1
Is sufficient weight given to travel-related CO2 emission
when assessing the environmental performance of
offices?
2
Aim and objectives
• Aim:– To determine whether, when assessing the
environmental performance of offices, CO2 emission from commuting and business travel is given sufficient weight
• Objectives:– Compare CO2 emissions resulting from
commuting/business travel with those from building operation
– Investigate weight given to each in BREEAM Offices
– Test whether method for assigning credits for travel-related CO2 emission efficiency is capable of discerning intra-urban differences in location
Source: BRE (2009)
Total UK Carbon emissions by activity
(end user figures)
4
Transport CO2 emission
Road transport accounts for 93% of transport emissions by source (excluding the UK’s share of international aviation and shipping)
70% commuting trips are by car, accounting for 73% of all commuting miles travelled (DoT, 2006)
5
Source: Transport Statistics GB (2007)
Transport CO2 emission
6
CO2 emission from commutingand business travel
• Office activity generates travel as a result of– workers commuting between home and workplace– customers/clients and suppliers visiting the
premises
• The frequency and length of trips and the mode of transport used will depend on:– The requirement for
• Physical presence of workforce• Face-to-face contact with clients
– The location of the office in relation to the location of:
• Workforce• Market• Complementary business activities
– Availability and cost of transport modes
7
CO2 emission from commutingand business travel• Cervero (1988) found that office decentralisation in N. America
led to longer journey distances and greater use of private vehicles
• In Canada the IBI Group (1990) found significant variation in public transport patronage depending on whether the urban form was decentralised, compact or nodal
• In the Netherlands Konings et al (1996) found that developments in existing city limits attracted a greater proportion of public transport commuting than urban extension or rural developments
• In the UK Titheridge and Hall (2006) found that the creation of new growth centres in South East England led to increased car use as the centres provide less opportunities for access by rail
• “The trend towards centralisation of services, distribution and retail provision, often at edge of town developments, …, have all contributed towards increasing demands for transport” (CfIT, 2007)
Office locations in the Bristol Sub-RegionOrdnance SurveyGazetteer and location data© Crown Copyright
Proportion of commuters travelling to office destination wards, classified by mode of travel
Office location
Car driver (inc taxi)
Car passen-
ger
Train Motor-cycle
Walk/bike
Bus
Clevedon 57% 4% 1% 1% 15% 2%
Portishead 63% 5% 0% 1% 11% 1%
Ham Green
55% 4% 0% 2% 18% 2%
Aztec West 76% 6% 0% 1% 9% 4%
Almonds-bury
77% 5% 0% 1% 6% 4%
Parkway 66% 6% 2% 1% 9% 7%
Brabazon 71% 6% 1% 4% 12% 4%
Bristol Bus P
70% 6% 4% 2% 10% 5%
City centre 47% 6% 2% 2% 19% 21%
Source: 2001 Census: Special Workplace Statistics (Level 2)
Proportion of commuters travelling to specific offices in Bristol (2000/1), classified by mode of travel
Office location
Car driver (inc taxi)
Car passen-
ger
Train Motor-cycle
Walk/bike
Bus
Out-of-town
Orange (Aztec West & Almonds-bury)
79% 7% - 2% 6% 7%
City centre
Orange 27% 4% 16% 8% 22% 7%
Andersons 23% - 29% - 25% 23%
Bristol & West
28% 8% 13% 2% 15% 36%
DAS 29% 21% 9% 2% 14% 25%
City centre average
27% 11% 17% 4% 19% 27%
Source: various travel surveys
Gross floor-space (m2) of sampleNat. vent.
cellular
Nat. vent. open-plan
Air-con standar
d
Air-conprestige
Sub-Total
Total
City Centre:Under 10 years
-
1,765 14,320
178,368
194,454
City Centre:10+ years
32,270
195,219
391,336
67,875
686,700
CITY CENTRE 881,153
Out-of-town:Under 10 years
- 43,193
91,760
-
134,953
Out-of-town:10+ years -
100,619
73,659
5,853
180,131
OUT-OF-TOWN
315,084
TOTAL 1,196,238
12
City Centre (overview)
13
North Fringe (Almondsbury and Aztec West Parks)
14
Emersons Green
15
Clevedon
16
2006(M&O)
2008
Criterion Credits
% Credits %
Management 4 5 10 12
Health and Wellbeing 15 18 14 15
Energy 23 28 21 19
Transport 17 21 10 8
Water 9 11 6 6
Materials 3 4 12 12.5
Waste - - 7 7.5
Land Use & Ecology 0 0 10 10
Pollution 11 13 12 10
TOTAL 82 100 102 100
BREEAM Offices
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NaturallyVentilated
Cellular
NaturallyVentilatedOpen Plan
Air-conditioned
Standard
Air-conditioned
Prestige
kgCO2/m2 of
treated floor area [1]
14.8 18.7 38.0 56.4
kgCO2/occu-pant
118.4 149.6 304.0 451.2
Proportion of Bristol stock (in terms of gross floor-space)
3% 28% 48% 21%
[1] Source: Carbon Trust (2000)
Weighted average CO2 emission per worker per annum for Bristol = 286kg
Annual CO2 emission fromoffice occupancy
18
Mode Km travelled per person per
year commuting / on
business
