BREEAM 2011 Ene01 Calculation Methodology Review Executive ... · Part of the BRE Trust Background BREEAM 2011 Ene01 Calculation Procedure Significant changes were made to the way

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Part of the BRE Trust

Executive Summary A new calculation methodology for determining the number of credits achieved in the Ene01 ‘Reduction of CO2 emissions’ assessment issue was introduced in BREEAM New Construction 2011 (BREEAM NC).

The new methodology uses a triple metric approach that addresses energy demand, energy consumption and CO2 emissions. It is a departure from previous versions of BREEAM which awarded credits based solely on a single, carbon emissions metric. This change was made to enhance the ability of BREEAM to promote designs that minimise energy demand and consumption in buildings, and then to reduce the carbon emissions resulting from that energy use.

The translators of performance contained within the calculation - and hence the credit scales - were based on a representative sample of building types using well established building modelling methods.

Since introducing the new calculation methodology, BRE Global has received feedback from a number of assessors and consultants querying the performance of their building’s’ when using it, specifically:

1 the validity of the performance modelling undertaken to generate the translators of performance that help to determine the number of credits scored;

2 the effect that the new calculation methodology has on buildings with different servicing strategies;

3 the consequences of the using the triple metric approach for buildings with combined heat and power (CHP) systems.

In response to the queries, BRE Global has collected energy performance data for in excess of 500 buildings and carried out detailed analyses to review how the new calculation methodology is performing. This paper describes these and the changes that will be made to the Ene01 assessment issue.

In respect of queries 1 and 2 above, the analysis has confirmed that the new calculation methodology is working as intended and that the original performance modelling and assumptions made in establishing the new scoring systems are valid. BRE Global has also been able to confirm that the new methodology does not penalise naturally ventilated or air conditioned buildings. Information on mixed mode buildings was limited in the data set and although it did not highlight any concerns with the current translators, BRE Global will continue to monitor this through future assessment data.

The review of how the new calculation methodology impacts on buildings with CHP systems has confirmed that CHP is being penalised, due to inconsistencies in the consideration of system boundaries, and that this needs to be addressed. In addition, the final part of the review has indicated that the current benchmark scale used to translate building performance into credits achieved, may be too onerous for parts of the scale.

The main outcomes of the review are as follows:

1 The translators of performance will continue to be based on the performance modelling of the original stock of buildings for the 2011 version of BREEAM NC, and will be updated as necessary to reflect the latest building energy performance data available for future versions.

2 The use of combined translators to represent buildings with all servicing strategies will remain in the current version of BREEAM NC, whilst further investigation into the performance of mixed-mode buildings will be undertaken as more energy performance data becomes available.

3 The energy consumption translator will be updated for use with the 2011 version of BREEAM NC to consider primary energy rather than delivered energy (as it has done to date), to ensure CHP systems are not penalised.

4 The use of primary energy rather than delivered energy in the calculation of the consumption metric will result in minor changes to the performance indicator weightings used to calculate the overall Energy Performance Ratio for New Construction.

5 The existing building Energy Performance Ratio–BREEAM credit scale will be replaced with a new scale for use with the 2011 version of BREEAM NC.

BREEAM 2011 Ene01 Calculation Methodology Review

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BackgroundBREEAM 2011 Ene01 Calculation Procedure

Significant changes were made to the way in which Ene01 credits are calculated as part of the BREEAM NC 2011 update. In previous versions of BREEAM the Ene01 credits have been determined based solely on a building’s carbon emissions, e.g. the CO2 index in BREEAM 2008, but in BREEAM 2011 the credits are based on three parameters of modelled building performance:

1 Energy demand (built form / fabric efficiency)

2 Energy consumption (systems efficiency)

3 CO2 emissions (energy source)

The performance of the actual building against each of these parameters is compared to the notional level (as defined in the 2010 version of the Building Regulations, Part L2a). A percentage improvement is calculated, based on the demand, consumption and CO2 emissions generated, using approved building energy calculation software.

