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Ene 04 Low and zero carbon technologies

Number of credits available Minimum standards
5 Yes


To reduce carbon emissions and atmospheric pollution by encouraging local energy generation from renewable sources to supply a significant proportion of the energy demand.

Assessment Criteria

This issue is split into three parts:

The following is required to demonstrate compliance for:

Feasibility study/Renewable supply contract

One credit

  1. A feasibility study has been carried out by an energy specialist (see Compliance notes) to establish the most appropriate local (on-site or near-site) low or zero carbon (LZC) energy source for the building/development. This study covers as a minimum:
    1. Energy generated from LZC energy source per year
    2. Life cycle cost of the potential specification, accounting for payback
    3. Local planning criteria, including land use and noise
    4. Feasibility of exporting heat/electricity from the system
    5. Any available grants
    6. All technologies appropriate to the site and energy demand of the development.
    7. Reasons for excluding other technologies.
    8. 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/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.
  2. A local LZC energy technology has been specified for the building/development in line with the recommendations of the above feasibility study.
  3. The feasibility study has been carried out at RIBA stage C (concept design) or equivalent procurement stage.


  1. The organisation that occupies the building has in place a contract with an energy supplier to provide electricity for the assessed building/development from a 100% renewable energy source. This supply must be delivered by an accredited external renewable source. The contract must be valid for a minimum of 3 years from the date the assessed building becomes occupied.

Low or zero carbon technology specification and installation (3 credits plus an exemplary credit)

Up to three credits

  1. Criteria 1 to 3 are achieved.
  2. A local LZC energy technology has been installed in line with the recommendations of the feasibility study and this method of supply results in a reduction in regulated CO2 emissions as follows:
No of credits % reduction in regulated CO2 emissions
1 10%
2 20%
Exemplary level 30%
No of credits % reduction in life cycle CO2 emissions
1 N/A (study only)
2 10%
3 20%
Exemplary level 30%

The LCA study must be completed in accordance with ISO 14044:2006 Environmental Management Life Cycle Assessment – Requirements and Guidelines1ISO 14044:2006 Environmental Management Life Cycle Analysis, principals and Framework, International Standards Organisation, Geneva

The LCA must consider a 60 year period (a typical assumption for the life of a building) and any necessary replacements/maintenance requirements within this period.

  1. Figures used for calculations of the percentage carbon reduction provided by LZC technology are based on the output from approved energy modelling software.

Free cooling

One credit

  1. Where, regardless of the percentage reduction in the building’s CO2 emissions from LZC sources and number of BREEAM credits achieved above, the building utilises ANY of the following free cooling strategies and where applicable the first credit within the BREEAM issue Hea 03 Thermal comfort has been achieved:
    1. Night-time cooling (requires fabric to have a high thermal mass)
    2. Ground coupled air cooling
    3. Displacement ventilation (not linked to any active cooling system)
    4. Ground water cooling
    5. Surface water cooling
    6. Evaporative cooling, direct or indirect
    7. Desiccant dehumidification and evaporative cooling, using waste heat
    8. Absorption cooling, using waste heat.
    9. The building does not require any form of cooling (i.e. naturally ventilated)

Exemplary level criteria

The exemplary level criteria to achieve an innovation credit for this BREEAM issue are outlined in the section above.

Compliance Notes





Shell only

To award credits for speculative buildings the feasibility study must be completed as part of the shell only design and build. Where appropriate, as determined by the recommendations of the feasibility study and practicality of installing the LZC technology during the tenant fit-out works, responsibility for specifying/installing the relevant LZC technology can be passed to the future tenant in order to comply with the remaining criteria for this issue. In these circumstances compliance is demonstrated at the design and post construction stages of assessment via either:

  1. Option 1 – Inclusion of the relevant clause(s) in a tenancy lease agreement between the developer and tenant/s (full value of available credits)
  2. Option 2 – N/A
  3. Option 3 – Developer/Tenant collaboration (full value of available credits)

Refer to Appendix D – BREEAM New Construction and shell and core/speculative assessments of this Scheme Document for further description of the above options.


Feasibility study. See criteria 1 & 3

When undertaking a feasibility study at a stage later than concept design (RIBA stage C or equivalent), an additional element will need to be included in the report to highlight the local LZC energy sources which have been discounted due to the constraints placed on the project by the late consideration, and the reason for their omission. If the feasibility study discounts 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 was commissioned at the concept design (outline proposals) stage or earlier and in the unlikely event the study concludes that the specification of any local LZC technology is unfeasible, the first credit can still be awarded; however subsequent credits for installing LZC technology to meet a percentage of building energy demand will not be achievable.


