04. Low carbon design – Above Green

(6 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)
LZC technologies (4 credits).

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 existing building site during the Concept Design stage and identifies opportunities for the implementation of passive design solutions that reduce building energy demand (see criterion 5 ).

The building uses passive design measures to make a meaningful reduction in building energy demand in line with the findings of the passive design analysis (see CN2.12).

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 CN2.1

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 CN2.3).

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

Up to three credits - LZC technology specification and installation

Criteria 7 to 8 are achieved

A local LZC energy technology has been installed in line with the recommendations of the feasibility study and it can be demonstrated this method of supply results in a reduction in building CO₂ emissions (see Relevant definitions as set out in Table 30

The percentage reduction in building CO₂ emissions has been calculated using approved energy calculation (modelling) software by a suitably qualified energy modelling engineer (see Relevant Definitions).

Table 30: Percentage reduction in building CO₂ emissions

Number of credits	% reduction in building CO₂ emissions
1	10%
2	20%
3	30%

Checklists and tables

None.

Compliance notes

Ref	Terms	Description
Applicable assessment criteria
CN1	Part 1: Fabric and structure	Criteria 1 to 3 Criteria 4 to 6 , options 1 to 3 listed in CN2.1 only
CN1.1	Part 2: Core services	All criteria in this issue are applicable
CN1.2	Part 3: Local services	Criteria 1 to 3 are applicable to consider local services that utilise passive design
CN1.3	Part 4: Interior design	This issue is not applicable
General
CN2	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.
CN2.1	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.
CN2.2	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.
CN2.3	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.
CN2.4	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 infeasible 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 infeasible, the LZC credit could still be awarded.
CN2.5	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.
CN2.6	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.
CN2.7	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.
CN2.8	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.
CN2.9	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.
CN2.10	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 CN2.11, 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.
CN2.11	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.
CN2.12	Meaningful reduction. See criterion 3 .	The amount of energy reduction is not specified in the criteria in this issue. However, it should not be a trivial amount. As a guide, the passive design measures should contribute at least a 5% reduction in overall building energy demand.
CN2.13	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.
CN2.14	Countries with national energy strategy heavily based on renewables	Four credits can be awarded by default where: The building is located in a country where the energy supply from the mains grid is highly decarbonised, 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.
CN2.15	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
CN3	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.
CN3.1	Historic buildings	Under some circumstances an LZC feasibility study may be undertaken however due to heritage building consent or local planning regulations in a heritage conservation area, there may be no recommendations that can be implemented. In this situation, this may be compliant with criteria 7 and 8 provided it can be demonstrated that a wide range of options have been considered with consultation input from the local authority conservation or heritage officer, e.g. considering options for locating LZCs out of public view etc. and the report contains evidence to support these findings.

Methodology

Passive design analysis

The reduction in energy demand associated with the implementation of passive design measures should be demonstrated by comparing the energy demand for the refurbished building with the proposed or new passive design measures, to the energy demand for the existing building. Only the savings that are directly attributable to the proposed passive design measures should be accounted for when undertaking this comparison The energy demand for both scenarios should be calculated by a suitably qualified energy modelling engineer (see Relevant definitions) using approved building energy modelling software (see CN2.13).

Any design assumptions relating to building operation, e.g. occupied hours, internal gains, set temperatures etc. should be consistent between the existing and refurbished building models.

Low and zero carbon feasibility study

The reduction in CO₂ emissions associated with the specification of LZC technologies is demonstrated by comparing the CO₂ emissions for the refurbished building including new or additional LZC technologies to the CO₂ emissions for the existing building. Only the savings that are directly attributable to the proposed LZC technologies should be accounted for when undertaking the comparison.

The CO₂ emissions for both scenarios should be calculated by a suitably qualified energy modelling engineer (see Relevant definitions) using approved building energy modelling software (see CN2.13).

Any design assumptions relating to building operation, e.g. occupied hours, internal gains, set temperatures etc. should be consistent between the existing and refurbished building models.

Evidence

criteria	Interim design stage	Final post-construction stage
All	One or more of the appropriate evidence types listed in 4.0 The BREEAM evidential requirements section can be used to demonstrate compliance with these criteria.
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

Approved building energy modelling software: Refer to Ene 01 Reduction of energy use and carbon emissions.
Building CO₂ emissions: This is the building's CO₂ emissions associated with building services energy including fixed internal lighting systems, fixed heating or cooling, hot water service or mechanical ventilation. It is expressed as kgCO₂/m²/year and calculated in accordance with approved building energy calculation software.
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 Ene 01 Reduction of energy use and carbon emissions.
On-site LZC: Refer to Ene 01 Reduction of energy use and carbon emissions.
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 Ene 01 Reduction of energy use and carbon emissions.

Other information

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.