In determining a building’s overall performance in Ene01, the ratio of performance is calculated for each of the three parameters. Relative weights are then assigned to each of the performance indicators to reflect the maximum that each parameter can contribute to the overall Energy Performance Ratio for New Constructions (EPRNC) and ultimately the BREEAM credits.

This ensures that standard practice against the energy efficiency or consumption scale cannot be completely offset by best practice against the carbon performance scale through the specification of low or zero carbon, on or off-site energy solutions. Therefore, BREEAM seeks to encourage and reward a holistic approach to reducing energy and CO2 emissions, through a balance of good building design and systems specification.

The weightings are intended to reflect the degree of influence that a designer has over the buildings performance against each parameter. In terms of their derivation, the weightings are inversely proportional to the standard deviation of the modelled performance of each parameter for the modelled sample set.

The translator of performance for each of the three parameters is based on performance modelling of the same stock of actual buildings used to determine the weightings described above. Using data from this modelling, a normal distribution of performance was established for each parameter which was then used to define a translator of actual building performance into the EPRNC ratio. This is then converted into BREEAM credits.

BRE Global has always intended to use performance data from actual certified buildings to inform and re-define the scales for future versions of the New Construction scheme, to ensure that BREEAM continues to align with achievable and cost effective best practice.

A more detailed description of the calculation procedure, including further information on the principles that have steered the allocation of credits to the EPRNC ratio is included in the Ene01 ‘Additional Information’ section of the BREEAM New Construction 2011 Technical Manual.


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Feedback receivedBRE Global has received queries from a number of assessors and consultants concerning some of the results that have been generated using the new calculation methodology. This feedback can be grouped into the three issues outlined below.

The accuracy of the existing demand, consumption and CO2 emissions translators

The demand, consumption and CO2 emissions translators are key to determining how many credits are achieved in Ene01 so it is important to ensure that the original performance modelling used to inform the translators was representative of the actual building stock and that the ‘policy decisions’ made to define best practice were reasonable.

In order to check whether this original stock of buildings is representative, BRE Global has collected energy performance data for in excess of 500 buildings, recalculated the translators and compared them to the original translators to check for any discrepancies.

The relative performance of naturally ventilated, mixed mode and air conditioned buildings

The existing translators of performance do not differentiate between buildings with different servicing strategies.

In order to check if this approach penalises any particular servicing strategy and determine whether there is a case for using separate translators, BRE Global separated the energy data received into groups of naturally ventilated, air conditioned and mixed-mode buildings to see how each of the individual translators for each servicing strategy compares to the ‘combined’ translators.

The performance of buildings that incorporate Combined Heat and Power (CHP) systems

Buildings with CHP systems have previously been able to score well in Ene01 because when correctly specified, CHP systems can make a significant contribution to reducing CO2 emissions.

To achieve a high level of performance in Ene01 using the new calculation methodology, the design must address all three parameters of performance. This means that buildings with CHP which might have scored well previously without addressing demand and consumption are no longer able to do so. However, there has been some concern that it is still difficult for buildings with CHP systems to score well in Ene01 and meet BREEAM’s minimum standards, even when they have a load profile well suited to CHP and a high level of energy efficiency measures in place.

BRE Global has undertaken the modelling and analysis outlined below to establish whether the current methodology penalises CHP installations due to a possible inconsistency in the calculation procedure - and in particular the way in which the National Calculation Methodology (NCM) generates the actual and notional energy consumption figures that inform the Ene01 calculation. Additional modelling of a range of CHP scenarios has been carried out to explore these concerns in more detail as follows:

1 A building type with a load profile known to be suitable for CHP was modelled first with a conventional heating, ventilation and air conditioning (HVAC) system, and then with CHP to see what effect the introduction of CHP had on the individual consumption and CO2 parameters, the overall EPRNC and the credits scored.

2 Further analysis was carried out on the models for the original stock of buildings used to generate the existing translators to investigate how CHP performs in typical scenarios which are known to incorporate a reasonable level of energy efficiency measures.

