3	LZC feasibility study. See criterion 8 .	The LZC study should cover as a minimum: Energy generated from LZC energy source per year Carbon dioxide savings from LZC energy source per year Life cycle cost of the potential specification, accounting for payback Local planning criteria, including land use and noise Feasibility of exporting heat or electricity or both from the system Any available grants All technologies appropriate to the site and energy demand of the development Reasons for excluding other technologies Where appropriate to the building type, connecting the proposed building to an existing local community CHP system or source of waste heat or power OR specifying a building or site CHP system or source of waste heat or power with the potential to export excess heat or power via a local community energy scheme.
CN3.4	LZC feasibility study timing. See criterion 8 .	When undertaking a feasibility study at a stage later than Concept Design, an additional element would need to be included in the report to highlight the local LZC energy sources which had been discounted due to the constraints placed on the project by the late consideration, and the reason for their omission. If the feasibility study discounted all local LZC as unfeasible due to the late stage in the project that the study was commissioned, then the credit for the feasibility study must be withheld. If the feasibility study was commissioned at the Concept Design stage or earlier, and in the unlikely event the study concluded that the specification of any local LZC technology was unfeasible, the LZC credit could still be awarded.
CN3.5	Recognised 'local' LZC technologies. See criterion 8 .	Technologies eligible to contribute to achieving the requirements of this issue must produce energy from renewable sources and meet all other ancillary requirements as defined by Directive 2009/28/EC of the European Parliament and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources and amending and subsequently repealing Directives 2001/77/EC and 2003/30/EC (www.eur-lex.europa.eu). The following requirements must also be met. There must be a private wire arrangement for the supply of energy produced to the building under assessment. Where the country of assessment has an independent national certification scheme for installers of small scale renewable energy or Combined Heat and Power systems, these technologies must be certified in accordance with the national scheme. The accreditation scheme must align with the directives listed above, or an equivalent country or regional directive or standard. Air source heat pumps can only be considered as a renewable technology when used in heating mode. Refer to Annex VII of Directive 2009/28/EC for more detail on accounting of energy from heat pumps. Where independent accreditation schemes do not exist in the country of assessment, the design team must demonstrate they have investigated the competence of the installer selected to install the LZC technology and that they are confident the installers have the skill and competence to install the technology appropriately.
CN3.6	Other technology not listed. See criterion 8 .	Other systems may be acceptable as part of a LZC strategy under this issue but are not inherently considered as LZC technologies. Acceptability will be dependent on the nature of the system proposed and the carbon benefits achieved. The BREEAM Assessor must confirm acceptability with BRE if in doubt.
CN3.7	Waste heat from a building - related operational process. See criterion 8 .	Waste heat from an operational process that takes place within the assessed building (or on the assessed site) can be considered as 'low carbon' for the purpose of this BREEAM issue. This is on the condition that the generation of the heat from the process is integral to the assessed building. Examples of operational processes and functions include manufacturing processes, high temperature oven or kiln, compressors serving process plant, microbrewery, crematorium, testing and commissioning boilers for training or manufacture, and data centres. It does not include waste heat from IT or server rooms, which could be used as part of conventional heat recovery measures.
CN3.8	Community and near-site schemes. See criterion 8 .	'Local' does not have to mean on site; community schemes (near site) can be used as a means of demonstrating compliance, as this BREEAM issue seeks to encourage the installation of on site and near site LZC technologies.
CN3.9	Waste incineration. See criterion 8 .	Waste heat from an incineration plant can only be considered as low carbon for the purpose of this BREEAM issue under the following circumstances: All other LZC technologies have been considered and discounted in the feasibility study and; EITHER The local authority or region in which the incineration plant is located is demonstrably meeting its annual waste reuse and recycling targets and waste management policies; OR There is a near site or on site facility connected to the building, via a private wire arrangement, which is demonstrably removing reusable and recyclable waste material prior to incineration.