Recognised ‘local’ LZC technologies See criterion 2

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 (

The following requirements must also be met:

  1. Where not provided by accredited external renewables there must be a direct supply of energy produced to the building under assessment.
  2. Where covered by the Microgeneration Certification Scheme (MCS), technologies under 50kWe or 45kWth must be MCS (or equivalent) certified products installed by MCS (or equivalent) certified installers.
  3. Combined Heat and Power (CHP) schemes above 50kWe must be certified under the CHPQA standard.

CHP schemes fuelled by mains gas are eligible to contribute to performance against this issue. Where these schemes are above 50kWe they must be certified under the Combined Heat and Power Quality Assurance (CHPQA).

  1. Air source heat pumps can only be considered as a renewable technology when used in heating mode. Refer to Annex VI of Directive 2009/28/EC for more detail on accounting of energy from heat pumps.


LZC technology not listed See criterion 2 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.


Waste heat from a building related operational process See criterion 1 Waste heat from a process that takes place within the assessed building (or on the assessed site), for the purpose of this BREEAM issue, can be considered as ‘Low carbon’. This is on the condition that the generation of the heat from the process is integral to the assessed building.


Community and off-site schemes See criterion 1 ‘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, accredited external renewables (except where stated to achieve one credit) cannot be used to demonstrate compliance with the criteria of this BREEAM issue.


Waste incineration See criterion 1

Waste heat from an incineration plant can only be considered as low carbon for the purpose of this BREEAM issue under the following circumstances:

  1. All other LZC technologies have been considered and discounted in the feasibility study and EITHER
  2. The Local Authority or region in which the incineration plant is located is demonstrably meeting its annual waste reuse/recycling targets and waste management policies OR
  3. A near or onsite facility connected to the building, via a private wire arrangement, which is demonstrably removing re-usable and recyclable waste material prior to incineration.


First generation biofuels

See criterion 1

Given the current uncertainty over their impact on biodiversity, global food production and greenhouse gas savings, plus the ease of inter-changeability between fossil fuels, BREEAM does not recognise or reward building systems fuelled by first generation biofuels manufactured from feedstock’s 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 the compliance note below 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.


Second generation biofuels and biofuels from waste streams See criterion 1

BREEAM recognises that biofuels produced from biomass which is a by-product 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 and other waste vegetable matter to produce biofuel. Such biofuels will, in principle be recognised by BREEAM for the purposes of defining low/zero carbon technologies, however due to the emerging nature of such technologies, full details will be required for review by BRE Global prior to confirmation of acceptability. Matters which will be required for consideration include the following:

  1. Type, provenance and sustainability of the biomass feedstock
  2. Avoidance/minimisation of fossil fuel use in extracting the biofuel
  3. Minimising fossil fuel use in transporting the biomass/biofuel
  4. Presence of a supply agreement and a robust supply chain
  5. Compatibility of the biofuel with the specified boiler/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.


More than one technology See criteria 1 & 6 The percentage can be made up from more than one of the above technologies.


Building assessed part of a larger development Where the building under assessment forms part of a larger development and either a new or existing LZC installation is provided for the whole site, then the amount of LZC energy generation counted for in this issue, and subsequent CO2 emissions saved, should be proportional to the building’s energy demand compared to the total energy demand for the site (see also note below on existing LZC technology).


LZC technology already available on site See criterion 1

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/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.


Calculation of the CO2 emissions saved See criterion 6

When calculating the energy contribution and CO2 emissions saved from the LZC installation the following rules should be applied:

  1. The net yield of the LZC installation(s) must be used (i.e. subtract any CO2 related to the energy used by the LZC technology itself such as pumps, inverters, controllers, etc.).
  2. The percentage CO2 savings should be calculated using the following assumptions:
    1. Renewable heat energy is displacing gas where the location for the building would practically have access to a gas connection. Where there is no access to a gas connection assume oil is being displaced.*
    2. Renewable electrical energy is displacing grid electricity at the national CO2 conversion rate.

In many instances, Low or Zero Carbon (LZCs) technologies may have been specified to help the building achieve its Target Emission Rate (TER). Furthermore, replacement of the LZCs with a gas boiler would result in the Building Emission Rate (BER) failing to achieve or better the TER and therefore failing to maintain performance in line with Building Regulations standards. This issue seeks to incentivise the provision of energy from LZC technologies within the standards set by Building Regulations. Therefore, for the purposes of this issue, the percentage reduction in regulated CO2emissions as a result of specifying an LZC technology should only account for CO2savings made on the TER and not the BER in such instances.

* The design team is required to provide the assessor with sufficient justification that gas is not available.


Regulated and unregulated energy

Refer to BREEAM issue .