3 Further analysis was undertaken for a selection of the building models to investigate how each individual parameter EPRNC and the combined EPRNC varied as the proportion of heat demand met by the CHP system was increased.

4. The results of the above analysis were used to help inform a general review of the way in which the Ene01 calculation procedure works with regards to the use of the outputs from the NCM.

The remainder of this paper describes these issues in more detail, outlines the approach BRE Global has taken to address them and presents the results of the analysis.


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Analysis

Accuracy of Original Translators

Figures 1 to 3 show the existing demand, consumption and CO2 translators and the updated translators that have been redefined using the expanded set of building performance data.

Figures 1 and 2 show that the updated demand and consumption translators are tighter than the existing translators, which means that buildings currently score slightly higher in these parameters than they would if the translators were based on the expanded set of building performance data.


Figure 1

Figure 2

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It is difficult to differentiate between the CO2 translators in Figure 3 since they are almost identical and one is hidden by the other. This means that in terms of CO2 emissions the sample building stock used for the initial performance modelling can be considered truly representative of the expanded set of building performance data received.


Figure 3

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Relative Performance of Buildings with Different Servicing Strategies

Figures 4 to 6 show the results of grouping the energy performance data into buildings with different servicing strategies, to determine whether the current approach of using ‘combined’ translators to represent naturally ventilated, air conditioned and mixed mode buildings is reasonable - or if separate translators would be more appropriate.

Figure 4 shows that the demand translators for naturally ventilated, air conditioned and mixed mode buildings are all within a reasonable tolerance of the combined translator, with the naturally ventilated curve being the closest match. Based on this data set, it can be seen that the effect of using the combined translator is to slightly penalise air conditioned and mixed mode buildings, whilst naturally ventilated buildings achieve a slightly higher EPRNC than they would if individual translators were used. However, it should be noted that the sample of mixed mode buildings was too small to make this curve statistically valid.


Figure 4

Figure 5

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Figure 5 shows that the consumption translators for both naturally ventilated and air conditioned buildings are very close to the combined translator, with naturally ventilated buildings again seeing a small benefit from using the combined translator and the air conditioned buildings being slightly penalised. There is, however, a marked difference between the combined and mixed mode translators, which suggests mixed mode buildings find it more difficult to score well in the consumption parameter and are therefore being penalised by using a combined translator approach.

The CO2 translators in Figure 6 mirror the results for the consumption parameter with the combined translator proving to be a very close approximation of the naturally ventilated and air conditioned buildings, whilst there is a marked difference with the translator for mixed mode buildings.

On the whole, the results are very positive in that they suggest both naturally ventilated and air conditioned buildings are treated fairly by the combined translator approach. There is, however, a discrepancy between the mixed mode and combined translators for the consumption and CO2 emissions translators, which may simply reflect the lack of data available here. Further investigation will be carried out on this curve as more data becomes available.

Performance of Buildings with Combined Heat and Power (CHP) Systems

The first stage of the CHP analysis consisted of creating a new hospital model using approved building energy calculation software to represent a building type with a load profile known to be suitable for CHP. This model was then used to run simulations with a traditional HVAC installation and subsequently a CHP system. The introduction of CHP led to an increase in energy consumption that resulted in a reduced individual consumption EPRNC, but this was outweighed by an improvement in the individual CO2 emissions EPRNC, which created an overall net gain in the combined EPRNC resulting in one additional credit.

Having confirmed that it was possible to achieve an increase in EPRNC through the specification of CHP with a building known to have a suitable load profile, the next stage of the analysis looked at the impact of introducing CHP to the original stock of modelled buildings that were used to create the existing translators and as such have already been modified to a best practice configuration in terms of energy efficiency. The results showed that the losses in the consumption parameter were generally balanced by the gains in the CO2 parameter with the overall combined EPRNC seeing little change.

