Calculating whole life cost and whole life carbon footprint of pavement projects

1. WLCO2T
Calculating whole life cost and whole life carbon
footprint of pavement projects
June 01, 2012

2. 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
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3. Context
• 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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4. Context
“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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5. Context
“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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COMPANY CONFIDENTIAL: Use this space for disclaimer if needed.
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6. Context
“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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7. What does the app do?
• 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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8. How does the app work?
• 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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9. How does the app work?
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10. Treatments database
Flexible pavements Structural Patch: 100mm depth
Retexture: Limestone Structural Patch: 150mm depth
Retexture: Flint Structural Patch: 200mm depth
Emulsion tack coat Recycled Thin Surf.: 20mm
Thin Surfacing: 20mm Recycled Thin Surf.: 25mm
Thin Surfacing: 25mm Recycled Thin Surf.: 30mm
Thin Surfacing: 30mm Recycled Resurface (to same level)
High Friction Surfacing (new) Recycled Resurface (Por. Asphalt)
High Friction Surfacing (replacement) Recycled Inlay: 100mm
Resurface (to same level) Recycled P/O + Overlay: 50mm (Net)
Resurface (Porous Asphalt) Recycled P/O + Overlay:100mm (Net)
Inlay: 100mm Recycled P/O + Overlay: 150mm (Net)
Plane off + Overlay: 50mm (Net) Recycled P/O + Overlay: 200mm (Net)
Plane off + Overlay:100mm (Net) Recycled P/O + Overlay: 250mm (Net)
Plane off + Overlay:150mm (Net) Recycled Reconst.: 150mm Full flex.
Plane off + Overlay:200mm (Net) Recycled Reconst.: 200mm Full Flex..
Plane off + Overlay:250mm (Net) Recycled Reconst.: 200mm Flex. Comp.
Reconstruction: 150mm Full flex. Recycled Reconst.: 250mm Full Flex.
Reconstruction: 200mm Full Flex. Recycled Reconst.: 250mm Flex. Comp.
Reconstruction: 200mm Flex. Comp. Recycled Reconst.: 300mm Full Flex.
Reconstruction: 250mm Full Flex. Recycled Reconst.: 300mm Flex. Comp.
Reconstruction: 250mm Flex. Comp. Recycled Reconst.: 350mm Full Flex.
Reconstruction: 300mm Full Flex. Recycled Reconst.: 350mm Flex. Comp.
Reconstruction: 300mm Flex. Comp. Recycled Reconst.: 400mm Full Flex.
Reconstruction: 350mm Full Flex. Recycled Reconst.: 400mm Flex. Comp.
Reconstruction: 350mm Flex. Comp. Recycled Structural Patch: 50mm depth
Reconstruction: 400mm Full Flex. Recycled Structural Patch: 100mm depth
Reconstruction: 400mm Flex. Comp. Recycled Structural Patch: 150mm depth
Structural Patch: 50mm depth Recycled Structural Patch: 200mm depth
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11. Treatments database
Concrete pavements Overlay: 150mm
Thin Surf.: 30mm Overlay: 180mm
Thin Bonded Repairs Overlay: 300mm
Full Depth Repairs: JRC Overlay: 200mm of CRCP
Full Depth Repairs: URC Crack & Seat with 150mm Overlay
Retexture: Limestone Crack & Seat with 180mm Overlay
Retexture: Flint Crack & Seat with 300mm Overlay
Joint seal JRC: longitudinal(*)
Reconstruction: CRCR with 100mm Bit
Joint seal URC: longitudinal(*)
Reconstruction: CRCR with 150mm Bit
Joint seal JRC: transverse(*)
Reconstruction: CRCR with 200mm Bit
Joint seal URC: transverse(*)
Joint saw-cut & seal JRC: longitudinal(*) Reconstruction: 200mm JRC
Joint saw-cut & seal URC: longitudinal(*) Reconstruction: 200mm URC
Joint saw-cut & seal JRC: transverse(*) Reconstruction: 200mm CRCP
Joint saw-cut & seal URC: transverse (*) Reconstruction: 250mm JRC
Joint Repairs Reconstruction: 250mm URC
Punch Out Repairs Reconstruction: 250mm CRCP
Vacuum Grout: Bay Reconstruction: 300mm JRC
Vacuum Grout: Joint Reconstruction: 300mm URC
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12. Input screen
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13. Input screen
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14. Build scenarios