CO2 emission (kg/km/person)
CO2 emission (kg/person) weighted by
distance travelled by each mode
Walk / Bike 51 (1%) 0 0
Car driver 2,285 (69%) 0.1710 (single) 267.68
Car passenger 304 (9%) 0.0855 (share) 2.37
Motorcycle 26 (1%) 0.0872 0.01
Other private 31 (1%) - -
Local bus 109 (3%) 0.0762 0.27
Rail / underground
440 (13%) 0.0486 (train) 2.81
Other public 90 (3%) - -
All modes 3,336 (100%) 273
Annual CO2 emission fromcommuting / business travel
Sources: Dept for Transport, National Atmospheric Emissions Inventory
19
2006 2008
Criterion Credits
% Credits %
Energy 23 28 21 19
Transport 17 21 10 8
BREEAM Offices
• Not all of the transport credits relate to location• In 2006 it was 12 out of 17 credits but in 2008 it
was only four out of the 10 available• This means that in 2008 only 3% of total
BREEAM credits are available for location-dependent transport features (compared to 15% in 2006)
• Given the amount of CO2 emitted as a result of commuting/business travel, this might be regarded as rather low
20
2006• Access to public
transport (up to 2 credits)
• CO2 emissions from commuting and business travel (up to 10 credits)
• Cyclist facilities (up to 3 credits)
• Carried out a travel survey (1 credit)
• Implemented a travel plan (1 credit)
2008• Access to the public
transport network (up to 3 credits)
• Access to local amenities (1 credit)
• Cyclist facilities (up to 2 credits)
• Site layout that ensures pedestrian and cyclist safety (1 credit)
• Travel plan (1 credit)• Restricted parking (up
to 2 credits)
BREEAM Transport Credits
21
Access to public transport (2006)Ordnance SurveyGazetteer and location data© Crown Copyright
500m network distances from public transport nodes
PeakService
Daytimeservice
City centre office space
100% 100%
Out of town office space
11% 77%
Commuting and business travel (2006)
Office location
Proportion using each mode
Kg CO2 per person per
year weighted by mode Source
Car driver (inc taxi)
CarPass’r Train
Motor-cycle
Walk/bike Bus
England 69% - 8% 1% 14% 7% 272 DfT (2008) Transport Statistics GBSouth-West 76% - 2% 1% 15% 5% 298
Temple Quay 27% 11% 17% 4% 19% 27% 114 Travel survey data from Bristol Council
and Orange plc
City centre 47% 6% 2% 2% 19% 21% 187 2001 Census
Bristol Out-of-town
Orange 79% 7% - 2% 6% 7% 311 Orange plc
Clevedon 57% 4% 1% 1% 15% 2% 224
2001 Census
Portishead 63% 5% 0% 1% 11% 1% 248
Ham Green 55% 4% 0% 2% 18% 2% 216
Aztec West 76% 6% 0% 1% 9% 4% 299
Almondsbury 77% 5% 0% 1% 6% 4% 303
Parkway 66% 6% 2% 1% 9% 7% 260
Brabazon 71% 6% 1% 4% 12% 4% 280
BBP 70% 6% 4% 2% 10% 5% 276
Dist travelled each year on commuting / business (km)
2,285 304 439 26 51 109DfT (2008) Transport
Statistics GB
CO2 emission (kg/km) 0.1710 0.0855 0.0486 0.0872 0 0.0762 National Atmospheric Emissions Inventory
Annual CO2 emission by mode (kg)
391 26 21 2 0 8
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Access to public transport (2008)Ordnance Survey
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eDist
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No. Service
sFreq SWT
Reliability Factor
Total Access Time
Equivalent Doorstep
FrequencyAccess Index Total
Zz 1 325 4.06 41 16 8.05 0.75 12.86 2.33 1.17
8 325 4.06 33 20 10.00 0.75 14.81 2.03 1.01
9 325 4.06 30 22 11.00 0.75 15.81 1.90 0.95
40 325 4.06 37 18 8.92 0.75 13.73 2.18 1.09
41 325 4.06 31 21 10.65 0.75 15.46 1.94 0.97
54 325 4.06 53 12 6.23 0.75 11.04 2.72 2.72
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0 0.75 114.81 0.26 0.13
X14 325 4.06 9 73 36.67 0.75 41.48 0.72 0.36
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Equivalent Doorstep Frequency = 30 / (walk time + waiting time)
EDFsotherallEDFAI e __5.0maxmod
Walk time (mins) = Distance (metres) / 80 (metres per minute)
Waiting time (mins) = 0.5 * (660 mins / number of services)Additional waiting time is incorporated to reflect service reliability- Buses = 2 mins- Trains = 0.75 mins Range
of IndexBREEAM Credits
>= 2.00 1
>= 4.00 2
>= 8.00 3
27
Access to local amenities (2008)
28
ConclusionsWeighting• Despite CO2 emission per worker from building operation and
travel being comparable, there is a substantial difference in the credit-weighting allocated to each
• Under the current version of BREEAM for offices, only a maximum of 4% of the available credits can be awarded for ensuring the office location is environmentally sustainable
Model sophistication• Using the 2006 model parameters the results show that all city
centre locations and nearly all out-of-town locations receive maximum BREEAM credits
• Using the 2008 method there is little to distinguish one city centre location from another and, out of town, only one office location receives any credits
• It would appear from these results that the 2008 version of the assessment method is not able to discern intra-urban differences in the sustainability of office locations