Having determined that it is possible to achieve small gains in some instances, but that on the whole the introduction of CHP to buildings with good levels of energy efficiency makes only a marginal difference to the overall EPRNC, the next stage of analysis aimed to establish the reason why more significant improvements are not being generated. To carry out this analysis, the modelling was extended to look at the effects on the individual and


Figure 6

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overall EPRNC as CHP is introduced and the proportion of building heat demand met by the CHP system is increased.

The analysis showed that where the thermal output from the CHP system only meets a small proportion of the overall heat demand, the losses in the consumption parameter are not balanced by the gains seen in the CO2 parameter, and the overall EPRNC reduces as a consequence. In some instances, it is not until the actual consumption has increased to the point at which it matches the notional consumption and the individual consumption EPRNC is reduced to zero that the overall EPRNC starts to improve in line with improvements seen in the CO2 parameter, since it is not being penalised any further in the consumption parameter. However, even once this point has been reached, the maximum improvement over the original EPRNC calculated using a conventional HVAC system is very minor and may only account for an increase in credits if the EPRNC happened to be close to a credit boundary to begin with.

It is clear from the energy performance data received to date and the analysis carried out that buildings with CHP are likely to score less well in the consumption parameter which effectively means that the number of Ene01 credits available may be reduced by up to a third (since the energy consumption performance weighting is currently 0.34). To understand why buildings with CHP score relatively poorly in the consumption parameter, it is necessary to consider how the design and actual consumption figures are generated in the National Calculation Methodology (NCM).

The NCM considers ‘delivered energy’ which effectively means the total energy (typically electricity and gas) delivered to the building as metered at the property boundary. It is this use of ‘delivered energy’ as opposed to ‘primary energy’ to calculate the consumption parameter that is causing CHP systems to be penalised by the current methodology.

Figure 7 shows an example building with an annual electric and heat demand both equalling 5000kWh. In the first scenario, which uses a traditional boiler installation to meet the heat demand and grid supplied electricity to meet 100% of the electrical demand, it can be seen that the ‘delivered energy’ is slightly higher than the total energy demand at 10,900kWh compared to 10,000kWh due to the boiler efficiency losses.

In the second scenario which uses a CHP unit sized to meet 100% of the heat demand and 60% of the electrical demand with the remaining 40% of the electrical demand being met by grid supplied electricity, the delivered energy is 12,000kWh i.e. around 10% above that for the first scenario. Therefore, in terms of ‘delivered energy’ it can be seen that the conventional HVAC installation is preferable to the CHP system.


BUILDING

POWER STATION40% EFFICIENCY

BOILER85% EFFICIENCY

CHP UNIT30% ELEC EFF

50% THERMAL EFF

BUILDING

ELECTRIC DEMAND

30kWh

HEATDEMAND50kWh

PRIMARY ENERGYCONVERSION,

TRANSMISSION AND DISTRIBUTION LOSSES

DELIVERED ENERGY PLANT EFFICIENCY


FUEL INPUT

12500kWh

ELEC METER

5000kWh

GAS METER

5900kWh


FUEL INPUT

5000kWh

ELEC METER

2000kWh

GAS METER

10000kWh

FUEL INPUT

5900kWh

FUEL INPUT

10000kWh

ENERGY DEMAND

BOILER85% EFFICIENCY

ELECTRIC DEMAND5000kWh

HEATDEMAND5000kWh

5000kWh

BUILDING

CHP UNIT30% ELEC EFF

50% THERM EFF

ELECTRIC DEMAND5000kWh

HEATDEMAND5000kWh

5000kWh

2000kWh

3000kWh

CHP INSTALLATION SIZED TO MEET 100% OF HEAT DEMAND

CONVENTIONAL HVAC INSTALLATION

5000kWh

Figure 7

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The reason that the ‘delivered energy’ is higher for the CHP scenario is that part of the electrical generation required to meet the overall electrical demand is taking place within the building, which means that the efficiencies associated with this electrical generation are accounted for. Including the efficiency of electrical generation from on-site systems but ignoring the efficiencies associated with grid supplied electricity generation means that the overall efficiency benefits of CHP systems are not currently recognised in the consumption parameter. It is therefore necessary to take a more holistic approach that considers the efficiencies of energy generation and transmission outside the building as well as within it, which effectively means considering ‘primary energy’ instead of ‘delivered energy’. Figure 7 shows that once the efficiencies of grid supplied electricity generation and transmission are included, the total primary energy for the CHP scenario is around 20% below that for the conventional HVAC scenario.