CN3.10	First generation biofuels. See criterion 8 .	Given the current uncertainty over their impact on biodiversity, global food production and greenhouse gas savings, plus the ease of interchangeability between fossil fuels, BREEAM does not recognise or reward building systems fuelled by first generation biofuels manufactured from feedstocks, e.g. biofuels manufactured from sugars, seeds, grain, animal fats etc. where these are grown or farmed for the purposes of biofuel production. Subject to review against the criteria set out in CN3.11, BREEAM may recognise systems using second generation biofuels (see Relevant definitions) or biofuels manufactured from biodegradable waste materials, e.g. biogas, waste vegetable oil or locally and sustainably sourced solid biofuels, e.g. woodchip, wood pellets, where these are not interchangeable with fossil fuels or first generation biofuels.
CN3.11	Second generation biofuels and biofuels from waste streams. See criterion 8 .	BREEAM recognises that biofuels produced from biomass which is a byproduct of other processes may provide a more sustainable alternative to fossil fuels. Typically, these use waste feedstock consisting of residual non-food parts of current food crops, industry waste such as woodchips, other waste vegetable matter and waste fish oil from sustainable fish stocks to produce biofuel. Such biofuels will, in principle be recognised by BREEAM for the purposes of defining LZC technologies. However due to the emerging nature of such technologies, full details would be required for review by BRE Global prior to confirmation of acceptability. Matters which would be required for consideration include the following: Type, provenance and sustainability of the biomass feedstock Avoidance or minimisation of fossil fuel use in extracting the biofuel Minimising fossil fuel use in transporting the biomass or biofuel Presence of a supply agreement and a robust supply chain Compatibility of the biofuel with the specified boiler or plant and manufacturer's warranty issues. The use of other recycled or waste-derived biofuels such as waste oil from catering may also be recognised by BREEAM subject to the above criteria. For smaller scale applications, the assessor will, in addition, be required to demonstrate that the biofuel is locally sourced. BREEAM does not qualify the term 'locally sourced' or specify a minimum supply contract. However, the assessor must determine and demonstrate that these are reasonable for the particular application.
CN3.12	Approved building energy modelling software	In countries with an existing National Calculation Methodology (NCM), the tools approved for use under the NCM can be used as approved building energy calculation software. These will be confirmed by BRE as part of the approved standards and weightings list process. Where the design team wishes to use an alternative modelling software package for the purposes of assessing this BREEAM issue, please refer to the Approved standards and weightings list to determine whether the modelling software package meets the minimum requirements in terms of: Minimum capabilities design features testing. Where those minimum requirements are met, approval from BRE Global will be required (via the approved standards and weightings list process) before the package can be used for the purposes of demonstrating compliance with Ene 04.
CN3.13	Countries with national energy strategy heavily based on renewables	One credit can be awarded by default where: The building is located in a country where the energy supply from the mains grid is highly de-carbonised, due to this supply being generated from renewable sources AND The feasibility study considers the use of energy from the grid in addition to all other fuel types used within the building AND The feasibility study clearly confirms that the introduction of local LZC technologies on site would have an adverse effect on the overall related emissions.
CN3.14	LZC technology already available on site	For developments where there is an existing LZC energy source that can supply a compliant percentage of energy to the assessed building, a feasibility study will still have to be carried out to demonstrate that the existing technology is the most appropriate for the assessed building or development. The study should seek to identify any other options to supply a higher proportion of the building's energy demand in addition to that supplied by the existing source. In order to be compliant, the energy from any existing LZC energy source must be offsetting the carbon from the building in addition to any existing carbon offsetting that it was established for.
Building type specific
CN4	Schools: information communication technology (ICT) classrooms	With respect to the free cooling credit, it is possible for ICT classrooms to be designed to avoid the use of active cooling. Hence, they are not exempt from the requirements of this issue, i.e. if active cooling were used to treat these spaces, it would not be possible to achieve the free cooling credit within this BREEAM issue.

