WLCO2T URS

WLCO2T

Calculating whole life cost and whole life carbon

footprint of pavement projects

June 01, 2012

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Contents

• Context

• What does the app do?

• How does the app work?

• How to use the app

• Case study 1: Determine the optimum maintenance strategy

• Case study 2: Determine the optimum year for intervention

• Summary

• Limitations

• Future developments

2

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Context

3

• Current legislation

• Carbon Reduction Commitment Energy Efficiency Scheme

• Climate Change Levy

• Climate Change Agreements

• Building Regulations

• EU Energy Performance in Buildings Directive

• EU Energy Trading Scheme

• Future legislation

• Market mechanism

• Emissions trading

• Clean Development Mechanism

• Joint implementation

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Context

4

“Less carbon does not mean less construction. It means constructing different

forms of infrastructure, by different methods, using different materials. And to do

that we need to develop new skills and new tools.

We need new tools for project appraisal. Today this is about whole-life costs and

net present value in monetary terms. We refer to 'Capex' and 'Opex'. We now

need to add the carbon factor. We need to know how much carbon will be

embodied in the proposed infrastructure, and how much will be used during

construction and operation.

We need to know the 'CapCarb' and 'OpCarb' - new terms for most of us. And

importantly we need to understand the relationship and trade-off between these

two measures.”

Peter Hansford, ICE President

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Context

5COMPANY CONFIDENTIAL: Use this space for disclaimer if needed.

“While there are noticeable highs and lows in year to year data, over longer

periods of time there is a discernable warming trend across the globe. Natural

causes can explain only a small part of this warming. The overwhelming

majority of scientists agree that this is due to rising concentrations of heat-

trapping greenhouse gases in the atmosphere caused by human activities”.

To avoid these problems, we will have to significantly reduce our energy

needs and generate more power from non-carbon sources. The transition to a

low carbon economy presents major global opportunities for business. The

demand for low carbon and environmental goods and services is already

worth £3.2 trillion per year, and is predicted to increase as the move to a low

carbon economy occurs.”

www.metoffice.gov.uk/climate-change

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Context

6

“Global warming could shrink the global economy by 20% while taking action

now would cost just 1% of global gross domestic product.”

The Economics of Climate Change, Sir Nicholas Stern

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What does the app do?

7

• Calculates costs and emissions associated with pavement maintenance based

on quantities of resources required during a 60 year analysis period

• The app allows decision makers to understand the balance between cost and

carbon by calculating the following parameters for a range of alternative

maintenance strategies:

• Capital cost (Capex): discounted costs in Years 1 - 5

• Operational cost (Opex): discounted costs in Years 6 - 60

• Whole life cost (WLC): discounted costs in Years 1 - 60

• Capital carbon footprint (CapCarb): carbon in Years 1 - 5

• Operational carbon footprint (OpCarb): carbon in Years 6 - 60

• Whole life carbon footprint (WLCO2): carbon in Years 1 - 60

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How does the app work?

8

• Built on standard approach to whole life cost analysis

• Considers initial maintenance and future maintenance

• Database contains unit costs for a range of treatments

• Follows basic HM Treasury rules for project appraisal

• 60 year analysis period

• 3.5% discount for first 30 years

• 3.0% discount rate thereafter

• Residual value is taken into account

• Carbon emissions factors included in treatments database

(ICE CESMM3 Carbon and Price Book 2011)

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How does the app work?

9

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Treatments database

10

Flexible pavements

Retexture: Limestone

Retexture: Flint

Emulsion tack coat

Thin Surfacing: 20mm



High Friction Surfacing (new)

High Friction Surfacing (replacement)

Resurface (to same level)

Resurface (Porous Asphalt)

Inlay: 100mm

Plane off + Overlay: 50mm (Net)

Plane off + Overlay:100mm (Net)




Reconstruction: 150mm Full flex.

Reconstruction: 200mm Full Flex.

Reconstruction: 200mm Flex. Comp.









Structural Patch: 50mm depth




Recycled Thin Surf.: 20mm



Recycled Resurface (to same level)

Recycled Resurface (Por. Asphalt)

Recycled Inlay: 100mm

Recycled P/O + Overlay: 50mm (Net)

Recycled P/O + Overlay:100mm (Net)




Recycled Reconst.: 150mm Full flex.

Recycled Reconst.: 200mm Full Flex..

Recycled Reconst.: 200mm Flex. Comp.

Recycled Reconst.: 250mm Full Flex.