Table 1

Energy Demand kWh Delivered Energy kWh Primary Energy kWh

Conventional HVAC Installation 10000 10900 18400

CHP Installation 10000 12000 15000

Table 1 summarises the energy demand, delivered energy and primary energy figures for the HVAC and CHP examples in Figure 7.

Changing to ‘primary energy’ would affect all building types since the efficiency of electricity generation would be considered for all electrical demand. This will in effect mean that any buildings with high electrical loads and particularly those which use direct electricity to meet the space heating or hot water demand are likely to see a fall in the consumption EPRNC.

The change to a primary energy consumption translator would also change the individual parameter weightings because the standard deviation of modelled performance is lower for ‘primary energy’ than ‘delivered energy’. The weightings are inversely proportional to the standard deviation of modelled performance which means that the consumption weighting would increase to reflect the lower standard deviation whilst the demand and CO2 parameter weightings would decrease accordingly.

Additional Analysis: Linear EPR-Credit Translator

The final part in the process of determining how many BREEAM credits can be awarded is to compare the overall EPRNC against a table of benchmarks and minimum standards. This final section of the analysis considers the performance of the existing benchmark scale and reviews the assumptions that were made to define it.

The existing BREEAM NC 2011 scale was generated by defining 4 fixed points as described below:

1 The EPRNC required to achieve 1 credit was set at 0.05 to recognise buildings which achieved a small improvement over a building regulations compliant design

2 The EPRNC required to achieve 15 credits (maximum) was set to 0.9 which means that a building would need to achieve 80%, 80% and 100% in the individual demand, consumption and CO2 EPRNC respectively. The 100% improvement in the CO2 parameter means that the building is required to have zero net CO2 emissions to achieve the maximum credits available (a BREEAM policy for achieving the maximum Ene01 credits available).

3 To establish the minimum EPRNC for an ‘outstanding’ rating it was decided that a building should achieve 80%, 80% and 60% for the demand, consumption and CO2 EPRNC respectively which equates to an overall EPRNC of 0.72.

4 To establish the minimum EPRNC for an ‘excellent’ rating, it was decided that the building should achieve 60%, 60% and 40% for the demand, consumption and CO2 EPRNC respectively which equates to an overall EPRNC of 0.55.

In addition to the overall EPRNC, there are minimum requirements relating specifically to the CO2 parameter that need to be met to achieve an Excellent or Outstanding rating, however these minimum requirements do not have an impact on defining the EPRNC-credit scale.

In keeping with previous BREEAM schemes the number of credits awarded for ‘excellent’ and ‘outstanding’ ratings were set to 6 and 10 respectively. These 4 fixed points were used to define the scale and calculate the EPRNC required to achieve the credits as indicated by the blue curve in Figure 8.


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Figure 8 shows that as a consequence of taking the approach outlined above, the improvement in EPRNC required to move between credits is greater at the lower end of the scale where an increase in EPRNC of 0.1 is required to move from 1 to 2 credits than it is at the upper end of the scale where an increase of only 0.3 is required to move from 14 to 15 credits. This approach was adopted on the basis that it should be easier to make initial gains in building performance whilst it becomes harder to make further gains as the overall performance of the building improves. However, this is already accounted for to some degree by the individual translators of performance which means applying a further correction through EPRNC-credit scale is unnecessarily demanding.

The energy performance data received has shown that a significant number of buildings struggle to reach 6 credits i.e. the point where subsequent credits become relatively ‘easier’ to achieve which suggests that the initial EPRNC-credit ratio is too harsh and the scale is not working as intended.