Multi-residential accommodation with CSH assessed self-contained dwellings

For buildings with self-contained dwellings also being assessed under the Code for Sustainable Homes (CSH), the following applies:

Credits achieved under issue Ene 7 of the CSH cannot be applied directly to issue Ene 04 for assessments of multi-residential buildings. This is due to the differing requirement and number of credits assessed in BREEAM. Where specific criteria in this BREEAM issue, identical to that of the CSH, have been demonstrably achieved under a CSH assessment, then the CSH assessment and evidence of compliance can be used to assess and demonstrate compliance with the relevant corresponding criteria in this BREEAM issue.


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 mechanical cooling, as such they are not exempt from the requirements of this issue i.e. if mechanical cooling is used to treat these spaces it will not be possible to achieve the free cooling credit within this BREEAM issue.


Requirement to achieve first credit within Hea 03 where applicable. See criterion 8 This requirement is set as a condition of awarding the free cooling credit to ensure that the cooling strategy implemented is fit for purpose i.e. it achieves the required internal thermal comfort conditions.

Schedule of Evidence

Ref Design stage
Post-construction stage

The feasibility study report.

Design drawings or relevant section/clauses of the building specification or contract.

As design stage AND

BREEAM Assessor’s site inspection report and photographic evidence AND/OR “As built” drawings


Name and details of supplier

Details of the source of supply.

A copy of the contract or other formal documentation confirming the length of contract to supply 100% renewable energy.

As design stage

Evidence (as outlined above) confirming compliance with the first credit.

Report, calculations/outputs from the manufacturer, supplier, engineer or approved modelling software confirming carbon savings as a result of the installed LZC technology.

A copy of the LCA study report/findings (if relevant) demonstrating the percentage carbon saving over the lifetime of the LZC system.

Evidence (as outlined above) confirming compliance with the first credit.

As design stage evidence (using post construction details if changes have been made since the design stage assessment) plus,

BREEAM Assessor’s site inspection report and photographic evidence AND/OR “As built” drawings


Correspondence from the building services engineer summarising the ‘purpose designed’ free cooling strategy.

The results from a dynamic simulation model demonstrating the feasibility of the free cooling strategy.

Evidence as required for the first credit within the BREEAM issue Hea 03 Thermal comfort

As design stage

BREEAM Assessor’s site inspection report and photographic evidence AND/OR “As built” drawings

Evidence as required for the first credit within the BREEAM issue Hea 03 Thermal comfort.

Additional Information

Relevant definitions

Accredited External Renewables
Refer to BREEAM issue .
Approved Energy Modelling Software
Refer to .
Dynamic Simulation Model (DSM)
Refer to .
Energy Specialist
An individual who has acquired substantial expertise or a recognised qualification for undertaking assessments, designs and installations of low or zero carbon solutions in the commercial buildings sector and is not professionally connected to a single low or zero carbon technology or manufacturer.
First and second generation biofuels
First generation biofuels are biofuels made from sugar, starch, vegetable oil, or animal fats using conventional technology. Second generation biofuels are biofuels from lignocellulosic biomass feedstock using advanced technical processes2Sustainable Bioenergy: a framework for decision makers, United Nations – Energy, 2007. 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 chillers.
Life Cycle Cost
Refer to BREEAM issue Man 05 Life cycle cost and service life planning.
Life Cycle Assessment
The requirement to look at the carbon balance of each technology over its whole life. This is to encourage people to consider both operational savings or emissions and also the savings or emissions over the whole life of the technology (from ‘cradle to grave’) therefore reflecting that different technologies have different life spans and impacts at each stage of the life cycle.
Microgeneration Certification Scheme (MCS)
The Microgeneration Certification Scheme (MCS) is an independent scheme that certifies microgeneration products and installers in accordance with consistent standards. It is designed to evaluate microgeneration products and installers against robust criteria, and provides consumers with an independent indication of the reliability of products, assurance that the installation will be carried out to the appropriate standard and a route for complaints should there be any issues.
The MCS is a United Kingdom Accreditation Service (UKAS) accredited certification scheme covering all microgeneration products and services. It has support from the Department of Energy and Climate Change (DECC), industry and non-governmental groups as a prime method for making a substantial contribution to cutting the UK’s dependency on fossil fuels and carbon dioxide emissions.
Near-site LZC
Refer to BREEAM issue.
On-site renewable
Refer to BREEAM issue .
Private wire arrangement
Refer to BREEAM issue .
Payback period
The period of time needed for a financial return on an investment to equal the sum of the original investment
Regulated energy
Refer to BREEAM issue .
Unregulated energy
Refer to BREEAM issue .

Checklists and Tables


Calculation procedures


Other information