Recycled Structural Patch: 50mm depth




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Treatments database

11

Concrete pavements

Thin Surf.: 30mm

Thin Bonded Repairs

Full Depth Repairs: JRC

Full Depth Repairs: URC

Retexture: Limestone

Retexture: Flint

Joint seal JRC: longitudinal(*)

Joint seal URC: longitudinal(*)

Joint seal JRC: transverse(*)

Joint seal URC: transverse(*)

Joint saw-cut & seal JRC: longitudinal(*)

Joint saw-cut & seal URC: longitudinal(*)

Joint saw-cut & seal JRC: transverse(*)

Joint saw-cut & seal URC: transverse (*)

Joint Repairs

Punch Out Repairs

Vacuum Grout: Bay

Vacuum Grout: Joint

Overlay: 150mm

Overlay: 180mm

Overlay: 300mm

Overlay: 200mm of CRCP

Crack & Seat with 150mm Overlay



Reconstruction: CRCR with 100mm Bit



Reconstruction: 200mm JRC

Reconstruction: 200mm URC

Reconstruction: 200mm CRCP



Reconstruction: 250mm CRCP



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Input screen

12

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Input screen

13

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Build scenarios

14

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Results

15

Option DescriptionCapital Cost

(£)

Operational

Cost (£)

Whole Life

Cost (£)

CapCarb

(tCO2)

OpCarb

(tCO2)

Whole

Life

Carbon

Footprint

(tCO2)

A 20 year fully flexible design £207,174.00 £249,323.30 £456,497.30 172.18 618.66 790.84

B 40 year fully flexible design £259,208.40 £158,394.23 £417,602.63 464.81 620.83 1,085.65

C 40 year rigid design £324,733.20 £175,523.23 £500,256.43 0.00 156.02 156.02

D do minimum £11,087.39 £355,117.83 £366,205.23 5.76 501.66 507.43

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Case study 1: strategy selection

16

• Three-lane dual carriageway in London

• Significant structural deterioration

• Client needs to select the treatment that optimises cost and carbon to

progress to detailed design

• Maintenance strategies

• 20 year fully flexible design

• 20 year flexible composite design

• 40 year fully flexible design

• 40 year rigid design

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17

Year Option A Option B Option C Option D

20 year flexible design 20 year flexible composite design 40 year flexible design 40 year rigid design

2011: Year 01 Reconstruction: 250mm Full Flex. Reconstruction: 250mm Flex Comp. Reconstruction: 350mm Full Flex. Reconstruction: 200mm CRCP

- - - - -

2020: Year 10 Resurface (to same level) Resurface (to same level) Resurface (to same level) Resurface (to same level)

- - - - -

2030: Year 20 Reconstruction: 250mm Full Flex. Reconstruction: 250mm Flex Comp. Resurface (to same level) Resurface (to same level)

- - - - -


- - - - -

2050: Year 40 Reconstruction: 250mm Full Flex. Reconstruction: 250mm Flex Comp. Reconstruction: 350mm Full Flex. Reconstruction: 200mm CRCP

- - - - -


- - - - -

2070: Year 60 Reconstruction: 250mm Full Flex. Reconstruction: 250mm Flex Comp. Resurface (to same level) Resurface (to same level)

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18


(£)

Operational

Cost (£)

Whole Life

Cost (£)

CapCarb

(tCO2)

OpCarb

(tCO2)

Whole Life

Carbon

Footprint

(tCO2)

A 20 year flexible design £207,174.00 £249,323.30 £456,497.30 172.18 618.66 790.84

B 20 year flexible composite design £246,199.80 £284,951.71 £531,151.51 453.86 1,285.45 1,739.30

C 40 year flexible design £259,208.40 £158,394.23 £417,602.63 464.81 620.83 1,085.65

D 40 year rigid design £300,161.40 £169,099.85 £469,261.25 8,063.89 8,219.90 16,283.79

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19

Whole Life Cost

£0.00

£100,000.00

£200,000.00

£300,000.00

£400,000.00

£500,000.00

£600,000.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve N

PV

(£)

Option A

Option B

Option C

Option D

Whole Life Carbon Footprint

0.00

2000.00

4000.00

6000.00

8000.00

10000.00

12000.00

14000.00

16000.00

18000.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve C

arb

on

Fo

otp

rin

t (t

CO

2)

Option A

Option B

Option C

Option D

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20

Whole Life Cost

£0.00

£100,000.00

£200,000.00

£300,000.00

£400,000.00

£500,000.00

£600,000.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve N

PV

(£)

Option A

Option B

Option C

Option D


0.00

2000.00

4000.00

6000.00

8000.00

10000.00

12000.00

14000.00

16000.00

18000.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve C

arb

on

Fo

otp

rin

t (t

CO

2)

Option A

Option B

Option C

Option D

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Case study 2: time for intervention

21

• Option A selected from Case Study 1

• Now study the impact of continuing with routine maintenance to defer the

major capital expenditure

• Maintenance strategies

• Construct option A in Year 1

• Routine maintenance in Year 1, construct option A in Year 2

• Routine maintenance in Years 1 and 2, construct option A in Year 3

• Routine maintenance in Years 1, 2 and 3, construct option A in Year 4


(£)