Using an alternative linear translator as indicated by the red line in Figure 8 would mean that a building which achieves 50% of the total EPRNC available would achieve 50% of the total credits available (provided that any additional minimum requirements for the CO2 parameter were also met). This approach is simple, takes any ‘assumption’ out of the equation and allows the individual translators to do any correction necessary in terms of compensating for best practice performance.

With the exception of buildings with an EPRNC between 0.05 and 0.06 which score 0 credits instead of 1, all buildings would benefit from replacing the existing credits scale with a linear version, with those which have an EPRNC ranging from around 0.4 to 0.7 (currently scoring 4 to 9 credits) benefiting the most by seeing an increase of up to 3 credits.


Figure 8

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Conclusions

Accuracy of Existing Translators

The curves for the updated translators are very close to those of the existing translators which suggests that the original stock of buildings used to inform the translators is representative of the actual building stock and the translators are working as intended. The translators of performance will therefore continue to be based on the performance modelling of the original stock of buildings for all assessments carried out under BREEAM New Construction 2011.

Whilst the original translators bear a very close resemblance to the updated translators, there has been some movement which is to be expected. BRE Global will continue to collect data and review these benchmarks and we intend to update them as part of the next revision to BREEAM New Construction. This will ensure they reflect the most up to date performance data from BREEAM certified buildings and that BREEAM continues to align with achievable and cost effective best practice.

Relative Performance of Buildings with Different Servicing Strategies

The individual analysis of the energy performance data for naturally ventilated, air conditioned and mixed mode buildings has shown that on the whole the individual translator curves for each servicing strategy are within a reasonable tolerance of the combined translator curve. The majority of any discrepancies are very minor and based on the current energy performance data received, the combined translator approach is working appropriately and effectively for naturally ventilated and air conditioned buildings.

The consumption and CO2 emissions translators for mixed mode buildings suggest that it may currently be more difficult for mixed mode buildings to score as well in the consumption and subsequently CO2 emissions parameters. However, BRE Global have only received limited data on mixed-mode buildings and as such it has not yet been possible to establish the accuracy of the updated mixed mode translator curve or the reason for this discrepancy, and therefore no firm conclusions can be reached in this respect.

BRE Global will continue to review the energy performance data received for mixed mode buildings and will carry out further analysis to establish the validity and reason for the current discrepancy. However, since the majority of results suggest that using a combined translator is a reasonable approximation for all buildings regardless of the servicing strategy employed, BRE Global will maintain the combined translator approach for BREEAM New Construction 2011 and currently intend to continue this for any future revisions.

Performance of Buildings with CHP Systems

The analysis has shown that whilst it is possible to make small improvements over conventional solutions by using CHP systems, the use of delivered energy instead of primary energy in the consumption parameter is penalising CHP systems. The calculation methodology will therefore be updated to account for primary energy instead of delivered energy to recognise the potential for efficiency savings associated with CHP installations.

Article 9 of the Energy Performance of Buildings (EPBD) recast (2010), ‘Nearly Zero-Energy Buildings’ outlines the requirement to provide a national definition of zero energy, which includes a primary energy indicator expressed in kWh/m2/yr. In response to this requirement, the primary energy factors that will be used to determine primary energy use in the next version of the NCM were established earlier this year and can now be used to inform the Ene01 calculation procedure through updating the Ene01 tools and the BREEAM Ene01compliance checker website. The primary energy factors are however, still under consultation and subject to review.

In practice, the change from delivered energy to primary energy will mean that a new translator of performance will be used for the consumption parameter. The new translator will be based on the same performance modelling of the original stock of buildings, but the data set taken from this performance modelling will be different. The change to primary energy will affect the performance of all buildings. Those which rely on direct electricity to meet heating and hot water demands are likely to see a reduction in their consumption EPRNC whilst those with CHP likely to see a benefit where demand is managed sensibly.

The introduction of the new primary energy consumption translator will result in changes to the individual parameter weightings as indicated in Table 2.