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15. Results
Whole
Life
Capital Cost Operational Whole Life CapCarb OpCarb
Option Description Carbon
(£) Cost (£) Cost (£) (tCO2) (tCO2)
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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16. Case study 1: strategy selection
• 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. Case study 1: strategy selection
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)
- - - - -
2040: Year 30 Resurface (to same level) Resurface (to same level) 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
- - - - -
2060: Year 50 Resurface (to same level) Resurface (to same level) Resurface (to same level) Resurface (to same level)
- - - - -
2070: Year 60 Reconstruction: 250mm Full Flex. Reconstruction: 250mm Flex Comp. Resurface (to same level) Resurface (to same level)
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18. Case study 1: strategy selection
Whole Life
Capital Cost Operational Whole Life CapCarb OpCarb Carbon
Option Description
(£) Cost (£) Cost (£) (tCO2) (tCO2) 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. Case study 1: strategy selection
Whole Life Cost
£600,000.00
£500,000.00
£400,000.00
Cumulative NPV (£)
Option A
Option B
£300,000.00
Option C
Option D
£200,000.00
£100,000.00
£0.00
0 10 20 30 40 50 60
Years
Whole Life Carbon Footprint
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20. £0.00
Case study 1: strategy selection 0 10 20 30
Years
40 50 60
Whole Life Carbon Footprint
18000.00
16000.00
Cumulative Carbon Footprint (tCO2)
14000.00
12000.00
Option A
10000.00
Option B
Option C
8000.00
Option D
6000.00
4000.00
2000.00
0.00
0 10 20 30 40 50 60
Years
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21. Case study 2: time for intervention
Whole Life
Capital Cost Operational Whole Life CapCarb OpCarb Carbon
Option Description
(£) Cost (£) Cost (£) (tCO2) (tCO2) 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
• 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
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22. Case study 2: time for intervention
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. -
2033: Year 23 - - - Reconstruction: 250mm Full Flex.
- - - - -
2040: Year 30 Resurface (to same level) - - -
2041: Year 31 - Resurface (to same level) - -
2042: Year 32 - - Resurface (to same level) -
2043: Year 33 - - - Resurface (to same level)
- - - - -
2050: Year 40 Reconstruction: 250mm Full Flex. - - -
2051: Year 41 - Reconstruction: 250mm Full Flex. - -
2052: Year 42 - - Reconstruction: 250mm Full Flex. -
2053: Year 43 - - - Reconstruction: 250mm Full Flex.
- - - - -
2060: Year 50 Resurface (to same level) - - -
2061: Year 51 - Resurface (to same level) - -
2062: Year 52 - - Resurface (to same level) -
2063: Year 53 - - - Resurface (to same level)
- - - - -
2070: Year 60 Reconstruction: 250mm Full Flex. - - -
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23. Case study 2: time for intervention
Whole Life
Capital Cost Operational Whole Life CapCarb OpCarb Carbon
Option Description
(£) Cost (£) Cost (£) (tCO2) (tCO2) 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. Case study 2: time for intervention
Whole Life Cost
£500,000.00
£450,000.00
£400,000.00
£350,000.00
Cumulative NPV (£)
£300,000.00 Option A
Option B
£250,000.00
Option C
£200,000.00 Option D
£150,000.00
£100,000.00
£50,000.00
£0.00
0 10 20 30 40 50 60
Years
Whole Life Carbon Footprint
900.00
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800.00

25. £50,000.00
£0.00
Case study 2: time for intervention 0 10 20 30
Years
40 50 60
Whole Life Carbon Footprint
900.00
800.00
Cumulative Carbon Footprint (tCO2)
700.00
600.00
Option A
500.00
Option B
Option C
400.00
Option D
300.00
200.00
100.00
0.00
0 10 20 30 40 50 60
Years
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26. Summary
• 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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27. Limitations
• 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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28. Future development
• 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
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29. steve.finnie@urs.com
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