Operational

Cost (£)

Whole Life

Cost (£)

CapCarb

(tCO2)

OpCarb

(tCO2)

Whole Life

Carbon

Footprint

(tCO2)

A 20 year flexible design £207,174.00 £249,323.30 £456,497.30 172.18 618.66 790.84

B 20 year flexible composite design £246,199.80 £284,951.71 £531,151.51 453.86 1,285.45 1,739.30

C 40 year flexible design £259,208.40 £158,394.23 £417,602.63 464.81 620.83 1,085.65

D 40 year rigid design £300,161.40 £169,099.85 £469,261.25 8,063.89 8,219.90 16,283.79

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22

Year Option A Option B Option C Option D

20 year flexible design 20 year flexible design 20 year flexible design 20 year flexible design

deferred by 1 year deferred by 2 years deferred by 3 years

2011: Year 01 Reconstruction: 250mm Full Flex. Structural Patch: 50mm depth Structural Patch: 50mm depth Structural Patch: 50mm depth

2012: Year 02 - Reconstruction: 250mm Full Flex. Structural Patch: 50mm depth Structural Patch: 50mm depth

2013: Year 03 - - Reconstruction: 250mm Full Flex. Structural Patch: 50mm depth

2014: Year 04 - - - Reconstruction: 250mm Full Flex.

- - - - -

2020: Year 10 Resurface (to same level) - - -

2021: Year 11 - Resurface (to same level) - -

2022: Year 12 - - Resurface (to same level) -

2023: Year 13 - - - Resurface (to same level)

- - - - -

2030: Year 20 Reconstruction: 250mm Full Flex. - - -

2031: Year 21 - Reconstruction: 250mm Full Flex. - -

2032: Year 22 - - Reconstruction: 250mm Full Flex. -


- - - - -





- - - - -


2051: Year 41 - Reconstruction: 250mm Full Flex. - -

2052: Year 42 - - Reconstruction: 250mm Full Flex. -


- - - - -





- - - - -


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23


(£)

Operational

Cost (£)

Whole Life

Cost (£)

CapCarb

(tCO2)

OpCarb

(tCO2)

Whole Life

Carbon

Footprint

(tCO2)

A 20 year flexible design (year 1) £207,174.00 £249,323.30 £456,497.30 172.18 618.66 790.84

B 20 year flexible design (year 2) £204,215.24 £214,594.59 £418,809.82 137.94 365.64 503.58

C 20 year flexible design (year 3) £201,356.53 £207,337.77 £408,694.29 139.86 365.64 505.50

D 20 year flexible design (year4) £198,594.49 £200,326.34 £398,920.83 141.78 365.64 507.43

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24

Whole Life Cost

£0.00

£50,000.00

£100,000.00

£150,000.00

£200,000.00

£250,000.00

£300,000.00

£350,000.00

£400,000.00

£450,000.00

£500,000.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve N

PV

(£)

Option A

Option B

Option C

Option D


0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

800.00

900.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve C

arb

on

Fo

otp

rin

t (t

CO

2)

Option A

Option B

Option C

Option D

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25

Whole Life Cost

£0.00

£50,000.00

£100,000.00

£150,000.00

£200,000.00

£250,000.00

£300,000.00

£350,000.00

£400,000.00

£450,000.00

£500,000.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve N

PV

(£)

Option A

Option B

Option C

Option D


0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

800.00

900.00

0 10 20 30 40 50 60

Years

Cu

mu

lati

ve C

arb

on

Fo

otp

rin

t (t

CO

2)

Option A

Option B

Option C

Option D

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Summary

26

• Allows decision makers to understand the trade off between cost and carbon for

a range of options, can be used to:

• Select options for further design development

• Demonstrate the optimum time to invest to obtain maximum value for money

• Relatively quick and easy to use

• Enables appraisal of various options under a single system architecture

• Database can be populated with project-specific cost and carbon data

• Cost and carbon data are mutually exclusive items in the database so, the app

can be used to study both parameters together or one parameter individually

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Limitations

27

• Can analyse four alternative maintenance strategies

• Inputs cannot be saved for future editing

• Costs do not include:

• Preliminaries

• Traffic Management

• User delay costs

• Non pavement items

• Optimism bias

• Carbon emissions factors for some treatments are not available

• Particularly rigid pavement maintenance treatments

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Future development

28

• Improve user friendliness

• Include new-build construction activities

• Include Traffic Management costs

• Link to other highway asset types

• Earthworks

• Street lighting

• Adopt system architecture for other linear assets

• Rail

• Drainage

29

[email protected]

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