Table 2

Performance Indicator Existing Weighting Revised Weighting

Energy demand 0.28 0.25

Energy consumption 0.34 0.41

CO2 emissions 0.38 0.34


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EPR-Credit Translator

The existing EPRNC-credit translator will be replaced by a linear translator which will result in the majority of projects receiving additional credits under Ene01.

Table 3

Credits Existing EPRNC Revised EPRNC

1 0.05 0.06

2 0.15 0.12

3 0.25 0.18

4 0.35 0.24

5 0.45 0.3

6 0.55 0.36

7 0.59 0.42

8 0.63 0.48

9 0.67 0.54

10 0.72 0.6

11 0.75 0.66

12 0.79 0.72

13 0.83 0.78

14 0.87 0.84

15 0.9 0.9

The change to a linear translator will mean that the minimum EPRNC requirement to achieve an Excellent or Outstanding rating would reduce from 0.55 to 0.36 and from 0.72 to 0.6 respectively. Table 2 above shows the revised EPRNC-credit scale in full.

It should be noted that whilst the EPRNC-credit scale will be updated, the minimum requirements relating to the CO2 parameter will remain unchanged so that a 25% and 40% improvement over the TER are still required to achieve ‘excellent’ and ‘outstanding’ ratings respectively, and a 100% improvement over the TER i.e. zero net CO2 emissions is still required to achieve 15 credits.

Implementing the changes to the BREEAM New Construction 2011 version

The changes described in this paper are effective immediately (15th June 2012). The following section summarises the effect of the changes to existing BREEAM tools and assessments.

BREEAM calculator tools

The BREEAM 2011 Assessment Scoring and Reporting tool (version 2.80) has been updated to reflect the change to the EPR-credit scale and is available from the BREEAM Assessors Extranet. The BREEAM Pre-Assessment Estimator has also been updated (version 2.50) and is available from the BREEAM website and Assessors Extranet.

BREEAM Compliance Checker website

As described above, current versions of the approved building energy modelling software calculate energy consumption on the basis of delivered energy, not primary energy. In the short term therefore it will not be possible to use the figures reported in the BRUKL Output Document (technical data sheet) to accurately determine the number of BREEAM credits achieved. Until such time as the next version of the National Calculation Methodology is revised to include primary energy, BREEAM assessors and consultants will need to upload their BRUKL output files to the BREEAM Compliance Checker website to accurately calculate and verify the three EPRs for demand, consumption and CO2 and the number of BREEAM credits achieved.

www.epbhub.net/BREEAM


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Buildings that have based their BREEAM performance on the existing BREEAM New Construction 2011 Ene01 methodology (issues 1.0 and 2.0 of the Technical Manual)

As a result of the changes described in this paper BRE Global envisage that in most cases the number of Ene01 credits achieved will increase or remain unchanged for building designs that have already undergone some form of 2011 pre-assessment (but not completed their assessment to certification).

Building designs that have undertaken a pre-assessment and progressed on the basis of an assumed number of Ene01 credits determined using the existing EPR-credit benchmark scale and/or delivered energy, have the option to continue to apply through to certification the existing EPR-BREEAM credit scale defined with the current issue of the BREEAM New Construction 2011 Technical Guide (issue 2.0). The assessment report should identify that this is the case.

Buildings that have been BREEAM certified or currently undergoing quality assurance

Assessors or clients whose buildings have been certified or whose assessments are currently undergoing quality assurance, and based their BREEAM performance on the existing BREEAM New Construction 2011 Ene01 methodology (issues 1.0 and 2.0 of the Technical Manual) should contact BRE Global directly to discuss options for updating their report and/or re-certifying their assessment if desired. Certification will not be revoked as a result of this change where updating is not carried out.


BRE Global Bucknalls Lane Watford WD25 9XX

Tel. +44 (0)1923 664462 Email. [email protected] Web. www.breeam.org

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BREEAM 2011 Ene01 Calculation Methodology Review Executive ... · Part of the BRE Trust Background BREEAM 2011 Ene01 Calculation Procedure Significant changes were made to the way