Methodology

Passive design analysis

Any savings resulting from the incorporation of passive design measures should be demonstrated by comparing the energy demand, primary energy consumption or CO₂ emissions for the building with and without the proposed passive design measures adopted, as identified in the passive design analysis.

To enable a baseline for comparison to be established, a ‘standard building’ should be modelled with fabric performance equivalent to that of the local Building Regulations Notional Building and without the passive design measures where feasible (i.e. building orientation is likely to be fixed).

With the exception of any changes to account for passive design measures and fabric performance, this ‘standard building’ should be modelled as equivalent to the actual building.

Any savings in energy demand, primary energy consumption or CO₂ emissions should then be calculated by comparing the respective outputs from two building models representing the proposed building specification, and the ‘standard building’ specification.

These calculations should be carried out by a building services engineer or by an accredited energy assessor (see Ene 01 Reduction of energy use and carbon emissions – Relevant Definitions).

Low and zero carbon feasibility study

The demand reduction from low or zero carbon (LZC) technologies is demonstrated by comparing regulated carbon dioxide (CO₂) emissions with LZC technologies to the actual building regulated emissions without LZCs.

When the CO₂ savings are compared for different technologies, they may be estimated separately from the building energy model where appropriate, e.g. by using manufacturers' data, simple hand calculations or spreadsheets.

For the specified technology or technologies the demand reductions are modelled using dynamic simulation modelling. The energy supply used for the base case is mains gas and grid electricity. If mains gas were not available at the site, then oil may be used instead. The base case includes any passive design or free cooling measures adopted for the first two credits.

Evidence

criteria

Interim design stage

Final post-construction stage

1, 3

The passive design analysis report.

Evidence confirming the meaningful reduction in the building energy demand.

As design stage AND

BREEAM Assessor’s site inspection report and photographic evidence or

as-built drawings.

4, 7

Results from a dynamic simulation model demonstrating the feasibility of the free cooling strategy and meeting the first credit for Hea 04 Thermal comfort.

As per interim design stage.

Additional information

Relevant definitions

Energy specialist: An individual who has acquired substantial expertise or a recognised qualification for undertaking assessments, designs and installations of LZC solutions in the building sector and is not professionally connected to a single LZC technology or manufacturer.
First and second generation biofuels: First generation biofuels are fuels made from sugar, starch, vegetable oil, or animal fats using conventional technology. Second generation biofuels are fuels from lignocellulosic biomass feedstock using advanced technical processes1. Common first generation biofuels include vegetable oil, biodiesel and bioalcohols.
Free cooling: The ability of the building to provide cooling to the internal occupied areas without the need to rely on energy-consuming mechanical cooling. Free cooling is an enhanced passive design method that requires engineering design and modelling to demonstrate its effectiveness. Other similar methods include enhanced passive ventilation and enhanced daylighting.
Near-site LZC: Refer to .
On-site LZC: Refer to .
Payback period: The period of time needed for a financial return on an investment to equal the sum of the original investment.
Suitably qualified energy modelling engineer: Refer to .

Other information

Passive design aim

Unlike Ene 01 Reduction of energy use and carbon emissions (which is focused on demonstrable and robust performance improvement), Ene 04 Low carbon design aims to encourage project teams to consider a particular design approach.

In relation to the passive design credit, this is mostly reflected in criterion 2; the passive design analysis which is intended to encourage project teams to proactively consider the ways in which the building could benefit from, and adopt passive design measures (such as those listed in CN3).

However, to ensure that the analysis results in constructive outcomes, this has been defined as a minimum 5% reduction of the overall building energy demand, primary energy consumption or CO₂ emissions. Assessors should be aware that, in the majority of cases, it is likely that this threshold will easily be met and that the focus of their assessment should be predominately directed towards the design process that has informed the passive design analysis.

LZC feasibility study

The LZC feasibility study in BREEAM is intended to encourage the study to be done early in the project, not just before construction starts, so that the most appropriate solutions can be adopted. Also, this credit does not permit technologies that are not best practice or sustainable or cannot be modelled with a robust method.